第一篇：機械工程英語最新版翻譯(推薦使用)

機械工程英語

第一單元

Materials may be grouped in several ways.Scientists often classify materials by their state: solid, liquid, or gas.They also separate them into organic(once living)and inorganic(never living)materials.材料可以按多種方法分類。科學家常根據狀態將材料分為：固體、液體或氣體。他們也把材料分為有機材料(曾經有生命的)和無機材料(從未有生命的)。

For industrial purposes, materials are divided into engineering materials or nonengineering materials.Engineering materials are those used in manufacture and become parts of products.就工業效用而言，材料被分為工程材料和非工程材料。那些用于加工制造并成為產品組成部分的就是工程材料。

Nonengineering materials are the chemicals, fuels, lubricants, and other materials used in the manufacturing process, which do not become part of the product.非工程材料則是化學品、燃料、潤滑劑以及其它用于加工制造過程但不成為產品組成部分的材料。

Engineering materials may be further subdivided into: ①Metal ②Ceramics ③Composite ④Polymers, etc.工程材料還能進一步細分為：①金屬材料②陶瓷材料③復合材料 ④聚合材料，等等。Metals and Metal Alloys 金屬和金屬合金

Metals are elements that generally have good electrical and thermal conductivity.Many metals have high strength, high stiffness, and have good ductility.金屬就是通常具有良好導電性和導熱性的元素。許多金屬具有高強度、高硬度以及良好的延展性。Some metals, such as iron, cobalt and nickel, are magnetic.At low temperatures, some metals and intermetallic compounds become superconductors.某些金屬能被磁化，例如鐵、鈷和鎳。在極低的溫度下，某些金屬和金屬化合物能轉變成超導體。

What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table.Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans.合金與純金屬的區別是什么？純金屬是在元素周期表中占據特定位置的元素。例如電線中的銅和制造烹飪箔及飲料罐的鋁。Alloys contain more than one metallic element.Their properties can be changed by changing the elements present in the alloy.Examples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium;and gold jewelry which usually contains an alloy of gold and nickel.合金包含不止一種金屬元素。合金的性質能通過改變其中存在的元素而改變。金屬合金的例子有：不銹鋼是一種鐵、鎳、鉻的合金，以及金飾品通常含有金鎳合金。

Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio.為什么要使用金屬和合金？許多金屬和合金具有高密度，因此被用在需要較高質量體積比的場合。Some metal alloys, such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy.Many alloys also have high fracture toughness, which means they can withstand impact and are durable.某些金屬合金，例如鋁基合金，其密度低，可用于航空航天以節約燃料。許多合金還具有高斷裂韌性，這意味著它們能經得起沖擊并且是耐用的。

What are some important properties of metals? Density is defined as a material’s mass divided by its volume.Most metals have relatively high densities, especially compared to polymers.金屬有哪些重要特性？ 密度定義為材料的質量與其體積之比。大多數金屬密度相對較高，尤其是和聚合物相比較而言。

Materials with high densities often contain atoms with high atomic numbers, such as gold or lead.However, some metals such as aluminum or magnesium have low densities, and are used in applications that require other metallic properties but also require low weight.高密度材料通常由較大原子序數原子構成，例如金和鉛。然而，諸如鋁和鎂之類的一些金屬則具有低密度，并被用于既需要金屬特性又要求重量輕的場合。

Fracture toughness can be described as a material’s ability to avoid fracture, especially when a flaw is introduced.Metals can generally contain nicks and dents without weakening very much, and are impact resistant.A football player counts on this when he trusts that his facemask won’t shatter.斷裂韌性可以描述為材料防止斷裂特別是出現缺陷時不斷裂的能力。金屬一般能在有缺口和凹痕的情況下不顯著削弱，并且能抵抗沖擊。橄欖球運動員據此相信他的面罩不會裂成碎片。Plastic deformation is the ability of bend or deform before breaking.As engineers, we usually design materials so that they don’t deform under normal conditions.You don’t want your car to lean to the east after a strong west wind.塑性變形就是在斷裂前彎曲或變形的能力。作為工程師，設計時通常要使材料在正常條件下不變形。沒有人愿意一陣強烈的西風過后自己的汽車向東傾斜。

However, sometimes we can take advantage of plastic deformation.The crumple zones in a car absorb energy by undergoing plastic deformation before they break.然而，有時我們也能利用塑性變形。汽車上壓皺的區域在它們斷裂前通過經歷塑性變形來吸收能量。The atomic bonding of metals also affects their properties.In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere.Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires.金屬的原子連結對它們的特性也有影響。在金屬內部，原子的外層階電子由所有原子共享并能到處自由移動。由于電子能導熱和導電，所以用金屬可以制造好的烹飪鍋和電線。

It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal.No photons pass through.因為這些階電子吸收到達金屬的光子，所以透過金屬不可能看得見。沒有光子能通過金屬。

Alloys are compounds consisting of more than one metal.Adding other metals can affect the density, strength, fracture toughness, plastic deformation, electrical conductivity and environmental degradation.合金是由一種以上金屬組成的混合物。加一些其它金屬能影響密度、強度、斷裂韌性、塑性變形、導電性以及環境侵蝕。For example, adding a small amount of iron to aluminum will make it stronger.Also, adding some chromium to steel will slow the rusting process, but will make it more brittle.例如，往鋁里加少量鐵可使其更強。同樣，在鋼里加一些鉻能減緩它的生銹過程，但也將使它更脆。

Ceramics and Glasses 陶瓷和玻璃 A ceramic is often broadly defined as any inorganic nonmetallic material． By this definition, ceramic materials would also include glasses;however, many materials scientists add the stipulation that “ceramic” must also be crystalline.陶瓷通常被概括地定義為無機的非金屬材料。照此定義，陶瓷材料也應包括玻璃；然而許多材料科學家添加了“陶瓷”必須同時是晶體物組成的約定。

A glass is an inorganic nonmetallic material that does not have a crystalline structure.Such materials are said to be amorphous.玻璃是沒有晶體狀結構的無機非金屬材料。這種材料被稱為非結晶質材料。Properties of Ceramics and Glasses Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance.陶瓷和玻璃的特性

高熔點、低密度、高強度、高剛度、高硬度、高耐磨性和抗腐蝕性是陶瓷和玻璃的一些有用特性。Many ceramics are good electrical and thermal insulators.Some ceramics have special properties: some ceramics are magnetic materials;some are piezoelectric materials;and a few special ceramics are superconductors at very low temperatures.Ceramics and glasses have one major drawback: they are brittle.許多陶瓷都是電和熱的良絕緣體。某些陶瓷還具有一些特殊性能：有些是磁性材料，有些是壓電材料，還有些特殊陶瓷在極低溫度下是超導體。陶瓷和玻璃都有一個主要的缺點：它們容易破碎。

Ceramics are not typically formed from the melt.This is because most ceramics will crack extensively(i.e.form a powder)upon cooling from the liquid state.陶瓷一般不是由熔化形成的。因為大多數陶瓷在從液態冷卻時將會完全破碎(即形成粉末)。

Hence, all the simple and efficient manufacturing techniques used for glass production such as casting and blowing, which involve the molten state, cannot be used for the production of crystalline ceramics.Instead, “sintering” or “firing” is the process typically used.因此，所有用于玻璃生產的簡單有效的—諸如澆鑄和吹制這些涉及熔化的技術都不能用于由晶體物組成的陶瓷的生產。作為替代，一般采用“燒結”或“焙燒”工藝。

In sintering, ceramic powders are processed into compacted shapes and then heated to temperatures just below the melting point.At such temperatures, the powders react internally to remove porosity and fully dense articles can be obtained.在燒結過程中，陶瓷粉末先擠壓成型然后加熱到略低于熔點溫度。在這樣的溫度下，粉末內部起反應去除孔隙并得到十分致密的物品。An optical fiber contains three layers: a core made of highly pure glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage.光導纖維有三層：核心由高折射指數高純光傳輸玻璃制成，中間層為低折射指數玻璃，是保護核心玻璃表面不被擦傷和完整性不被破壞的所謂覆層，外層是聚合物護套，用于保護光導纖維不受損。

In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light.為了使核心玻璃有比覆層大的折射指數，在其中摻入微小的、可控數量的能減緩光速而不會吸收光線的雜質或攙雜劑。

Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle.由于核心玻璃的折射指數比覆層大，只要在全內反射過程中光線照射核心/覆層分界面的角度比臨界角大，在核心玻璃中傳送的光線將仍保留在核心玻璃中。

The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with little loss of intensity.全內反射現象與核心玻璃的高純度一樣，使光線幾乎無強度損耗傳遞長距離成為可能。

Composites 復合材料

Composites are formed from two or more types of materials.Examples include polymer/ceramic and metal/ceramic composites.Composites are used because overall properties of the composites are superior to those of the individual components.復合材料由兩種或更多材料構成。例子有聚合物/陶瓷和金屬/陶瓷復合材料。之所以使用復合材料是因 為其全面性能優于組成部分單獨的性能。For example: polymer/ceramic composites have a greater modulus than the polymer component, but aren’t as brittle as ceramics.Two types of composites are: fiber-reinforced composites and particle-reinforced composites.例如：聚合物/陶瓷復合材料具有比聚合物成分更大的模量，但又不像陶瓷那樣易碎。

復合材料有兩種：纖維加強型復合材料和微粒加強型復合材料。Fiber-reinforced Composites Reinforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers.Fibers increase the modulus of the matrix material.纖維加強型復合材料

加強纖維可以是金屬、陶瓷、玻璃或是已變成石墨的被稱為碳纖維的聚合物。纖維能加強基材的模量。The strong covalent bonds along the fiber’s length give them a very high modulus in this direction because to break or extend the fiber the bonds must also be broken or moved.沿著纖維長度有很強結合力的共價結合在這個方向上給予復合材料很高的模量，因為要損壞或拉伸纖維就必須破壞或移除這種結合。

Fibers are difficult to process into composites, making fiber-reinforced composites relatively expensive.把纖維放入復合材料較困難，這使得制造纖維加強型復合材料相對昂貴。Fiber-reinforced composites are used in some of the most advanced, and therefore most expensive sports equipment, such as a time-trial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix.纖維加強型復合材料用于某些最先進也是最昂貴的運動設備，例如計時賽競賽用自行車骨架就是用含碳纖維的熱固塑料基材制成的。

Body parts of race cars and some automobiles are composites made of glass fibers(or fiberglass)in a thermoset matrix.競賽用汽車和某些機動車的車體部件是由含玻璃纖維(或玻璃絲)的熱固塑料基材制成的。

Fibers have a very high modulus along their axis, but have a low modulus perpendicular to their axis.Fiber composite manufacturers often rotate layers of fibers to avoid directional variations in the modulus.纖維在沿著其軸向有很高的模量，但垂直于其軸向的模量卻較低。纖維復合材料的制造者往往旋轉纖維層以防模量產生方向變化。

Particle-reinforced composites Particles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous materials, including polymers and carbon black.微粒加強型復合材料

用于加強的微粒包含了陶瓷和玻璃之類的礦物微粒，鋁之類的金屬微粒以及包括聚合物和碳黑的非結晶質微粒。

Particles are used to increase the modulus of the matrix, to decrease the permeability of the matrix, to decrease the ductility of the matrix.An example of particle-reinforced composites is an automobile tire which has carbon black particles in a matrix of polyisobutylene elastomeric polymer.微粒用于增加基材的模量、減少基材的滲透性和延展性。微粒加強型復合材料的一個例子是機動車胎，它就是在聚異丁烯人造橡膠聚合物基材中加入了碳黑微粒。Polymers 聚合材料

A polymer has a repeating structure, usually based on a carbon backbone.The repeating structure results in large chainlike molecules.Polymers are useful because they are lightweight, corrosion resistant, easy to process at low temperatures and generally inexpensive.聚合物具有一般是基于碳鏈的重復結構。這種重復結構產生鏈狀大分子。由于重量輕、耐腐蝕、容易在較低溫度下加工并且通常較便宜，聚合物是很有用的。

Some important characteristics of polymers include their size(or molecular weight), softening and melting points, crystallinity, and structure.The mechanical properties of polymers generally include low strength and high toughness.Their strength is often improved using reinforced composite structures.聚合材料具有一些重要特性，包括尺寸(或分子量)、軟化及熔化點、結晶度和結構。聚合材料的機械性能一般表現為低強度和高韌性。它們的強度通常可采用加強復合結構來改善。Important Characteristics of Polymers Size.Single polymer molecules typically have molecular weights between 10,000 and 1,000,000g/mol—that can be more than 2,000 repeating units depending on the polymer structure!聚合材料的重要特性

尺寸：單個聚合物分子一般分子量為10,000到1,000,000g/mol之間，具體取決于聚合物的結構—這可以比2,000個重復單元還多。

The mechanical properties of a polymer are significantly affected by the molecular weight, with better engineering properties at higher molecular weights.聚合物的分子量極大地影響其機械性能，分子量越大，工程性能也越好。

Thermal transitions.The softening point(glass transition temperature)and the melting point of a polymer will determine which it will be suitable for applications.These temperatures usually determine the upper limit for which a polymer can be used.熱轉換性：聚合物的軟化點(玻璃狀轉化溫度)和熔化點決定了它是否適合應用。這些溫度通常決定聚合物能否使用的上限。

For example, many industrially important polymers have glass transition temperatures near the boiling point of water(100℃, 212℉), and they are most useful for room temperature applications.Some specially engineered polymers can withstand temperatures as high as 300℃(572℉).例如，許多工業上的重要聚合物其玻璃狀轉化溫度接近水的沸點(100℃, 212℉)，它們被廣泛用于室溫下。而某些特別制造的聚合物能經受住高達300℃(572℉)的溫度。

Crystallinity.Polymers can be crystalline or amorphous, but they usually have a combination of crystalline and amorphous structures(semi-crystalline).結晶度：聚合物可以是晶體狀的或非結晶質的，但它們通常是晶體狀和非結晶質結構的結合物(半晶體)。Interchain interactions.The polymer chains can be free to slide past one another(thermo-plastic)or they can be connected to each other with crosslinks(thermoset or elastomer).Thermo-plastics can be reformed and recycled, while thermosets and elastomers are not reworkable.原子鏈間的相互作用：聚合物的原子鏈可以自由地彼此滑動(熱可塑性)或通過交鍵互相連接(熱固性或彈性)。熱可塑性材料可以重新形成和循環使用，而熱固性與彈性材料則是不能再使用的。

Intrachain structure.The chemical structure of the chains also has a tremendous effect on the properties.Depending on the structure the polymer may be hydrophilic or hydrophobic(likes or hates water), stiff or flexible, crystalline or amorphous, reactive or unreactive.鏈內結構：原子鏈的化學結構對性能也有很大影響。根據各自的結構不同，聚合物可以是親水的或憎水的(喜歡或討厭水)、硬的或軟的、晶體狀的或非結晶質的、易起反應的或不易起反應的。

第二單元

The understanding of heat treatment is embraced by the broader study of metallurgy.Metallurgy is the physics, chemistry, and engineering related to metals from ore extraction to the final product.對熱處理的理解包含于對冶金學較廣泛的研究。冶金學是物理學、化學和涉及金屬從礦石提煉到最后產物的工程學。Heat treatment is the operation of heating and cooling a metal in its solid state to change its physical properties.According to the procedure used, steel can be hardened to resist cutting action and abrasion, or it can be softened to permit machining.熱處理是將金屬在固態加熱和冷卻以改變其物理性能的操作。按所采用的步驟，鋼可以通過硬化來抵抗切削和磨損，也可以通過軟化來允許機加工。

With the proper heat treatment internal stresses may be removed, grain size reduced, toughness increased, or a hard surface produced on a ductile interior.The analysis of the steel must be known because small percentages of certain elements, notably carbon, greatly affect the physical properties.使用合適的熱處理可以去除內應力、細化晶粒、增加韌性或在柔軟材料上覆蓋堅硬的表面。因為某些元素(尤其是碳)的微小百分比極大地影響物理性能，所以必須知道對鋼的分析。

Alloy steel owe their properties to the presence of one or more elements other than carbon, namely nickel, chromium, manganese, molybdenum, tungsten, silicon, vanadium, and copper.Because of their improved physical properties they are used commercially in many ways not possible with carbon steels.合金鋼的性質取決于其所含有的除碳以外的一種或多種元素，如鎳、鉻、錳、鉬、鎢、硅、釩和銅。由于合金鋼改善的物理性能，它們被大量使用在許多碳鋼不適用的地方。

The following discussion applies principally to the heat treatment of ordinary commercial steels known as plain carbon steels.With this process the rate of cooling is the controlling factor, rapid cooling from above the critical range results in hard structure, whereas very slow cooling produces the opposite effect.下列討論主要針對被稱為普通碳鋼的工業用鋼而言。熱處理時冷卻速率是控制要素，從高于臨界溫度快速冷卻導致堅硬的組織結構，而緩慢冷卻則產生相反效果。A Simplified Iron-carbon Diagram 簡化鐵碳狀態圖

If we focus only on the materials normally known as steels, a simplified diagram is often used.如果只把注意力集中于一般所說的鋼上，經常要用到簡化鐵碳狀態圖。

Those portions of the iron-carbon diagram near the delta region and those above 2% carbon content are of little importance to the engineer and are deleted.A simplified diagram, such as the one in Fig.2.1, focuses on the eutectoid region and is quite useful in understanding the properties and processing of steel.鐵碳狀態圖中靠近三角區和含碳量高于2%的那些部分對工程師而言不重要，因此將它們刪除。如圖2.1所示的簡化鐵碳狀態圖將焦點集中在共析區，這對理解鋼的性能和處理是十分有用的。The key transition described in this diagram is the decomposition of single-phase austenite(γ)to the two-phase ferrite plus carbide structure as temperature drops.在此圖中描述的關鍵轉變是單相奧氏體(γ)隨著溫度下降分解成兩相鐵素體加滲碳體組織結構。Control of this reaction, which arises due to the drastically different carbon solubility of austenite and ferrite, enables a wide range of properties to be achieved through heat treatment.控制這一由于奧氏體和鐵素體的碳溶解性完全不同而產生的反應，使得通過熱處理能獲得很大范圍的特性。To begin to understand these processes, consider a steel of the eutectoid composition, 0.77% carbon, being slow cooled along line x-x’ in Fig.2.1.At the upper temperatures, only austenite is present, the 0.77% carbon being dissolved in solid solution with the iron.When the steel cools to 727℃(1341℉), several changes occur simultaneously.為了理解這些過程，考慮含碳量為0.77%的共析鋼，沿著圖2.1的x-x’線慢慢冷卻。在較高溫度時，只存在奧氏體，0.77%的碳溶解在鐵里形成固溶體。當鋼冷卻到727℃(1341℉)時，將同時發生若干變化。The iron wants to change from the FCC austenite structure to the BCC ferrite structure, but the ferrite can only contain 0.02% carbon in solid solution.鐵需要從面心立方體奧氏體結構轉變為體心立方體鐵素體結構，但是鐵素體只能容納固溶體狀態的0.02%的碳。

The rejected carbon forms the carbon-rich cementite intermetallic with composition Fe3C.In essence, the net reaction at the eutectoid is austenite 0.77%C→ferrite 0.02%C+cementite 6.67%C.被析出的碳與金屬化合物Fe3C形成富碳的滲碳體。本質上，共析體的基本反應是奧氏體0.77%的碳→鐵素體0.02%的碳+滲碳體6.67%的碳。

Since this chemical separation of the carbon component occurs entirely in the solid state, the resulting structure is a fine mechanical mixture of ferrite and cementite.Specimens prepared by polishing and etching in a weak solution of nitric acid and alcohol reveal the lamellar structure of alternating plates that forms on slow cooling.由于這種碳成分的化學分離完全發生在固態中，產生的組織結構是一種細致的鐵素體與滲碳體的機械混合物。通過打磨并在弱硝酸酒精溶液中蝕刻制備的樣本顯示出由緩慢冷卻形成的交互層狀的薄片結構。

This structure is composed of two distinct phases, but has its own set of characteristic properties and goes by the name pearlite, because of its resemblance to mother-of-pearl at low magnification.這種結構由兩種截然不同的狀態組成，但它本身具有一系列特性，且因與低倍數放大時的珠母層有類同之處而被稱為珠光體。

Steels having less than the eutectoid amount of carbon(less than 0.77%)are known as hypo-eutectoid steels.Consider now the transformation of such a material represented by cooling along line y-y’ in Fig.2.1.含碳量少于共析體(低于0.77%)的鋼稱為亞共析鋼。現在來看這種材料沿著圖2.1中y-y’ 線冷卻的轉變情況。

At high temperatures, the material is entirely austenite, but upon cooling enters a region where the stable phases are ferrite and austenite.Tie-line and level-law calculations show that low-carbon ferrite nucleates and grows, leaving the remaining austenite richer in carbon.在較高溫度時，這種材料全部是奧氏體，但隨著冷卻就進入到鐵素體和奧氏體穩定狀態的區域。由截線及杠桿定律分析可知，低碳鐵素體成核并長大，剩下含碳量高的奧氏體。

At 727℃(1341℉), the austenite is of eutectoid composition(0.77% carbon)and further cooling transforms the remaining austenite to pearlite.The resulting structure is a mixture of primary or pro-eutectoid ferrite(ferrite that formed above the eutectoid reaction)and regions of pearlite.在727℃(1341℉)時，奧氏體為共析組成(含碳量0.77%)，再冷卻剩余的奧氏體就轉化為珠光體。作為結果的組織結構是初步的共析鐵素體(在共析反應前的鐵素體)和部分珠光體的混合物。

Hypereutectoid steels are steels that contain greater than the eutectoid amount of carbon.When such steel cools, as shown in z-z’ of Fig.2.1 the process is similar to the hypo-eutectoid case, except that the primary or pro-eutectoid phase is now cementite instead of ferrite.過共析鋼是含碳量大于共析量的鋼。當這種鋼冷卻時，就像圖2.1的z-z’線所示，除了初步的共析狀態用滲碳體取代鐵素體外，其余類似亞共析鋼的情況。

As the carbon-rich phase forms, the remaining austenite decreases in carbon content, reaching the eutectoid composition at 727℃(1341℉).As before, any remaining austenite transforms to pearlite upon slow cooling through this temperature.隨著富碳部分的形成，剩余奧氏體含碳量減少，在727℃(1341℉)時達到共析組織。就像以前說的一樣，當緩慢冷卻到這溫度時所有剩余奧氏體轉化為珠光體。

It should be remembered that the transitions that have been described by the phase diagrams are for equilibrium conditions, which can be approximated by slow cooling.With slow heating, these transitions occur in the reverse manner.應該記住由狀態圖描述的這種轉化只適合于通過緩慢冷卻的近似平衡條件。如果緩慢加熱，則以相反的方式發生這種轉化。

However, when alloys are cooled rapidly, entirely different results may be obtained, because sufficient time is not provided for the normal phase reactions to occur, in such cases, the phase diagram is no longer a useful tool for engineering analysis.然而，當快速冷卻合金時，可能得到完全不同的結果。因為沒有足夠的時間讓正常的狀態反應發生，在這種情況下對工程分析而言狀態圖不再是有用的工具。

Hardening 淬火

Hardening is the process of heating a piece of steel to a temperature within or above its critical range and then cooling it rapidly.淬火就是把鋼件加熱到或超過它的臨界溫度范圍，然后使其快速冷卻的過程。If the carbon content of the steel is known, the proper temperature to which the steel should be heated may be obtained by reference to the iron-iron carbide phase diagram.However, if the composition of the steel is unknown, a little preliminary experimentation may be necessary to determine the range.如果鋼的含碳量已知，鋼件合適的加熱溫度可參考鐵碳合金狀態圖得到。然而當鋼的成分不知道時，則需做一些預備試驗來確定其溫度范圍。

A good procedure to follow is to heat-quench a number of small specimens of the steel at various temperatures and observe the result, either by hardness testing or by microscopic examination.When the correct temperature is obtained, there will be a marked change in hardness and other properties.要遵循的合適步驟是將這種鋼的一些小試件加熱到不同的溫度后淬火，再通過硬度試驗或顯微鏡檢查觀測結果。一旦獲得正確的溫度，硬度和其它性能都將有明顯的變化。

In any heat-treating operation the rate of heating is important.Heat flows from the exterior to the interior of steel at a definite rate.If the steel is heated too fast, the outside becomes hotter than the interior and uniform structure cannot be obtained.在任何熱處理作業中，加熱的速率都是重要的。熱量以一定的速率從鋼的外部傳導到內部。如果鋼被加熱得太快，其外部比內部熱就不能得到均勻的組織結構。If a piece is irregular in shape, a slow rate is all the more essential to eliminate warping and cracking.The heavier the section, the longer must be the heating time to achieve uniform results.如果工件形狀不規則，為了消除翹曲和開裂最根本的是加熱速率要緩慢。截面越厚，加熱的時間就要越長才能達到均勻的結果。

Even after the correct temperature has been reached, the piece should be held at that temperature for a sufficient period of time to permit its thickest section to attain a uniform temperature.即使加熱到正確的溫度后，工件也應在此溫度下保持足夠時間以讓其最厚截面達到相同溫度。

The hardness obtained from a given treatment depends on the quenching rate, the carbon content, and the work size.In alloy steels the kind and amount of alloying element influences only the hardenability(the ability of the workpiece to be hardened to depths)of the steel and does not affect the hardness except in unhardened or partially hardened steels.通過給定的熱處理所得到的硬度取決于淬火速率、含碳量和工件尺寸。除了非淬硬鋼或部分淬硬鋼外，合金鋼中合金元素的種類及含量僅影響鋼的淬透性(工件被硬化到深層的能力)而不影響硬度。

Steel with low carbon content will not respond appreciably to hardening treatment.As the carbon content in steel increases up to around 0.60%, the possible hardness obtainable also increases.含碳量低的鋼對淬火處理沒有明顯的反應。隨著鋼的含碳量增加到大約0.60%，可能得到的硬度也增加。Above this point the hardness can be increased only slightly, because steels above the eutectoid point are made up entirely of pearlite and cementite in the annealed state.Pearlite responds best to heat-treating operations;and steel composed mostly of pearlite can be transformed into a hard steel.高于此點，由于超過共析點鋼完全由珠光體和退火狀態的滲碳體組成，硬度增加并不多。珠光體對熱處理作業響應最好；基本由珠光體組成的鋼能轉化成硬質鋼。

As the size of parts to be hardened increases, the surface hardness decreases somewhat even though all other conditions have remained the same.There is a limit to the rate of heat flow through steel.即使所有其它條件保持不變，隨著要淬火的零件尺寸的增加其表面硬度也會有所下降。熱量在鋼中的傳導速率是有限的。

No matter how cool the quenching medium may be, if the heat inside a large piece cannot escape faster than a certain critical rate, there is a definite limit to the inside hardness.However, brine or water quenching is capable of rapidly bringing the surface of the quenched part to its own temperature and maintaining it at or close to this temperature.無論淬火介質怎么冷，如果在大工件中的熱量不能比特定的臨界速率更快散發，那它內部硬度就會受到明確限制。然而鹽水或水淬火能夠將被淬零件的表面迅速冷卻至本身溫度并將其保持或接近此溫度。

Under these circumstances there would always be some finite depth of surface hardening regardless of size.This is not true in oil quenching, when the surface temperature may be high during the critical stages of quenching.在這種情況下不管零件尺寸如何，其表面總歸有一定深度被硬化。但油淬情況就不是如此，因為油淬時在淬火臨界階段零件表面的溫度可能仍然很高。Tempering 回火

Steel that has been hardened by rapid quenching is brittle and not suitable for most uses.By tempering or drawing, the hardness and brittleness may be reduced to the desired point for service conditions．

快速淬火硬化的鋼是硬而易碎的，不適合大多數場合使用。通過回火，硬度和脆性可以降低到使用條件所需要的程度。

As these properties are reduced there is also a decrease in tensile strength and an increase in the ductility and toughness of the steel.The operation consists of reheating quench-hardened steel to some temperature below the critical range followed by any rate of cooling.隨著這些性能的降低，拉伸強度也降低而鋼的延展性和韌性則會提高。回火作業包括將淬硬鋼重新加熱到低于臨界范圍的某一溫度然后以任意速率冷卻。

Although this process softens steel, it differs considerably from annealing in that the process lends itself to close control of the physical properties and in most cases does not soften the steel to the extent that annealing would.The final structure obtained from tempering a fully hardened steel is called tempered martensite.雖然這過程使鋼軟化，但它與退火是大不相同的，因為回火適合于嚴格控制物理性能并在大多數情況下不會把鋼軟化到退火那種程度。回火完全淬硬鋼得到的最終組織結構被稱為回火馬氏體。Tempering is possible because of the instability of the martensite, the principal constituent of hardened steel.Low-temperature draws, from 300℉ to 400℉(150℃~205℃), do not cause much decrease in hardness and are used principally to relieve internal strains.由于馬氏體這一淬硬鋼主要成分的不穩定性，使得回火成為可能。低溫回火，300℉到400℉(150℃~205℃)，不會引起硬度下降很多，主要用于減少內部應變。

As the tempering temperatures are increased, the breakdown of the martensite takes place at a faster rate, and at about 600℉(315℃)the change to a structure called tempered martensite is very rapid.The tempering operation may be described as one of precipitation and agglomeration or coalescence of cementite.隨著回火溫度的提高，馬氏體以較快的速率分解，并在大約600℉(315℃)迅速轉變為被稱為回火馬氏體的結構。回火作業可以描述為滲碳體析出和凝聚或聚結的過程。A substantial precipitation of cementite begins at 600℉(315℃), which produces a decrease in hardness.Increasing the temperature causes coalescence of the carbides with continued decrease in hardness.滲碳體的大量析出開始于600℉(315℃)，這使硬度下降。溫度的上升會使碳化物聚結而硬度繼續降低。In the process of tempering, some consideration should be given to time as well as to temperature.Although most of the softening action occurs in the first few minutes after the temperature is reached, there is some additional reduction in hardness if the temperature is maintained for a prolonged time.在回火過程中，不但要考慮溫度而且要考慮時間。雖然大多數軟化作用發生在達到所需溫度后的最初幾分鐘，但如果此溫度維持一段延長時間，仍會有些額外的硬度下降。

Usual practice is to heat the steel to the desired temperature and hold it there only long enough to have it uniformly heated.通常的做法是將鋼加熱到所需溫度并且僅保溫到正好使其均勻受熱。

Two special processes using interrupted quenching are a form of tempering.In both, the hardened steel is quenched in a salt bath held at a selected lower temperature before being allowed to cool.These processes, known as austempering and martempering, result in products having certain desirable physical properties.兩種采用中斷淬火的特殊工藝也是回火的形式。這兩種工藝中，淬硬鋼在其被允許冷卻前先在一選定的較低溫度鹽浴淬火。這兩種分別被稱為奧氏體回火和馬氏體回火的工藝，能使產品具有特定所需的物理性能。Annealing 退火

The primary purpose of annealing is to soften hard steel so that it may be machined or cold worked.退火的主要目的是使堅硬的鋼軟化以便機加工或冷作。

This is usually accomplished by heating the steel too slightly above the critical temperature, holding it there until the temperature of the piece is uniform throughout, and then cooling at a slowly controlled rate so that the temperature of the surface and that of the center of the piece are approximately the same.通常是非常緩慢地將鋼加熱到臨界溫度以上，并將其在此溫度下保持到工件全部均勻受熱，然后以受控的速率慢慢地冷卻，這樣使得工件表面和內部的溫度近似相同。

This process is known as full annealing because it wipes out all trace of previous structure, refines the crystalline structure, and softens the metal.Annealing also relieves internal stresses previously set up in the metal.這過程被稱為完全退火，因為它去除了以前組織結構的所有痕跡、細化晶粒并軟化金屬。退火也釋放了先前在金屬中的內應力。

The temperature to which a given steel should be heated in annealing depends on its composition;for carbon steels it can be obtained readily from the partial iron-iron carbide equilibrium diagram.When the annealing temperature has been reached, the steel should be held there until it is uniform throughout.給定的鋼其退火溫度取決于它的成分；對碳鋼而言可容易地從局部的鐵碳合金平衡圖得到。達到退火溫度后，鋼應當保持在此溫度等到全部均勻受熱。

This usually takes about 45min for each inch(25mm)of thickness of the largest section.For maximum softness and ductility the cooling rate should be very slow, such as allowing the parts to cool down with the furnace.The higher the carbon content, the slower this rate must be.加熱時間一般以工件的最大截面厚度計每英寸(25mm)大約需45min。為了得到最大柔軟性和延展性冷卻速率應該很慢，比如讓零件與爐子一起冷下來。含碳量越高，冷卻的速率必須越慢。

The heating rate should be consistent with the size and uniformity of sections, so that the entire part is brought up to temperature as uniformly as possible.加熱的速率也應與截面的尺寸及均勻程度相協調，這樣才能使整個零件盡可能均勻地加熱。Normalizing and Spheroidizing 正火和球化

The process of normalizing consists of heating the steel about 50℉ to 100℉(10℃~40℃)above the upper critical range and cooling in still air to room temperature.正火處理包括先將鋼加熱到高于上臨界區50℉到100℉(10℃~40℃)然后在靜止的空氣中冷卻到室溫。This process is principally used with low-and medium-carbon steels as well as alloy steels to make the grain structure more uniform, to relieve internal stresses, or to achieve desired results in physical properties.Most commercial steels are normalized after being rolled or cast.退火主要用于低碳鋼、中碳鋼及合金鋼，使晶粒結構更均勻、釋放內應力或獲得所需的物理特性。大多數商業鋼材在軋制或鑄造后都要退火。

Spheroidizing is the process of producing a structure in which the cementite is in a spheroidal distribution.If steel is heated slowly to a temperature just below the critical range and held there for a prolonged period of time, this structure will be obtained.球化是使滲碳體產生成類似球狀分布結構的工藝。如果把鋼緩慢加熱到恰好低于臨界溫度并且保持較長一段時間，就能得到這種組織結構。

The globular structure obtained gives improved machinability to the steel.This treatment is particularly useful for hypereutectoid steels that must be machined.所獲得的球狀結構改善了鋼的可切削性。此處理方法對必須機加工的過共析鋼特別有用。Surface Hardening 表面硬化 Carburizing The oldest known method of producing a hard surface on steel is case hardening or carburizing.Iron at temperatures close to and above its critical temperature has an affinity for carbon.滲碳

最早的硬化鋼表面的方法是表面淬火或滲碳。鐵在靠近并高于其臨界溫度時對碳具有親合力。The carbon is absorbed into the metal to form a solid solution with iron and converts the outer surface into high-carbon steel.The carbon is gradually diffused to the interior of the part.The depth of the case depends on the time and temperature of the treatment.碳被吸收進金屬與鐵形成固溶體使外表面轉變成高碳鋼。碳逐漸擴散到零件內部。滲碳層的深度取決于熱處理的時間和溫度。

Pack carburizing consists of placing the parts to be treated in a closed container with some carbonaceous material such as charcoal or coke.It is a long process and used to produce fairly thick cases of from 0.03 to 0.16 in.(0.76~4.06mm)in depth.固體滲碳的方法是將要處理的零件與木炭或焦炭這些含碳的材料一起放入密閉容器。這是一個較長的過程，用于產生深度為0.03到0.16 英寸(0.76~4.06mm)這么厚的硬化層。

Steel for carburizing is usually a low-carbon steel of about 0.15% carbon that would not in itself responds appreciably to heat treatment.In the course of the process the outer layer is converted into high-carbon steel with a content ranging from 0.9% to 1.2% carbon.用于滲碳的一般是含碳量約為0.15%、本身不太適合熱處理的低碳鋼。在處理過程中外層轉化為含碳量從0.9%到1.2%的高碳鋼。

A steel with varying carbon content and, consequently, different critical temperatures requires a special heat treatment.含碳量變化的鋼具有不同的臨界溫度，因此需要特殊的熱處理。

Because there is some grain growth in the steel during the prolonged carburizing treatment, the work should be heated to the critical temperature of the core and then cooled, thus refining the core structure.The steel should then be reheated to a point above the transformation range of the case and quenched to produce a hard, fine structure.由于在較長的滲碳過程中鋼內部會有些晶粒生長，所以工件應該加熱到核心部分的臨界溫度再冷卻以細化核心部分的組織結構。然后重新加熱到高于外層轉變溫度再淬火以生成堅硬、細致的組織結構。

The lower heat-treating temperature of the case results from the fact that hypereutectoid steels are normally austenitized for hardening just above the lower critical point.A third tempering treatment may be used to reduce strains.由于恰好高于低臨界溫度通常使過共析鋼奧氏體化而硬化，所以對外層采用較低的熱處理溫度。第三次 回火處理可用于減少應變。Carbonitriding Carbonitriding, sometimes known as dry cyaniding or nicarbing, is a case-hardening process in which the steel is held at a temperature above the critical range in a gaseous atmosphere from which it absorbs carbon and nitrogen.碳氮共滲

碳氮共滲，有時也稱為干法氰化或滲碳氮化，是一種表面硬化工藝。通過把鋼放在高于臨界溫度的氣體中，讓它吸收碳和氮。

Any carbon-rich gas with ammonia can be used.The wear-resistant case produced ranges from 0.003 to 0.030 inch(0.08~ 0.76mm)in thickness.An advantage of carbonitriding is that the hardenability of the case is significantly increased when nitrogen is added, permitting the use of low-cost steels.可以使用任何富碳氣體加氨氣，能生成厚度從0.003到0.030英寸(0.08~ 0.76mm)的耐磨外層。碳氮共滲的優點之一是加入氮后外層的淬透性極大增加，為使用低價鋼提供條件。Cyaniding Cyaniding, or liquid carbonitriding as it is sometimes called, is also a process that combines the absorption of carbon and nitrogen to obtain surface hardness in low-carbon steels that do not respond to ordinary heat treatment.氰化

氰化，有時稱為液體碳氮共滲，也是一種結合了吸收碳和氮來獲得表面硬度的工藝，它主要用于不適合通常熱處理的低碳鋼。

The part to be case hardened is immersed in a bath of fused sodium cyanide salts at a temperature slightly above the Ac1 range, the duration of soaking depending on the depth of the case.The part is then quenched in water or oil to obtain a hard surface.需表面硬化的零件浸沒在略高于Ac1溫度熔化的氰化鈉鹽溶液中，浸泡的持續時間取決于硬化層的深度。然后將零件在水或油中淬火。

Case depths of 0.005 to 0.015in.(0.13~0.38mm)may be readily obtained by this process.Cyaniding is used principally for the treatment of small parts.通過這樣處理可以容易地獲得0.005到0.015英寸(0.13~0.38mm)的硬化深度。氰化主要用于處理小零件。Nitriding Nitriding is somewhat similar to ordinary case hardening, but it uses a different material and treatment to create the hard surface constituents.滲氮

滲氮有些類似普通表面硬化，但它采用不同的材料和處理方法來產生堅硬表面成分。In this process the metal is heated to a temperature of around 950℉(510℃)and held there for a period of time in contact with ammonia gas.Nitrogen from the gas is introduced into the steel, forming very hard nitrides that are finely dispersed through the surface metal.這種工藝中金屬加熱到約950℉(510℃)，然后與氨氣接觸一段時間。氨氣中的氮進入鋼內，形成細微分布于金屬表面又十分堅固的氮化物。Nitrogen has greater hardening ability with certain elements than with others, hence, special nitriding alloy steels have been developed.氮與某些元素的硬化能力比其它元素大，因此開發了專用的滲氮合金鋼。

Aluminum in the range of 1% to 1.5% has proved to be especially suitable in steel, in that it combines with the gas to form a very stable and hard constituent.The temperature of heating ranges from 925℉ to 1,050℉(495℃~565℃).在鋼中含鋁1%到1.5%被證明特別合適，它能與氨氣結合形成很穩定堅固的成分。其加熱溫度范圍為925℉到1,050℉(495℃~565℃)。

Liquid nitriding utilizes molten cyanide salts and, as in gas nitriding, the temperature is held below the transformation range.Liquid nitriding adds more nitrogen and less carbon than either cyaniding or carburizing in cyanide baths.液體滲氮利用熔化的氰化物鹽，就像氣體滲氮，溫度保持在低于轉化范圍內。液體滲氮時在氰化物溶液中加入比氰化及滲碳都較多的氮和較少的碳。

Case thickness of 0.001 to 0.012in.(0.03~0.30mm)is obtained, whereas for gas nitriding the case may be as thick as 0.025 in.(0.64mm).In general the uses of the two-nitriding processes are similar.液體滲氮可以獲得厚度為0.001到0.012英寸(0.03~0.30mm)的硬化層，然而氣體滲氮則能獲得厚0.025英寸(0.64mm)的硬化層。一般而言兩種滲氮方法的用途是類似的。

Nitriding develops extreme hardness in the surface of steel.This hardness ranges from 900 to 1,100 Brinell, which is considerably higher than that obtained by ordinary case hardening.滲氮在鋼表面獲得遠遠超出正常標準的硬度。其硬度范圍為900到1,100布氏硬度，這遠高于普通表面硬化所獲得的硬度。

Nitriding steels, by virtue of their alloying content, are stronger than ordinary steels and respond readily to heat treatment.It is recommended that these steels be machined and heat-treated before nitriding, because there is no scale or further work necessary after this process.由于滲氮鋼的合金比例，它們比普通鋼更強，也容易熱處理。建議對這種鋼在滲氮前先機加工和熱處理，因為滲氮后沒有剝落并不需要更多的加工。

Fortunately, the interior structure and properties are not affected appreciably by the nitriding treatment and, because no quenching is necessary, there is little tendency to warp, develop cracks, or change condition in any way.The surface effectively resists corrosive action of water, saltwater spray, alkalies, crude oil, and natural gas.值得慶幸的是由于滲氮處理一點都不影響內部結構和性能，也無需淬火，所以幾乎沒有任何產生翹曲、裂縫及變化條件的趨勢。這種表面能有效地抵御水、鹽霧、堿、原油和天然氣的腐蝕反應。第三單元

Casting is a manufacturing process in which molten metal is poured or injected and allowed to solidify in a suitably shaped mold cavity.During or after cooling, the cast part is removed from the mold and then processed for delivery.鑄造是一種將熔化的金屬倒入或注入合適的鑄模腔并且在其中固化的制造工藝。在冷卻期間或冷卻后，把鑄件從鑄模中取出，然后進行交付。

Casting processes and cast-material technologies vary from simple to highly complex.Material and process selection depends on the part’s complexity and function, the product’s quality specifications, and the projected cost level.鑄造工藝和鑄造材料技術從簡單到高度復雜變化很大。材料和工藝的選擇取決于零件的復雜性和功能、產品的質量要求以及成本預算水平。

Castings are parts that are made close to their final dimensions by a casting process.With a history dating back 6,000 years, the various casting processes are in a state of continuous refinement and evolution as technological advances are being made.通過鑄造加工，鑄件可以做成很接近它們的最終尺寸。回溯6,000年歷史，各種各樣的鑄造工藝就如同科技進步一樣處于一個不斷改進和發展的狀態。

Sand Casting 砂型鑄造 Sand casting is used to make large parts(typically iron, but also bronze, brass, aluminum).Molten metal is poured into a mold cavity formed out of sand(natural or synthetic).砂型鑄造用于制造大型零件(具有代表性是鐵，除此之外還有青銅、黃銅和鋁)。將熔化的金屬倒入由型砂(天然的或人造的)做成鑄模腔。

The processes of sand casting are discussed in this section, including patterns, sprues and runners, design considerations, and casting allowance.本節討論砂型鑄造工藝，包括型模、澆注口、澆道、設計考慮因素及鑄造余量。

The cavity in the sand is formed by using a pattern(an approximate duplicate of the real part), which are typically made out of wood, sometimes metal.The cavity is contained in an aggregate housed in a box called the flask.砂型里的型腔是采用型模(真實零件的近似復制品)構成的，型模一般為木制，有時也用金屬制造。型腔整個包含在一個被放入稱為砂箱的箱子里的組合體內。

Core is a sand shape inserted into the mold to produce the internal features of the part such as holes or internal passages.Cores are placed in the cavity to form holes of the desired shapes.Core print is the region added to the pattern, core, or mold that is used to locate and support the core within the mold.砂芯是插入鑄模的砂型，用于生成諸如孔或內通道之類的內部特征。砂芯安放在型腔里形成所需形狀的孔洞。砂芯座是加在型模、砂芯或鑄模上的特定區域，用來在鑄模內部定位和支撐砂芯。

A riser is an extra void created in the mold to contain excessive molten material.The purpose of this is to feed the molten metal to the mold cavity as the molten metal solidifies and shrinks, and thereby prevents voids in the main casting.冒口是在鑄模內部增加的額外空間，用于容納過多的熔化金屬。其目的是當熔化金屬凝固和收縮時往型腔里補充熔化金屬，從而防止在主鑄件中產生孔隙。

In a two-part mold, which is typical of sand castings, the upper half, including the top half of the pattern, flask, and core is called cope and the lower half is called drag, as shown in Fig.3.1.The parting line or the parting surface is line or surface that separates the cope and drag.在典型砂型鑄造的兩箱鑄模中，上半部分(包括型模頂半部、砂箱和砂芯)稱為上型箱，下半部分稱為下型箱，見圖3.1所示。分型線或分型面是分離上下型箱的線或面。

The drag is first filled partially with sand, and the core print, the cores, and the gating system are placed near the parting line.The cope is then assembled to the drag, and the sand is poured on the cope half, covering the pattern, core and the gating system.首先往下型箱里部分地填入型砂和砂芯座、砂芯，并在靠近分型線處放置澆注系統。然后將上型箱與下型箱裝配在一起，再把型砂倒入上型箱蓋住型模、砂芯和澆注系統。

The sand is compacted by vibration and mechanical means.Next, the cope is removed from the drag, and the pattern is carefully removed.The object is to remove the pattern without breaking the mold cavity.型砂通過振動和機械方法壓實。然后從下型箱上撤掉上型箱，小心翼翼地取出型模。其目的是取出型模而不破壞型腔。

This is facilitated by designing a draft, a slight angular offset from the vertical to the vertical surfaces of the pattern.This is usually a minimum of 1.5mm(0.060in.), whichever is greater.The rougher the surface of the pattern, the more the draft to be provided.通過設計拔模斜度—型模垂直相交表面的微小角度偏移量—來使取出型模變得容易。拔模斜度最小一般為1.5mm(0.060in.)，只能比此大。型模表面越粗糙，則拔模斜度應越大。

The molten material is poured into the pouring cup, which is part of the gating system that supplies the molten material to the mold cavity.熔化的金屬從澆注杯注入型腔，澆注杯是澆注系統向型腔提供熔化金屬的部分。

The vertical part of the gating system connected to the pouring cup is the sprue, and the horizontal portion is called the runners and finally to the multiple points where it is introduced to the mold cavity called the gates.將澆注系統的垂直部分與澆注杯連接的是澆注口，澆注系統的水平部分稱為澆道，最后到多點把熔化金屬導入型腔的稱為閘道。

Additionally there are extensions to the gating system called vents that provide the path for the built-up gases and the displaced air to vent to the atmosphere.除此之外，還有稱為排放口的澆注系統延長段，它為合成氣體和置換空氣排放到大氣提供通道。

The cavity is usually made oversize to allow for the metal contraction as it cools down to room temperature.This is achieved by making the pattern oversize.To account for shrinking, the pattern must be made oversize by these factors on the average.These are linear factors and apply in each direction.型腔通常大于所需尺寸以允許在金屬冷卻到室溫時收縮。這通過把型模做得大于所需尺寸來達到。為解決收縮效應，一般而言型模做得比所需尺寸大，必須考慮線性因素并作用于各個方向。

These shrinkage allowances are only approximate, because the exact allowance is determined by the shape and size of the casting.In addition, different parts of the casting might require different shrinkage allowances.收縮余量僅僅是近似的，因為準確的余量是由鑄件的形狀和尺寸決定的。另外，鑄件的不同部分也可能需要不同的收縮余量。Sand castings generally have a rough surface sometimes with surface impurities, and surface variations.A machining(finish)allowance is made for this type of defect.砂型鑄件一般表面粗糙，有時還帶有表面雜質和表面變異。對這類缺陷采用機加工(最后一道工序)的余量。In general, typical stages of sand casting operation include(as shown in Fig.3.2): 1.Patterns are made.These will be the shape used to form the cavity in the sand.一般而言，砂型鑄造作業的典型階段包括(如圖3.2所示)： 1.制作型模。做成用于在型砂中形成型腔的形狀。

2.Cores may also be made at this time.These cores are made of bonded sand that will be broken out of the cast part after it is complete.3.Sand is mulled(mixed)thoroughly with additives such as bentonite to increase bonding and overall strength.2.同時還要制作砂芯。這些砂芯用粘結砂做成，等鑄件完成后將被打碎取出。3.型砂與膨潤土之類的添加劑充分地混合以增強連接及整體強度。

4.Sand is formed about the patterns, and gates, runners, risers, vents and pouring cups are added as needed.A compaction stage is typically used to ensure good coverage and solid molds.4.型砂在型模周圍成形，并根據需要安放閘道、澆道、冒口、排放口和澆注杯等。通常要采取壓緊步驟來保證良好的覆蓋和堅固的鑄型。

Cores may also be added to make concave or internal features for the cast part.Alignment pins may also be used for mating the molds later.Chills may be added to cool large masses faster.安放砂芯來制成鑄件的凹形結構或內部特征。為了以后鑄模匹配還要用到定位銷。對大質量鑄件可能需要加入冷卻物來使其較快冷卻。

5.The patterns are removed, and the molds may be put through a baking stage to increase strength.6.Mold halves are mated and prepared for pouring metal.5.取走型模，將鑄模烘焙以增加強度。

6.匹配上下鑄模，做好澆鑄金屬的準備。

7.Metal is preheated in a furnace or crucible until is above the liquidus temperature in a suitable range(we don’t want the metal solidifying before the pour is complete).The exact temperature may be closely controlled depending upon the application.7.金屬在熔爐或坩堝中預熱到高于液化溫度的一個合適范圍內(不希望金屬在澆鑄完成前凝固)。確切的溫度要根據應用場合嚴格控制。

Degassing, and other treatment processes may be done at this time, such as removal of impurities(i.e.slag).Some portion of this metal may be remelted scrap from previously cast parts—10% is reasonable.在此期間還要進行排氣和其它處理步驟，例如去除雜質(即熔渣)。可以加入一定量原先是這種金屬鑄件的廢料再融化—10%是適當的。8.The metal is poured slowly, but continuously into the mold until the mold is full.9.As the molten metal cools(minutes to days), the metal will shrink and the volume will decrease.During this time molten metal may backflow from the molten risers to feed the part and maintain the same shape.8.將金屬緩慢而連續地注滿型模。

9.隨著熔化金屬的冷卻(幾分鐘到幾天)，金屬收縮體積減小。在此期間熔化金屬可能從冒口回流供給零件以保持其形狀不變。

10.Once the part starts to solidify small dendrites of solid material form in the part.During this time metal properties are being determined, and internal stresses are being generated.If a part is allowed to cool slowly enough at a constant rate then the final part will be relatively homogenous and stress free.10.在零件開始凝固其內部形成固態金屬的小型樹枝狀結晶期間金屬性能被確定，同時也產生了內應力。如果零件以恒定速率冷卻得足夠緩慢，最終零件將相對均質并釋放內應力。

11.Once the part has completely solidified below the eutectic point it may be removed with no concern for final metal properties.At this point the sand is simply broken up, and the part removed.At this point the surface will have a quantity of sand adhering to the surface, and solid cores inside.11.一旦零件在共析點以下完全凝固，可以不考慮金屬的最后性能而將其取出。這時可以簡單地打碎砂型并取出零件，但零件表面會有大量型砂粘附著，內部還有實心的砂芯。

12.A bulk of the remaining sand and cores can be removed by mechanically striking the part.Other options are to use a vibrating table, sand/shot blaster, hand labor, etc.12.大量的剩余型砂和砂芯要通過機械敲擊零件來去除。其它的選擇還有采用振動臺、噴砂/噴丸機、手工作業等等。

13.The final part is cut off the runner gate system, and is near final shape using cutters, torches, etc.Grinding operations are used to remove any remaining bulk.14.The part is taken down to final shape using machining operations.And cleaning operations may be used to remove oxides, etc.13.最后零件要用刀具、噴槍等切掉澆道閘道系統，這樣就接近最終形狀了。再用磨削作業去除多余的部分。14.通過機加工將零件切削到最終形狀。可能還要用清洗作業去除氧化物等。Investment casting 熔模鑄造

Investment casting is also known as the lost wax process.This process is one of the oldest manufacturing processes.The Egyptians used it in the time of the Pharaohs to make gold jewelry(hence the name Investment)some 5,000 years ago.熔模鑄造也稱為失蠟加工。這是最古老的制造工藝之一。大約在5,000年前的法老王時代，埃及人就用它制造黃金飾品(因此而得名投資)。

Intricate shapes can be made with high accuracy.In addition, metals that are hard to machine or fabricate are good candidates for this process.It can be used to make parts that cannot be produced by normal manufacturing techniques, such as turbine blades that have complex shapes, or airplane parts that have to withstand high temperatures.復雜的形狀能被高精度地制造。另外較難機加工或制作的金屬都能用此工藝。它還能用于生產一般制造技術無法生產的零件，例如有復雜形狀的渦輪葉片或必須耐得住高溫的飛機零件。

The mold is made by making a pattern using wax or some other material that can be melted away.This wax pattern is dipped in refractory slurry, which coats the wax pattern and forms a skin.This is dried and the process of dipping in the slurry and drying is repeated until a robust thickness is achieved.制作鑄型的型模采用石蠟或其它一些能被融化掉的材料做成。石蠟型模浸泡在耐熱漿里，讓它覆蓋型模并形成外殼，然后使其變干。重復這個浸泡、變干的過程直至獲得足夠的厚度。After this, the entire pattern is placed in an oven and the wax is melted away.This leads to a mold that can be filled with the molten metal.Because the mold is formed around a one-piece pattern(which does not have to be pulled out from the mold as in a traditional sand casting process), very intricate parts and undercuts can be made.完成后把整個型模放在烤箱里融化石蠟。這樣就做成了能填充熔化金屬的鑄型。由于這種鑄型是環繞整塊型模形成的(無需像傳統的砂型鑄造工藝那樣拔模)，能制作十分復雜的零件和浮雕。

The wax pattern itself is made by duplicating using a stereo lithography or similar model—which has been fabricated using a computer solid model master.石蠟型模本身能用立體制版或類似的模型復制—這可以采用計算機立體模型原版制作。

The materials used for the slurry are a mixture of plaster, a binder and powdered silica, a refractory, for low temperature melts.For higher temperature melts, sillimanite or alumina-silicate is used as a refractory, and silica is used as a binder.對較低熔化溫度而言，用于耐熱漿的材料是石膏作粘合劑和用粉末狀硅石作耐溫材料的混合物。對較高熔化溫度而言，則采用硅線石或氧化鋁硅酸鹽作耐溫材料、無水硅酸作粘合劑。

Depending on the fineness of the finish desired additional coatings of sillimanite and ethyl silicate may be applied.The mold thus produced can be used directly for light castings, or be reinforced by placing it in a larger container and reinforcing it more slurry.根據最后所需光潔度也可采用硅線石和乙烷基硅酸鹽。這樣生成的鑄模可直接用于薄壁鑄件或通過將其放在較大容器內用更多耐熱漿加強。

Just before the pour, the mold is pre-heated to about 1,000℃(1,832℉)to remove any residues of wax, harden the binder.The pour in the pre-heated mold also ensures that the mold will fill completely.在正要澆鑄之前，將型模預熱到約1,000℃(1,832℉)以去除剩余石蠟、硬化粘合劑。在預熱的型模中澆鑄也能保證型模完全充滿。

Pouring can be done using gravity, pressure or vacuum conditions.Attention must be paid to mold permeability when using pressure, to allow the air to escape as the pour is done.澆鑄可采用重力、壓力或真空條件來實現。當使用壓力時必須注意滲透性，以便在澆鑄的同時讓空氣逸出。

Tolerances of 0.5% of length are routinely possible, and as low as 0.15% is possible for small dimensions.Castings can weigh from a few grams to 35kg(0.1oz to 80lb), although the normal size ranges from 200g to about 8kg(7oz to 15 lb).Normal minimum wall thicknesses are about 1mm to about 0.5mm(0.040~ 0.020 in.)for alloys that can be cast easily.一般公差可能為長度的0.5%，小尺寸可能低到0.15%。雖然通常尺寸的鑄件重量范圍為200g到約8kg(7oz到15lb)，但實際可從幾克到35kg(0.1oz to 80lb)。對容易鑄造的合金而言，通常壁厚約為1mm到0.5mm(0.040~ 0.020 in.)。

The types of materials that can be cast are aluminum alloys, bronzes, tool steels, stainless steels, stellite, hastelloys, and precious metals.Parts made with investment castings often do not require any further machining, because of the close tolerances that can be achieved.可以用于鑄造的材料類型有：鋁合金、青銅、工具鋼、不銹鋼、鎢鉻鈷合金、鎳基合金和貴金屬。采用熔模鑄造的零件常常不需要進一步加工，因為熔模鑄造能達到精密的公差。Centrifugal Casting 離心鑄造

Centrifugal casting(Fig.3.3)as a category includes centrifugal casting, semi-centrifugal casting and centrifuging.In centrifugal casting, a permanent mold is rotated about its axis at high speeds(300 to 3,000rpm)as the molten metal is poured.離心鑄造(圖3.3)作為一個種類包括了離心鑄造、半離心鑄造和離心法鑄造。離心鑄造中，永久性的型模在熔化金屬澆鑄時以較高速度(300到3,000rpm)繞其軸線旋轉。The molten metal is centrifugally thrown towards the inside mold wall, where it solidifies after cooling.The casting is usually a fine grain casting with a very fine-grained outer diameter, which is resistant to atmospheric corrosion, a typical situation with pipes.The inside diameter has more impurities and inclusions, which can be machined away.受離心力作用熔化金屬被拋向型模的內壁，在那里冷卻后固化。這種鑄件通常為外徑處晶粒非常細小的細晶粒鑄件，能耐大氣腐蝕，典型的情況是管子。內徑處則有較多的雜質和內含物，但可用機加工去除。

Only cylindrical shapes can be produced with this process.Size limits are up to 3m(10feet)diameter and 15m(50 feet)length.Wall thickness can be 2.5mm to 125mm(0.1~5.0in.).The tolerances that can be held on the OD can be as good as 2.5mm(0.1in.)and on the ID can be 3.8mm(0.15in.).The surface finish ranges from 2.5mm to 12.5mm(0.1~0.5in.)rms(root-mean-square).只有圓柱形才能用此工藝生產。尺寸限制為直徑大到3m(10feet)、長度大到15m(50feet)。壁厚為2.5mm到125mm(0.1~5.0in.)。外徑公差保持在2.5mm(0.1in.)以內，內徑公差保持在3.8mm(0.15in.)以內。表面粗糙度的有效值(均方根)范圍為2.5mm到12.5mm(0.1~0.5in.)。

Typical materials that can be cast with this process are iron, steel, stainless steels, and alloys of aluminum, copper and nickel.Two materials can be cast by introducing a second material during the process.Typical parts made by this process are pipes, boilers, pressure vessels, flywheels, cylinder liners and other parts that are axis-symmetric.可用此工藝鑄造的典型材料有：鐵、鋼、不銹鋼以及鋁、銅和鎳的合金。通過在生產過程中加入第二種材料能進行兩種材料鑄造。采用這種工藝制造的典型零件有：管子、鍋爐、壓力容器、飛輪、汽缸襯墊和其它軸對稱零件。

Semi-centrifugal casting.The molds used can be permanent or expendable, can be stacked as necessary.The rotational speeds are lower than those used in centrifugal casting.半離心鑄造：型模可以是永久性的或是消耗性的，可根據需要疊加。它的旋轉速度比離心鑄造低。The center axis of the part has inclusion defects as well as porosity and thus is suitable only for parts where this can be machined away.This process is used for making wheels, nozzles and similar parts where the axis of the part is removed by subsequent machining.零件的中心軸附近存在缺陷和孔隙，因此僅適用于能將這些機加工去除的零件。這種工藝被用于制造車輪、管嘴及類似的隨后可用機加工去除中心軸部分的零件。

Centrifuging.Centrifuging is used for forcing metal from a central axis of the equipment into individual mold cavities that are placed on the circumference.This provides a means of increasing the filling pressure within each mold and allows for reproduction of intricate details.This method is often used for the pouring of investment casting pattern.離心法鑄造：離心法鑄造用于迫使金屬從設備的中心軸進入分布在圓周上的單獨型腔。它為每個型腔提供了一種增加填充壓力方法并允許再現復雜細節。這種方法常用于澆鑄熔模鑄型。

Full-mold casting is a technique similar to investment casting, but instead of wax as the expendable material, polystyrene foam is used as the pattern.The foam pattern is coated with a refractory material.The pattern is encased in a one-piece sand mold.As the metal is poured, the foam vaporizes, and the metal takes its place.實型鑄造是與熔模鑄造類似的技術，但它用做型模的消耗材料是聚苯乙烯泡沫而不是石蠟。泡沫型模用難熔材料覆蓋。型模裝入整體砂模中。當金屬澆入時，泡沫材料蒸發，金屬取代其位置。

This can make complex shaped castings without any draft or flash.However, the pattern cost can be high due to the expendable nature of the pattern.Minimum wall thicknesses are 2.5mm, tolerances can be held to 0.3% on dimensions.Surface finish can be held from 2.5μm to 25μm(0.1μin.to 1.0μin.)rms(root-mean-square).它能制造沒有拔模斜度和縫脊的復雜形狀鑄件。然而由于型模的消耗特性，型模成本可能較高。最小壁厚為2.5mm，公差能保持在尺寸的0.3% 之內。表面粗糙度的有效值(均方根)能保持在2.5μm至25μm(0.1μin.至1.0μin.)之間。Size limits are from 400g(1lb)to several tons.No draft allowance is required.Typical materials that can be cast with this process are aluminum, iron, steel, nickel alloys, copper alloys.Types of parts that can be made using these processes are pump housings, manifolds, and auto brake components.重量限制從400g(1lb)到數噸。無需留拔模余量。這種工藝所用的典型材料有：鋁、鐵、鋼、鎳合金、銅合金。可以采用這些工藝制造的零件類型有泵殼、復式接頭和自動剎車部件。

Introduction 引言

Forging is an important hot-forming process.It is used in producing components of all shapes and sizes, from quite small items to large units weighing several tons.鍛造是一種重要的熱成型工藝。它能用于生產各種形狀和尺寸、從很小到重量數噸的零件。

Forging is the process by which metal is heated and is shaped by plastic deformation by suitably applying compressive force.Usually the compressive force is in the form of hammer blows using a power hammer or a press, as shown in Fig.4.1.在鍛造過程中先將金屬加熱，然后施加合適的壓力使其塑性變形。通常壓力都是以由如圖4.1所示的動力錘或壓力機提供的錘擊形式出現。

Hand forging tools comprise variously shaped hammers.The base on which the work is supported during forging is the anvil.手工鍛造工具包括各種不同形狀的錘子。在鍛造中用于支撐工件的基礎是鐵砧。

For the semimechanized forging of small to medium-sized components, forging hammers powered by various means are employed.The feature common to all of them is that, like the hand forging hammer, they utilize the energy of a falling weight to develop the pressure needed for shaping the metal.對小到中等尺寸零件的半機械化鍛造而言，鍛錘可采用多種動力。就其一般特性而言，都象手工鍛錘一樣，它們均利用落重能量來產生金屬成型所需的壓力。

Larger components are forged by means of forging presses operated by steam or compressed air or by hydraulic or electric power.Largely automatic forging machines are used for the quantity production of engineering parts.鍛造大零件則要用到蒸汽、壓縮空氣、液力或電力驅動的鍛壓機。大型的自動化鍛機用于工程零件的批量生產。A distinction may be made between open-die forging, usually in the form of hammer forging, and closed-die forging.In hammer forging, the component is shaped by hammer blows aided by relatively simple tools.These may include open dies i.e., dies that do not completely enclose the metal to be shaped.錘鍛中常用的開式模鍛與閉式模鍛是有區別的。在錘鍛中零件通過錘擊輔之以相對簡單的工具成型。其中包括開式鍛模，就是不完全封閉被成型金屬的模具。

One of the basic operations of hammer forging is the elongation of a piece of metal by stretching with hammer blows, causing it to become thinner and longer.In hand forging the work-piece is usually turned 90°after each blow, in order to forge it thoroughly and prevent its lateral expansion.錘鍛的基本操作之一就是通過錘擊使金屬伸長，促成其變細變長。手工鍛造時一般在每次錘擊后都轉過90°以充分鍛打工件并防止橫向膨脹。

The opposite of elongation is upsetting, which produces compressive shortening.For example, the diameter of a bar can be increased by heating and hammering axially.與伸長相反的是鐓粗，即產生壓縮性縮短。例如，棒料的直徑可以通過加熱和軸向錘擊而增大。More important is closed-die forging, very widely used for mass production in industry, in which the metal is shaped by pressing between a pair of forging dies.The upper die is usually attached to the ram of a forging press or a forging hammer, while the lower die is stationary.更重要的是閉式模鍛，在工業上廣泛用于規模生產。閉式模鍛中金屬在一對鍛模之間擠壓成型。頂模通常放在鍛壓機的撞頭或鍛錘上，而底模則是固定的。

Together they form a closed die.Closed-die forging can produce components of greater complexity and accuracy, with a better surface finish than the more traditional methods not using closed dies.The dies are made of special heat-resistant and wear-resistant tool steels.兩者合在一起形成閉式鍛模。閉式模鍛能生產高度復雜和精確的零件，而且表面光潔度要比不用閉式鍛模的更傳統方法好。閉式鍛模采用特殊的耐熱、耐磨工具鋼制成。

A piece of hot metal sufficient to slightly overfill the die shape is placed in the bottom die, and the top die is forced against it, so that the metal takes the internal shape of the die.將一塊大小足以充填模腔并能稍有溢出的加熱金屬放入底模，并將頂模加壓合攏，這塊金屬便獲得該模腔的形狀。

Closed-die forging is used for the rapid production of large numbers of fairly small parts and also for very large components.For the latter, e.g., modern jet-aircraft components, giant hydraulically operated presses are used, which can develop forces of 50,000 tons and more.閉式模鍛用于相當小的零件大批量快速生產，也可用于很大的零件。對后者而言，例如現代噴氣飛機零件，使用能產生50,000噸以上壓力的巨型液力鍛壓機。

One valuable feature of forging is that it improves the strength of the metal by refining the structure and making it uniform;so for heavy forgings, such as marine propeller shafts, an immensely powerful hydraulic press squeezes the metal with a force sometimes as great as 10,000 tonnes.鍛造有價值的特性之一是它通過使金屬組織均勻而改善強度，因此對諸如船舶螺旋槳軸之類的重型鍛件，要用能達10,000噸壓力的龐大而有力的液壓機來擠壓金屬。

Although the hydraulic forging press is a more expensive piece of equipment than a drop-forge, it has advantages beside those of giving greater strength and more uniform structure to large components.On account of the high pressure and squeezing action, it operates with less noise and vibration than a drop-forge.雖然這種液壓鍛機比落錘鍛造要昂貴得多，但它除了能給予大零件較高的強度和更均勻的組織外還有其它優點。由于較高的壓力和擠壓作用，它比落錘鍛造噪聲及振動都小得多。

As ingots of steel weighing 30 tonnes or more are forged in this way, manual operation is impossible and it is essential that all the manipulation of the ingot is done mechanically.由于這種情況下被鍛鋼坯重量大于30噸，人工操作是不可能的，鋼坯的所有操作都必須是機械化的。Forging refines the grain structure and improves physical properties of the metal.With proper design, the grain flow can be oriented in the direction of principal stresses encountered in actual use.鑄造細化金屬的晶粒組織、改善其物理性能。通過適當的設計，可以使晶粒流動方向與實際使用時的主應力方向一致。

As shown in Fig.4.2, grain flow is the direction of the pattern that the crystals take during plastic deformation.Physical properties(such as strength, ductility and toughness)are much better in a forging than in the base metal, which has crystals randomly oriented.如圖4.2所示，晶粒流動的方向就是在塑性變形期間結晶排列的方向。鍛件的物理性能(如強度、延展性和韌性)遠好于基礎金屬，因為基礎金屬的晶粒是無序排列的。

Forgings are consistent from piece to piece, without any of the porosity, voids, inclusions and other defects.Thus, finishing operations such as machining do not expose voids, because there aren’t any.Also coating operations such as plating or painting are straightforward due to a good surface, which needs very little preparation.鍛件各部分是連貫一致的，沒有孔隙、空洞、雜質及其它缺陷。因此像機加工之類的精加工工序不會受空洞的影響，因為根本就不存在。另外由于鍛件良好的表面，像電鍍或油漆之類的涂裝工序就很簡單，幾乎不需要做準備工作。

Forgings yield parts that have high strength to weight ratio, thus are often used in the design of aircraft frame members.A forged metal can result in the following: 鍛造生產的零件具有較高的強度重量比，所以常被用在飛機結構零件的設計中。

鍛造金屬可以導致下列結果：

Increase length, decrease cross-section, called drawing out the metal.Decrease length, increase cross-section, called upsetting the metal.Change length, change cross-section, by squeezing in closed impression dies.This results in favorable grain flow for strong parts.●增加長度、減小橫截面，稱為延伸金屬。●減小長度、增加橫截面，稱為鐓粗金屬。●通過用封閉鍛模擠壓，改變長度和橫截面。

這導致有利的晶粒流使零件堅固。Common Forging Processes 常用的鍛造工藝

The metal can be forged hot(above recrystallization temperatures)or cold.金屬既可熱鍛(高于再結晶溫度)也可冷鍛。

Open die forgings/Hand forgings.Open die forgings or hand forgings are made with repeated blows in an open die, where the operator manipulates the workpiece in the die.The finished product is a rough approximation of the die.This is what a traditional blacksmith does, and is an old manufacturing process.開式模鍛/手工鍛：開式模鍛或手工鍛就是操作者操縱工件在開式鍛模中反復擊打。完成的產品是鍛模的粗糙近似物。這就是傳統鐵匠干的活，是較古老的制造工藝。

Impression die forgings/Precision forgings.Impression die forgings and precision forgings are further refinements of the blocker forgings.The finished part more closely resembles the die impression.壓模鍛/精密鍛：壓模鍛和精密鍛是雛形模鍛的進一步改進。完成的零件與模膛更相似。

Press forgings.Press forgings use a slow squeezing action of a press, to transfer a great amount of compressive force to the workpiece.Unlike an open-die forging where multiple blows transfer the compressive energy to the outside of the product, press forging transfers the force uniformly to the bulk of the material.壓鍛：壓鍛通過壓力機緩慢的擠壓動作將巨大的壓力傳遞給工件。不像開式模鍛那樣需要多次擊打把壓縮能量傳遞到零件外表面，壓鍛能將力均勻地傳遞給材料的主體。

This results in uniform material properties and is necessary for large weight forgings.Parts made with this process can be quite large as much as 125kg(260lb)and 3m(10 feet)long.這使材料性能一致，對大重量鍛件而言是十分必要的。采用此工藝生產的零件重量可達125kg(260lb)而長度可達3m(10 feet)。

Upset forgings.Upset forging increases cross-section by compressing the length, this is used in making heads on bolts and fasteners, valves and other similar parts.頂鍛：頂鍛通過壓縮長度增加橫截面，用于在螺栓等緊固件、柱塞及類似零件上制造頭部。Roll forgings.In roll forging, a bar stock, round or flat is placed between die rollers which reduces the cross-section and increases the length to form parts such as axles, leaf springs etc.This is an essential form of draw forging.滾鍛：在滾鍛時，圓的或是扁平的棒料放在模輥之間縮小橫截面增加長度制成諸如輪軸、板簧之類的零件。這是軋鍛的基本形式。

Swaging.Swaging—a tube or rod is forced inside a die and the diameter is reduced as the cylindrical object is fed.The die hammers the diameter and causes the metal to flow inward causing the outer diameter of the tube or the rod to take the shape of the die.型鍛：型鍛—將圓管或圓棒強制壓入鍛模，隨著圓柱形物體的被壓入其直徑減小。鍛模錘擊橫斷面使金屬向內流動導致圓管或圓棒的外徑變為鍛模的形狀。

Net shape/Near-net shape forging.In net shape or near-net shape forging, forging results in wastage of material in the form of material flash and subsequent machining operations, as shown in Fig.4.3.This wastage can be as high as 70% for gear blanks, and even 90% in the case of aircraft structural parts.純型/近似純型鍛 ：采用純型鍛或近似純型鍛，產生材料損耗的主要形式是飛邊以及隨后的機加工，如圖4.3所示。齒輪毛坯材料損耗為70%，而飛機結構零件的材料損耗甚至達90%。

Net-shape and near-net-shape processes minimize the waste by making precision dies, producing parts with very little draft angle(less than 1°).These types of processes often eliminate or reduce machining.純型鍛和近似純型鍛工藝通過制作精密模具并生產鍛模斜角很小(小于1°)的零件能使材料損耗最小化。此類工藝通常可以省去或減少機加工。

The processes are quite expensive in terms of tooling and the capital expenditure required.Thus, these processes can be only justified for current processes that are very wasteful where the material savings will pay for the significant increase in tooling costs.從模具的角度而言這些工藝是相當昂貴的，需要資金投入。因此這些工藝只有對目前很浪費的生產過程，在材料節約足以補償模具成本的大量增加時才是合理的。Die Design Consideration 鍛模設計的考慮因素

Parting surface should be along a single plane if possible, else following the contour of the part.The parting surface should be through the center of the part, not near the upper or lower edges.如果可能分模面應沿著單一平面，否則就順著零件輪廓方向。分模面應經過零件中心，而不要靠近上下邊緣。If the parting line cannot be on a single plane, then it is good practice to use symmetry of the design to minimize the side thrust forces.Any point on the parting surface should be less than 75°from the principal parting plane.如果分模面不能在單一平面，利用設計的對稱性來減小側向推力不失為一種好方法。分模面上任意點與主分模面的夾角應小于75°。

As in most forming processes, use of undercuts should be avoided as these will make the removal of the part difficult, if not impossible.如同大多數成型工藝，如果不是非用不可，盡量避免采用凹槽，因為凹槽會使零件難以取出。

Generous fillets and radius should be provided to aid in material flow during the forging process.Sharp corners are stress-risers in the forgings, as well as make the dies weak in service.Ribs should not be high or narrow;this makes it difficult for the material to flow.應提供盡可能大的倒角和半徑以幫助材料在鍛造過程中流動。銳角會增加鍛件中的應力，同時在使用時削弱鍛模。

加勁肋不要過高、過窄，因為這會造成材料流動困難。

Tolerances 公差

Dimension tolerances are usually positive and are approximately 0.3% of the dimension, rounded off to the next higher 0.5mm(0.020in.).尺寸公差通常為正，大約取為該尺寸的0.3%，并圓整到較大的0.5mm(0.020in.)。

Die wear tolerances are lateral tolerances(parallel to the parting plane)and are roughly +0.2% for copper alloys to +0.5% for aluminum and steel.鍛模磨損公差為側向公差(平行于分模面)，對銅合金大約為+0.2%，對鋁和鋼大約為+0.5%。

Die closure tolerances are in the direction of opening and closing, and range from 1mm(0.040in.)for small forgings, die projection area＜150cm2(23in.2), to 6.25mm(0.25in.)for large forgings, die projection area＞6,500cm2(100in.2).鍛模的閉合公差處于開閉的方向上，范圍從對較小鍛件[其投影面積＜150cm2(23in.2)]取為1mm(0.040in.)，到較大鍛件[其投影面積＞6,500cm2(100in.2)]取為6.25mm(0.25in.)。

Die match tolerances are to allow for shift in the upper die with respect to the lower die.鍛模的配合公差是為了允許上模能根據下模替換。

A proper lubricant is necessary for making good forgings.The lubricant is useful in preventing sticking of the workpiece to the die, and also acts as a thermal insulator to help reduce die wear.制造良好的鍛件必須有合適的滑潤劑。滑潤劑對防止工件粘住鍛模很有用，還可以作為絕熱體幫助減少鍛模磨損。

Powder metallurgy(Fig.5.1)uses sintering process for making various parts out of metal powder.The metal powder is compacted by placing in a closed metal cavity(the die)under pressure.粉末冶金(圖5.1)采用燒結工藝將金屬粉末制成各種各樣的零件。金屬粉末放在封閉的金屬腔(模具)中在壓力下被壓實。

This compacted material is placed in an oven and sintered in a controlled atmosphere at high temperatures and the metal powders coalesce and form a solid.A Second pressing operation, repressing, can be done prior to sintering to improve the compaction and the material properties.被壓實的材料置于爐內燒結，在高溫下爐內環境可控，金屬粉末熔合形成固體。在燒結前可以進行二次擠壓作業(再擠壓)以改善壓實狀態和材料性能。

Powder metallurgy is a highly developed method of manufacturing reliable ferrous and nonferrous parts.Made by mixing elemental or alloy powders and compacting the mixture in a die, the resultant shapes are then sintered or heated in a controlled atmosphere furnace.粉末冶金是一種高度發達的制造可靠鐵或非鐵零件的方法。通過混合元素或合金粉末并在模具中壓實混合物，再燒結或在環境可控爐內加熱制成最終形狀。

Material 材料

The majority of the structural components produced by fixed die pressing are iron-based.The powders are elemental, pre-alloyed, or partially alloyed.大多數用固定模壓制的結構件都是鐵基的。粉末可以是單一元素、預先合金或部分合金。

Elemental powders, such as iron and copper, are easy to compress to relatively high densities, produce pressed compacts with adequate strength for handling during sintering, but do not produce very high strength sintered parts.諸如鐵、銅之類的單一元素粉末較容易被壓得相對密度較高、生產具備足夠強度的壓制物供燒結處理，但是無法制造出很高強度的燒結零件。

Pre-alloyed powders are harder, less compressible and hence require higher pressing loads to produce high density compacts.However, they are capable of producing high strength sintered materials.預先合金粉末比較硬、不容易壓實，因此需要較高的擠壓力來產生高密度的壓制物。然而它們能生成高強度燒結材料。Pre-alloying is also used when the production of a homogeneous material from elemental powders requires very high temperatures and long sintering times.The best examples are the stainless steels, whose chromium and nickel contents have to be pre-alloyed to allow economic production by powder metallurgy.如果用單一元素粉末生產均勻材料需要很高溫度和較長燒結時間，也可用預先合金。最好的例子是不銹鋼，因含有鉻和鎳成分，所以粉末冶金必須用預先合金才經濟。

Partially alloyed powders are a compromise approach.Elemental powders, e.g.iron with 2wt.% copper, are mixed to produce an homogeneous blend which is then partially sintered to attach the copper particles to the iron particles without producing a fully diffused powder but retaining the powder form.部分合金粉末是一種折衷的方法。單一元素粉末，例如鐵與2%的銅(重量百分比)混合均勻，經部分燒結后銅微粒粘附到鐵微粒上而沒有產生充分擴散的粉末卻保留了粉末的形態。

In this way the compressibilities of the separate powders in the blend are maintained and the blend will not segregate during transportation and use.用這種方法混合物中單獨粉末的可壓縮性得以維持，在運送和使用期間結合將不會分離。

A similar technique is to “glue” the small percentage of alloying element onto the iron powder.This “glueing” technique is successfully used to introduce carbon into the blends, a technique which prevents carbon segregation and dusting, producing so-called “clean” powders.另一種類似的技術是把小百分比的合金元素“粘合”到鐵微粒上。這種“粘合”技術已成功用于將碳引入結合物，一種防止碳分離并起塵的技術，生產所謂的“清潔”粉末。Powder Consolidation 粉末合成

Components or articles are produced by forming a mass of powder into a shape, then consolidating to form inter-particle metallurgical bonds.通過將大量的粉末放入模具成型為零件或物品，然后合成為內有微粒的冶金結合物。

An elevated temperature diffusion process referred to as sintering, sometimes assisted by external pressure, accomplishes this.The material is never fully molten, although there might be a small volume fraction of liquid present during the sintering process.Sintering can be regarded as welding the particles present in the initial useful shape.提升溫度擴散工藝被稱為燒結，有時還輔之以外界的壓力來達到目的。雖然在燒結過程中可能會有少量液態出現，但材料決不是全熔化。燒結可以被看作是把微粒焊接成初始的有用形狀。

As a general rule both mechanical and physical properties improve with increasing density.Therefore the method selected for the fabrication of a component by powder metallurgy will depend on the level of performance required from the part.Many components are adequate when produced at 85~90% of theoretical full density whist others require full density for satisfactory performance.作為普遍規律，隨著密度的增加機械和物理性能均改善。因此選擇何種粉末冶金方法來制作零件取決于其所需的性能級別。許多零件只需理論全密度的85~90%而其它的則需全密度才能滿足要求。

Some components, in particular bush type bearings often made from copper and its alloys, are produced with significant and controlled levels of porosity, the porosity being subsequently filled with a lubricant.Fortunately there is a wide choice of consolidation techniques available.有些零件，尤其是襯套式軸承常用銅及其合金制作，控制多孔性程度的意義重大，因為這些孔隨后要填充潤滑劑。

還好有多種合成技術可供選擇。Cold Uniaxial Pressing Elemental metal, or an atomized pre-alloyed powder is mixed with a lubricant, typically lithium stearate(0.75 wt.%), and pressed at pressures of say, 600MPa(87,000lb/in.2)in metal dies.冷單向擠壓

單一元素金屬，或極小顆粒的預先合金粉末與潤滑劑(一般是鋰硬脂酸鹽，重量百分比0.75%)混合，然后在金屬模具中施加壓力[比如600MPa(87,000lb/in.2)]擠壓。

Cold compaction ensures that the as-compacted, or “green”, component is dimensionally very accurate, as it is moulded precisely to the size and shape of the die.冷擠壓能保證被壓制或“未加工”的零件尺寸十分精確，因為它被精確地按模具的尺寸和形狀成型。One disadvantage of this technique is the differences in pressed density that can occur in different parts of the component due to particle/particle and die wall/particle frictional effects.Typical as-pressed densities for soft iron components would be 7.0g/cc, i.e.about 90% of theoretical density.這種技術的缺點之一是由于微粒/微粒和模壁/微粒間的摩擦效應，零件不同部位的壓實密度存在差異。典型的軟鐵零件壓制密度為7.0g/cc，即大約是理論密度的90%。

Compaction pressure rises significantly if higher as-pressed densities are required, and this practice becomes uneconomic due to higher costs for the larger presses and stronger tools to withstand the higher pressures.如果需要較高的壓實密度則壓實壓力要顯著提高，因為大型壓力機成本較高并且在較高壓力下模具強度要更高這樣就不合算。

Cold Isostatic Pressing Metal powders are contained in an enclosure e.g.a rubber membrane or a metallic can that is subjected to isostatic, which is uniform in all directions, external pressure.As the pressure is isostatic the as-pressed component is of uniform density.冷均衡擠壓

金屬粉末裝入均衡受壓的橡膠膜或金屬罐內，其所受外壓力在各個方向都是均勻的。由于壓力是均衡的，所以壓制零件密度是均勻的。

Irregularly shaped powder particles must be used to provide adequate green strength in the as-pressed component.This will then be sintered in a suitable atmosphere to yield the required product.必須采用不規則形狀粉末微粒為壓制零件提供足夠的未加工強度。然后放入合適的環境中燒結成所需產品。Normally this technique is only used for semi-fabricated products such as bars, billets, sheet, and roughly shaped components, all of which require considerable secondary operations to produce the final, accurately dimensioned component.通常這種技術只用于制作諸如棒料、坯段、薄板及粗糙成型零件之類的半成品，所有這些都需要大量進一步加工才能生產出最終尺寸精確的零件。

Again, at economical working pressures, products are not fully dense and usually need additional working such as hot extrusion, hot rolling or forging to fully density the material.此外使用經濟工作壓力的產品不是充分致密的，一般需要增加諸如熱擠壓、熱軋或鍛之類的額外工序來使材料達到全密度。Sintering Sintering is the process whereby powder compacts are heated so that adjacent particles fuse together, thus resulting in a solid article with improved mechanical strength compared to the powder compact.燒結

燒結就是通過把粉末壓制物加熱使鄰近的微粒熔合在一起的工藝，它能生成比粉末壓制物機械強度更好的固體物。

This “fusing” of particles results in an increase in the density of the part and hence the process is sometimes called densification.There are some processes such as hot isostatic pressing which combine the compaction and sintering processes into a single step.微粒的“熔合”導致零件密度增加，因此該工藝有時被稱為致密化。還有一些工藝如熱均衡擠壓，將壓實和燒結工藝合并為單一步驟。

After compaction the components pass through a sintering furnace.This typically has two heating zones, the first removes the lubricant, and the second higher temperature zone allows diffusion and bonding between powder particles.零件壓實后通過燒結爐。一般有兩個加熱區，第一個去除潤滑劑，第二個溫度更高的區域讓粉末微粒之間擴散并結合。

A range of atmospheres, including vacuum, are used to sinter different materials depending on their chemical compositions.As an example, precise atmosphere control allows iron/carbon materials to be produced with specific carbon compositions and mechanical properties.根據不同材料的化學成分，燒結的環境包括真空狀態也各不相同。例如精確的環境控制可使鐵/碳材料生成特殊碳化物和機械性能。

The density of the component can also change during sintering, depending on the materials and the sintering temperature.These dimensional changes can be controlled by an understanding and control of the pressing and sintering parameters, 根據材料和燒結溫度的不同，零件的密度在燒結過程中也會改變。因為尺寸的變化可以通過了解并調節擠壓及燒結參數進行控制，and components can be produced with dimensions that need little or no rectification to meet the dimensional tolerances.Note that in many cases all of the powder used is present in the finished product, scrap losses will only occur when secondary machining operations are necessary.所以零件尺寸幾乎無需校正就能滿足尺寸公差。可以看到在很多情況下所有使用的粉末都包含在制成品中，廢料損失僅產生于需要輔助機加工時。Hot Isostatic Pressing Powders are usually encapsulated in a metallic container but sometimes in glass.The container is evacuated, the powder out-gassed to avoid contamination of the materials by any residual gas during the consolidation stage and sealed-off.熱均衡擠壓

粉末通常封裝在金屬容器內有時也裝在玻璃容器內。把容器抽真空，粉末抽氣是為了防止材料在合成階段和密封時被殘留氣體污染。

It is then heated and subjected to isostatic pressure sufficient to plastically deform both the container and the powder.再加熱并施加均衡壓力足以使容器和粉末都塑性變形。

The rate of densification of the powder depends upon the yield strength of the powder at the temperatures and pressures chosen.At moderate temperature the yield strength of the powder can still be high and require high pressure to produce densification in an economic time.粉末致密率取決于該粉末在選定溫度和壓力下的屈服強度。中等溫度下粉末的屈服強度仍然較高，因此需要較高壓力使其在經濟時間內致密化。

Typical values might be 1120℃ and 100MPa for ferrous alloys.By pressing at very much higher temperatures lower pressures are required as the yield strength of the material is lower.Using a glass enclosure atmospheric pressure(15psi)is used to consolidate bars and larger billets.對鐵合金典型的數值為1120℃和100MPa。由于很高溫度下材料的屈服強度較低，因此只需較低壓力就能擠壓。采用玻璃容器時可用大氣壓力(15psi)合成棒料和較大坯段。

The technique requires considerable financial investment as the pressure vessel has to withstand the internal gas pressure and allow the powder to be heated to high temperatures.因為壓力容器必須經受住內氣壓并允許粉末加熱到較高溫度，所以這種技術需要相當可觀的資金投入。As with cold isostatic pressing only semi-finished products are produced, either for subsequent working to smaller sizes, or for machining to finished dimensions.此工藝與采用冷均衡擠壓一樣只能生產半成品，可以通過后續加工至較小尺寸，也能用機加工到最終尺寸。

Hot Forging(Powder Forging)Cold pressed and sintered components have the great advantage of being close to final shape(near-net shape), but are not fully dense.Where densification is essential to provide adequate mechanical properties, the technique of hot forging, or powder forging, can be used.熱鍛(粉末鍛造)冷擠壓和燒結零件主要優點是接近最終形狀(近似純形)，但不是充分致密的。當為了提供足夠的機械性能而致密化是必須時，可以采用熱鍛或粉末鍛造技術。

In powder forging an as-pressed component is usually heated to a forging temperature significantly below the usual sintering temperature of the material and then forged in a closed die.This produces a fully dense component with the shape of the forging die and appropriate mechanical properties.在粉末鍛造中，壓制零件一般加熱到遠低于該材料通常燒結溫度的鍛造溫度，然后在閉模中鍛造。這能生產具有鍛模形狀和合適機械性能的充分致密零件。

Powder forged parts generally are not as close to final size or shape as cold pressed and sintered parts.These results from the allowances made for thermal expansion effects and the need for draft angles on the forging tools.Further, minimal machining is required but when all things are considered this route is often very cost-effective.粉末鍛造零件通常不像冷擠壓和燒結零件那樣接近最終尺寸或形狀。這是由于為熱膨脹效應而設置允差以及在鍛模上需要拔模斜角所致。此外還需少量機加工，但全面考慮這種方法通常還是很劃算的。Metal Injection Moulding(MIM)Injection moulding is very widely used to produce precisely shaped plastic components in complex dies.As injection pressures are low it is possible to manufacture complex components, even some with internal screw threads, by the use of side cores and split tools.金屬注塑成型(MIM)注塑成型被很廣泛地用于在復雜模具中生產形狀精確的塑料零件。注塑壓力較低使得制作復雜零件成為可能，通過采用側面型芯和分離工具甚至可以帶有內螺紋。

By mixing fine, typically less than 20 μm diameter, spherical metal powders with thermoplastic binders, metal filled plastic components can be produced with many of the features available in injection moulded plastics.After injection moulding, the plastic binder material is removed to leave a metal skeleton which is then sintered at high temperature.將細小(直徑一般小于20μm)球形金屬粉末與熱塑性粘合劑混合，能生產具有多數注塑成型塑料特征的金屬充滿塑料零件。注塑成型后，去除塑料粘合材料剩下金屬骨架，然后在高溫下燒結。

Dimensional control can be exercised on the as-sintered component as the injected density is sensibly uniform so shrinkage on sintering is also uniform.燒結零件可以實現尺寸控制，因為注塑密度明顯均勻，所以燒結收縮也是均勻的。Shrinkage can be large, due to both the fine particle size of the powders and the substantial proportion of polymer binder used.由于所用粉末細小微粒的尺寸和聚合物粘合劑的真實比例，收縮可以比較大。

Features 特征

For high tolerance parts, a sintering part is put back into a die and repressed.In genera this makes the part more accurate with a better surface finish.對較大公差的零件，燒結后可放回模具重新擠壓。一般而言這會使零件更精確同時具有更好的表面光潔度。A part has many voids that can be impregnated.One method is to use an oil bath.Another method uses vacuum first, then impregnation.零件有許多可供填充的空間。一種方法是采用油浴。另一種方法是先抽真空然后再充滿。

A part surface can be infiltrated with a low melting point metal to increase density, strength, hardness, ductility and impact resistance.Plating, heat treating and machining operations can also be used.零件表面能被低熔點金屬滲透以增大密度、強度、硬度、延展性和抗沖擊能力。仍然可以進行電鍍、熱處理和機加工作業。Advantages 優點

Good tolerances and surface finish Highly complex shapes made quickly Can produce porous parts and hard to manufacture materials(e.g.cemented oxides)良好的公差和表面光潔度 高度復雜的形狀能快速制作

能制作多孔零件和難以加工材料(如粘結氧化物)Pores in the metal can be filled with other materials/metals Surfaces can have high wear resistance Porosity can be controlled Low waste Automation is easy 金屬中的氣孔可用其它材料/金屬填充 表面能具有較高的耐磨性 孔隙率可以控制 較低損耗 容易自動化

Physical properties can be controlled Variation from part to part is low Hard to machine metals can be used easily No molten metals 物理性能可以控制

零件之間的變化較小

難以機加工的金屬能被容易使用

無需熔化金屬

No need for many/any finishing operations Permits high volume production of complex shapes Allows non-traditional alloy combinations Good control of final density 不需要很多/任何修整作業

允許加工復雜形狀的大體積產品 允許非傳統合金結合

對最終密度能很好地控制

Disadvantages 缺點

Metal powders deteriorate quickly when stored improperly Fixed and setup costs are high Part size is limited by the press and compression of the powder used 如果存放不當金屬粉末質量很快降低 安裝和調整的成本較高

零件尺寸受壓力機和所用粉末壓縮的限制 Sharp corners and varying thickness can be hard to produce Non-moldable features are impossible to produce 銳角和變厚度較難加工

不適合模壓的東西不可能生產

Injection molding(Fig.6.1)is the predominant process for fabrication of thermoplastics into finished forms, and is increasingly being used for thermosetting plastics, fiber-filled composites, and elastomers.注塑成型(圖6.1)是將熱塑性塑料制成最終形狀的主要工藝，并且越來越多地用于熱硬化性塑料、纖維填充合成物和人造橡膠。

It is the process of choice for tremendous variety of parts ranging in weight from 5g to 85kg.It is estimated that 25% of all thermoplastics are injection molded.它是重量范圍為5g到85kg極大一類零件可選用的工藝。估計所有熱塑性塑料中有25%是采用注塑成型的。

If newer modifications, such as reaction injection molding, and the greatly increased rate of adoption of plastics as substitutes for metals are considered, it is likely that the worldwide industrial importance of injection molding will continue to increase.如果考慮到新近的改進(例如反作用注塑成型)和采用塑料替代金屬的高增長率，注塑成型在世界范圍的工業重要性很可能將繼續增加。

Currently, probably close to half of all major processing units is injection molding machines.In 1988, a dollar sale of new injection molding machinery in the U.S.was approximately 65% of total major polymer machinery sales volume;this included 4,600 injection molding units.當前，大概所有主要處理設備的近一半是注塑成型機。1988年，美國新的注塑成型機械銷售約占全部主要聚合物機械銷售量的65%，其中包括4,600臺注塑成型設備。

The machines and their products are ubiquitous and are synonymous with plastics for many people.這類機械和它們的產品普遍存在，對許多人來說與塑料是同義的。

A reciprocating screw injection molding machine combines the functions of an extruder and a compressive molding press.往復螺旋注射成型機把壓出機和成型壓力機的功能結合起來。

It takes solid granules of thermoplastic resin, melts and pressurizes them in the extruder section, forces the melt at high velocity and pressure through carefully designed flow channels into a cooled mold, then ejects the finished part(s), and automatically recycles.把熱塑性塑料樹脂的固體顆粒在壓出部分融化并增壓，迫使其高速融化并通過仔細設計的流動通道進入冷卻模具，噴射成最終零件，然后自動再循環。

This machine is a descendant of the plunger type “stuffing machine” patented by the Hyatt brothers in 1872 to mold celluloid.In 1878, the Hyatts developed the first multicavity mold, but it was not until 1938 that Quillery(France)patented a machine incorporating a screw to plasticize the elastomer being molded.這種機械是1872年Hyatt兄弟獲得專利權的融化賽璐珞的活塞型“填充機”的派生物。1878年Hyatt兄弟開發了第一個多槽模具，但直到1938年Quillery(法國)才發明了用螺旋增塑人造橡膠并使其成型的一體化機械。In 1956, Ankerwerk Nuremberg commercialized the modern reciprocating screw injection molding machine for thermoplastics.Today, over 50 machine manufacturers are listed in Modern Plastics Encyclopedia, offering machines to the U.S.market ranging from 2 to 6,000 tons clamping capacity.1956年，Ankerwerk Nuremberg使用于熱塑性塑料的現代往復螺旋注塑成型機商業化。今天，已有超過50家制造商列入現代塑料制品百科全書，能為美國市場提供壓制能力從2到6,000噸的機械。

(A machine with a 10,000-ton capacity has been built to mold 264-gallon HDPE trash containers.)A host of suppliers of auxiliary equipment, molds, instruments, and controls service this major segment of the polymer industry.(一臺能力為10,000噸用于成型264加侖高密度聚乙烯垃圾箱的機械也已制成)。許多輔助設備、模具、儀器和控制系統供應商在為聚合物工業的這一主要部分服務。

Injection molding is particularly worthy of intensive study because it combines many areas of interest extrusion, mold design, rheology, sophisticated hydraulic and electronic controls, robotic accessories, design of complex products, and, of course, the integration of materials science and process engineering.注塑成型對深入研究很有價值，因為它結合了許多重要領域，如擠壓、模具設計、流變學、完備的液壓和電子控制、機器人配件、復雜產品的設計，當然還有材料科學與加工工程的綜合。

The objectives of injection molding engineers are simple enough: to obtain minimum cycle time with minimum scrap, to attain specified product performance with assurance, to minimize production costs due to downtime or any other reasons, and to steadily increase in expertise and competitiveness.注塑成型工程師的目標很簡單：在最少廢料的情況下取得最小循環時間，在有保證的情況下獲得指定產品性能，將由停工或其它原因產生的生產成本最小化，還有穩定地增加專門知識和競爭力。

Profit margins for custom injection molders are said to be generally skimpy;an established way to improve profits is to be selected for more demanding, higher margin jobs that demand the highest level of efficiency and competence.傳統的注塑成型機利潤盈余據說一般是不足的；為了更多需求及更高盈余工作需要選擇一種改善利潤的確定方法，它要求最高水平的效率和能力。This text will concentrate on the reciprocating screw machine for thermoplastics, which has largely replaced the older reciprocating plunger types except for very small-capacity machines.本文將集中論述熱塑性塑料用的往復螺旋機，除了小容量機械外它已在很大程度上取代了較老的往復活塞式機械。

Injection Molding Materials 注塑成型材料

It is not possible to injection-mold all polymers.Some polymers like PTFE(Poly-tetra-fluoro-ethylene), cannot be made to flow freely enough to make them suitable for injection molding.要注塑成型所有聚合物是不可能的。像聚四氟乙烯之類的聚合物就不能自由流動得足以適合注塑成型。Other polymers, such as a mixture of resin and glass fiber in woven or mat form, are unsuitable by their physical nature for use in the process.In general, polymers which are capable of being brought to a state of fluidity can be injection-molded.其它聚合物，例如樹脂和編織的或墊子形的玻璃纖維的混合物，由于它們的物理性質不適合使用此工藝。一般而言，能進入流動狀態的聚合物都可以注塑成型。

The vast majority of injection molding is applied to thermoplastic polymers.This class of materials consists of polymers which always remain capable of being softened by heat and of hardening on cooling, even after repeated cycling.注塑成型的絕大多數都用于熱塑性聚合物。這類材料由具有加熱軟化、冷卻硬化甚至可重復循環能力的聚合物組成。

This is because the long-chain molecules of the material always remain as separate entities and do not form chemical bonds to one another.An analogy car, be made to a block of ice that can be softened(i.e.turned back to liquid), poured into any shape cavity, and then cooled to become a solid again.這是由于這類材料的長鏈分子總是保持分離的實體并不相互形成化學連結。一輛由冰塊制成的模擬汽車，可以融化(即轉化為液態)，倒入任何形狀的空腔，然后冷卻重新變成固體。

This property differentiates thermoplastic materials from thermosetting ones.In the latter type of polymer, chemical bonds are formed between the separate molecule chains during processing.In this case the chemical bonding referred to as cross linking is the hardening mechanism.這個特性將熱塑性材料與熱硬化性材料區分開。后者在加工過程中分離的分子鏈之間形成化學連結。在此情況下作為交聯的化學連結是硬化機制。

In general, most of the thermoplastic materials offer high impact strength, corrosion resistance, and easy processing with good flow characteristics for molding complex designs.Thermoplastics are generally divided into two classes: namely crystalline and amorphous.一般而言，大多數熱塑性材料具有較高的抗沖擊強度、耐腐蝕性以及良好流動性使其容易加工而適于復雜成型設計。熱塑性塑料通常分為兩類：即結晶質的和非結晶質的。

Crystalline polymers have an ordered molecular arrangement, with a sharp melting point.Due to the ordered arrangement at molecules, the crystalline polymers reflect most incidents light and generally appear opaque.結晶質聚合物具有規則的分子排列及明顯的熔點。由于規則的分子排列，結晶質聚合物能反射大多數特定光線并一般表現為不透明的。They also undergo a high shrinkage or reduction in volume during solidification.Crystalline polymers usually are more resistant to organic solvents and have good fatigue and wear-resistant properties.Crystalline polymers also generally are denser and have better mechanical properties than amorphous polymers.它們在固化過程中收縮較大或體積減少較多。結晶質聚合物通常多能抵御有機溶劑并具有良好的抗疲勞和磨損特性。結晶質聚合物通常也比非結晶質聚合物更致密并且具有更好的機械性能。

The main exception to this rule is polycarbonate, which is the amorphous polymer of choice for high quality transparent moldings, and has excellent mechanical properties.其中主要例外是聚碳酸酯，它是可選用做高質量透明注塑件的非結晶質聚合物，并具有卓越的機械性能。

The mechanical properties of thermoplastics, while substantially lower than those of metals, can be enhanced for some applications through the addition of glass fiber reinforcement.This takes the form of short-chopped fibers, a few millimeters in length, which are randomly mixed with the thermoplastic resin.就本質而言，熱塑性塑料的機械性能低于金屬，但可以通過加入玻璃纖維強化予以增強來適應某些運用。常用幾毫米長的短碎纖維隨機地與熱塑性樹脂混合。The fibers can occupy up to one third of the material volume to considerably improve the material strength and stiffness.The negative effect of this reinforcement is usually a decrease in impact strength and an increase in abrasiveness.纖維可占材料體積的三分之一以極大改善材料的強度和硬度。這種加強的負作用通常是抗沖擊強度降低及磨損性增加。

The latter also has an effect on processing since the life of the mold cavity is typically reduced from about 1,000,000 parts for plain resin parts to about 300,000 for glass-filled parts.后者對加工過程也有影響，因為模具腔的壽命從典型的普通樹脂零件大約1,000,000件減少到玻璃纖維填充樹脂零件的約300,000件。

Perhaps the main weakness of injection-molded parts is the relatively low service temperatures to which they can be subjected.Thermoplastic components can only rarely be operated continuously above 250℃, with an absolute upper service temperature of about 400℃.注塑成型零件的主要缺點或許是它們能承受的工作溫度相對較低。熱塑性塑料零件只有很少能連續運行在250℃以上，其絕對最高工作溫度約為400℃。

The temperature at which a thermoplastic can be operated under load can be defined qualitatively by the heat deflection temperature.This is the temperature at which a simply supported beam specimen of the material, with a centrally applied load, reaches a predefined deflection.熱塑性塑料帶載運行溫度可從質量上定義為熱偏差溫度。這是中心承載的該材料簡支梁達到預定偏差的溫度。The temperature value obviously depends upon the conditions of the test and the allowed deflection and for this reason, the test values are only really useful for comparing different polymers.其溫度值明顯取決于試驗條件和允許偏差，因此對比較不同的聚合物而言只有試驗數據是真正有用的。Cycle of Operation 作業循環

The reciprocating screw injection molding machine is considered as consisting of two halves: a fixed injection side, and a movable clamp side.往復螺旋注塑成型機被認為由兩部分組成：一個固定注塑端和一個活動夾具端。

The injection side contains the extruder that receives solid resin in pellet or granular form and converts it into a viscous liquid or melt that can be forced through the connecting nozzle, spine, and runners to the gates that lead into the mold cavities.注塑端包含壓出機，它接受小球或粒狀的固體樹脂，然后將其轉化為粘性液體或稱為融化，再強迫其通過連接噴嘴、中心和澆道到閘道進入模具腔。

The mold is tightly clamped against injection pressure and is cooled well below the melt temperature of the thermoplastic.When the parts in the cavities have cooled sufficiently the mold halves are opened at the mold parting plane and the parts ejected by a knockout system drop into a receiving bin below.模具被緊緊地夾住以抵抗注塑壓力，并在熱塑性塑料的融化溫度以下很好地冷卻。當模腔內的零件充分冷卻，剖分模在模具分模面處打開，推出系統將零件推出落入下面的接收容器內。This summarizes the overall cycle, but leaves out much vital detail that is necessary for understanding the process.However, with this introduction, it is possible to understand the advantages and disadvantages of the process.這概述了整個循環，但省略了許多對理解此工藝所必需的很重要細節。然而通過本介紹，了解這種工藝的優缺點仍是可能的。

Effects of Process Variables on Orientation 加工變量對方向性的影響

In injection molding, any variation in processing that keeps the molding resin hot throughout filling allows increased relaxation and, therefore, decreased orientation.Some of the steps that can be taken to reduce orientation are as follows.在注塑成型時，整個填料過程始終保持成型樹脂高溫的任何加工變化都會增加松弛作用而減少方向性。下面是可以用于減少方向性的若干措施。

Faster injection(up to a point): less cooling during filling, hence a thinner initial frozen layer, lower viscosity due to shear thinning;better flow to corners;and less crystallinity all favor lower subsurface orientation.The primary effect is that the gate will freeze more quickly.At that point, orientation stops and relaxation starts.較快注塑(到點)：在填料過程中冷卻較少，因此初始固化層較薄，由于剪應變稀少而粘性較低；能較好地流到角落；結晶度較小；所有這些促成表面下的方向性也較低。主要效果是閘道將較快固化。這樣使得方向性停止產生而松弛作用開始增加。

Higher melt and mold temperatures: lower melt viscosity, easier filling, and greater relaxation favor reduced orientation.Reduced packing time and pressure: overpacking inhibits relaxation processes.較高的融化和成型溫度：融化粘性較低，更容易填充，較大松弛作用促成方向性減少。

減少擠壓時間和壓力：過度擠壓會抑制松弛過程。

Reduced gate size: larger gates take longer to freeze off and permit increased orientation.減小閘道尺寸：閘道越大則固化時間越長并會使方向性增加。

Excessively high injection speed can cause high surface orientation and increase susceptibility to stress cracking.For example, moldings that are to be electroplated, and will be subject to acid solutions during plating, must be made using very slow injection speeds to minimize surface orientation.過高的注塑速度會引起較高的表面方向性及增加應力破裂的敏感性。例如，要電鍍的注塑件在電鍍時會經受酸溶液，必須采用很低的注塑速度制造以使表面方向性最小化。

On the other hand, the transverse motion component of the melt front in most moldings can cause transverse subsurface orientation superimposed on the primary orientation, giving a desirable biaxial orientation effect.另一方面，大多數注塑件的融化前部橫向運動部分能導致在主要方向性上有層理的表面下橫向方向性，產生需要的雙軸方向性效應。

Orientation can be seriously increased by obstructions to flow during filling of the cavity.Flow around an obstruction causes a decrease in melt front speed and leads to high local viscosity and reduced relaxation.This is also likely to occur near the end of the filling phase if gating is inadequate.在填充模腔時流動受到阻礙會極大地增加方向性。圍繞障礙物流動使融化前部的速度下降并產生較高的局部粘性而減少松弛作用。如果閘道不適當，這也很可能發生在接近填充結束階段。

The molder must recognize the dangers of excessive fill speed, insufficient injection pressure, excessive melt temperature, and inadequate packing.These dangers are weighed against the opposing effects on orientation discussed above.注塑工必須認識過快填充速度、不足注塑壓力、過高融化溫度和不充分擠壓的危害性。這些危害性要與上述方向性的反向效應相權衡。

Thicker parts delay cooling and increase relaxation time and tend to result in lower orientation.Thicker parts also tend to warp less.Therefore, a minimum wall thickness can be established by experience for various shapes, materials, and process combinations.較厚零件會延遲冷卻并且增加松弛時間，趨向于導致較低的方向性。較厚零件也有助于減少翹曲。因此，對各種形狀、材料和工藝組合能通過經驗來確定最小壁厚。

Lower molecular weight and broader molecular weight distribution in thermoplastics favor lower orientation and reduced internal stress in moldings.在熱塑性塑料中較小的分子量以及較寬泛的分子量分布促成方向性減少同時降低注塑件中的內應力。

The skin thickness ratio is affected by process variables in the same way as one would predict for the orientation;that is, it decreases as the melt or mold temperatures and cavity pressure increases.Tensile strength and stiffness increase as skin thickness ratio increases.Microscopic examination thus provides another way of studying the process efficiently.外殼厚度比受加工變量影響的方式與方向性預測一樣；也就是它能隨融化或成型溫度及模腔壓力的增加而減少。拉伸強度和硬度隨外殼厚度比增加而增加。因而顯微鏡檢查提供了有效研究該工藝的另一方法。Advantages 優點

1.High production rates.For example, a CD disk can be produced with a 10~12s cycle in high melt flow index PC.1.高生產率：例如，一張CD盤在高融體流動指數生產控制中只需10~12s一個循環就能生產出來。

2.Relatively low labor content.One operator can frequently take care of two or more machines, particularly the moldings are unloaded automatically onto conveyors.2.相對較少的工作內容：一個操作者經常可以照看兩臺以上機械，尤其是當成品能自動卸到輸送機上時。

3.Parts require little or no finishing.For example, flash can be minimized and molds can be arranged to automatically separate runners and gates from the part itself.4.Very complex shapes can be formed.Advances in mold tooling are largely responsible.3.零件幾乎不需要修整：例如，飛邊可以最小化并且模具能被設計成自動將澆道和閘道從零件本身分離。

4.非常復雜的形狀也能成型：模具的進步很大程度上是可靠的。

5.Flexibility of design(finishes, colors, inserts, materials).More than one material can be molded through co-injection.Foam core materials with solid skins are efficiently produced.Thermosetting plastics and fiber-reinforced shapes are injection molded.5.設計的靈活性(光潔度、顏色、插入物、材料)：通過復合注塑可以成型多于一種材料。可以高效地生產帶有固體外殼的泡沫型芯材料。熱硬化性塑料和纖維加強形狀都可以注塑成型。

6.Minimum scrap loss.Runners, gates, and scrap can usually be reground.Recycled thermoplastics can be injection molded.6.廢料損失最小化：澆道、閘道和廢料通常可以重新研磨。循環熱塑性塑料可以注塑成型。7.Close tolerances are obtainable.Modern microprocessor controls, fitted to precision molds, and elaborate hydraulics, facilitate tolerances in the 0.1% range on dimensions and weights(but not without a high level of operational skills in constant attendance).7.能得到接近的公差：現代微處理器控制、合適的精密模具和精心制作的液壓設備使得尺寸和重量的公差保持在0.1% 的范圍內(但不是沒有在持續照看時的高水平操作技能)。

8.Makes best use of the unique attributes of polymers, such as flow ability, light weight, transparency, and corrosion resistance.This is evident from the number and variety of molded plastic products in everyday use.8.充分利用聚合物諸如流動能力、重量輕、透明和耐腐蝕等獨特屬性：從日常使用成型塑料產品的數量和種類就能明顯看到。

Disadvantages and Problems 缺點和問題

1.High investment in equipment and tools requires high production volumes.2.Lack of expertise and good preventive maintenance can cause high startup and running costs.1.較高的設備和模具投資需要較高生產量才合算。

2.缺少專門技術和良好的預防性維修會導致較高的啟動和運行成本。

3.Quality is sometimes difficult to determine immediately.For example, post-mold warpage may render parts unusable because of dimensional changes that are not completed for weeks or months after molding.3.質量有時難以馬上確定。例如，成型后的翹曲會導致零件不能用，因為在成型后幾星期甚至幾個月尺寸變化都不能完成。

4.Attention is required on many details requiring a wide variety of skills and cross-disciplinary knowledge.5.Part design sometimes is not well suited to efficient molding.4.對許多需要廣泛多樣性技能和交叉學科知識的細節必須加以注意。5.零件設計有時不能很好地適應有效率的成型。6.Lead time for mold design, mold manufacture and debugging trials is sometimes very long.6.模具設計、模具制造和調試試驗這些先導工作有時要花費很長時間。

The importance of machining processes can be emphasised by the fact that every product we use

in our daily life has undergone this process either directly or indirectly.(1)In USA, more than $100 billions are spent annually on machining and related operations.機加工過程的重要性可通過日常生活使用的每件產品都直接或間接經歷這一過程的事實來強調。(1)在美國，每年花在機加工及其相關作業上的費用都多于千億美元。

(2)A large majority(above 80%)of all the machine tools used in the manufacturing industry have undergone metal cutting.(3)An estimate showed that about 10 to 15% of all the metal produced in USA was converted into chips.(2)用于制造業的全部機床中的大多數(多于80%)都經歷過金屬切削。(3)有估計顯示美國生產的所有金屬中約10到15%轉變成了切屑。

These facts show the importance of metal cutting in general manufacturing.It is therefore important to understand the metal cutting process in order to make the best use of it.這些事實說明了金屬切削在常規制造中的重要性。因此了解金屬切削過程以充分利用它是重要的。A number of attempts have been made in understanding the metal cutting process and using this knowledge to help improve manufacturing operations which involved metal cutting.在了解金屬切削過程并運用這些知識幫助改善與金屬切削有關的制造作業方面已經做了許多努力。

A typical cutting tool in simplified form is shown in Fig.7.1.The important features to be observed are follows.典型切削刀具的簡化形式如圖7.1所示。要注意的重要特征如下。

1.Rake angle.It is the angle between the face of the tool called the rake face and the normal to the machining direction.Higher the rake angle, better is the cutting and less are the cutting forces, increasing the rake angle reduces the metal backup available at the tool rake face.1.前角：它是被稱為前傾面的刀具面與垂直機加工方向的夾角。前角越大，則切削越好且切削力越小，增加前角可以減少刀具前傾面上產生的金屬阻塞。

This reduces the strength of the tool tip as well as the heat dissipation through the tool.Thus, there is a maximum limit to the rake angle and this is generally of the order of 15°for high speed steel tools cutting mild steel.It is possible to have rake angles at zero or negative.但這會和減少通過刀具散發的熱量一樣減少刀尖強度。因此前角有一最大限制，用高速鋼刀具切削低碳鋼通常為15°。前角取零度或負值也是可能的。

2.Clearance angle.This is the angle between the machined surface and the underside of the tool called the flank face.The clearance angle is provided such that the tool will not rub the machined surface thus spoiling the surface and increasing the cutting forces.A very large clearance angle reduces the strength of the tool tip, and hence normally an angle of the order of 5~6°is used.2.后角：這是機加工面與被稱為后側面的刀具底面夾角。后角使刀具不產生會損壞機加工面的摩擦和增加切削力。很大的后角會削弱刀尖的強度，因此一般采用5~6°的后角。

The conditions which have an important influence on metal cutting are work material, cutting tool material, cutting tool geometry, cutting speed, feed rate, depth of cut and cutting fluid used.對金屬切削有重要影響的條件有工件材料、刀具材料、刀具幾何形狀、切削速度、進給率、切削深度和所用的切削液。The cutting speed, v, is the speed with which the cutting tool moves through the work material.This is generally expressed in metres per second(ms-1).切削速度v指切削刀具經過工件材料的移動速度。通常用米每秒(ms-1)表示。

Feed rate, f, may be defined as the small relative movement per cycle(per revolution or per stroke)of the cutting tool in a direction usually normal to the cutting speed direction.Depth of cut, d, is the normal distance between the unmachined surface and the machined surface.進給率f可定義為每循環(每轉或每行程)切削刀具在通常為垂直于切削速度方向的次要相對運動。

切削深度d是未加工面與已加工面之間的垂直距離。

Chip Formation 切屑的形成

Metal cutting process is a very complex process.Fig.7.2 shows the basic material removal operation schematically.金屬切削過程是一個很復雜的過程。圖7.2用圖的形式顯示了基本材料去除作業。

The metal in front of the tool rake face gets immediately compressed, first elastically and then plastically.This zone is traditionally called shear zone in view of fact that the material in the final form would be removed by shear from the parent metal.在刀具前傾面前的金屬直接受到壓縮，首先彈性變形然后塑性變形。考慮到最終形狀中的材料是通過剪切從母體金屬去除的，此區域傳統上稱為剪切區。

The actual separation of the metal starts as a yielding or fracture, depending upon the cutting conditions, starting from the cutting tool tip.Then the deformed metal(called chip)flows over the tool(rake)face.金屬的實際分離始于屈服或斷裂(視切削條件而定)，從切削刀尖開始。然后變形金屬(稱為切屑)流過刀具(前傾)面。

If the friction between the tool rake face and the underside of the chip(deformed material)is considerable, then the chip gets further deformed, which is termed as secondary deformation.The chip after sliding over the tool rake face is lifted away from the tool, and the resultant curvature of the chip is termed as chip curl.如果刀具前傾面與切屑(變形金屬)底面之間的摩擦相當大，那么切屑進一步變形，這也叫做二次變形。滑過刀具前傾面的切屑被提升離開刀具，切屑彎曲的結果被稱為切屑卷。

Plastic deformation can be caused by yielding, in which case strained layers of material would get displaced over other layers along the slip-planes which coincide with the direction of maximum shear stress.屈服能導致塑性變形，在這種情況下材料變形層沿著與最大剪應力方向一致的滑移面被其它層所取代。A chip is variable both in size and shape in actual manufacturing practice.Study of chips is one of the most important things in metal cutting.As would be seen later, the mechanics of metal cutting are greatly dependent on the shape and size of the chips produced.在實際加工過程中切屑的尺寸和形狀都是變化的。對切屑的研究是金屬切削最重要的事情之一。如同后面將要看到的那樣，金屬切削力學極大地依賴于所產生切屑的形狀和尺寸。

Chip formation in metal cutting could be broadly categorised into three types:(Fig.7.3)(1)Discontinuous chip(2)Continuous chip(3)Continuous chip with BUE(Built up edge)金屬切削中的切屑形成可以寬泛地分成三個類型(圖7.3)：(1)間斷切屑(2)連續切屑

(3)帶切屑瘤的連續切屑 Discontinuous Chip.The segmented chip separates into short pieces, which may or may not adhere to each other.Severe distortion of the metal occurs adjacent to the face, resulting in a crack that runs ahead of the tool.間斷切屑：分段的切屑分散成小碎片，既可能相互附著也可能不相互附著。在靠近切削面處發生金屬的劇烈變形，導致在運動刀具前方金屬層產生裂縫。

Eventually, the shear stress across the chip becomes equal to the shear strength of the material, resulting in fracture and separation.With this type of chip, there is little relative movement of the chip along the tool face, Fig.7.3a.最后，橫過切屑的剪切應力與材料的剪切強度相等，造成斷裂和分離。生成這類切屑時，切屑沿刀具面幾乎沒有相對運動，見圖7.3a。

Continuous chip.The continuous chip is characterized by a general flow of the separated metal along the tool face.There may be some cracking of the chip, but in this case it usually does not extend far enough to cause fracture.連續切屑：連續的切屑一般具有分離金屬沿刀具面流動的特征。切屑可能有一些破裂，但在這種情況下切屑通常不會延長到足以引起斷裂。

This chip is formed at the higher cutting speeds when machining ductile materials.There is little tendency for the material to adhere to the tool.The continuous chip usually shows a good cutting ratio and tends to produce the optimum surface finish, but it may become an operating hazard, Fig.7.3b.這種切屑形成于用較高切削速度機加工有延展性的材料時。材料幾乎沒有粘附刀具的傾向。連續切屑通常具有良好的切削率和趨向于產生最適宜的表面光潔度，但可能成為操作的危險之源，見圖7.3b。

Continuous with a built-up edge.This chip shows the existence of a localized, highly deformed zone of material attached or “welded” on the tool face.帶切屑瘤的連續切屑：這種切屑顯示了粘合或“焊接”在刀具面上材料局部高度變形區的存在。Actually, analysis of photomicrographs shows that this built-up edge is held in place by the static friction force until it becomes so large that the external forces acting on it cause it to dislodge, with some of it remaining on the machined surface and the rest passing off on the back side of the chip, Fig.7.3c.實際上，對顯微照片的分析顯示這種切屑瘤受到靜摩擦力抑制直至它變得大到作用在它上面的外力使其移動，一些留在機加工表面上而另一些延伸到切屑的背面，見圖7.3c。Shear Zone 剪切區

There are basically two schools of thought in the analysis of the metal removal process.One school of thought is that the deformation zone is very thin and planar as shown in Fig.7.4a.The other school thinks that the actual deformation zone is a thick one with a fan shape as shown in Fig.7.4b.在對金屬去除過程的分析中主要存在兩種思想學派。一種思想學派認為變形區如圖7.4a所示那樣非常薄而平坦。另一學派則認為真實變形區象圖7.4b所示那樣為一厚的帶有扇形的區域。

Though the first model(Fig.7.4a)is convenient from the point of analysis, physically it is impossible to exist.This is because for the transition from undeformed material to deform to take place along a thin plane, the acceleration across the plane has to be infinity.雖然第一種模型(圖7.4a)從分析的角度看是方便的，但實際上是不可能存在的。這是由于未變形的材料沿著剪切面發生變形，而且越過剪切面的加速度無窮大。

Similarly the stress gradient across the shear plane has to be very large to be practical.同樣在實際運用中越過剪切面的應力梯度必須很大才行。

In the second model(Fig.7.4b)by making the shear zone over a region, the transitions in velocities and shear stresses could be realistically accounted for.在第二種模型(圖7.4b)中讓剪力區分布于一個范圍，速度和剪應力的轉變能說明得更符合實際。The angle made by the shear plane with the cutting speed vector, Φ is a very important parameter in metal cutting.Higher the shear angle better is the cutting performance.From a view of the Fig.7.4a, it can be observed that a higher rake angles give rise to higher shear angles.由剪切面和切削速度矢量形成的角度Φ在金屬切削中是一個十分重要的參數。剪切角越大，切削作業越好。從圖7.4a觀察，可以看到較大的前角能增大剪切角。Cutting Tool Materials 切削刀具材料

Various cutting tool materials have been used in the industry for different applications.A number of developments have occurred in the current century.在工業中為了不同的應用可以使用各種各樣的切削刀具材料。在最近的百年里產生了許多進展。

A large variety of cutting tool materials has been developed to cater to the variety of materials

used in these programmes.Before we discuss the properties of these materials, let us look at the important characteristics expected of a cutting tool material.多種切削刀具材料被開發出來以滿足這些方案中使用材料的多樣性。討論這些材料性能之前，先看一下作為切削刀具材料應具備哪些重要特性。

1.Higher hardness than that of the workpiece material being machined, so that it can penetrate into the work material.2.Hot hardness, which is the ability of the material to retain its hardness at elevated temperatures in view of the high temperatures existing in the cutting zone.1.硬度要比被切削工件材料高，這樣它才能進入工件材料。

2.熱硬度，即材料由于存在于切削區的高溫而升溫時仍能保持其硬度的能力。

3.Wear resistance—The chip-tool and chip-work interfaces are exposed to such severe conditions that adhesive and abrasion wear is very common.The cutting tool material should therefore have high abrasion resistance to improve the effective life of the tool.3.耐磨性—切屑-刀具與切屑-工件的接觸界面處于如此嚴酷的狀態，粘附和磨損是很普遍的。因此切削刀具材料應具有高耐磨性以提高刀具的有效壽命。

4.Toughness—Even though the tool is hard, it should have enough toughness to withstand the impact loads that come in the beginning of cut or force fluctuations due to imperfections in the work material.This requirement is going to be more useful for the interrupted cutting, e.g.milling.4.韌性—雖然刀具是堅硬的，但也應有足夠的韌性以經受住沖擊載荷，這些載荷來自于切削的開始或由于工件材料的缺陷而產生的作用力波動。這個要求對如銑削之類的間斷切削更有用。

5.Low friction—The coefficient of friction between the chip and tool should be low.This would allow for lower wear rates and better chip flow.5.低摩擦系數—切屑與刀具間的摩擦系數應當較低。這會使磨損率較小及切屑流動更好。

6.Thermal characteristics—Since a lot of heat is generated at the cutting zone, the tool material should have higher thermal conductivity to dissipate this heat in the shortest time, otherwise the tool temperature would become high, reducing its life.6.熱特性—因為大量的熱產生在切削區，刀具材料應當具有較高的熱傳導性以在最短的時間內散發熱量，否則刀具溫度會升高，壽命會減少。

All these characteristics may not be found in a single tool material.Improved tool materials have been giving a better cutting performance.所有這些特性不可能存在于單一刀具材料中。改進的刀具材料已經被賦予較好的切削性能。

Surface Finish 表面光潔度

Machining operations are utilized in view of the better surface finish that could be achieved by it compared to other manufacturing operations.由于機加工能獲得比其它制造作業更好的表面光潔度，所以機加工作業具有實用價值。

Thus it is important to know what would be the effective surface finish that can be achieved in a machining operation.The surface finish in a given machining operation is a result of two factors: 因而了解能在機加工作業中獲得怎樣的實際表面光潔度是重要的。給定機加工作業中的表面光潔度是兩個因素共同作用的結果：

(1)the ideal surface finish, which is a result of the geometry of the manufacturing process which can be determined by considering the geometry of the machining operation, and(2)the natural component, which is a result of a number of uncontrollable factors in machining, which is difficult to predict.理想的表面光潔度，是通過考慮機加工作業的幾何體系所決定的制造工藝幾何學的結果，和 自然要素，即在機加工中一些難以預測的不可控因素作用的結果。

Ideal Surface Finish in Turning The actual turning tool used would have a nose radius in place of the sharp tool point, which

modifies the surface geometry as shown in Fig.7.5a.If the feed rate is very small, as is normal in finish turning, the surface is produced purely by the nose radius alone as shown in Fig.7.5.車削中的理想表面光潔度

實際使用的車削刀具有一個刀尖半徑取代鋒利刀尖，它將表面幾何形狀加工為如圖7.5a所示。如果進給率很小，象精車中很正常的那樣，工件表面則完全是由刀尖半徑單獨產生的，如圖7.5所示。For the case in Fig.7.5, the surface roughness value is to be Ra=8f2/(18R√3)

Where: Ra is the surface roughness value R is the nose radius f is the feed rate 對圖7.5這種情況，表面粗糙度值為

Ra=8f2/(18R√3)式中：Ra是表面粗糙度值 R是刀尖半徑 f是進給率

The above are essentially geometric factors and the values represent an ideal situation.The actual surface finish obtained depends to a great extent upon a number of factors such as: 上述基本為幾何要素，其值代表了理想情況。而實際獲得的表面光潔度很大程度上還取決于下列一些因素：

(1)the cutting process parameter, speed, feed and depth of cut(2)the geometry of the cutting tool(3)application of cutting fluid(4)work and tool material characteristics(5)rigidity of the machine tool and the consequent vibrations.(1)切削工藝參數、速度、進給和切削深度(2)切削刀具的幾何形狀(3)切削液的運用

(4)工件和刀具的材料特性

(5)機床的剛度及其伴隨發生的振動

The major influence on surface finish is exerted by the feed rate and cutting speed.As the feed decreases, from the above equations, we can see that the roughness index decreases.對表面光潔度產生主要影響的是進給率和切削速度。從上述公式可以看到，隨著進給的減少，粗糙度指標會降低。

Similarly as the cutting speed increases, we have better surface finish.Thus while making a choice of cutting process parameters for finish, it is desirable to have high cutting speed and small feed rates.同樣隨著切削速度的增大，能得到較好表面光潔度。因此在為光潔度而選擇切削工藝參數時，采用較高的切削速度和較小的進給率是適當的。Cutting Fluids 切削液

The functions of cutting fluids(which are often erroneously called coolants)are: To cool the tool and workpiece To reduce the friction 切削液(經常誤稱為冷卻液)的功能如下： 冷卻刀具和工件 減少摩擦

To protect the work against rusting To improve the surface finish

To prevent the formation of built-up edge To wash away the chips from the cutting zone 保護工件不生銹 改善表面光潔度 防止切屑瘤的形成 從切削區沖掉切屑

However, the prime function of a cutting fluid in a metal cutting operation is to control the total heat.This can be done by dissipating the heat generated as well as reducing it.The mechanisms by which a cutting fluid performs these functions are: cooling action and lubricating action.然而，在金屬切削作業中切削液的主要功能是控制總熱量。這可通過既散發又減少所產生的熱量來達到。切削液實現這些功能的機理是：冷卻作用和潤滑作用。

Cooling action.Originally it was assumed that cutting fluid improves the cutting performance by its cooling properties alone.That is why the name coolant was given to it.冷卻作用：最初設想切削液僅僅是通過冷卻特性來改善切削作業。這也是它曾被稱為冷卻液的原因。Since most of the tool wear mechanisms are thermally activated, cooling the chip tool interface helps in retaining the original properties of the tool and hence prolongs its life.由于大多數刀具的磨損機理都是由熱引起的，冷卻切屑刀具接觸界面有助于保持刀具的原有特性，從而延長其使用壽命。

However, a reduction in the temperature of the workpiece may under certain conditions increase the shear flow stress of the workpiece, thereby decreasing tool life.It has been shown through a number of investigations that cooling in fact is one of the major factors in improving the cutting performance.可是工件溫度的降低在特定條件下會增加工件的剪切流動應力，從而降低刀具壽命。通過一些研究已經表明實際上冷卻只是改善切削作業的主要因素之一。

Lubricating action.The best improvement in cutting performance can be achieved by the lubricating action since this reduces the heat generated, thus reducing the energy input to the metal cutting operation.潤滑作用：切削作業的最大改善可通過潤滑作用來達到，由于它減少了熱量的產生因而減少了金屬切削作業的能量輸入。

However, if the cutting fluid is to be effective, it must reach the chip tool interface.But it is not easy to visualize how it is accomplished in the case of a continuous turning with a single point turning tool, specially when the chip-tool contact pressure is as high as 70 MPa.可是，如果要使切削液起作用就必須讓它到達切屑刀具接觸界面。但如何在采用單尖刀具連續車削的場合尤其是切屑-刀具接觸壓力高達70MPa時實現并非易事。

Merchant thought that minute asperities existed at the chip-tool interface and the fluid was drawn into the interface by the capillary action of the interlocking network of these surface asperities.Merchant認為：在切屑與刀具接觸界面上存在微小的粗粒，切削液通過這些表面的微小粗粒組成連鎖的網絡的毛細管被吸入到切屑與刀具的接觸界面上。

Grinding is a manufacturing process that involves the removal of metal by employing a rotating abrasive wheel.The latter simulates a milling cutter with an extremely large number of miniature cutting edges.磨削是通過采用旋轉磨輪去除金屬的制造工藝。磨輪用非常大量的微型切削刃模仿銑刀進行切削。Generally, grinding is considered to be a finishing process that is usually used for obtaining high-dimensional accuracy and better surface finish.Grinding can be performed on flat, cylindrical, or even internal surfaces by employing specialized machine tools, which are referred to as grinding machines.一般而言，磨削被認為是一種通常用于獲得高尺寸精度和較好表面光潔度的精加工作業。磨削通過采用被稱為磨床的特殊機床能在平面、圓柱面甚至內表面上進行。

Obviously, grinding machines differ in construction as well as capabilities, and the type to be employed is determined mainly by the geometrical shape and nature of the surface to be ground, e.g., cylindrical surfaces are ground on cylindrical grinding machines.顯然，磨床根據結構和功能的不同有所區別，使用何種形式的磨床主要取決于被磨削表面的幾何形狀和物理性質。例如，圓柱面在外圓磨床上磨削。Type of Grinding Operations 磨削作業的類型

1.Surface grinding.As the name surface grinding suggests, this operation involves grinding of flat or plane surfaces.Fig.8.1 indicates the two possible variations, either a horizontal or vertical machine spindle.1.表面磨削：就像其名稱暗示的那樣，表面磨削和平面磨削直接有關。圖8.1表示了兩種可能的變化：臥式磨床主軸或立式磨床主軸。

In the first case(horizontal spindle), the machine usually has a planer-type reciprocating table on which the workpiece is held.However, grinding machines with vertical spindles can have either a planer type table like that of the horizontal-spindle machine or a rotating worktable.在第一種情況(臥式主軸)，臥式磨床通常具有安裝工件的刨床式往復工作臺。而立式主軸磨床既可以像臥式主軸磨床那樣具有刨床式工作臺也可以具有旋轉工作臺。

Also, the grinding action in this case is achieved by the end face of the grinding wheel(Fig.8.1b), contrary to the case of horizontal-spindle machines, where the workpieces ground by the periphery of the grinding wheel.而且在這種情況下，磨削動作是通過砂輪端面完成的(圖8.1b)，這與通過砂輪周邊磨削工件的臥式主軸磨床正好相反。

Fig.8.1a and b also indicate the equations to be used for estimating the different parameters of the grinding operation, such as the machining time and the rate of metal removal.圖8.1a和b同時簡述了用于估計諸如加工時間和金屬去除率之類的磨削作業不同參數的方程式。

During the surface-grinding operations, heavy workpieces are either held in fixtures or clamped on the machine table by strap clamps and the like, whereas smaller workpieces are usually held by magnetic chucks.在平面磨削時，重的工件用夾具固定或用壓板等夾緊在磨床工作臺上，而小的工件則通常是用電磁卡盤固定的。2.Cylindrical grinding.In cylindrical grinding, the workpiece is held between centers during the grinding operation, and the wheel rotation is the source and cause for the rotary cutting motion, as shown in Fig.8.2.In fact, cylindrical grinding can be carried out by employing any of the following methods: 2.圓柱面磨削：在圓柱面磨削中，作業時工件支撐在兩頂尖之間，砂輪轉動是導致回轉切削運動的動力源，如圖8.2所示。實際上，圓柱面磨削能通過采用下列任意方法來實現：

(1)The transverse method, in which both the grinding wheel and the workpiece rotate and longitudinal linear feed is applied to enable grinding of the whole length.The depth of cut is adjusted by the cross feed of the grinding wheel into the workpiece.(1)橫向方法：這種方法中砂輪與工件均旋轉且采用線性縱向進給以保證能磨削整個長度。切削深度通過改變砂輪對工件的橫向進給來進行調整。

(2)The plunge-cut method, in which grinding is achieved through the cross feed of the grinding wheel and no axial feed is applied.As you can see, this method can be applied only when the surface to be ground is shorter than the width of the grinding wheel used.(2)插入-切削方法：這種方法通過砂輪的橫向進給完成磨削而不采用軸向進給。正如料想的那樣，這種方法只在要磨削表面比所用砂輪寬度短時才使用。

(3)The full-depth method, which is similar to the transverse method except that the grinding allowance is removed in a single pass.This method is usually recommended when grinding short rigid shafts.41(3)全深度方法：這種方法除了一次加工就能去除磨削余量外其它與橫向方法相同。這種方法通常在磨削較短剛性軸時推薦使用。

Internal grinding.Internal grinding is employed for grinding relatively short holes, as shown in Fig.8.3.The workpiece is held in a chuck or a special fixture.Both the grinding wheel and the workpiece rotate during the operation and feed is applied in the longitudinal direction.內表面磨削：內表面磨削用于相對較短的孔，如圖8.3所示。工件安裝在卡盤或特殊夾具上。作業時砂輪和工件都回轉并且采用縱向進給。

Any desired depth of cut can be obtained by the cross feed of the grinding wheel.A variation from this type is planetary internal grinding, which is recommended for heavy workpieces that cannot be held in chucks.通過砂輪的橫向進給能得到任意所需的切削深度。這種方法的一個變體是行星式內表面磨削，當工件較重不能用卡盤固定時推薦使用。

In that case, the grinding wheel not only spins around its own axis but also rotates around the centerline of the hole that is being ground.在這種情況下，砂輪不但繞自身軸線回轉，同時還繞被磨削孔的中心線旋轉。

Centerless grinding.Centerless grinding involves passing a cylindrical workpiece, which is supported by a rest blade, between two wheels, i.e., the grinding wheel and the regulating or feed wheel.無心磨削：無心磨削用于加工圓柱形工件，工件由托板支撐，在兩輪即砂輪和調節或進給輪之間通過去。The grinding wheel does the actual grinding, while the regulating wheel is responsible for rotating the workpiece as well as generating the longitudinal feed.This is possible because of the frictional characteristics of that wheel, which is usually made of rubber-bonded abrasive.砂輪完成實際磨削，而調節輪負責旋轉工件和產生縱向進給。由于調節輪通常用橡膠粘結的磨料制成，其摩擦特性使這成為可能。

As can be seen in Fig.8.4, the axis of the regulating wheel is tilted at a slight angle with the axis of the grinding wheel.Consequently, the peripheral velocity of the regulating wheel can be resolved into two components, namely, workpiece rotational speed and longitudinal feed.正如在圖8.4中所看到的那樣，調節輪的軸與砂輪軸傾斜一個微小角度。因此調節輪的圓周速度可以分解為兩個分量，即工件回轉速度和縱向進給。

These can be given by the following equations: Vworkpiece＝Vregulating wheel×cosα

Axial feed＝Vregulating wheel×c×sinα

Where c is a constant coefficient to account for the slip between the workpiece and the regulating wheel(c=0.94~0.98).其值可由下列公式給出：

V工件＝V調節輪×cosα

軸向進給＝V調節輪×c×sinα

式中c是考慮工件和調節輪之間滑動的恒定系數(c=0.94~0.98)。

The velocity of the regulating wheel is controllable and is used to achieve any desired rotational speed of the workpiece.The angleαis usually taken from 1°to 5°and the larger the angle, the larger the longitudinal feed would be.調節輪的速度是可控的并被用于實現工件任意所需的轉動速度。α角通常取1到 5°，這角度越大則縱向進給也將越大。

Whenαis taken as 0°, i.e., the two axes of the grinding and regulating wheels are parallel, there is no longitudinal feed of the workpiece.當α取0°時，即砂輪和調節輪軸線平行時，則工件沒有縱向進給。Grinding Wheels 砂輪

Grinding wheels are composed of abrasive grains having similar size and a binder.The actual grinding process is performed by the abrasive grains.Pores between the grains within the binder enable the grains to act as separate single-point cutting tools.砂輪由具有相近尺寸的磨料顆粒和粘合劑組成。實際磨削作業由磨粒完成。在粘合劑中磨粒之間的孔隙使磨粒能象獨立的單刃切削刀具一樣工作。

These pores also provide space for the generated chips, thus preventing the wheel from clogging.In addition, pores assist the easy flow of coolants to enable efficient and prompt removal of the heat generated during the grinding process.這些孔隙同時還為產生的切屑提供空間以防砂輪堵塞。另外孔隙幫助冷卻液容易流動，從而使在磨削作業中產生的熱量能有效而迅速地散發。

Grinding wheels are identified based on their shape and size, kind of abrasive, grain size, binder, grade(hardness), and structure.砂輪根據它們的形狀和尺寸、磨料的類型、磨粒的大小、粘合劑、等級(硬度)和結構組織來分類。Shape and size of grinding wheels.Grinding wheels differ in shape and size, depending upon the purpose for which they are to be used.Various shapes are shown in Fig.8.5 and include the following types: 砂輪的形狀和尺寸：根據砂輪的用途，它們的形狀和尺寸是不同的。各種形狀如圖8.5所示，其中包括： 1)Straight wheels used for surface, cylindrical, internal, and centerless grinding.2)Bevelled-face or tapered wheels used for grinding threads, gear teeth, and the like.3)Straight recessed wheels for cylindrical grinding and facing.1)用于表面、圓柱面、內部和無心磨削的直輪。2)用于磨削螺紋、齒輪輪齒之類的斜面或錐形輪。

3)用于圓柱面和端面磨削的直凹輪。

4)Abrasive disks for cutoff and slotting operations.(thickness 0.02 up to 0.2in.(0.5 to 5mm)).5)Cylinders, straight cups, and flaring cups are used for surface grinding with the end face of the wheel.4)用于切斷和開槽作業的砂輪片(其厚度從0.02到0.2英寸(0.5到5毫米))。

5)用其端面進行表面磨削的圓柱、直杯及外展杯狀砂輪。

The main dimensions of a grinding wheel are the outside diameter D, the bore diameter d, and the height H.These dimensions vary widely, depending upon the grinding process for which the wheel is to be used.砂輪的主要尺寸有外徑D、孔徑d和厚度H。根據采用砂輪的磨削工藝，這些尺寸變化很大。

Kind of abrasive.Grinding wheels can be made of natural abrasives such as quartz, emery, and corundum or of industrially prepared chemical compounds such as aluminum oxide or silicon carbide(known as carborundum).磨料的類型：砂輪可以由象石英、金剛砂、剛玉之類的自然磨料制成，或者由象氧化鋁或碳化硅(也稱人造金剛砂)之類的工業制備的化學化合物制成。Generally, silicon carbide grinding wheels are used when grinding low-tensile-strength materials like cast iron, whereas aluminum oxide wheels are employed for grinding high-strength metals such as alloy steel, hardened steel, and the like.當磨削象鑄鐵類低拉伸強度材料時，一般采用碳化硅砂輪，而磨削合金鋼、淬火鋼等高強度金屬則要用氧化鋁砂輪。

Grain size of abrasive used.As you may expect, the grain size of the abrasive particles of the wheel plays a fundamental role in determining the quality of ground surface obtained.所用磨粒的尺寸：正如料想的那樣，砂輪磨粒的尺寸對決定所得磨削表面的質量起著根本的作用。The finer the grains, the smoother the ground surface is.Therefore, coarse-grained grinding wheels are used for roughing operations, whereas fine-grained wheels are employed in final finishing

operations.磨粒越細，磨削表面越光滑。所以，粗粒砂輪用于粗加工，而細粒砂輪則用于最后精加工。

The grade of the bond.The grade of the bond is actually an indication of the resistance of the bond to pulling off the abrasive grains from the grinding wheel.Generally, wheels having hard grades are used for grinding soft materials and vice versa.粘結體的等級：粘結體的等級實際上是其抵抗將磨粒從砂輪上拉脫的指標。一般而言，具有較硬等級的砂輪用于磨削較軟材料，反之亦然。

If a hard-grade wheel were to be used for grinding a hard material, the dull grains would not be pulled off from the bond quickly enough, thus impeding the self-dressing process of the surface of the wheel and finally resulting in clogging of the wheel and burns on the ground surface.如果較硬等級的砂輪用于磨削較硬材料，磨鈍的磨粒將不能足夠快地脫離粘結體，這會妨礙砂輪表面的自修復，最終導致砂輪的堵塞并在被磨表面留下灼斑。

In fact, the cutting properties of all grinding wheels must be restored periodically by dressing with a cemented carbide roller or a diamond tool to give the wheel the exact desired shape and remove all worn abrasive grains.實際上，所有砂輪的磨削性能都必須定期地通過使用硬質合金滾輪或金剛石修整器修整而被恢復，以求很準確地把砂輪加工成要求的形狀，并去除已磨鈍的磨粒。

Structure.Structure refers to the amount of void space between the abrasive grains.When grinding softer metals, larger void space are needed to facilitate the flow of the removed chips.結構組織：結構組織與磨粒間的空隙量有關。當磨削較軟金屬時，需要較大的空隙以便去除切屑的流動。The binder.Abrasive particles are bonded together in many different ways.These include bond, silicate, rubber, resinoid, shellac, and oxychloride.Nevertheless, the bond is the most commonly used one.粘合劑：磨粒可用多種不同方法粘結在一起。其中包括粘合劑、硅酸鹽、橡膠、樹脂、蟲膠和氯氧化物。然而，粘合劑是最常用的。

In fact, the standard marking system is employed for distinguishing grinding wheels, by providing all the preceding parameters in a specific sequence.在實際生產中，為了區分砂輪采用標準標注系統，通過用一特定順序將所有上述參數都表示出來。Lapping 研磨

Lapping is a finishing operation used on flat and cylindrical surfaces.The lap, shown in Fig.9.1a, is usually made of cast iron, copper, leather, or cloth.研磨是一種用于平面和圓柱面的精加工作業。研具，如圖9.1a所示，通常用鑄鐵、銅、皮革或布制成。The abrasive particles are embedded in the lap, or they may be carried through slurry.Depending on the hardness of the workpiece, lapping pressures range from 7kPa to 140kPa(1 to 20 psi).研磨微粒嵌入研具內，或者可以通過液體攜帶。根據工件硬度，研磨壓力可在7kPa到140kPa(1到20psi)范圍中取。

Lapping has two main functions.Firstly, it produces a superior surface finish with all machining marks being removed from the surface.Secondly, it is used as a method of obtaining very close fits between mating parts such as pistons and cylinders.研磨有兩個主要作用。首先，它通過去除所有機加工痕跡能產生較好的表面光潔度。其次，它能用作獲得像活塞與氣缸之類配件間過盈配合的方法。

The lapped workpiece surface may look smooth but it is actually filled with microscopic peaks, valleys, scratches and pits.Few surfaces are perfectly flat.Lapping minimizes the surface irregularities, thereby increasing the available contact area.研磨后的工件表面可能看似平滑，其實布滿著微觀峰、谷、劃痕和凹陷。幾乎沒有表面是完全平整的。研磨使表面不規則最小化，因而增加了有效接觸面積。

The drawing in Fig.9.1a shows two surfaces.The upper one is how a surface might look before lapping

and the lower one after lapping.Lapping removes the microscopic mountain tops and produces relatively flat plateaus.Entire microscopic mountain ranges may need to be ground down in order to increase the available contact area.圖9.1a上顯示了兩個表面。上面是研磨前表面可能的外觀模樣而下面則是研磨后的模樣。研磨去除了微觀峰頂從而產生相對平坦的平臺。整個微觀山脈范圍都需要磨去以增加有效接觸面積。

Production lapping on flat or cylindrical pieces is done on machines such as those shown in Fig.9.1b and 9.1c.Lapping is also done on curved surfaces, such as spherical objects and lenses, using specially shaped laps.研磨平面或圓柱面工件的生產過程是在如圖9.1b和9.1c那樣的機器上完成的。研磨也可采用特殊成型研具在諸如球形物體和透鏡之類的曲面上進行。Polishing 拋光

Polishing is a process that produces a smooth, lustrous surface finish.Two basic mechanisms are involved in the polishing process:(a)fine-scale abrasive removal, and(b)softening and smearing of surface layers by frictional heating during polishing.拋光是生成平滑、有光澤表面光潔度的工藝。拋光工藝涉及兩種基本機理：(a)精細等級磨粒去除，和(b)在拋光中通過摩擦生熱軟化并抹光表面層。

Electropolishing Electropolishing is an electrochemical process similar to, but the reverse of, electroplating.The electropolishing process smoothes and streamlines the microscopic surface of a metal object.Mirror-like finishes can be obtained on metal surfaces by electropolishing.電解拋光

電解拋光是一種與電鍍相似的電化學工藝，但過程與電鍍正好相反。電解拋光工藝使金屬物體的微觀表面平滑和簡單化。通過電解拋光能在金屬表面得到鏡面光潔度。In electropolishing, the metal is removed ion by ion from the surface of the metal object being polished.Electrochemistry and the fundamental principles of electrolysis(Faraday’s Law)replace traditional mechanical finishing techniques.在電解拋光中，金屬是逐個離子地從被拋光金屬物體表面去除的。電化學和電解基本原理(Faraday定理)取代了傳統的機械精加工技術。

In basic terms, the object to be electropolished is immersed in an electrolyte and subjected to a direct electrical current.The object is maintained anodic, with the cathodic connection being made to a nearby metal conductor.用基本術語說，要電解拋光的物體被浸沒在電解液中并且通上直流電。該物體為陽極，陰極連接到附近的金屬導體上。

Smoothness of the metal surface is one of the primary and most advantageous effects of electropolishing.During the process, a film of varying thickness covers the surface of the metal.This film is thickest over micro depressions and thinnest over micro projections.金屬表面的平滑是電解拋光主要的和最有優勢的效應之一。在此過程中，一變化著厚度的膜覆蓋在金屬表面上。該膜在微觀凹陷處最厚而在微觀凸出處最薄。

Electrical resistance is at a minimum wherever the film is thinnest, resulting in the greatest rate of metallic dissolution.Electropolishing selectively removes microscopic high points or “peaks” faster than the rate of attack on the corresponding micro-depressions or “valleys”.電阻在膜最薄處最小，導致最大金屬分解率。電解拋光選擇性地去除微觀高點或“峰” 快于對相應微觀凹陷處或“谷”的侵蝕速率。

Stock is removed as metallic salt.Metal removal under certain circumstances is controllable and can be held to 0.0001 to 0.0025 mm.原材料以金屬鹽的形式被去除。在特定環境下金屬的去除是可控的并且保持在0.0001 到0.0025mm范圍內。Chemical Mechanical Polishing

Chemical mechanical polishing is becoming an increasingly important step in the fabrication of multi-level integrated circuits.Chemical mechanical polishing refers to polishing by abundant slurry that interacts both chemically and mechanically with the surface being polished.化學機械拋光

化學機械拋光正在多層集成電路制造領域成為日益重要的步驟。化學機械拋光是指大量拋光液與被拋光表面產生化學和機械作用的拋光。

During the chemical mechanical polishing process, a rotating wafer is pressed face down onto a rotating, resilient polishing pad while polishing slurry containing abrasive particles and chemical reagents flows in between the wafer and the pad.在化學機械拋光過程中，旋轉晶片面向下壓在旋轉、有回彈力的拋光襯墊上，而同時含有研磨微粒和化學反應物的拋光液流過晶片與襯墊之間。

The combined action of polishing pad, abrasive particles and chemical reagents results in material removal and polishing of the wafer surface.Chemical mechanical polishing creates flat, damage-free on a variety of brittle materials and it is used extensively on silicon wafers in the manufacture of integrated circuits.拋光襯墊、研磨微粒和化學反應物的共同作用導致晶片表面的材料去除并拋光。化學機械拋光可使多種易碎材料平整且不受損害，因此在集成電路制造中被廣泛地用在硅晶片上。

Chemical mechanical polishing is a complicated multiphase process.It mainly includes the following two dynamics.First, the active component in polishing slurry reacts with the atoms of the wafer, and the process is chemical reaction step with oxidation-reductive reaction.化學機械拋光是一種復雜的多相工藝。它主要包括下列兩個動態過程：第一，拋光液中活性成分與晶片的原子發生反應，這是帶有氧化-還原反應的化學反應步驟。

The second step is the process of desorption, that is to say, the resultants gradually separate from the wafer surface and new surface is exposed to polishing slurry.If chemical reactive rate is smaller, the total removal rate of the wafer is also small;furthermore, the surface degree of finish is not good.第二步是解吸附過程，即反應產物逐漸從晶片表面分離并將新表面暴露給拋光液。如果化學反應速率較小，晶片的總去除率也較小，而且表面光潔程度不夠好。

On the contrary, even if chemical reaction is very rapid, but desorption is very slow, the total removal rate is not good.Because resultants connot separate from the wafer surface, the active component in the polishing slurry cannot expose and react with the atoms on the new surface, which holds up chemical reaction.與之相反，即使化學反應很快，但解吸附很慢，則總去除率也不夠好。因為反應產物不能從晶片表面分離，拋光液中活性成分就不能暴露并與新表面上的原子起反應，這會抑制化學反應。

The balance and compositive effects of two steps decide the total removal rate and its surface degree of finish.這兩個步驟的平衡與合成效應決定了總去除率和表面光潔程度。The processes of surface engineering, or surface treatments, tailor the surfaces of engineering materials to:(1)control friction and wear,(2)improve corrosion resistance,(3)change physical property, e.g., conductivity, resistivity, and reflection,(4)alter dimension,(5)vary appearance, e.g., color and roughness,(6)reduce cost.進行表面工程或表面處理的目的是：(1)控制摩擦和磨損，(2)改善抗腐蝕性，(3)改變物理性能，例如，傳導率、電阻系數和反射率，(4)修改尺寸，(5)變更外觀，例如顏色和粗糙程度，(6)降低成本。Common surface treatments can be divided into two major categories: treatments that cover the surfaces and treatments that alter the surfaces.通常的表面處理可以分為兩個主要類型：覆蓋表面的處理和改變表面的處理。Covering the Surface

覆蓋表面

The treatments that cover the surfaces include organic coatings and inorganic coatings.覆蓋表面的處理包括有機涂層和無機涂層。

The inorganic coatings perform electroplatings, conversion coatings, thermal sprayings, hot dippings, furnace fusings, or coat thin films, glass, ceramics on the surfaces of the materials.無機涂層有電鍍、轉化層、熱噴涂、熱浸漬、熔爐熔融、或在材料表面涂上薄膜、玻璃、陶瓷。

Electroplating is an electrochemical process by which metal is deposited on a substrate by passing a current through the bath.電鍍是一種在電鍍槽通上電流使金屬沉淀在基體上的電化學過程。

Usually there is an anode(positively charged electrode), which is the source of the material to be deposited;the electrochemistry which is the medium through which metal ions are exchanged and transferred to the substrate to be coated;and a cathode(negatively charged electrode)which is the substrate to be coated.通常有一個陽極(正電極)，是要沉淀材料的來源；電化學反應是使金屬離子交換并遷移到要覆蓋基體上的中間過程；以及一個陰極(負電極)，即要覆蓋的基體。

Plating is done in a plating bath which is usually a non-metallic tank(usually plastic).The tank is filled with electrolyte which has the metal, to be plated, in ionic form.電鍍在通常為非金屬容器(一般是塑料)的電鍍槽中進行。該容器裝滿了含有離子態被鍍金屬的電解液。The anode is connected to the positive terminal of the power supply.The anode is usually the metal to be plated(assuming that the metal will corrode in the electrolyte).For ease of operation, the metal is in the form of nuggets and placed in an inert metal basket made out non-corroding metal(such as titanium or stainless steel).陽極與電源正極相連。陽極通常為被鍍金屬(假定該金屬能在電解液中腐蝕)。為了操作容易，該金屬呈固體小塊形式并置于由抗腐蝕金屬(如鈦或不銹鋼)制成的惰性金屬筐內。

The cathode is the workpiece, the substrate to be plated.This is connected to the negative terminal of the power supply.The power supply is well regulated to minimize ripples as well to deliver a steady predictable current, under varying loads such as those found in plating tanks.陰極是工件，即要鍍的基體，連接到電源的負極。很好地調節電源使波動最小化并在載荷變化情況(如同電鍍容器中看到的那樣)下提供穩定的可預知電流。

As the current is applied, positive metal ions from the solution are attracted to the negatively charged cathode and deposit on the cathode.As a replenishment for these deposited ions, the metal from the anode is dissolved and goes into the solution and balances the ionic potential.一旦通上電流，來自溶液的正的金屬離子被吸引到帶負電的陰極并沉淀在其上。作為這些沉淀離子的補充，來自陽極的金屬被溶解并進入溶液平衡離子勢能。

Thermal spraying process.Thermal spraying metal coatings are depositions of metal which has been melted immediately prior to projection onto the substrate.The metals used and the application systems used vary but most applications result in thin coatings applied to surfaces requiring improvement to their corrosion or abrasion resistance properties.熱噴涂工藝：熱噴涂金屬涂層是金屬熔化后立即投射到基體上形成的金屬沉積層。所用的金屬和應用系統都可以變化，但大多數應用都是在要求改善抗腐蝕或耐磨性能的表面涂上薄層。

Thermal spray is a generic term for a broad class of related processes in which molten droplets of metals, ceramics, glasses, and/or polymers are sprayed onto a surface to produce a coating, to form a free-standing near-net-shape, or to create an engineered material with unique properties.熱噴涂是用于很大一類相關工藝的一個通用術語，噴涂到表面產生涂層的熔化小滴可以是金屬、陶瓷、玻璃和/或聚合物，形成獨立的近似純形或產生具有獨特性能的設計材料。

In principle, any material with a stable molten phase can be thermally sprayed, and a wide range of pure and composite materials are routinely sprayed for both research and industrial applications.47 Deposition rates are very high in comparison to alternative coating technologies.大體上，有穩定熔化狀態的任何材料都可以熱噴涂，范圍寬闊的純凈和合成材料一般都能噴涂用于研究及工業目的。其沉積率與可供選擇的涂層技術比較是很高的。

Deposit thickness of 0.1 to 1mm is common, and thickness greater than 1cm can be achieved with some materials.沉淀厚度普遍為0.1到1mm，對某些材料則沉淀厚度可以達到1cm以上。

The process for application of thermal spray metal is relatively simple and consists of the following stages.(1)Melting the metal at the gun.(2)Spraying the liquid metal onto the prepared substrate by means of compressed air.熱噴涂金屬的應用工藝相對簡單并由下列階段組成：

(1)在噴槍內熔化金屬。

(2)通過壓縮空氣將液態金屬噴涂在準備好的基體上。

(3)Molten particles are projected onto the cleaned substrate.There are two main types of wire application available today namely arc spray and gas spray.(3)熔化微粒投射在清潔過的基體上。

現在有兩種主要的金屬絲應用類型可選用，也就是電弧噴涂和氣體噴涂。

ARC—A pair of wires are electrically energized so that an arc is struck across the tips when brought together through a pistol.Compressed air is blown across the arc to atomise and propel the autofed metal wire particles onto the prepared workpiece.電弧噴涂—當一對金屬絲通過手持噴槍連到一起時，通上電橫過其末端劃燃電弧。壓縮空氣吹過電弧使其霧化并驅使自動送料金屬絲微粒到準備好的工件上。

GAS—In combustion flame spraying the continuously moving wire is passed through a pistol, melted by a conical jet of burning gas.The molten wire tip enters the cone, atomises and is propelled onto the substrate.氣體噴涂—連續移動的金屬絲在燃燒火焰噴射中通過手持噴槍，并被燃燒氣體的錐形噴嘴所熔化。熔化后的金屬絲頂端進入錐體霧化并驅使其到基體上。

Thin-Film Coatings.Physical Vapor Deposition(PVD)and Chemical Vapor Deposition(CVD)are two most common types of thin-film coating methods.薄膜涂層：物理蒸發沉淀(PVD)和化學蒸發沉淀(CVD)是兩種最常見薄膜涂層方法的類型。

PVD coatings involve atom-by-atom, molecule-by-molecule, or ion deposition of various materials on solid substrates in vacuum systems.物理蒸發沉淀涂層涉及到在真空裝置內各種各樣的材料原子緊靠原子、分子緊靠分子或離子沉淀于固態基體上。

Thermal evaporation uses the atomic cloud formed by the evaporation of the coating metal in a vacuum environment to coat all the surfaces in the line of sight between the substrate and the target.It is often used in producing thin, 0.5μm, decorative shiny coatings on plastic parts.熱蒸發利用涂層金屬在真空環境中蒸發形成的微粒子霧將基體和靶材之間可見范圍內所有表面覆蓋。在塑料零件上生成較薄(0.5μm)的、裝飾性的、有光澤的涂層時常常用到它。The thin coating, however, is fragile and not good for wear applications.The thermal evaporation process can also coat a very thick, 1mm, layer of heat-resistant materials, such as MCrAIY—a metal, chromium, aluminum, and yttrium alloys, on jet engine parts.然而，這種薄涂層是易碎的并不適合用于磨損場合。熱蒸發工藝也能在噴氣發動機零件上覆蓋很厚(1mm)的耐熱材料涂層，例如MCrAIY—一種金屬、鉻、鋁和釔合金。

Sputtering applies high-technology coatings such as ceramics, metal alloys, organic and inorganic compounds by connecting the workpiece and the substance to a high-voltage DC power supply in an argon vacuum system.48 反應濺射法通過在氬真空設備中連接工件和具有特定成分的材料到高壓直流電來應用諸如陶瓷、金屬合金、有機和無機化合物之類的高技術涂層。

The plasma is established between the substrate(workpiece)and the target(donor)and transposes the sputtered off target atoms to the surface of the substrate.等離子區形成于基體(工件)和靶材(原料物質)之間并將被濺射的靶材原子轉移到基體的表面上。When the substrate is non-conductive, e.g., polymer, a radio-frequency(RF)sputtering is used instead.Sputtering can produce thin, less than 3μm(120μin), hard thin-film coatings, e.g., titanium nitride(TIN)which is harder than the hardest metal.如果基體不導電，例如聚合物，則采用射頻(RF)濺射代替。反應濺射法可以生成較薄(小于3μm(120μin))的、堅硬薄膜涂層，像比最硬金屬還硬的氮化鈦(TIN)。

Sputtering is now widely applied on cutting tools, forming tools, injection molding tools, and common tools such as punches and dies, to increase wear resistance and service life.現在反應濺射法已被廣泛應用于切削刀具、成型工具、注射模具和諸如沖頭和沖模之類的通用器具，以增強其耐磨性和使用壽命。

CVD is capable of producing thick, dense, ductile, and good adhesive coatings on metals and non-metals such as glass and plastic.Contrasting to the PVD coating in the “line of sight”, the CVD can coat all surfaces of the substrate.化學蒸發沉淀能在金屬和像玻璃和塑料之類的非金屬上生成較厚的、致密的、有延伸性的和帶良好粘性的涂層。與物理蒸發沉淀在“可見范圍”對比，化學蒸發沉淀能將基體的所有表面都覆蓋。

Conventional CVD coating process requires a metal compound that will volatilize at a fairly low temperature and decompose to a metal when it contacts with the substrate at higher temperature.常規的化學蒸發沉淀涂層工藝需要一種容易在相當低溫度下揮發并且在較高溫度下與基體接觸時能分解成純金屬的金屬化合物。

The most well known example of CVD is the nickel carbonyl(NiCO4)coating as thick as 2.5mm(0.1in.)on glass windows and containers to make them explosion or shatter resistant.最為人熟知的化學蒸發沉淀例子是在玻璃窗和容器上鍍厚為2.5mm(0.1in.)的羰基鎳(NiCO4)涂層使它們能抵抗爆裂或破碎。

Diamond CVD coating process is introduced to increase the surface hardness of cutting tools.However, the process is done at the temperatures higher than 700℃(1300℉)which will soften most tool steel.為增加切削刀具表面硬度引入了鉆石化學蒸發沉淀涂層工藝。可是此工藝要在高于700℃(1300℉)的溫度下才能實現，這溫度會軟化大多數工具鋼。Thus, the application of diamond CVD is limited to materials which will not soften at this temperature such as cemented carbides.因而鉆石化學蒸發沉淀的應用受到材料限制，要求材料在此溫度下不軟化例如硬質合金。

Plasma-Assisted CVD coating process can be performed at lower temperature than diamond CVD coatings.This CVD process is used to apply diamond coatings or silicon carbide barrier coatings on plastic films and semiconductors, including the state of the art 0.25μm semiconductors.等離子體輔助化學蒸發沉淀涂層工藝可以在比鉆石化學蒸發沉淀涂層低的溫度下操作。這種化學蒸發沉淀用于在塑料膜和半導體(包括人工0.25μm半導體的情況)上覆蓋鉆石涂層或碳化硅隔離涂層。Altering the Surfaces 改變表面

The treatments that alter the surfaces include hardening treatments, high-energy processes and special treatments.改變表面的處理包括淬火處理、高能加工和特殊處理。

High-energy processes are relatively new surface treatment methods.They can alter the properties of surfaces without changing the dimension of the surface.Common high-energy processes，49 including electron beam treatment, ion implantation, and laser beam treatment, are briefly discussed as follows: 高能加工是相對較新的表面處理方法。它們能在不改變表面尺寸的情況下改變表面性能。通用的高能加工包括電子束處理、離子注入和激光束處理簡要討論如下：

Electron beam treatment.Electron beam treatment alters the surface properties by rapid heating—using electron beam and rapid cooling—in the order of 106℃/see in a very shallow region, 100μm, near the surface.This technique can also be used in hardfacing to produce “surface alloys”.電子束處理：電子束處理在靠近表面很淺(100μm)的區域通過用電子束快速加熱并以106℃/秒等級快速冷卻來改變表面性能。這種技術也被用于表面硬化產生“表面合金”。Ion implantation.Ion implantation uses electron beam or plasma to impinge gas atoms to ions with sufficient energy, and embed these ions into atomic lattice of the substrate, accelerated by magnetic coils in a vacuum chamber.The mismatch between ion implant and the surface of a metal creates atomic defects that harden the surface.離子注入：離子注入采用電子束或等離子體通過真空室內磁性線圈加速以足夠的能量將氣體原子撞擊為離子，并把這些離子嵌入基體的原子點陣中。離子注入和金屬表面之間的錯配產生了硬化表面的原子瑕疵。Laser beam treatment.Similar to electron beam treatment, laser beam treatment alters the surface properties by rapid heating and rapid cooling in a very shallow region near the surface.It can also be used in hardfacing to produce “surface alloys”.激光束處理：與電子束處理類似，激光束處理通過在靠近表面很淺的區域快速加熱和快速冷卻來改變表面性能。它也可以用于表面硬化產生“表面合金”。

The results of high-energy processes are not well known or very well controlled.But the preliminary results look promising.Further development is needed in high-energy processes, especially in implant dosages and treatment methods.高能加工的結果不能充分地了解或很好地控制。但初步結果看來是有前途的。高能加工需要進一步的開發，特別是注入劑量和處理方法。The Lathe and Its Construction 車床及其結構

A lathe is a machine tool used primarily for producing surfaces of revolution and flat edges.車床是主要用于生成旋轉表面和平整邊緣的機床。

Based on their purpose, construction, number of tools that can simultaneously be mounted, and degree of automation, lathes-or, more accurately, lathe-type machine tools can be classified as follows: 根據它們的使用目的、結構、能同時被安裝刀具的數量和自動化的程度，車床—或更確切地說是車床類的機床，可以被分成以下幾類：(1)Engine lathes(2)Toolroom lathes(3)Turret lathes(4)Vertical turning and boring mills(5)Automatic lathes(6)Special-purpose lathes(1)普通車床(2)萬能車床(3)轉塔車床(4)立式車床(5)自動車床(6)特殊車床

In spite of that diversity of lathe-type machine tools, they all have common features with respect to construction and principle of operation.These features can best be illustrated by

第二篇：機械工程英語翻譯

Unit1

1、What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table.Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans.合金與純金屬的區別是什么？純金屬是在元素周期表中占據特定位置的元素。例如電線中的銅和制造烹飪箔及飲料罐的鋁。

Alloys contain more than one metallic element.Their properties can be changed by changing the elements present in the alloy.Examples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium;and gold jewelry which usually contains an alloy of gold and nickel.合金包含不止一種金屬元素。合金的性質能通過改變其中存在的元素而改變。金屬合金的例子有：不銹鋼是一種鐵、鎳、鉻的合金，以及金飾品通常含有金鎳合金。

2、Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio.為什么要使用金屬和合金？許多金屬和合金具有高密度，因此被用在需要較高質量體積比的場合。

Some metal alloys,such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy.Many alloys also have high fracture toughness, which means they can withstand impact and are durable.某些金屬合金，例如鋁基合金，其密度低，可用于航空航天以節約燃料。許多合金還具有高斷裂韌性，這意味著它們能經得起沖擊并且是耐用的。

3、The atomic bonding of metals also affects their properties.In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere.Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires.金屬的原子連結對它們的特性也有影響。在金屬內部，原子的外層階電子由所有原子共享并能到處自由移動。由于電子能導熱和導電，所以用金屬可以制造好的烹飪鍋和電線。

It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal.No photons pass through.因為這些階電子吸收到達金屬的光子，所以透過金屬不可能看得見。沒有光子能通過金屬.4、Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance.陶瓷和玻璃的特性高熔點、低密度、高強度、高剛度、高硬度、高耐磨性和抗腐蝕性是陶瓷和玻璃的一些有用特性。

Many ceramics are good electrical and thermal insulators.Some ceramics have special properties: some ceramics are magnetic materials;some are piezoelectric materials;and a few special ceramics are superconductors at very low temperatures.Ceramics and glasses have one major drawback: they are brittle.許多陶瓷都是電和熱的良絕緣體。某些陶瓷還具有一些特殊性能：有些是磁性材料，有些是壓電材料，還有些特殊陶瓷在極低溫度下是超導體。陶瓷和玻璃都有一個主要的缺點：它們容易破碎。

5、An optical fiber contains three layers: a core made of highly pure glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage.光導纖維有三層：核心由高折射指數高純光傳輸玻璃制成，中間層為低折射指數玻璃，是保護核心玻璃表面不被擦傷和完整性不被破壞的所謂覆層，外層是聚合物護套，用于保護光導纖維不受損。

In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light.為了使核心玻璃有比覆層大的折射指數，在其中摻入微小的、可控數量的能減緩光速而不會吸收光線的雜質或攙雜劑。

Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle.由于核心玻璃的折射指數比覆層大，只要在全內反射過程中光線照射核心/覆層分界面的角度比臨界角大，在核心玻璃中傳送的光線將仍保留在核心玻璃中。The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with little loss of intensity.全內反射現象與核心玻璃的高純度一樣，使光線幾乎無強度損耗傳遞長距離成為可能。Unit7

1、The importance of machining processes can be emphasised by the fact that every product we use in our daily life has undergone this process either directly or indirectly.機加工過程的重要性可通過日常生活使用的每件產品都直接或間接經歷這一過程的事實來強調。(1)In USA, more than $100 billions are spent annually on machining and related operations.(2)A large majority(above 80%)of all the machine tools used in the manufacturing industry have undergone metal cutting.(3)An estimate showed that about 10 to 15% of all the metal produced in USA was converted into chips.(1)在美國，每年花在機加工及其相關作業上的費用都多于千億美元

(2)用于制造業的全部機床中的大多數(多于80%)都經歷過金屬切削。(3)有估計顯示美國生產的所有金屬中約10到15%轉變成了切屑。

2、Chip Formation 切屑的形成

Metal cutting process is a very complex process.Fig.7.2 shows the basic material removal operation schematically.金屬切削過程是一個很復雜的過程。圖7.2用圖的形式顯示了基本材料去除作業。The metal in front of the tool rake face gets immediately compressed, first elastically and then plastically.This zone is traditionally called shear zone in view of fact that the material in the final form would be removed by shear from the parent metal.在刀具前傾面前的金屬直接受到壓縮，首先彈性變形然后塑性變形。考慮到最終形狀中的材料是通過剪切從母體金屬去除的，此區域傳統上稱為剪切區。The actual separation of the metal starts as a yielding or fracture, depending upon the cutting conditions, starting from the cutting tool tip.Then the deformed metal(called chip)flows over the tool(rake)face.金屬的實際分離始于屈服或斷裂(視切削條件而定)，從切削刀尖開始。然后變形金屬(稱為切屑)流過刀具(前傾)面。

If the friction between the tool rake face and the underside of the chip(deformed material)is considerable, then the chip gets further deformed, which is termed as secondary deformation.The chip after sliding over the tool rake face is lifted away from the tool, and the resultant curvature of the chip is termed as chip curl.如果刀具前傾面與切屑(變形金屬)底面之間的摩擦相當大，那么切屑進一步變形，這也叫做二次變形。滑過刀具前傾面的切屑被提升離開刀具，切屑彎曲的結果被稱為切屑卷。

3、Discontinuous Chip.The segmented chip separates into short pieces, which may or may not adhere to each other.Severe distortion of the metal occurs adjacent to the face, resulting in a crack that runs ahead of the tool.間斷切屑：分段的切屑分散成小碎片，既可能相互附著也可能不相互附著。在靠近切削面處發生金屬的劇烈變形，導致在運動刀具前方金屬層產生裂縫。Eventually, the shear stress across the chip becomes equal to the shear strength of the material, resulting in fracture and separation.With this type of chip, there is little relative movement of the chip along the tool face, Fig.7.3a.最后，橫過切屑的剪切應力與材料的剪切強度相等，造成斷裂和分離。生成這類切屑時，切屑沿刀具面幾乎沒有相對運動，見圖7.3a。

4、Cutting Fluids 切削液

The functions of cutting fluids(which are often erroneously called coolants)are: ? To cool the tool and workpiece ? To reduce the friction ? To protect the work against rusting ? To improve the surface finish ? To prevent the formation of built-up edge ? To wash away the chips from the cutting zone 切削液(經常誤稱為冷卻液)的功能如下：

? 冷卻刀具和工件 ? 減少摩擦 ? 保護工件不生銹 ? 改善表面光潔度

? 防止切屑瘤的形成 ? 從切削區沖掉切屑

However, the prime function of a cutting fluid in a metal cutting operation is to control the total heat.This can be done by dissipating the heat generated as well as reducing it.The mechanisms by which a cutting fluid performs these functions are: cooling action and lubricating action.然而，在金屬切削作業中切削液的主要功能是控制總熱量。這可通過既散發又減少所產生的熱量來達到。切削液實現這些功能的機理是：冷卻作用和潤滑作用

5、Lubricating action.The best improvement in cutting performance can be achieved by the lubricating action since this reduces the heat generated, thus reducing the energy input to the metal cutting operation.潤滑作用：切削作業的最大改善可通過潤滑作用來達到，由于它減少了熱量的產生因而減少了金屬切削作業的能量輸入。

However, if the cutting fluid is to be effective, it must reach the chip tool interface.But it is not easy to visualize how it is accomplished in the case of a continuous turning with a single point turning tool, specially when the chip-tool contact pressure is as high as 70 MPa.可是，如果要使切削液起作用就必須讓它到達切屑刀具接觸界面。但如何在采用單尖刀具連續車削的場合尤其是切屑-刀具接觸壓力高達70MPa時實現并非易事。

Merchant thought that minute asperities existed at the chip-tool interface and the fluid was drawn into the interface by the capillary action of the interlocking network of these surface asperities.Merchant認為：在切屑與刀具接觸界面上存在微小的粗粒，切削液通過這些表面的微小粗粒組成連鎖的網絡的毛細管被吸入到切屑與刀具的接觸界面上。

第八單元

1、Grinding is a manufacturing process that involves the removal of metal by employing a rotating abrasive wheel.The latter simulates a milling cutter with an extremely large number of miniature cutting edges.磨削是通過采用旋轉磨輪去除金屬的制造工藝。磨輪用非常大量的微型切削刃模仿銑刀進行切削。

Generally, grinding is considered to be a finishing process that is usually used for obtaining high-dimensional accuracy and better surface finish.Grinding can be performed on flat, cylindrical, or even internal surfaces by employing specialized machine tools, which are referred to as grinding machines.一般而言，磨削被認為是一種通常用于獲得高尺寸精度和較好表面光潔度的精加工作業。磨削通過采用被稱為磨床的特殊機床能在平面、圓柱面甚至內表面上進行。

Obviously, grinding machines differ in construction as well as capabilities, and the type to be employed is determined mainly by the geometrical shape and nature of the surface to be ground, e.g., cylindrical surfaces are ground on cylindrical grinding machines.顯然，磨床根據結構和功能的不同有所區別，使用何種形式的磨床主要取決于被磨削表面的幾何形狀和物理性質。例如，圓柱面在外圓磨床上磨削。

2、Internal grinding.Internal grinding is employed for grinding relatively short holes, as shown in Fig.8.3.The workpiece is held in a chuck or a special fixture.Both the grinding wheel and the workpiece rotate during the operation and feed is applied in the longitudinal direction.內表面磨削：內表面磨削用于相對較短的孔，如圖8.3所示。工件安裝在卡盤或特殊夾具上。作業時砂輪和工件都回轉并且采用縱向進給。

Any desired depth of cut can be obtained by the cross feed of the grinding wheel.A variation from this type is planetary internal grinding, which is recommended for heavy workpieces that cannot be held in chucks.通過砂輪的橫向進給能得到任意所需的切削深度。這種方法的一個變體是行星式內表面磨削，當工件較重不能用卡盤固定時推薦使用。

In that case, the grinding wheel not only spins around its own axis but also rotates around the centerline of the hole that is being ground.在這種情況下，砂輪不但繞自身軸線回轉，同時還繞被磨削孔的中心線旋轉。

3、Grinding Wheels 砂輪

Grinding wheels are composed of abrasive grains having similar size and a binder.The actual grinding process is performed by the abrasive grains.Pores between the grains within the binder enable the grains to act as separate single-point cutting tools.砂輪由具有相近尺寸的磨料顆粒和粘合劑組成。實際磨削作業由磨粒完成。在粘合劑中磨粒之間的孔隙使磨粒能象獨立的單刃切削刀具一樣工作。These pores also provide space for the generated chips, thus preventing the wheel from clogging.In addition, pores assist the easy flow of coolants to enable efficient and prompt removal of the heat generated during the grinding process.這些孔隙同時還為產生的切屑提供空間以防砂輪堵塞。另外孔隙幫助冷卻液容易流動，從而使在磨削作業中產生的熱量能有效而迅速地散發。

Grinding wheels are identified based on their shape and size, kind of abrasive, grain size, binder, grade(hardness), and structure.砂輪根據它們的形狀和尺寸、磨料的類型、磨粒的大小、粘合劑、等級(硬度)和結構組織來分類

4、The grade of the bond.The grade of the bond is actually an indication of the resistance of the bond to pulling off the abrasive grains from the grinding wheel.Generally, wheels having hard grades are used for grinding soft materials and vice versa.粘結體的等級：粘結體的等級實際上是其抵抗將磨粒從砂輪上拉脫的指標。一般而言，具有較硬等級的砂輪用于磨削較軟材料，反之亦然。

If a hard-grade wheel were to be used for grinding a hard material, the dull grains would not be pulled off from the bond quickly enough, thus impeding the self-dressing process of the surface of the wheel and finally resulting in clogging of the wheel and burns on the ground surface.如果較硬等級的砂輪用于磨削較硬材料，磨鈍的磨粒將不能足夠快地脫離粘結體，這會妨礙砂輪表面的自修復，最終導致砂輪的堵塞并在被磨表面留下灼斑。In fact, the cutting properties of all grinding wheels must be restored periodically by dressing with a cemented carbide roller or a diamond tool to give the wheel the exact desired shape and remove all worn abrasive grains.實際上，所有砂輪的磨削性能都必須定期地通過使用硬質合金滾輪或金剛石修整器修整而被恢復，以求很準確地把砂輪加工成要求的形狀，并去除已磨鈍的磨粒。第十一單元

1、The Lathe and Its Construction 車床及其結構

A lathe is a machine tool used primarily for producing surfaces of revolution and flat edges.車床是主要用于生成旋轉表面和平整邊緣的機床。

Based on their purpose, construction, number of tools that can simultaneously be mounted, and degree of automation, lathes-or, more accurately, lathe-type machine tools can be classified as follows: 根據它們的使用目的、結構、能同時被安裝刀具的數量和自動化的程度，車床—或更確切地說是車床類的機床，可以被分成以下幾類：

(1)Engine lathes(2)Toolroom lathes(3)Turret lathes(4)Vertical turning and boring mills(5)Automatic lathes(6)Special-purpose lathes(1)普通車床(2)萬能車床(3)轉塔車床(4)立式車床(5)自動車床(6)特殊車床

2、The carriage.The main function of the carriage is mounting of the cutting tools and generating longitudinal and/or cross feeds.It is actually an H-shaped block that slides on the lathe bed between the head stock and tail stock while being guided by the V-shaped guide ways of the bed.大拖板：大拖板的主要功能是安裝刀具和產生縱向和/或橫向進給。它實際上是一由車床床身V形導軌引導的、能在車床床身主軸箱和尾架之間滑動的H形滑塊。

The carriage can be moved either manually or mechanically by means of the apron and either the feed rod or the lead screw.大拖板能手動或者通過溜板箱和光桿(進給桿)或絲桿(引導螺桿)機動。

3、Turning tools.Turning tools can be either finishing or rough turning tools.Rough turning tools have small nose radii and are employed when deep cuts are made.車削刀具：車削刀具可以是精車刀具或粗車刀具。粗車刀具刀尖半徑較小，用于深切削。

On the other hand, finishing tools have larger nose radii and are used for obtaining the final required dimensions with good surface finish by making slight depths of cut.Rough turning tools can be right-hand or left-hand types, depending upon the direction of feed.They can have straight,bent, or offset shanks.而精車刀具刀尖半徑較大，用于通過微量進刀深度來獲得具有較好表面光潔度的最終所需尺寸。粗車刀具按其進給方向可以是右手型的或是左手型的。它們可以有直的、彎的或偏置的刀桿。

4、Cylindrical turning.Cylindrical turning is the simplest and the most common of all lathe operations.A single full turn of the workpiece generates a circle whose center falls on the lathe axis;this motion is then reproduced numerous times as a result of the axial feed motion of the tool.圓柱面車削：圓柱面車削是所有車床操作中最簡單也是最普通的。工件旋轉一整圈產生一個圓心落在車床主軸上的圓；由于刀具的軸向進給運動這種動作重復許多次。

The resulting machining marks are, therefore, a helix having a very small pitch, which is equal to the feed.Consequently, the machined surface is always cylindrical.所以，由此產生的機加工痕跡是一條具有很小節距的螺旋線，該節距等于進給。因此機加工表面始終是圓柱形的。

The axial feed is provided by the carriage or the compound rest, either manually or automatically, whereas the depth of cut is controlled by the cross slide.軸向進給通過大拖板或復式刀架手動或自動提供，然而切削深度則由橫向滑板控制。

In roughing cuts, it is recommended that large depths of cuts(up to 0.25in.or 6mm, depending upon the workpiece material)and smaller feeds would be used.On the other hand, very fine feeds, smaller depths of cut(less than 0.05in, or 0.4mm), and high cutting speeds are preferred for finishing cuts.粗車中，推薦使用較大切削深度(根據工件材料可達0.25英寸或6毫米)和較小進給。另一方面，精車則最好采用很小的進給、較小的切削深度(小于0.05英寸或0.4毫米)和較高的切削速度。第十二單元

1、Drilling and Drills 鉆削和鉆頭

Drilling involves producing through or blind holes in a work piece by forcing a tool, which rotates around its axis, against the work piece.鉆削就是通過迫使繞自身軸線旋轉的切削刀具進入工件而在其上生成通孔或盲孔。

Consequently, the range of cutting from that axis of rotation is equal to the radius of the required hole.In practice, two symmetrical cutting edges that rotate about the same axis are employed.因此，從旋轉軸線開始的切削范圍等于所需孔的半徑。實際上，使用的是兩條圍繞相同軸線旋轉的對稱切削刃。

2、Each of the cutting edges of a milling cutter acts as an individual single-point cutter when it engages with the workpiece metal.Therefore, each of those cutting edges has appropriate rake and relief angles.在銑刀切削工件金屬時，銑刀的每條切削刃都象一單獨的單刃刀具一樣作用。所以每條切削刃都適當的前后角。

Since only a few of the cutting edges are engaged with the workpiece at a time, heavy cuts can be taken without adversely affecting the tool life.In fact, the permissible cutting speeds and feeds for milling are three to four times higher than those for turning or drilling.由于同一時間只有部分切削刃切削工件，因此可以在對刀具壽命沒有不利影響的情況下承擔重型切削。事實上，銑削允許的切削速度和進給比車削或鉆削高三到四倍。

Moreover, the quality of the surfaces machined by milling is generally superior to the quality of surfaces machined by turning, shaping, or drilling.此外，由銑削加工的表面質量通常優于車削、刨削或鉆削加工的表面質量。A wide variety of milling cutters is available in industry.This, together with the fact that a milling machine is a very versatile machine tool, makes the milling machine the backbone of a machining workshop.工業上可采用的銑刀類型眾多。連同銑床是極通用機床的事實，使得銑床成為機加工車間的支柱。第十四單元

1、Dimensioning 標注尺寸

The design of a machine includes many factors other than those of determining the loads and stresses and selecting the proper materials.機械設計除了計算載荷和應力、選擇合適的材料外，還包括許多其它因素。Before construction or manufacture can begin, it is necessary to have complete assembly and detail drawings to convey all necessary information to the shop men.The designer frequently is called upon to check the drawings before they are sent to the shop.Much experience and familiarity with manufacturing processes are needed before one can become conversant with all phases of production drawings.在建造或制造開始前，完成裝配圖和零件圖以把必要信息傳達給車間工人是必須的。在送往車間前設計者常常被召集來檢查圖紙。而在精通生產圖紙的所有情況之前，需要有許多經驗并熟悉制造工藝。

2、The development of production processes for large-volume manufacture at low cost has been largely dependent upon interchangeability of component parts.Thus the designer must determine both the proper tolerances for the individual parts, and the correct amount of clearance or interference to permit assembly with the mating parts.大規模低成本制造生產工藝的發展很大程度取決于組成零件的互換性。因此設計者必須確定單個零件的合適公差以及配合零件裝配允許的正確間隙或過盈量。The manner of placing tolerances on drawings depends somewhat on the kind of product or type of manufacturing process.If the tolerance on a dimension is not specifically stated, the drawing should contain a blanket note which gives the value of the tolerance for such dimensions.在圖紙上標注公差的方法相當程度上依賴于產品的性質或制造工藝的類型。如果尺寸公差沒有特別注明，圖紙應該包含一個給出這些尺寸公差值的普遍適用注釋。

However, some companies do not use blanket notes on the supposition that if each dimension is considered individually, wider tolerances than those called for in the note could probably be specified.In any event it is very important that a drawing be free from ambiguities and be subject only to a single interpretation.然而有些公司不采用普遍適用注釋，假定每個尺寸是單獨被考慮的，可能會規定出比注釋中要求的更寬的公差。在任何情況下圖紙不模棱兩可并只服從于單一的解釋是十分重要的。

3、There should be no more dimensions than are absolutely necessary, and no feature should be located by more than one dimension in any direction.除絕對需要的尺寸外，不應該有更多的尺寸；而在任意方向上，只能在一個尺寸上標注特性要求。

It may be necessary occasionally to give an auxiliary dimension for reference, possibly for inspection.When this is so, the dimension should be enclosed in a bracket and marked for reference.Such dimensions are not governed by general tolerances.偶爾也可能為了檢查而必須給出供參考的輔助尺寸。在這種情況下，尺寸應該用括號括起來，以便參考。這樣的尺寸不受通用公差控制。Unit15

1、Ultrasonic machining,elecron-beam machining,plasma-jet machining ,and laser machining are all examples of these new processes.Another modern process is chemical etching ,which,unlike the others,was developed primarily for producing complex integral shapes in soft materials,namely ,aluminum alloys ,for the aircraft industry.1超聲加工，電子束加工，等離子射流加工，激光加工等就是特種加工工藝的代表。另一種現代加工方法是化學蝕刻法，與其他方法不同，它原來是為用軟材料即鋁合金、為飛機工業生產形狀復雜的整體零件而開發的。

2、The term electrical maching may be applied to a group of processes that employ an electric current or discharge to remove material.Removal of material though an electric current or discharge eliminates the inefficient conversion of electrical power to mechanical power characteristic of conventional machining and metal-deformation processes電加工這一術語適用于使用電流或放電以去除材料的一組加工方法。雖然電流或放電消除了電能的效率，消除了傳統機械加工和金屬變形過程中的電功率的低效率的轉換

The elimination of the mechanical stage also overcomes one difficulty inherent in conventional machining ,namely ,the increase in tool forces and tool wear encountered when machining the harder metals and alloys used in modern engineering practice 在機械加工階段也克服了傳統加工方法存在的困難，即，在現代工程實踐中加工較難的金屬和合金時切削力和道具磨損的增加。

3、The erosive action of electric sparks has long been known.Two recent discoveries,however,have made spark-cutting practical.A DC spark causes greater erosion of the electrode connected to the positive pole of the power supply——very important，if tool wear is to be minimized and the work erosion rate maximized.The second important discovery is that the rate of erosion by the spark is greatly increased if it is made to take place in a liquid rather than air.It must be noted that if a spark is permitted to last to long ,it will degenerate into a stationary arc which is not suitable for machining.電火花的侵蝕作用早已公知的。然而，最近的兩項發現是電火花加工能實際使用。直流電火花使在與電源正極相連的電極處產生較大的蝕除，如果要使刀具磨損最小而使工件蝕除率最大的話，這一點是非常重要的。第二個重要的發現是如果電火花的蝕除發生在液體而不是空氣中那么它的蝕除率會大大提高。必須指出的是,如果一個火花被允許長時間持續,它將退化為一個不適合用于加工的穩定電弧。V unit16

1、laser beam machining(LBM)utilises the energy from the coherent light beams called laser(light amplification by stimulated emission of radiation).The basic principle utilised in LBM is that under proper conditions light energy of a particular frequency is used to stimulate the electrons in an atom to emit additional light with exactly the same characteristics of the original light source.激光加工利用稱為激光的相干光束的能量(光受激輻射放大器)。激光加工的基本原理是在一定條件下采用特定頻率的光激發原子中的電子，是其發射特征與原光源完全相同的光 Part2 第一單元

1、The modern digital computer is an electronic machine that can perform mathematical and logical calculations and data processing functions in accordance with a predetermined program of instructions.The computer itself is referred to as hardware, whereas the various programs are referred to as software.現在數字計算機是一部能夠根據預定的程序來完成數字和邏輯運算以及數據處理功能的電子設備，計算機本身稱為硬件，而各種各樣的程序稱為軟件。In a network,all computers are connected and communicated with each other according to some kinds of enacted regulations or agreement ,which are called the “network protocols “.the main function of network protocols is realizing the orderly transmission or acceptance of information.The most common protocol which is being used is Transport Control Protocol /Internet Protocol(TCP/IP).Among many system models illustrating network protocols in the world ,the ISO/OSI network model enacted by International Standardization Organization has divided the whole system into seven layers ,each layer has its own name and function respectively.在網絡中所有的計算機都根據一些準則和協議進行連接和通信，規則和協議稱為網絡協議。網絡協議的主要功能是實現信息的有序傳遞或接受。最常用的協議是傳輸控制協議/互聯網協議（TCP / IP）。在世界上許多系統模型，說明網絡協議由國際標準化組織制定的ISO / OSI網絡模型將整個系統分為七層,每一層分別有自己的名稱和功能

2、the widest area network in the world is Internet.it is one kind of wide area virtual networks,which uses TCP/IP protocol and interconnects more than tens of million computers around the world into a gigantic network system互聯網是世界上最寬廣的區域網，它是一種大范圍的虛擬網絡，利用TCP / IP協議，使世界各地數以百萬的電腦變成一個龐大的網絡系統。

Each computer of internet has its sole address in the world ,thus its application can overcome the limitation of continents,countries and areas ,and make up a virtual space in which every person can receive the latest news and enjoy the fastest service even when he is in the most remote area of the world.互聯網上的每臺計算機都有唯一的地址，因此它的應用可以克服大陸、國家和地區,的限制，并組成一個虛擬的空間。每個人都可以獲得的最新消息和享受最快的服務即使他是在世界最偏遠的地區。today more and more computers and devices are connected with internet system,more and more service and information can be offered by the utlization of internet,and it has become an important base for information super highway structure plan in many countries one of fastest growing +課本99頁藍體字

今天,越來越多的電腦和設備被互聯網系統連接，越來越多的服務和信息被互聯網的使用所提供，在許多國家信息高速公路結構計劃已成為一項重要的基礎研究。互聯網發展最快的領域之一是萬維網的應用，在互聯網中，各種信息，如文本、圖像、聲音和許多其他多媒體文件，可以通過超文本鏈接功能共同觀看和導航。with the rapid development of information and electronics technology ,internet is developing by an incredibly speed and it has become an indispensable component of human‘s civilization隨著信息和電子技術的快速發展，互聯網以一個令人難以置信的速度發展，它已成為人類文明的不可或缺的組成部分。unit11課本173頁

第三篇：機械工程英語翻譯

? Types of Materials

材料的類型

Materials may be grouped in several ways.Scientists often classify materials by their state: solid, liquid, or gas.They also separate them into organic(once living)and inorganic(never living)materials.材料可以按多種方法分類。科學家常根據狀態將材料分為：固體、液體或氣體。他們也把材料分為有機材料(曾經有生命的)和無機材料(從未有生命的)。

For industrial purposes, materials are divided into engineering materials or nonengineering materials.Engineering materials are those used in manufacture and become parts of products.就工業效用而言，材料被分為工程材料和非工程材料。那些用于加工制造并成為產品組成部分的就是工程材料。

Nonengineering materials are the chemicals, fuels, lubricants, and other materials used in the manufacturing process, which do not become part of the product.非工程材料則是化學品、燃料、潤滑劑以及其它用于加工制造過程但不成為產品組成部分的材料。

Engineering materials may be further subdivided into: ①Metal ②Ceramics ③Composite ④Polymers, etc.工程材料還能進一步細分為：①金屬材料②陶瓷材料③復合材料 ④聚合材料，等等。

? Metals and Metal Alloys

金屬和金屬合金

Metals are elements that generally have good electrical and thermal conductivity.Many metals have high strength, high stiffness, and have good ductility.金屬就是通常具有良好導電性和導熱性的元素。許多金屬具有高強度、高硬度以及良好的延展性。

Some metals, such as iron, cobalt and nickel, are magnetic.At low temperatures, some metals and intermetallic compounds become superconductors.某些金屬能被磁化，例如鐵、鈷和鎳。在極低的溫度下，某些金屬和金屬化合物能轉變成超導體。

What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table.Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans.合金與純金屬的區別是什么？純金屬是在元素周期表中占據特定位置的元素。例如電線中的銅和制造烹飪箔及飲料罐的鋁。

Alloys contain more than one metallic element.Their properties can be changed by changing the elements present in the alloy.Examples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium;and gold jewelry which usually contains an alloy of gold and nickel.合金包含不止一種金屬元素。合金的性質能通過改變其中存在的元素而改變。金屬合金的例子有：不銹鋼是一種鐵、鎳、鉻的合金，以及金飾品通常含有金鎳合金。

Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio.為什么要使用金屬和合金？許多金屬和合金具有高密度，因此被用在需要較高質量體積比的場合。

Some metal alloys, such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy.Many alloys also have high fracture toughness, which means they can withstand impact and are durable.某些金屬合金，例如鋁基合金，其密度低，可用于航空航天以節約燃料。許多合金還具有高斷裂韌性，這意味著它們能經得起沖擊并且是耐用的。

What are some important properties of metals?

Density is defined as a material’s mass divided by its volume.Most metals have relatively high densities, especially compared to polymers.金屬有哪些重要特性？

密度定義為材料的質量與其體積之比。大多數金屬密度相對較高，尤其是和聚合物相比較而言。

Materials with high densities often contain atoms with high atomic numbers, such as gold or lead.However, some metals such as aluminum or magnesium have low densities, and are used in applications that require other metallic properties but also require low weight.高密度材料通常由較大原子序數原子構成，例如金和鉛。然而，諸如鋁和鎂之類的一些金屬則具有低密度，并被用于既需要金屬特性又要求重量輕的場合。

Fracture toughness can be described as a material’s ability to avoid fracture, especially when a flaw is introduced.Metals can generally contain nicks and dents without weakening very much, and are impact resistant.A football player counts on this when he trusts that his facemask won’t shatter.斷裂韌性可以描述為材料防止斷裂特別是出現缺陷時不斷裂的能力。金屬一般能在有缺口和凹痕的情況下不顯著削弱，并且能抵抗沖擊。橄欖球運動員據此相信他的面罩不會裂成碎片。

Plastic deformation is the ability of bend or deform before breaking.As engineers, we usually design materials so that they don’t deform under normal conditions.You don’t want your car to lean to the east after a strong west wind.塑性變形就是在斷裂前彎曲或變形的能力。作為工程師，設計時通常要使材料在正常條件下不變形。沒有人愿意一陣強烈的西風過后自己的汽車向東傾斜。

However, sometimes we can take advantage of plastic deformation.The crumple zones in a car absorb energy by undergoing plastic deformation before they break.然而，有時我們也能利用塑性變形。汽車上壓皺的區域在它們斷裂前通過經歷塑性變形來吸收能量。

The atomic bonding of metals also affects their properties.In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere.Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires.金屬的原子連結對它們的特性也有影響。在金屬內部，原子的外層階電子由所有原子共享并能到處自由移動。由于電子能導熱和導電，所以用金屬可以制造好的烹飪鍋和電線。

It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal.No photons pass through.因為這些階電子吸收到達金屬的光子，所以透過金屬不可能看得見。沒有光子能通過金屬。

Alloys are compounds consisting of more than one metal.Adding other metals can affect the density, strength, fracture toughness, plastic deformation, electrical conductivity and environmental degradation.合金是由一種以上金屬組成的混合物。加一些其它金屬能影響密度、強度、斷裂韌性、塑性變形、導電性以及環境侵蝕。

For example, adding a small amount of iron to aluminum will make it stronger.Also, adding some chromium to steel will slow the rusting process, but will make it more brittle.例如，往鋁里加少量鐵可使其更強。同樣，在鋼里加一些鉻能減緩它的生銹過程，但也將使它更脆。

? Ceramics and Glasses 陶瓷和玻璃

A ceramic is often broadly defined as any inorganic nonmetallic material． By this definition, ceramic materials would also include glasses;however, many materials scientists add the stipulation that “ceramic” must also be crystalline.陶瓷通常被概括地定義為無機的非金屬材料。照此定義，陶瓷材料也應包括玻璃；然而許多材料科學家添加了“陶瓷”必須同時是晶體物組成的約定。

A glass is an inorganic nonmetallic material that does not have a crystalline structure.Such materials are said to be amorphous.玻璃是沒有晶體狀結構的無機非金屬材料。這種材料被稱為非結晶質材料。Properties of Ceramics and Glasses

Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance.陶瓷和玻璃的特性

高熔點、低密度、高強度、高剛度、高硬度、高耐磨性和抗腐蝕性是陶瓷和玻璃的一些有用特性。

Many ceramics are good electrical and thermal insulators.Some ceramics have special properties: some ceramics are magnetic materials;some are piezoelectric materials;and a few special ceramics are superconductors at very low temperatures.Ceramics and glasses have one major drawback: they are brittle.許多陶瓷都是電和熱的良絕緣體。某些陶瓷還具有一些特殊性能：有些是磁性材料，有些是壓電材料，還有些特殊陶瓷在極低溫度下是超導體。陶瓷和玻璃都有一個主要的缺點：它們容易破碎。

Ceramics are not typically formed from the melt.This is because most ceramics will crack extensively(i.e.form a powder)upon cooling from the liquid state.陶瓷一般不是由熔化形成的。因為大多數陶瓷在從液態冷卻時將會完全破碎(即形成粉末)。

Hence, all the simple and efficient manufacturing techniques used for glass production such as casting and blowing, which involve the molten state, cannot be used for the production of crystalline ceramics.Instead, “sintering” or “firing” is the process typically used.因此，所有用于玻璃生產的簡單有效的—諸如澆鑄和吹制這些涉及熔化的技術都不能用于由晶體物組成的陶瓷的生產。作為替代，一般采用“燒結”或“焙燒”工藝。

In sintering, ceramic powders are processed into compacted shapes and then heated to temperatures just below the melting point.At such temperatures, the powders react internally to remove porosity and fully dense articles can be

obtained.在燒結過程中，陶瓷粉末先擠壓成型然后加熱到略低于熔點溫度。在這樣的溫度下，粉末內部起反應去除孔隙并得到十分致密的物品。

An optical fiber contains three layers: a core made of highly pure glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage.光導纖維有三層：核心由高折射指數高純光傳輸玻璃制成，中間層為低折射指數玻璃，是保護核心玻璃表面不被擦傷和完整性不被破壞的所謂覆層，外層是聚合物護套，用于保護光導纖維不受損。

In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light.為了使核心玻璃有比覆層大的折射指數，在其中摻入微小的、可控數量的能減緩光速而不會吸收光線的雜質或攙雜劑。

Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle.由于核心玻璃的折射指數比覆層大，只要在全內反射過程中光線照射核心/覆層分界面的角度比臨界角大，在核心玻璃中傳送的光線將仍保留在核心玻璃中。

The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with little loss of intensity.全內反射現象與核心玻璃的高純度一樣，使光線幾乎無強度損耗傳遞長距離成為可能。

? Composites

復合材料

Composites are formed from two or more types of materials.Examples include polymer/ceramic and metal/ceramic composites.Composites are used because overall properties of the composites are superior to those of the individual components.復合材料由兩種或更多材料構成。例子有聚合物/陶瓷和金屬/陶瓷復合材料。之所以使用復合材料是因為其全面性能優于組成部分單獨的性能。

For example: polymer/ceramic composites have a greater modulus than the polymer component, but aren’t as brittle as ceramics.Two types of composites are: fiber-reinforced composites and particle-reinforced composites.例如：聚合物/陶瓷復合材料具有比聚合物成分更大的模量，但又不像陶瓷那樣易碎。

復合材料有兩種：纖維加強型復合材料和微粒加強型復合材料。Fiber-reinforced Composites

Reinforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers.Fibers increase the modulus of the matrix material.纖維加強型復合材料

加強纖維可以是金屬、陶瓷、玻璃或是已變成石墨的被稱為碳纖維的聚合物。纖維能加強基材的模量。The strong covalent bonds along the fiber’s length give them a very high modulus in this direction because to break or extend the fiber the bonds must also be broken or moved.沿著纖維長度有很強結合力的共價結合在這個方向上給予復合材料很高的模量，因為要損壞或拉伸纖維就必須破壞或移除這種結合。

Fibers are difficult to process into composites, making fiber-reinforced composites relatively expensive.把纖維放入復合材料較困難，這使得制造纖維加強型復合材料相對昂貴。

Fiber-reinforced composites are used in some of the most advanced, and therefore most expensive sports equipment, such as a time-trial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix.纖維加強型復合材料用于某些最先進也是最昂貴的運動設備，例如計時賽競賽用自行車骨架就是用含碳纖維的熱固塑料基材制成的。

Body parts of race cars and some automobiles are composites made of glass fibers(or fiberglass)in a thermoset matrix.競賽用汽車和某些機動車的車體部件是由含玻璃纖維(或玻璃絲)的熱固塑料基材制成的。

Fibers have a very high modulus along their axis, but have a low modulus perpendicular to their axis.Fiber composite manufacturers often rotate layers of fibers to avoid directional variations in the modulus.纖維在沿著其軸向有很高的模量，但垂直于其軸向的模量卻較低。纖維復合材料的制造者往往旋轉纖維層以防模量產生方向變化。Particle-reinforced composites

Particles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as

aluminum, and amorphous materials，including polymers and carbon black.微粒加強型復合材料

用于加強的微粒包含了陶瓷和玻璃之類的礦物微粒，鋁之類的金屬微粒以及包括聚合物和碳黑的非結晶質微粒。

Particles are used to increase the modulus of the matrix, to decrease the permeability of the matrix, to decrease the ductility of the matrix.An example of particle-reinforced composites is an automobile tire which has carbon black particles in a matrix of polyisobutylene elastomeric polymer.微粒用于增加基材的模量、減少基材的滲透性和延展性。微粒加強型復合材料的一個例子是機動車胎，它就是在聚異丁烯人造橡膠聚合物基材中加入了碳黑微粒。

? Polymers

聚合材料

A polymer has a repeating structure, usually based on a carbon backbone.The repeating structure results in large chainlike molecules.Polymers are useful because they are lightweight, corrosion resistant, easy to process at low temperatures and generally inexpensive.聚合物具有一般是基于碳鏈的重復結構。這種重復結構產生鏈狀大分子。由于重量輕、耐腐蝕、容易在較低溫度下加工并且通常較便宜，聚合物是很有用的。

Some important characteristics of polymers include their size(or molecular weight), softening and melting points, crystallinity, and structure.The mechanical properties of polymers generally include low strength and high toughness.Their strength is often improved using reinforced composite structures.聚合材料具有一些重要特性，包括尺寸(或分子量)、軟化及熔化點、結晶度和結構。聚合材料的機械性能一般表現為低強度和高韌性。它們的強度通常可采用加強復合結構來改善。Important Characteristics of Polymers

Size.Single polymer molecules typically have molecular weights between 10,000 and 1,000,000g/mol—that can be more than 2,000 repeating units depending on the polymer structure!聚合材料的重要特性

尺寸：單個聚合物分子一般分子量為10,000到1,000,000g/mol之間，具體取決于聚合物的結構—這可以比2,000個重復單元還多。

The mechanical properties of a polymer are significantly affected by the molecular weight, with better engineering properties at higher molecular weights.聚合物的分子量極大地影響其機械性能，分子量越大，工程性能也越好。

Thermal transitions.The softening point(glass transition temperature)and the melting point of a polymer will determine which it will be suitable for applications.These temperatures usually determine the upper limit for which a polymer can be used.熱轉換性：聚合物的軟化點(玻璃狀轉化溫度)和熔化點決定了它是否適合應用。這些溫度通常決定聚合物能否使用的上限。

For example, many industrially important polymers have glass transition temperatures near the boiling point of water(100℃, 212℉), and they are most useful for room temperature applications.Some specially engineered polymers can withstand temperatures as high as 300℃(572℉).例如，許多工業上的重要聚合物其玻璃狀轉化溫度接近水的沸點(100℃, 212℉)，它們被廣泛用于室溫下。而某些特別制造的聚合物能經受住高達300℃(572℉)的溫度。

Crystallinity.Polymers can be crystalline or amorphous, but they usually have a combination of crystalline and amorphous structures(semi-crystalline).結晶度：聚合物可以是晶體狀的或非結晶質的，但它們通常是晶體狀和非結晶質結構的結合物(半晶體)。

Interchain interactions.The polymer chains can be free to slide past one another(thermo-plastic)or they can be connected to each other with crosslinks(thermoset or elastomer).Thermo-plastics can be reformed and recycled, while thermosets and elastomers are not reworkable.原子鏈間的相互作用：聚合物的原子鏈可以自由地彼此滑動(熱可塑性)或通過交鍵互相連接(熱固性或彈性)。熱可塑性材料可以重新形成和循環使用，而熱固性與彈性材料則是不能再使用的。

Intrachain structure.The chemical structure of the chains also has a tremendous effect on the properties.Depending on the structure the polymer may be hydrophilic or hydrophobic(likes or hates water), stiff or flexible, crystalline or amorphous, reactive or unreactive.鏈內結構：原子鏈的化學結構對性能也有很大影響。根據各自的結構不同，聚合物可以是親水的或憎水的(喜歡或討厭水)、硬的或軟的、晶體狀的或非結晶質的、易起反應的或不易起反應的。

The understanding of heat treatment is embraced by the broader study of metallurgy.Metallurgy is the physics, chemistry, and engineering related to metals from ore extraction to the final product.對熱處理的理解包含于對冶金學較廣泛的研究。冶金學是物理學、化學和涉及金屬從礦石提煉到最后產物的工程學。

Heat treatment is the operation of heating and cooling a metal in its solid state to change its physical properties.According to the procedure used, steel can be hardened to resist cutting action and abrasion, or it can be softened to permit machining.熱處理是將金屬在固態加熱和冷卻以改變其物理性能的操作。按所采用的步驟，鋼可以通過硬化來抵抗切削和磨損，也可以通過軟化來允許機加工。

With the proper heat treatment internal stresses may be removed, grain size reduced, toughness increased, or a hard surface produced on a ductile interior.The analysis of the steel must be known because small percentages of certain elements, notably carbon, greatly affect the physical properties.使用合適的熱處理可以去除內應力、細化晶粒、增加韌性或在柔軟材料上覆蓋堅硬的表面。因為某些元素(尤其是碳)的微小百分比極大地影響物理性能，所以必須知道對鋼的分析。

Alloy steel owe their properties to the presence of one or more elements other than carbon, namely nickel, chromium, manganese, molybdenum, tungsten, silicon, vanadium, and copper.Because of their improved physical properties they are used commercially in many ways not possible with carbon steels.合金鋼的性質取決于其所含有的除碳以外的一種或多種元素，如鎳、鉻、錳、鉬、鎢、硅、釩和銅。由于合金鋼改善的物理性能，它們被大量使用在許多碳鋼不適用的地方。

The following discussion applies principally to the heat treatment of ordinary commercial steels known as plain carbon steels.With this process the rate of cooling is the controlling factor, rapid cooling from above the critical range results in hard structure, whereas very slow cooling produces the opposite effect.下列討論主要針對被稱為普通碳鋼的工業用鋼而言。熱處理時冷卻速率是控制要素，從高于臨界溫度快速冷卻導致堅硬的組織結構，而緩慢冷卻則產生相反效果。

? A Simplified Iron-carbon Diagram 簡化鐵碳狀態圖

If we focus only on the materials normally known as steels, a simplified diagram is often used.如果只把注意力集中于一般所說的鋼上，經常要用到簡化鐵碳狀態圖。

Those portions of the iron-carbon diagram near the delta region and those above 2% carbon content are of little importance to the engineer and are deleted.A simplified diagram, such as the one in Fig.2.1, focuses on the eutectoid region and is quite useful in understanding the properties and processing of steel.鐵碳狀態圖中靠近三角區和含碳量高于2%的那些部分對工程師而言不重要，因此將它們刪除。如圖2.1所示的簡化鐵碳狀態圖將焦點集中在共析區，這對理解鋼的性能和處理是十分有用的。

The key transition described in this diagram is the decomposition of single-phase austenite(γ)to the two-phase ferrite plus carbide structure as temperature drops.在此圖中描述的關鍵轉變是單相奧氏體(γ)隨著溫度下降分解成兩相鐵素體加滲碳體組織結構。

Control of this reaction, which arises due to the drastically different carbon solubility of austenite and ferrite, enables a wide range of properties to be achieved through heat treatment.控制這一由于奧氏體和鐵素體的碳溶解性完全不同而產生的反應，使得通過熱處理能獲得很大范圍的特性。

To begin to understand these processes, consider a steel of the eutectoid composition, 0.77% carbon, being slow cooled along line x-x’ in Fig.2.1.At the upper temperatures, only austenite is present, the 0.77% carbon being dissolved in solid solution with the iron.When the steel cools to 727℃(1341℉), several changes occur simultaneously.為了理解這些過程，考慮含碳量為0.77%的共析鋼，沿著圖2.1的x-x’線慢慢冷卻。在較高溫度時，只存在奧氏體，0.77%的碳溶解在鐵里形成固溶體。當鋼冷卻到727℃(1341℉)時，將同時發生若干變化。

The iron wants to change from the FCC austenite structure to the BCC ferrite structure, but the ferrite can only contain 0.02% carbon in solid solution.鐵需要從面心立方體奧氏體結構轉變為體心立方體鐵素體結構，但是鐵素體只能容納固溶體狀態的0.02%的碳。

The rejected carbon forms the carbon-rich cementite intermetallic with composition Fe3C.In essence, the net reaction at the eutectoid is austenite 0.77%C→ferrite 0.02%C+cementite 6.67%C.被析出的碳與金屬化合物Fe3C形成富碳的滲碳體。本質上，共析體的基本反應是奧氏體0.77%的碳→鐵素體0.02%的碳+滲碳體6.67%的碳。

Since this chemical separation of the carbon component occurs entirely in the solid state, the resulting

structure is a fine mechanical mixture of ferrite and cementite.Specimens prepared by polishing and etching in a weak solution of nitric acid and alcohol reveal the lamellar structure of alternating plates that forms on slow cooling.由于這種碳成分的化學分離完全發生在固態中，產生的組織結構是一種細致的鐵素體與滲碳體的機械混合物。通過打磨并在弱硝酸酒精溶液中蝕刻制備的樣本顯示出由緩慢冷卻形成的交互層狀的薄片結構。

This structure is composed of two distinct phases, but has its own set of characteristic properties and goes by the name pearlite, because of its resemblance to mother-of-pearl at low magnification.這種結構由兩種截然不同的狀態組成，但它本身具有一系列特性，且因與低倍數放大時的珠母層有類同之處而被稱為珠光體。

Steels having less than the eutectoid amount of carbon(less than 0.77%)are known as hypo-eutectoid steels.Consider now the transformation of such a material represented by cooling along line y-y’ in Fig.2.1.含碳量少于共析體(低于0.77%)的鋼稱為亞共析鋼。現在來看這種材料沿著圖2.1中y-y’ 線冷卻的轉變情況。At high temperatures, the material is entirely austenite, but upon cooling enters a region where the stable phases are ferrite and austenite.Tie-line and level-law calculations show that low-carbon ferrite nucleates and grows, leaving the remaining austenite richer in carbon.在較高溫度時，這種材料全部是奧氏體，但隨著冷卻就進入到鐵素體和奧氏體穩定狀態的區域。由截線及杠桿定律分析可知，低碳鐵素體成核并長大，剩下含碳量高的奧氏體。

At 727℃(1341℉), the austenite is of eutectoid composition(0.77% carbon)and further cooling transforms the remaining austenite to pearlite.The resulting structure is a mixture of primary or pro-eutectoid ferrite(ferrite that formed above the eutectoid reaction)and regions of pearlite.在727℃(1341℉)時，奧氏體為共析組成(含碳量0.77%)，再冷卻剩余的奧氏體就轉化為珠光體。作為結果的組織結構是初步的共析鐵素體(在共析反應前的鐵素體)和部分珠光體的混合物。

Hypereutectoid steels are steels that contain greater than the eutectoid amount of carbon.When such steel cools, as shown in z-z’ of Fig.2.1 the process is similar to the hypo-eutectoid case, except that the primary or pro-eutectoid phase is now cementite instead of ferrite.過共析鋼是含碳量大于共析量的鋼。當這種鋼冷卻時，就像圖2.1的z-z’線所示，除了初步的共析狀態用滲碳體取代鐵素體外，其余類似亞共析鋼的情況。

As the carbon-rich phase forms, the remaining austenite decreases in carbon content, reaching the eutectoid composition at 727℃(1341℉).As before, any remaining austenite transforms to pearlite upon slow cooling through this temperature.隨著富碳部分的形成，剩余奧氏體含碳量減少，在727℃(1341℉)時達到共析組織。就像以前說的一樣，當緩慢冷卻到這溫度時所有剩余奧氏體轉化為珠光體。

It should be remembered that the transitions that have been described by the phase diagrams are for equilibrium conditions, which can be approximated by slow cooling.With slow heating, these transitions occur in the reverse manner.應該記住由狀態圖描述的這種轉化只適合于通過緩慢冷卻的近似平衡條件。如果緩慢加熱，則以相反的方式發生這種轉化。

However, when alloys are cooled rapidly, entirely different results may be obtained, because sufficient time is not provided for the normal phase reactions to occur, in such cases, the phase diagram is no longer a useful tool for engineering analysis.然而，當快速冷卻合金時，可能得到完全不同的結果。因為沒有足夠的時間讓正常的狀態反應發生，在這種情況下對工程分析而言狀態圖不再是有用的工具。

? Hardening

淬火

Hardening is the process of heating a piece of steel to a temperature within or above its critical range and then cooling it rapidly.淬火就是把鋼件加熱到或超過它的臨界溫度范圍，然后使其快速冷卻的過程。

If the carbon content of the steel is known, the proper temperature to which the steel should be heated may be obtained by reference to the iron-iron carbide phase diagram.However, if the composition of the steel is unknown, a little preliminary experimentation may be necessary to determine the range.如果鋼的含碳量已知，鋼件合適的加熱溫度可參考鐵碳合金狀態圖得到。然而當鋼的成分不知道時，則需做一些預備試驗來確定其溫度范圍。

A good procedure to follow is to heat-quench a number of small specimens of the steel at various temperatures and observe the result, either by hardness testing or by microscopic examination.When the correct temperature is obtained, there will be a marked change in hardness and other properties.要遵循的合適步驟是將這種鋼的一些小試件加熱到不同的溫度后淬火，再通過硬度試驗或顯微鏡檢查觀測結果。一

旦獲得正確的溫度，硬度和其它性能都將有明顯的變化。

In any heat-treating operation the rate of heating is important.Heat flows from the exterior to the interior of steel at a definite rate.If the steel is heated too fast, the outside becomes hotter than the interior and uniform structure cannot be obtained.在任何熱處理作業中，加熱的速率都是重要的。熱量以一定的速率從鋼的外部傳導到內部。如果鋼被加熱得太快，其外部比內部熱就不能得到均勻的組織結構。

If a piece is irregular in shape, a slow rate is all the more essential to eliminate warping and cracking.The heavier the section, the longer must be the heating time to achieve uniform results.如果工件形狀不規則，為了消除翹曲和開裂最根本的是加熱速率要緩慢。截面越厚，加熱的時間就要越長才能達到均勻的結果。

Even after the correct temperature has been reached, the piece should be held at that temperature for a sufficient period of time to permit its thickest section to attain a uniform temperature.即使加熱到正確的溫度后，工件也應在此溫度下保持足夠時間以讓其最厚截面達到相同溫度。

The hardness obtained from a given treatment depends on the quenching rate, the carbon content, and the work size.In alloy steels the kind and amount of alloying element influences only the hardenability(the ability of the workpiece to be hardened to depths)of the steel and does not affect the hardness except in unhardened or partially hardened steels.通過給定的熱處理所得到的硬度取決于淬火速率、含碳量和工件尺寸。除了非淬硬鋼或部分淬硬鋼外，合金鋼中合金元素的種類及含量僅影響鋼的淬透性(工件被硬化到深層的能力)而不影響硬度。

Steel with low carbon content will not respond appreciably to hardening treatment.As the carbon content in steel increases up to around 0.60%, the possible hardness obtainable also increases.含碳量低的鋼對淬火處理沒有明顯的反應。隨著鋼的含碳量增加到大約0.60%，可能得到的硬度也增加。Above this point the hardness can be increased only slightly, because steels above the eutectoid point are made up entirely of pearlite and cementite in the annealed state.Pearlite responds best to heat-treating operations;and steel composed mostly of pearlite can be transformed into a hard steel.高于此點，由于超過共析點鋼完全由珠光體和退火狀態的滲碳體組成，硬度增加并不多。珠光體對熱處理作業響應最好；基本由珠光體組成的鋼能轉化成硬質鋼。

As the size of parts to be hardened increases, the surface hardness decreases somewhat even though all other conditions have remained the same.There is a limit to the rate of heat flow through steel.即使所有其它條件保持不變，隨著要淬火的零件尺寸的增加其表面硬度也會有所下降。熱量在鋼中的傳導速率是有限的。

No matter how cool the quenching medium may be, if the heat inside a large piece cannot escape faster than a certain critical rate, there is a definite limit to the inside hardness.However, brine or water quenching is capable of rapidly bringing the surface of the quenched part to its own temperature and maintaining it at or close to this temperature.無論淬火介質怎么冷，如果在大工件中的熱量不能比特定的臨界速率更快散發，那它內部硬度就會受到明確限制。然而鹽水或水淬火能夠將被淬零件的表面迅速冷卻至本身溫度并將其保持或接近此溫度。

Under these circumstances there would always be some finite depth of surface hardening regardless of size.This is not true in oil quenching, when the surface temperature may be high during the critical stages of quenching.在這種情況下不管零件尺寸如何，其表面總歸有一定深度被硬化。但油淬情況就不是如此，因為油淬時在淬火臨界階段零件表面的溫度可能仍然很高。

? Tempering

回火

Steel that has been hardened by rapid quenching is brittle and not suitable for most uses.By tempering or drawing, the hardness and brittleness may be reduced to the desired point for service conditions．

快速淬火硬化的鋼是硬而易碎的，不適合大多數場合使用。通過回火，硬度和脆性可以降低到使用條件所需要的程度。

As these properties are reduced there is also a decrease in tensile strength and an increase in the ductility and toughness of the steel.The operation consists of reheating quench-hardened steel to some temperature below the critical range followed by any rate of cooling.隨著這些性能的降低，拉伸強度也降低而鋼的延展性和韌性則會提高。回火作業包括將淬硬鋼重新加熱到低于臨界范圍的某一溫度然后以任意速率冷卻。

Although this process softens steel, it differs considerably from annealing in that the process lends itself to close control of the physical properties and in most cases does not soften the steel to the extent that annealing would.The final structure obtained from tempering a fully hardened steel is called tempered martensite.雖然這過程使鋼軟化，但它與退火是大不相同的，因為回火適合于嚴格控制物理性能并在大多數情況下不會把鋼軟化到退火那種程度。回火完全淬硬鋼得到的最終組織結構被稱為回火馬氏體。

Tempering is possible because of the instability of the martensite, the principal constituent of hardened steel.Low-temperature draws, from 300℉ to 400℉(150℃~205℃), do not cause much decrease in hardness and are used principally to relieve internal strains.由于馬氏體這一淬硬鋼主要成分的不穩定性，使得回火成為可能。低溫回火，300℉到400℉(150℃~205℃)，不會引起硬度下降很多，主要用于減少內部應變。

As the tempering temperatures are increased, the breakdown of the martensite takes place at a faster rate, and at about 600℉(315℃)the change to a structure called tempered martensite is very rapid.The tempering operation may be described as one of precipitation and agglomeration or coalescence of cementite.隨著回火溫度的提高，馬氏體以較快的速率分解，并在大約600℉(315℃)迅速轉變為被稱為回火馬氏體的結構。回火作業可以描述為滲碳體析出和凝聚或聚結的過程。

A substantial precipitation of cementite begins at 600℉(315℃), which produces a decrease in hardness.Increasing the temperature causes coalescence of the carbides with continued decrease in hardness.滲碳體的大量析出開始于600℉(315℃)，這使硬度下降。溫度的上升會使碳化物聚結而硬度繼續降低。

In the process of tempering, some consideration should be given to time as well as to temperature.Although most of the softening action occurs in the first few minutes after the temperature is reached, there is some additional reduction in hardness if the temperature is maintained for a prolonged time.在回火過程中，不但要考慮溫度而且要考慮時間。雖然大多數軟化作用發生在達到所需溫度后的最初幾分鐘，但如果此溫度維持一段延長時間，仍會有些額外的硬度下降。

Usual practice is to heat the steel to the desired temperature and hold it there only long enough to have it uniformly heated.通常的做法是將鋼加熱到所需溫度并且僅保溫到正好使其均勻受熱。

Two special processes using interrupted quenching are a form of tempering.In both, the hardened steel is quenched in a salt bath held at a selected lower temperature before being allowed to cool.These processes, known as austempering and martempering, result in products having certain desirable physical properties.兩種采用中斷淬火的特殊工藝也是回火的形式。這兩種工藝中，淬硬鋼在其被允許冷卻前先在一選定的較低溫度鹽浴淬火。這兩種分別被稱為奧氏體回火和馬氏體回火的工藝，能使產品具有特定所需的物理性能。

? Annealing

退火

The primary purpose of annealing is to soften hard steel so that it may be machined or cold worked.退火的主要目的是使堅硬的鋼軟化以便機加工或冷作。

This is usually accomplished by heating the steel too slightly above the critical temperature, holding it there until the temperature of the piece is uniform throughout, and then cooling at a slowly controlled rate so that the temperature of the surface and that of the center of the piece are approximately the same.通常是非常緩慢地將鋼加熱到臨界溫度以上，并將其在此溫度下保持到工件全部均勻受熱，然后以受控的速率慢慢地冷卻，這樣使得工件表面和內部的溫度近似相同。

This process is known as full annealing because it wipes out all trace of previous structure, refines the crystalline structure, and softens the metal.Annealing also relieves internal stresses previously set up in the metal.這過程被稱為完全退火，因為它去除了以前組織結構的所有痕跡、細化晶粒并軟化金屬。退火也釋放了先前在金屬中的內應力。

The temperature to which a given steel should be heated in annealing depends on its composition;for carbon steels it can be obtained readily from the partial iron-iron carbide equilibrium diagram.When the annealing temperature has been reached, the steel should be held there until it is uniform throughout.給定的鋼其退火溫度取決于它的成分；對碳鋼而言可容易地從局部的鐵碳合金平衡圖得到。達到退火溫度后，鋼應當保持在此溫度等到全部均勻受熱。

This usually takes about 45min for each inch(25mm)of thickness of the largest section.For maximum softness and ductility the cooling rate should be very slow, such as allowing the parts to cool down with the furnace.The higher the carbon content, the slower this rate must be.加熱時間一般以工件的最大截面厚度計每英寸(25mm)大約需45min。為了得到最大柔軟性和延展性冷卻速率應該很慢，比如讓零件與爐子一起冷下來。含碳量越高，冷卻的速率必須越慢。

The heating rate should be consistent with the size and uniformity of sections, so that the entire part is brought up to temperature as uniformly as possible.加熱的速率也應與截面的尺寸及均勻程度相協調，這樣才能使整個零件盡可能均勻地加熱。

? Normalizing and Spheroidizing 正火和球化

The process of normalizing consists of heating the steel about 50℉ to 100℉

(10℃~40℃)above the upper critical range and cooling in still air to room temperature.正火處理包括先將鋼加熱到高于上臨界區50℉到100℉(10℃~40℃)然后在靜止的空氣中冷卻到室溫。

This process is principally used with low-and medium-carbon steels as well as alloy steels to make the grain structure more uniform, to relieve internal stresses, or to achieve desired results in physical properties.Most commercial steels are normalized after being rolled or cast.退火主要用于低碳鋼、中碳鋼及合金鋼，使晶粒結構更均勻、釋放內應力或獲得所需的物理特性。大多數商業鋼材在軋制或鑄造后都要退火。

Spheroidizing is the process of producing a structure in which the cementite is in a spheroidal distribution.If steel is heated slowly to a temperature just below the critical range and held there for a prolonged period of time, this structure will be obtained.球化是使滲碳體產生成類似球狀分布結構的工藝。如果把鋼緩慢加熱到恰好低于臨界溫度并且保持較長一段時間，就能得到這種組織結構。

The globular structure obtained gives improved machinability to the steel.This treatment is particularly useful for hypereutectoid steels that must be machined.所獲得的球狀結構改善了鋼的可切削性。此處理方法對必須機加工的過共析鋼特別有用。

? Surface Hardening 表面硬化

Carburizing

The oldest known method of producing a hard surface on steel is case hardening or carburizing.Iron at temperatures close to and above its critical temperature has an affinity for carbon.滲碳

最早的硬化鋼表面的方法是表面淬火或滲碳。鐵在靠近并高于其臨界溫度時對碳具有親合力。

The carbon is absorbed into the metal to form a solid solution with iron and converts the outer surface into high-carbon steel.The carbon is gradually diffused to the interior of the part.The depth of the case depends on the time and temperature of the treatment.碳被吸收進金屬與鐵形成固溶體使外表面轉變成高碳鋼。碳逐漸擴散到零件內部。滲碳層的深度取決于熱處理的時間和溫度。

Pack carburizing consists of placing the parts to be treated in a closed container with some carbonaceous material such as charcoal or coke.It is a long process and used to produce fairly thick cases of from 0.03 to 0.16 in.(0.76~4.06mm)in depth.固體滲碳的方法是將要處理的零件與木炭或焦炭這些含碳的材料一起放入密閉容器。這是一個較長的過程，用于產生深度為0.03到0.16 英寸(0.76~4.06mm)這么厚的硬化層。

Steel for carburizing is usually a low-carbon steel of about 0.15% carbon that would not in itself responds appreciably to heat treatment.In the course of the process the outer layer is converted into high-carbon steel with a content ranging from 0.9% to 1.2% carbon.用于滲碳的一般是含碳量約為0.15%、本身不太適合熱處理的低碳鋼。在處理過程中外層轉化為含碳量從0.9%到1.2%的高碳鋼。

A steel with varying carbon content and, consequently, different critical temperatures requires a special heat treatment.含碳量變化的鋼具有不同的臨界溫度，因此需要特殊的熱處理。

Because there is some grain growth in the steel during the prolonged carburizing treatment, the work should be heated to the critical temperature of the core and then cooled, thus refining the core structure.The steel should then be reheated to a point above the transformation range of the case and quenched to produce a hard, fine structure.由于在較長的滲碳過程中鋼內部會有些晶粒生長，所以工件應該加熱到核心部分的臨界溫度再冷卻以細化核心部分的組織結構。然后重新加熱到高于外層轉變溫度再淬火以生成堅硬、細致的組織結構。

The lower heat-treating temperature of the case results from the fact that hypereutectoid steels are normally austenitized for hardening just above the lower critical point.A third tempering treatment may be used to reduce strains.由于恰好高于低臨界溫度通常使過共析鋼奧氏體化而硬化，所以對外層采用較低的熱處理溫度。第三次回火處理可用于減少應變。Carbonitriding

Carbonitriding, sometimes known as dry cyaniding or nicarbing, is a case-hardening process in which the steel is

held at a temperature above the critical range in a gaseous atmosphere from which it absorbs carbon and nitrogen.碳氮共滲

碳氮共滲，有時也稱為干法氰化或滲碳氮化，是一種表面硬化工藝。通過把鋼放在高于臨界溫度的氣體中，讓它吸收碳和氮。

Any carbon-rich gas with ammonia can be used.The wear-resistant case produced ranges from 0.003 to 0.030 inch(0.08~ 0.76mm)in thickness.An advantage of carbonitriding is that the hardenability of the case is significantly increased when nitrogen is added, permitting the use of low-cost steels.可以使用任何富碳氣體加氨氣，能生成厚度從0.003到0.030英寸(0.08~ 0.76mm)的耐磨外層。碳氮共滲的優點之一是加入氮后外層的淬透性極大增加，為使用低價鋼提供條件。Cyaniding

Cyaniding, or liquid carbonitriding as it is sometimes called, is also a process that combines the absorption of carbon and nitrogen to obtain surface hardness in low-carbon steels that do not respond to ordinary heat treatment.氰化

氰化，有時稱為液體碳氮共滲，也是一種結合了吸收碳和氮來獲得表面硬度的工藝，它主要用于不適合通常熱處理的低碳鋼。

The part to be case hardened is immersed in a bath of fused sodium cyanide salts at a temperature slightly above the Ac1 range, the duration of soaking depending on the depth of the case.The part is then quenched in water or oil to obtain a hard surface.需表面硬化的零件浸沒在略高于Ac1溫度熔化的氰化鈉鹽溶液中，浸泡的持續時間取決于硬化層的深度。然后將零件在水或油中淬火。

Case depths of 0.005 to 0.015in.(0.13~0.38mm)may be readily obtained by this process.Cyaniding is used principally for the treatment of small parts.通過這樣處理可以容易地獲得0.005到0.015英寸(0.13~0.38mm)的硬化深度。氰化主要用于處理小零件。Nitriding

Nitriding is somewhat similar to ordinary case hardening, but it uses a different material and treatment to create the hard surface constituents.滲氮

滲氮有些類似普通表面硬化，但它采用不同的材料和處理方法來產生堅硬表面成分。

In this process the metal is heated to a temperature of around 950℉(510℃)and held there for a period of time in contact with ammonia gas.Nitrogen from the gas is introduced into the steel, forming very hard nitrides that are finely dispersed through the surface metal.這種工藝中金屬加熱到約950℉(510℃)，然后與氨氣接觸一段時間。氨氣中的氮進入鋼內，形成細微分布于金屬表面又十分堅固的氮化物。

Nitrogen has greater hardening ability with certain elements than with others, hence, special nitriding alloy steels have been developed.氮與某些元素的硬化能力比其它元素大，因此開發了專用的滲氮合金鋼。

Aluminum in the range of 1% to 1.5% has proved to be especially suitable in steel, in that it combines with the gas to form a very stable and hard constituent.The temperature of heating ranges from 925℉ to 1,050℉(495℃~565℃).在鋼中含鋁1%到1.5%被證明特別合適，它能與氨氣結合形成很穩定堅固的成分。其加熱溫度范圍為925℉到1,050℉(495℃~565℃)。

Liquid nitriding utilizes molten cyanide salts and, as in gas nitriding, the temperature is held below the transformation range.Liquid nitriding adds more nitrogen and less carbon than either cyaniding or carburizing in cyanide baths.液體滲氮利用熔化的氰化物鹽，就像氣體滲氮，溫度保持在低于轉化范圍內。液體滲氮時在氰化物溶液中加入比氰化及滲碳都較多的氮和較少的碳。

Case thickness of 0.001 to 0.012in.(0.03~0.30mm)is obtained, whereas for gas nitriding the case may be as thick as 0.025 in.(0.64mm).In general the uses of the two-nitriding processes are similar.液體滲氮可以獲得厚度為0.001到0.012英寸(0.03~0.30mm)的硬化層，然而氣體滲氮則能獲得厚0.025英寸(0.64mm)的硬化層。一般而言兩種滲氮方法的用途是類似的。

Nitriding develops extreme hardness in the surface of steel.This hardness ranges from 900 to 1,100 Brinell, which is considerably higher than that obtained by ordinary case hardening.滲氮在鋼表面獲得遠遠超出正常標準的硬度。其硬度范圍為900到1,100布氏硬度，這遠高于普通表面硬化所獲得的硬度。

Nitriding steels, by virtue of their alloying content, are stronger than ordinary steels and respond readily to heat treatment.It is recommended that these steels be machined and heat-treated before nitriding, because there is no scale or further work necessary after this process.由于滲氮鋼的合金比例，它們比普通鋼更強，也容易熱處理。建議對這種鋼在滲氮前先機加工和熱處理，因為滲氮后沒有剝落并不需要更多的加工。

Fortunately, the interior structure and properties are not affected appreciably by the nitriding treatment and, because no quenching is necessary, there is little tendency to warp, develop cracks, or change condition in any way.The surface effectively resists corrosive action of water, saltwater spray, alkalies, crude oil, and natural gas.值得慶幸的是由于滲氮處理一點都不影響內部結構和性能，也無需淬火，所以幾乎沒有任何產生翹曲、裂縫及變化條件的趨勢。這種表面能有效地抵御水、鹽霧、堿、原油和天然氣的腐蝕反應。

Casting is a manufacturing process in which molten metal is poured or injected and allowed to solidify in a suitably shaped mold cavity.During or after cooling, the cast part is removed from the mold and then processed for delivery.鑄造是一種將熔化的金屬倒入或注入合適的鑄模腔并且在其中固化的制造工藝。在冷卻期間或冷卻后，把鑄件從鑄模中取出，然后進行交付。

Casting processes and cast-material technologies vary from simple to highly complex.Material and process selection depends on the part’s complexity and function, the product’s quality specifications, and the projected cost level.鑄造工藝和鑄造材料技術從簡單到高度復雜變化很大。材料和工藝的選擇取決于零件的復雜性和功能、產品的質量要求以及成本預算水平。

Castings are parts that are made close to their final dimensions by a casting process.With a history dating back 6,000 years, the various casting processes are in a state of continuous refinement and evolution as technological advances are being made.通過鑄造加工，鑄件可以做成很接近它們的最終尺寸。回溯6,000年歷史，各種各樣的鑄造工藝就如同科技進步一樣處于一個不斷改進和發展的狀態。

? Sand Casting

砂型鑄造

Sand casting is used to make large parts(typically iron, but also bronze, brass, aluminum).Molten metal is poured into a mold cavity formed out of sand(natural or synthetic).砂型鑄造用于制造大型零件(具有代表性是鐵，除此之外還有青銅、黃銅和鋁)。將熔化的金屬倒入由型砂(天然的或人造的)做成鑄模腔。

The processes of sand casting are discussed in this section, including patterns, sprues and runners, design considerations, and casting allowance.本節討論砂型鑄造工藝，包括型模、澆注口、澆道、設計考慮因素及鑄造余量。

The cavity in the sand is formed by using a pattern(an approximate duplicate of the real part), which are typically made out of wood, sometimes metal.The cavity is contained in an aggregate housed in a box called the flask.砂型里的型腔是采用型模(真實零件的近似復制品)構成的，型模一般為木制，有時也用金屬制造。型腔整個包含在一個被放入稱為砂箱的箱子里的組合體內。

Core is a sand shape inserted into the mold to produce the internal features of the part such as holes or internal passages.Cores are placed in the cavity to form holes of the desired shapes.Core print is the region added to the pattern, core, or mold that is used to locate and support the core within the mold.砂芯是插入鑄模的砂型，用于生成諸如孔或內通道之類的內部特征。砂芯安放在型腔里形成所需形狀的孔洞。砂芯座是加在型模、砂芯或鑄模上的特定區域，用來在鑄模內部定位和支撐砂芯。

A riser is an extra void created in the mold to contain excessive molten material.The purpose of this is to feed the molten metal to the mold cavity as the molten metal solidifies and shrinks, and thereby prevents voids in the main casting.冒口是在鑄模內部增加的額外空間，用于容納過多的熔化金屬。其目的是當熔化金屬凝固和收縮時往型腔里補充熔化金屬，從而防止在主鑄件中產生孔隙。

In a two-part mold, which is typical of sand castings, the upper half, including the top half of the pattern, flask, and core is called cope and the lower half is called drag, as shown in Fig.3.1.The parting line or the parting surface is line or surface that separates the cope and drag.在典型砂型鑄造的兩箱鑄模中，上半部分(包括型模頂半部、砂箱和砂芯)稱為上型箱，下半部分稱為下型箱，見圖3.1所示。分型線或分型面是分離上下型箱的線或面。

The drag is first filled partially with sand, and the core print, the cores, and the gating system are placed near the parting line.The cope is then assembled to the drag, and the sand is poured on the cope half, covering the pattern, core

and the gating system.首先往下型箱里部分地填入型砂和砂芯座、砂芯，并在靠近分型線處放置澆注系統。然后將上型箱與下型箱裝配在一起，再把型砂倒入上型箱蓋住型模、砂芯和澆注系統。

The sand is compacted by vibration and mechanical means.Next, the cope is removed from the drag, and the pattern is carefully removed.The object is to remove the pattern without breaking the mold cavity.型砂通過振動和機械方法壓實。然后從下型箱上撤掉上型箱，小心翼翼地取出型模。其目的是取出型模而不破壞型腔。

This is facilitated by designing a draft, a slight angular offset from the vertical to the vertical surfaces of the pattern.This is usually a minimum of 1.5mm(0.060in.), whichever is greater.The rougher the surface of the pattern, the more the draft to be provided.通過設計拔模斜度—型模垂直相交表面的微小角度偏移量—來使取出型模變得容易。拔模斜度最小一般為1.5mm(0.060in.)，只能比此大。型模表面越粗糙，則拔模斜度應越大。

The molten material is poured into the pouring cup, which is part of the gating system that supplies the molten material to the mold cavity.熔化的金屬從澆注杯注入型腔，澆注杯是澆注系統向型腔提供熔化金屬的部分。

The vertical part of the gating system connected to the pouring cup is the sprue, and the horizontal portion is called the runners and finally to the multiple points where it is introduced to the mold cavity called the gates.將澆注系統的垂直部分與澆注杯連接的是澆注口，澆注系統的水平部分稱為澆道，最后到多點把熔化金屬導入型腔的稱為閘道。

Additionally there are extensions to the gating system called vents that provide the path for the built-up gases and the displaced air to vent to the atmosphere.除此之外，還有稱為排放口的澆注系統延長段，它為合成氣體和置換空氣排放到大氣提供通道。

The cavity is usually made oversize to allow for the metal contraction as it cools down to room temperature.This is achieved by making the pattern oversize.To account for shrinking, the pattern must be made oversize by these factors on the average.These are linear factors and apply in each direction.型腔通常大于所需尺寸以允許在金屬冷卻到室溫時收縮。這通過把型模做得大于所需尺寸來達到。為解決收縮效應，一般而言型模做得比所需尺寸大，必須考慮線性因素并作用于各個方向。

These shrinkage allowances are only approximate, because the exact allowance is determined by the shape and size of the casting.In addition, different parts of the casting might require different shrinkage allowances.收縮余量僅僅是近似的，因為準確的余量是由鑄件的形狀和尺寸決定的。另外，鑄件的不同部分也可能需要不同的收縮余量。

Sand castings generally have a rough surface sometimes with surface impurities, and surface variations.A machining(finish)allowance is made for this type of defect.砂型鑄件一般表面粗糙，有時還帶有表面雜質和表面變異。對這類缺陷采用機加工(最后一道工序)的余量。

In general, typical stages of sand casting operation include(as shown in Fig.3.2): 1.Patterns are made.These will be the shape used to form the cavity in the sand.一般而言，砂型鑄造作業的典型階段包括(如圖3.2所示)： 1.制作型模。做成用于在型砂中形成型腔的形狀。

2.Cores may also be made at this time.These cores are made of bonded sand that will be broken out of the cast part after it is complete.3.Sand is mulled(mixed)thoroughly with additives such as bentonite to increase bonding and overall strength.2.同時還要制作砂芯。這些砂芯用粘結砂做成，等鑄件完成后將被打碎取出。3.型砂與膨潤土之類的添加劑充分地混合以增強連接及整體強度。

4.Sand is formed about the patterns, and gates, runners, risers, vents and pouring cups are added as needed.A compaction stage is typically used to ensure good coverage and solid molds.4.型砂在型模周圍成形，并根據需要安放閘道、澆道、冒口、排放口和澆注杯等。通常要采取壓緊步驟來保證良好的覆蓋和堅固的鑄型。

Cores may also be added to make concave or internal features for the cast part.Alignment pins may also be used for mating the molds later.Chills may be added to cool large masses faster.安放砂芯來制成鑄件的凹形結構或內部特征。為了以后鑄模匹配還要用到定位銷。對大質量鑄件可能需要加入冷卻物來使其較快冷卻。

5.The patterns are removed, and the molds may be put through a baking stage to increase strength.6.Mold halves are mated and prepared for pouring metal.5.取走型模，將鑄模烘焙以增加強度。6.匹配上下鑄模，做好澆鑄金屬的準備。

7.Metal is preheated in a furnace or crucible until is above the liquidus temperature in a suitable range(we don’t want the metal solidifying before the pour is complete).The exact temperature may be closely controlled depending upon the application.7.金屬在熔爐或坩堝中預熱到高于液化溫度的一個合適范圍內(不希望金屬在澆鑄完成前凝固)。確切的溫度要根據應用場合嚴格控制。

Degassing, and other treatment processes may be done at this time, such as removal of impurities(i.e.slag).Some portion of this metal may be remelted scrap from previously cast parts—10% is reasonable.在此期間還要進行排氣和其它處理步驟，例如去除雜質(即熔渣)。可以加入一定量原先是這種金屬鑄件的廢料再融化—10%是適當的。

8.The metal is poured slowly, but continuously into the mold until the mold is full.9.As the molten metal cools(minutes to days), the metal will shrink and the volume will decrease.During this time molten metal may backflow from the molten risers to feed the part and maintain the same shape.8.將金屬緩慢而連續地注滿型模。

9.隨著熔化金屬的冷卻(幾分鐘到幾天)，金屬收縮體積減小。在此期間熔化金屬可能從冒口回流供給零件以保持其形狀不變。

10.Once the part starts to solidify small dendrites of solid material form in the part.During this time metal properties are being determined, and internal stresses are being generated.If a part is allowed to cool slowly enough at a constant rate then the final part will be relatively homogenous and stress free.10.在零件開始凝固其內部形成固態金屬的小型樹枝狀結晶期間金屬性能被確定，同時也產生了內應力。如果零件以恒定速率冷卻得足夠緩慢，最終零件將相對均質并釋放內應力。

11.Once the part has completely solidified below the eutectic point it may be removed with no concern for final metal properties.At this point the sand is simply broken up, and the part removed.At this point the surface will have a quantity of sand adhering to the surface, and solid cores inside.11.一旦零件在共析點以下完全凝固，可以不考慮金屬的最后性能而將其取出。這時可以簡單地打碎砂型并取出零件，但零件表面會有大量型砂粘附著，內部還有實心的砂芯。

12.A bulk of the remaining sand and cores can be removed by mechanically striking the part.Other options are to use a vibrating table, sand/shot blaster, hand labor, etc.12.大量的剩余型砂和砂芯要通過機械敲擊零件來去除。其它的選擇還有采用振動臺、噴砂/噴丸機、手工作業等等。13.The final part is cut off the runner gate system, and is near final shape using cutters, torches, etc.Grinding operations are used to remove any remaining bulk.14.The part is taken down to final shape using machining operations.And cleaning operations may be used to remove oxides, etc.13.最后零件要用刀具、噴槍等切掉澆道閘道系統，這樣就接近最終形狀了。再用磨削作業去除多余的部分。14.通過機加工將零件切削到最終形狀。可能還要用清洗作業去除氧化物等。

? Investment casting 熔模鑄造

Investment casting is also known as the lost wax process.This process is one of the oldest manufacturing processes.The Egyptians used it in the time of the Pharaohs to make gold jewelry(hence the name Investment)some 5,000 years ago.熔模鑄造也稱為失蠟加工。這是最古老的制造工藝之一。大約在5,000年前的法老王時代，埃及人就用它制造黃金飾品(因此而得名投資)。

Intricate shapes can be made with high accuracy.In addition, metals that are hard to machine or fabricate are good candidates for this process.It can be used to make parts that cannot be produced by normal manufacturing techniques, such as turbine blades that have complex shapes, or airplane parts that have to withstand high temperatures.復雜的形狀能被高精度地制造。另外較難機加工或制作的金屬都能用此工藝。它還能用于生產一般制造技術無法生產的零件，例如有復雜形狀的渦輪葉片或必須耐得住高溫的飛機零件。

The mold is made by making a pattern using wax or some other material that can be melted away.This wax pattern is dipped in refractory slurry, which coats the wax pattern and forms a skin.This is dried and the process of dipping in the slurry and drying is repeated until a robust thickness is achieved.制作鑄型的型模采用石蠟或其它一些能被融化掉的材料做成。石蠟型模浸泡在耐熱漿里，讓它覆蓋型模并形成外殼，然后使其變干。重復這個浸泡、變干的過程直至獲得足夠的厚度。

After this, the entire pattern is placed in an oven and the wax is melted away.This leads to a mold that can be filled with the molten metal.Because the mold is formed around a one-piece pattern(which does not have to be pulled out from the mold as in a traditional sand casting process), very intricate parts and undercuts can be made.完成后把整個型模放在烤箱里融化石蠟。這樣就做成了能填充熔化金屬的鑄型。由于這種鑄型是環繞整塊型模形成的(無需像傳統的砂型鑄造工藝那樣拔模)，能制作十分復雜的零件和浮雕。

The wax pattern itself is made by duplicating using a stereo lithography or similar model—which has been fabricated using a computer solid model master.石蠟型模本身能用立體制版或類似的模型復制—這可以采用計算機立體模型原版制作。

The materials used for the slurry are a mixture of plaster, a binder and powdered silica, a refractory, for low temperature melts.For higher temperature melts, sillimanite or alumina-silicate is used as a refractory, and silica is used as a binder.對較低熔化溫度而言，用于耐熱漿的材料是石膏作粘合劑和用粉末狀硅石作耐溫材料的混合物。對較高熔化溫度而言，則采用硅線石或氧化鋁硅酸鹽作耐溫材料、無水硅酸作粘合劑。

Depending on the fineness of the finish desired additional coatings of sillimanite and ethyl silicate may be applied.The mold thus produced can be used directly for light castings, or be reinforced by placing it in a larger container and reinforcing it more slurry.根據最后所需光潔度也可采用硅線石和乙烷基硅酸鹽。這樣生成的鑄模可直接用于薄壁鑄件或通過將其放在較大容器內用更多耐熱漿加強。

Just before the pour, the mold is pre-heated to about 1,000℃(1,832℉)to remove any residues of wax, harden the binder.The pour in the pre-heated mold also ensures that the mold will fill completely.在正要澆鑄之前，將型模預熱到約1,000℃(1,832℉)以去除剩余石蠟、硬化粘合劑。在預熱的型模中澆鑄也能保證型模完全充滿。

Pouring can be done using gravity, pressure or vacuum conditions.Attention must be paid to mold permeability when using pressure, to allow the air to escape as the pour is done.澆鑄可采用重力、壓力或真空條件來實現。當使用壓力時必須注意滲透性，以便在澆鑄的同時讓空氣逸出。

Tolerances of 0.5% of length are routinely possible, and as low as 0.15% is possible for small dimensions.Castings can weigh from a few grams to 35kg(0.1oz to 80lb), although the normal size ranges from 200g to about 8kg(7oz to 15 lb).Normal minimum wall thicknesses are about 1mm to about 0.5mm(0.040~ 0.020 in.)for alloys that can be cast easily.一般公差可能為長度的0.5%，小尺寸可能低到0.15%。雖然通常尺寸的鑄件重量范圍為200g到約8kg(7oz到15lb)，但實際可從幾克到35kg(0.1oz to 80lb)。對容易鑄造的合金而言，通常壁厚約為1mm到0.5mm(0.040~ 0.020 in.)。

The types of materials that can be cast are aluminum alloys, bronzes, tool steels, stainless steels, stellite, hastelloys, and precious metals.Parts made with investment castings often do not require any further machining, because of the close tolerances that can be achieved.可以用于鑄造的材料類型有：鋁合金、青銅、工具鋼、不銹鋼、鎢鉻鈷合金、鎳基合金和貴金屬。采用熔模鑄造的零件常常不需要進一步加工，因為熔模鑄造能達到精密的公差。

? Centrifugal Casting 離心鑄造

Centrifugal casting(Fig.3.3)as a category includes centrifugal casting, semi-centrifugal casting and centrifuging.In centrifugal casting, a permanent mold is rotated about its axis at high speeds(300 to 3,000rpm)as the molten metal is poured.離心鑄造(圖3.3)作為一個種類包括了離心鑄造、半離心鑄造和離心法鑄造。離心鑄造中，永久性的型模在熔化金屬澆鑄時以較高速度(300到3,000rpm)繞其軸線旋轉。

The molten metal is centrifugally thrown towards the inside mold wall, where it solidifies after cooling.The casting is usually a fine grain casting with a very fine-grained outer diameter, which is resistant to atmospheric corrosion, a typical situation with pipes.The inside diameter has more impurities and inclusions, which can be machined away.受離心力作用熔化金屬被拋向型模的內壁，在那里冷卻后固化。這種鑄件通常為外徑處晶粒非常細小的細晶粒鑄件，能耐大氣腐蝕，典型的情況是管子。內徑處則有較多的雜質和內含物，但可用機加工去除。

Only cylindrical shapes can be produced with this process.Size limits are up to 3m(10feet)diameter and 15m(50 feet)length.Wall thickness can be 2.5mm to 125mm(0.1~5.0in.).The tolerances that can be held on the OD can be as good as 2.5mm(0.1in.)and on the ID can be 3.8mm(0.15in.).The surface finish ranges from 2.5mm to 12.5mm(0.1~0.5in.)rms(root-mean-square).只有圓柱形才能用此工藝生產。尺寸限制為直徑大到3m(10feet)、長度大到15m(50feet)。壁厚為2.5mm到

125mm(0.1~5.0in.)。外徑公差保持在2.5mm(0.1in.)以內，內徑公差保持在3.8mm(0.15in.)以內。表面粗糙度的有效值(均方根)范圍為2.5mm到12.5mm(0.1~0.5in.)。

Typical materials that can be cast with this process are iron, steel, stainless steels, and alloys of aluminum, copper and nickel.Two materials can be cast by introducing a second material during the process.Typical parts made by this process are pipes, boilers, pressure vessels, flywheels, cylinder liners and other parts that are axis-symmetric.可用此工藝鑄造的典型材料有：鐵、鋼、不銹鋼以及鋁、銅和鎳的合金。通過在生產過程中加入第二種材料能進行兩種材料鑄造。采用這種工藝制造的典型零件有：管子、鍋爐、壓力容器、飛輪、汽缸襯墊和其它軸對稱零件。

Semi-centrifugal casting.The molds used can be permanent or expendable, can be stacked as necessary.The rotational speeds are lower than those used in centrifugal casting.半離心鑄造：型模可以是永久性的或是消耗性的，可根據需要疊加。它的旋轉速度比離心鑄造低。

The center axis of the part has inclusion defects as well as porosity and thus is suitable only for parts where this can be machined away.This process is used for making wheels, nozzles and similar parts where the axis of the part is removed by subsequent machining.零件的中心軸附近存在缺陷和孔隙，因此僅適用于能將這些機加工去除的零件。這種工藝被用于制造車輪、管嘴及類似的隨后可用機加工去除中心軸部分的零件。

Centrifuging.Centrifuging is used for forcing metal from a central axis of the equipment into individual mold cavities that are placed on the circumference.This provides a means of increasing the filling pressure within each mold and allows for reproduction of intricate details.This method is often used for the pouring of investment casting pattern.離心法鑄造：離心法鑄造用于迫使金屬從設備的中心軸進入分布在圓周上的單獨型腔。它為每個型腔提供了一種增加填充壓力方法并允許再現復雜細節。這種方法常用于澆鑄熔模鑄型。

Full-mold casting is a technique similar to investment casting, but instead of wax as the expendable material, polystyrene foam is used as the pattern.The foam pattern is coated with a refractory material.The pattern is encased in a one-piece sand mold.As the metal is poured, the foam vaporizes, and the metal takes its place.實型鑄造是與熔模鑄造類似的技術，但它用做型模的消耗材料是聚苯乙烯泡沫而不是石蠟。泡沫型模用難熔材料覆蓋。型模裝入整體砂模中。當金屬澆入時，泡沫材料蒸發，金屬取代其位置。

This can make complex shaped castings without any draft or flash.However, the pattern cost can be high due to the expendable nature of the pattern.Minimum wall thicknesses are 2.5mm, tolerances can be held to 0.3% on dimensions.Surface finish can be held from 2.5μm to 25μm(0.1μin.to 1.0μin.)rms(root-mean-square).它能制造沒有拔模斜度和縫脊的復雜形狀鑄件。然而由于型模的消耗特性，型模成本可能較高。最小壁厚為2.5mm，公差能保持在尺寸的0.3% 之內。表面粗糙度的有效值(均方根)能保持在2.5μm至25μm(0.1μin.至1.0μin.)之間。

Size limits are from 400g(1lb)to several tons.No draft allowance is required.Typical materials that can be cast with this process are aluminum, iron, steel, nickel alloys, copper alloys.Types of parts that can be made using these processes are pump housings, manifolds, and auto brake components.重量限制從400g(1lb)到數噸。無需留拔模余量。這種工藝所用的典型材料有：鋁、鐵、鋼、鎳合金、銅合金。可以采用這些工藝制造的零件類型有泵殼、復式接頭和自動剎車部件。

? Introduction

引言

Forging is an important hot-forming process.It is used in producing components of all shapes and sizes, from quite small items to large units weighing several tons.鍛造是一種重要的熱成型工藝。它能用于生產各種形狀和尺寸、從很小到重量數噸的零件。

Forging is the process by which metal is heated and is shaped by plastic deformation by suitably applying compressive force.Usually the compressive force is in the form of hammer blows using a power hammer or a press, as shown in Fig.4.1.在鍛造過程中先將金屬加熱，然后施加合適的壓力使其塑性變形。通常壓力都是以由如圖4.1所示的動力錘或壓力機提供的錘擊形式出現。

Hand forging tools comprise variously shaped hammers.The base on which the work is supported during forging

is the anvil.手工鍛造工具包括各種不同形狀的錘子。在鍛造中用于支撐工件的基礎是鐵砧。

For the semimechanized forging of small to medium-sized components, forging hammers powered by various means are employed.The feature common to all of them is that, like the hand forging hammer, they utilize the energy of a falling weight to develop the pressure needed for shaping the metal.對小到中等尺寸零件的半機械化鍛造而言，鍛錘可采用多種動力。就其一般特性而言，都象手工鍛錘一樣，它們均利用落重能量來產生金屬成型所需的壓力。

Larger components are forged by means of forging presses operated by steam or compressed air or by hydraulic or electric power.Largely automatic forging machines are used for the quantity production of engineering parts.鍛造大零件則要用到蒸汽、壓縮空氣、液力或電力驅動的鍛壓機。大型的自動化鍛機用于工程零件的批量生產。

A distinction may be made between open-die forging, usually in the form of hammer forging, and closed-die forging.In hammer forging, the component is shaped by hammer blows aided by relatively simple tools.These may include open dies i.e., dies that do not completely enclose the metal to be shaped.錘鍛中常用的開式模鍛與閉式模鍛是有區別的。在錘鍛中零件通過錘擊輔之以相對簡單的工具成型。其中包括開式鍛模，就是不完全封閉被成型金屬的模具。

One of the basic operations of hammer forging is the elongation of a piece of metal by stretching with hammer blows, causing it to become thinner and longer.In hand forging the work-piece is usually turned 90°after each blow, in order to forge it thoroughly and prevent its lateral expansion.錘鍛的基本操作之一就是通過錘擊使金屬伸長，促成其變細變長。手工鍛造時一般在每次錘擊后都轉過90°以充分鍛打工件并防止橫向膨脹。

The opposite of elongation is upsetting, which produces compressive shortening.For example, the diameter of a bar can be increased by heating and hammering axially.與伸長相反的是鐓粗，即產生壓縮性縮短。例如，棒料的直徑可以通過加熱和軸向錘擊而增大。

More important is closed-die forging, very widely used for mass production in industry, in which the metal is shaped by pressing between a pair of forging dies.The upper die is usually attached to the ram of a forging press or a forging hammer, while the lower die is stationary.更重要的是閉式模鍛，在工業上廣泛用于規模生產。閉式模鍛中金屬在一對鍛模之間擠壓成型。頂模通常放在鍛壓機的撞頭或鍛錘上，而底模則是固定的。

Together they form a closed die.Closed-die forging can produce components of greater complexity and accuracy, with a better surface finish than the more traditional methods not using closed dies.The dies are made of special heat-resistant and wear-resistant tool steels.兩者合在一起形成閉式鍛模。閉式模鍛能生產高度復雜和精確的零件，而且表面光潔度要比不用閉式鍛模的更傳統方法好。閉式鍛模采用特殊的耐熱、耐磨工具鋼制成。

A piece of hot metal sufficient to slightly overfill the die shape is placed in the bottom die, and the top die is forced against it, so that the metal takes the internal shape of the die.將一塊大小足以充填模腔并能稍有溢出的加熱金屬放入底模，并將頂模加壓合攏，這塊金屬便獲得該模腔的形狀。Closed-die forging is used for the rapid production of large numbers of fairly small parts and also for very large components.For the latter, e.g., modern jet-aircraft components, giant hydraulically operated presses are used, which can develop forces of 50,000 tons and more.閉式模鍛用于相當小的零件大批量快速生產，也可用于很大的零件。對后者而言，例如現代噴氣飛機零件，使用能產生50,000噸以上壓力的巨型液力鍛壓機。

One valuable feature of forging is that it improves the strength of the metal by refining the structure and making it uniform;so for heavy forgings, such as marine propeller shafts, an immensely powerful hydraulic press squeezes the metal with a force sometimes as great as 10,000 tonnes.鍛造有價值的特性之一是它通過使金屬組織均勻而改善強度，因此對諸如船舶螺旋槳軸之類的重型鍛件，要用能達10,000噸壓力的龐大而有力的液壓機來擠壓金屬。

Although the hydraulic forging press is a more expensive piece of equipment than a drop-forge, it has advantages beside those of giving greater strength and more uniform structure to large components.On account of the high pressure and squeezing action, it operates with less noise and vibration than a drop-forge.雖然這種液壓鍛機比落錘鍛造要昂貴得多，但它除了能給予大零件較高的強度和更均勻的組織外還有其它優點。由于較高的壓力和擠壓作用，它比落錘鍛造噪聲及振動都小得多。

As ingots of steel weighing 30 tonnes or more are forged in this way, manual operation is impossible and it is essential that all the manipulation of the ingot is done mechanically.由于這種情況下被鍛鋼坯重量大于30噸，人工操作是不可能的，鋼坯的所有操作都必須是機械化的。

Forging refines the grain structure and improves physical properties of the metal.With proper design, the grain flow can be oriented in the direction of principal stresses encountered in actual use.鑄造細化金屬的晶粒組織、改善其物理性能。通過適當的設計，可以使晶粒流動方向與實際使用時的主應力方向一致。

As shown in Fig.4.2, grain flow is the direction of the pattern that the crystals take during plastic deformation.Physical properties(such as strength, ductility and toughness)are much better in a forging than in the base metal, which has crystals randomly oriented.如圖4.2所示，晶粒流動的方向就是在塑性變形期間結晶排列的方向。鍛件的物理性能(如強度、延展性和韌性)遠好于基礎金屬，因為基礎金屬的晶粒是無序排列的。

Forgings are consistent from piece to piece, without any of the porosity, voids, inclusions and other defects.Thus, finishing operations such as machining

do not expose voids, because there aren’t any.Also coating operations such as plating or painting are straightforward due to a good surface, which needs very little preparation.鍛件各部分是連貫一致的，沒有孔隙、空洞、雜質及其它缺陷。因此像機加工之類的精加工工序不會受空洞的影響，因為根本就不存在。另外由于鍛件良好的表面，像電鍍或油漆之類的涂裝工序就很簡單，幾乎不需要做準備工作。

Forgings yield parts that have high strength to weight ratio, thus are often used in the design of aircraft frame members.A forged metal can result in the following:

鍛造生產的零件具有較高的強度重量比，所以常被用在飛機結構零件的設計中。

鍛造金屬可以導致下列結果：

? Increase length, decrease cross-section, called drawing out the metal.? Decrease length, increase cross-section, called upsetting the metal.? Change length, change cross-section, by squeezing in closed impression dies.This results in favorable grain flow for strong parts.●增加長度、減小橫截面，稱為延伸金屬。●減小長度、增加橫截面，稱為鐓粗金屬。●通過用封閉鍛模擠壓，改變長度和橫截面。

這導致有利的晶粒流使零件堅固。

? Common Forging Processes 常用的鍛造工藝

The metal can be forged hot(above recrystallization temperatures)or cold.金屬既可熱鍛(高于再結晶溫度)也可冷鍛。

Open die forgings/Hand forgings.Open die forgings or hand forgings are made with repeated blows in an open die, where the operator manipulates the workpiece in the die.The finished product is a rough approximation of the die.This is what a traditional blacksmith does, and is an old manufacturing process.開式模鍛/手工鍛：開式模鍛或手工鍛就是操作者操縱工件在開式鍛模中反復擊打。完成的產品是鍛模的粗糙近似物。這就是傳統鐵匠干的活，是較古老的制造工藝。

Impression die forgings/Precision forgings.Impression die forgings and precision forgings are further refinements of the blocker forgings.The finished part more closely resembles the die impression.壓模鍛/精密鍛：壓模鍛和精密鍛是雛形模鍛的進一步改進。完成的零件與模膛更相似。

Press forgings.Press forgings use a slow squeezing action of a press, to transfer a great amount of compressive force to the workpiece.Unlike an open-die forging where multiple blows transfer the compressive energy to the outside of the product, press forging transfers the force uniformly to the bulk of the material.壓鍛：壓鍛通過壓力機緩慢的擠壓動作將巨大的壓力傳遞給工件。不像開式模鍛那樣需要多次擊打把壓縮能量傳遞到零件外表面，壓鍛能將力均勻地傳遞給材料的主體。

This results in uniform material properties and is necessary for large weight forgings.Parts made with this process can be quite large as much as 125kg(260lb)and 3m(10 feet)long.這使材料性能一致，對大重量鍛件而言是十分必要的。采用此工藝生產的零件重量可達125kg(260lb)而長度可達3m(10 feet)。

Upset forgings.Upset forging increases cross-section by compressing the length, this is used in making heads on bolts and fasteners, valves and other similar parts.頂鍛：頂鍛通過壓縮長度增加橫截面，用于在螺栓等緊固件、柱塞及類似零件上制造頭部。

Roll forgings.In roll forging, a bar stock, round or flat is placed between die rollers which reduces the cross-section and increases the length to form parts such as axles, leaf springs etc.This is an essential form of draw forging.滾鍛：在滾鍛時，圓的或是扁平的棒料放在模輥之間縮小橫截面增加長度制成諸如輪軸、板簧之類的零件。這是軋鍛的基本形式。

Swaging.Swaging—a tube or rod is forced inside a die and the diameter is reduced as the cylindrical object is fed.The die hammers the diameter and causes the metal to flow inward causing the outer diameter of the tube or the rod to take the shape of the die.型鍛：型鍛—將圓管或圓棒強制壓入鍛模，隨著圓柱形物體的被壓入其直徑減小。鍛模錘擊橫斷面使金屬向內流動導致圓管或圓棒的外徑變為鍛模的形狀。

Net shape/Near-net shape forging.In net shape or near-net shape forging, forging results in wastage of material in the form of material flash and subsequent machining operations, as shown in Fig.4.3.This wastage can be as high as 70% for gear blanks, and even 90% in the case of aircraft structural parts.純型/近似純型鍛 ：采用純型鍛或近似純型鍛，產生材料損耗的主要形式是飛邊以及隨后的機加工，如圖4.3所示。齒輪毛坯材料損耗為70%，而飛機結構零件的材料損耗甚至達90%。

Net-shape and near-net-shape processes minimize the waste by making precision dies, producing parts with very little draft angle(less than 1°).These types of processes often eliminate or reduce machining.純型鍛和近似純型鍛工藝通過制作精密模具并生產鍛模斜角很小(小于1°)的零件能使材料損耗最小化。此類工藝通常可以省去或減少機加工。

The processes are quite expensive in terms of tooling and the capital expenditure required.Thus, these processes can be only justified for current processes that are very wasteful where the material savings will pay for the significant increase in tooling costs.從模具的角度而言這些工藝是相當昂貴的，需要資金投入。因此這些工藝只有對目前很浪費的生產過程，在材料節約足以補償模具成本的大量增加時才是合理的。

? Die Design Consideration 鍛模設計的考慮因素

? Parting surface should be along a single plane if possible, else following the contour of the part.The parting surface should be through the center of the part, not near the upper or lower edges.? 如果可能分模面應沿著單一平面，否則就順著零件輪廓方向。分模面應經過零件中心，而不要靠近上下邊緣。

If the parting line cannot be on a single plane, then it is good practice to use symmetry of the design to minimize the side thrust forces.Any point on the parting surface should be less than 75°from the principal parting plane.如果分模面不能在單一平面，利用設計的對稱性來減小側向推力不失為一種好方法。分模面上任意點與主分模面的夾角應小于75°。

? As in most forming processes, use of undercuts should be avoided as these will make the removal of the part difficult, if not impossible.? 如同大多數成型工藝，如果不是非用不可，盡量避免采用凹槽，因為凹槽會使零件難以取出。

? Generous fillets and radius should be provided to aid in material flow during the forging process.Sharp corners are stress-risers in the forgings, as well as make the dies weak in service.? Ribs should not be high or narrow;this makes it difficult for the material to flow.? 應提供盡可能大的倒角和半徑以幫助材料在鍛造過程中流動。銳角會增加鍛件中的應力，同時在使用時削弱鍛模。

? 加勁肋不要過高、過窄，因為這會造成材料流動困難。? Tolerances

公差

? Dimension tolerances are usually positive and are approximately 0.3% of the dimension, rounded off to the next higher 0.5mm(0.020in.).? 尺寸公差通常為正，大約取為該尺寸的0.3%，并圓整到較大的0.5mm(0.020in.)。

? Die wear tolerances are lateral tolerances(parallel to the parting plane)and are roughly +0.2% for copper alloys to +0.5% for aluminum and steel.? 鍛模磨損公差為側向公差(平行于分模面)，對銅合金大約為+0.2%，對鋁和鋼大約為+0.5%。

? Die closure tolerances are in the direction of opening and closing, and range from 1mm(0.040in.)for small forgings, die projection area＜150cm2(23in.2), to 6.25mm(0.25in.)for large forgings, die projection area＞6,500cm2(100in.2).? 鍛模的閉合公差處于開閉的方向上，范圍從對較小鍛件[其投影面積＜150cm2(23in.2)]取為1mm(0.040in.)，到

22較大鍛件[其投影面積＞6,500cm(100in.)]取為6.25mm(0.25in.)。

? Die match tolerances are to allow for shift in the upper die with respect to the lower die.? 鍛模的配合公差是為了允許上模能根據下模替換。

A proper lubricant is necessary for making good forgings.The lubricant is useful in preventing sticking of the workpiece to the die, and also acts as a thermal insulator to help reduce die wear.制造良好的鍛件必須有合適的滑潤劑。滑潤劑對防止工件粘住鍛模很有用，還可以作為絕熱體幫助減少鍛模磨損。

Powder metallurgy(Fig.5.1)uses sintering process for making various parts out of metal powder.The metal powder is compacted by placing in a closed metal cavity(the die)under pressure.粉末冶金(圖5.1)采用燒結工藝將金屬粉末制成各種各樣的零件。金屬粉末放在封閉的金屬腔(模具)中在壓力下被壓實。

This compacted material is placed in an oven and sintered in a controlled atmosphere at high temperatures and the metal powders coalesce and form a solid.A Second pressing operation, repressing, can be done prior to sintering to improve the compaction and the material properties.被壓實的材料置于爐內燒結，在高溫下爐內環境可控，金屬粉末熔合形成固體。在燒結前可以進行二次擠壓作業(再擠壓)以改善壓實狀態和材料性能。

Powder metallurgy is a highly developed method of manufacturing reliable ferrous and nonferrous parts.Made by mixing elemental or alloy powders and compacting the mixture in a die, the resultant shapes are then sintered or heated in a controlled atmosphere furnace.粉末冶金是一種高度發達的制造可靠鐵或非鐵零件的方法。通過混合元素或合金粉末并在模具中壓實混合物，再燒結或在環境可控爐內加熱制成最終形狀。

? Material

材料

The majority of the structural components produced by fixed die pressing are iron-based.The powders are elemental, pre-alloyed, or partially alloyed.大多數用固定模壓制的結構件都是鐵基的。粉末可以是單一元素、預先合金或部分合金。

Elemental powders, such as iron and copper, are easy to compress to relatively high densities, produce pressed compacts with adequate strength for handling during sintering, but do not produce very high strength sintered parts.諸如鐵、銅之類的單一元素粉末較容易被壓得相對密度較高、生產具備足夠強度的壓制物供燒結處理，但是無法制造出很高強度的燒結零件。

Pre-alloyed powders are harder, less

compressible and hence require higher pressing loads to produce high density compacts.However, they are capable of producing high strength sintered materials.預先合金粉末比較硬、不容易壓實，因此需要較高的擠壓力來產生高密度的壓制物。然而它們能生成高強度燒結材料。

Pre-alloying is also used when the production of a homogeneous material from elemental powders requires very high temperatures and long sintering times.The best examples are the stainless steels, whose chromium and nickel contents have to be pre-alloyed to allow economic production by powder metallurgy.如果用單一元素粉末生產均勻材料需要很高溫度和較長燒結時間，也可用預先合金。最好的例子是不銹鋼，因含有鉻和鎳成分，所以粉末冶金必須用預先合金才經濟。

Partially alloyed powders are a compromise approach.Elemental powders, e.g.iron with 2wt.% copper, are mixed to produce an homogeneous blend which is then partially sintered to attach the copper particles to the iron particles without producing a fully diffused powder but retaining the powder form.部分合金粉末是一種折衷的方法。單一元素粉末，例如鐵與2%的銅(重量百分比)混合均勻，經部分燒結后銅微粒粘附到鐵微粒上而沒有產生充分擴散的粉末卻保留了粉末的形態。

In this way the compressibilities of the separate powders in the blend are maintained and the blend will not segregate during transportation and use.用這種方法混合物中單獨粉末的可壓縮性得以維持，在運送和使用期間結合將不會分離。

A similar technique is to “glue” the small percentage of alloying element onto the iron powder.This “glueing” technique is successfully used to introduce carbon into the blends, a technique which prevents carbon segregation and dusting, producing so-called “clean” powders.另一種類似的技術是把小百分比的合金元素“粘合”到鐵微粒上。這種“粘合”技術已成功用于將碳引入結合物，一種防止碳分離并起塵的技術，生產所謂的“清潔”粉末。

? Powder Consolidation 粉末合成

Components or articles are produced by forming a mass of powder into a shape, then consolidating to form inter-particle metallurgical bonds.通過將大量的粉末放入模具成型為零件或物品，然后合成為內有微粒的冶金結合物。

An elevated temperature diffusion process referred to as sintering, sometimes assisted by external pressure, accomplishes this.The material is never fully molten, although there might be a small volume fraction of liquid present during the sintering process.Sintering can be regarded as welding the particles present in the initial useful shape.提升溫度擴散工藝被稱為燒結，有時還輔之以外界的壓力來達到目的。雖然在燒結過程中可能會有少量液態出現，但材料決不是全熔化。燒結可以被看作是把微粒焊接成初始的有用形狀。

As a general rule both mechanical and physical properties improve with increasing density.Therefore the method selected for the fabrication of a component by powder metallurgy will depend on the level of performance required from the part.Many components are adequate when produced at 85~90% of theoretical full density whist others require full density for satisfactory performance.作為普遍規律，隨著密度的增加機械和物理性能均改善。因此選擇何種粉末冶金方法來制作零件取決于其所需的性能級別。許多零件只需理論全密度的85~90%而其它的則需全密度才能滿足要求。

Some components, in particular bush type bearings often made from copper and its alloys, are produced with significant and controlled levels of porosity, the porosity being subsequently filled with a lubricant.Fortunately there is a wide choice of consolidation techniques available.有些零件，尤其是襯套式軸承常用銅及其合金制作，控制多孔性程度的意義重大，因為這些孔隨后要填充潤滑劑。

還好有多種合成技術可供選擇。Cold Uniaxial Pressing

Elemental metal, or an atomized pre-alloyed powder is mixed with a lubricant, typically lithium stearate(0.75 wt.%), and pressed at pressures of say, 600MPa(87,000lb/in.2)in metal dies.冷單向擠壓

單一元素金屬，或極小顆粒的預先合金粉末與潤滑劑(一般是鋰硬脂酸鹽，重量百分比0.75%)混合，然后在金屬模具中施加壓力[比如600MPa(87,000lb/in.2)]擠壓。

Cold compaction ensures that the as-compacted, or “green”, component is dimensionally very accurate, as it is moulded precisely to the size and shape of the die.冷擠壓能保證被壓制或“未加工”的零件尺寸十分精確，因為它被精確地按模具的尺寸和形狀成型。

One disadvantage of this technique is the differences in pressed density that can occur in different parts of the component due to particle/particle and die wall/particle frictional effects.Typical as-pressed densities for soft iron components would be 7.0g/cc, i.e.about 90% of theoretical density.這種技術的缺點之一是由于微粒/微粒和模壁/微粒間的摩擦效應，零件不同部位的壓實密度存在差異。典型的軟鐵零件壓制密度為7.0g/cc，即大約是理論密度的90%。

Compaction pressure rises significantly if higher as-pressed densities are required, and this practice becomes uneconomic due to higher costs for the larger presses and stronger tools to withstand the higher pressures.如果需要較高的壓實密度則壓實壓力要顯著提高，因為大型壓力機成本較高并且在較高壓力下模具強度要更高這樣就不合算。

Cold Isostatic Pressing

Metal powders are contained in an enclosure e.g.a rubber membrane or a metallic can that is subjected to isostatic, which is uniform in all directions, external pressure.As the pressure is isostatic the as-pressed component is of uniform density.冷均衡擠壓

金屬粉末裝入均衡受壓的橡膠膜或金屬罐內，其所受外壓力在各個方向都是均勻的。由于壓力是均衡的，所以壓制零件密度是均勻的。

Irregularly shaped powder particles must be used to provide adequate green strength in the as-pressed component.This will then be sintered in a suitable atmosphere to yield the required product.必須采用不規則形狀粉末微粒為壓制零件提供足夠的未加工強度。然后放入合適的環境中燒結成所需產品。

Normally this technique is only used for semi-fabricated products such as bars, billets, sheet, and roughly shaped components, all of which require considerable secondary operations to produce the final, accurately dimensioned component.通常這種技術只用于制作諸如棒料、坯段、薄板及粗糙成型零件之類的半成品，所有這些都需要大量進一步加工才能生產出最終尺寸精確的零件。

Again, at economical working pressures, products are not fully dense and usually need additional working such as hot extrusion, hot rolling or forging to fully density the material.此外使用經濟工作壓力的產品不是充分致密的，一般需要增加諸如熱擠壓、熱軋或鍛之類的額外工序來使材料達到全密度。Sintering

Sintering is the process whereby powder compacts are heated so that adjacent particles fuse together, thus resulting in a solid article with improved mechanical strength compared to the powder compact.燒結

燒結就是通過把粉末壓制物加熱使鄰近的微粒熔合在一起的工藝，它能生成比粉末壓制物機械強度更好的固體物。

This “fusing” of particles results in an increase in the density of the part and hence the process is sometimes called densification.There are some processes such as hot isostatic pressing which combine the compaction and sintering processes into a single step.微粒的“熔合”導致零件密度增加，因此該工藝有時被稱為致密化。還有一些工藝如熱均衡擠壓，將壓實和燒結工藝合并為單一步驟。

After compaction the components pass through a sintering furnace.This typically has two heating zones, the first removes the lubricant, and the second higher temperature zone allows diffusion and bonding between powder particles.零件壓實后通過燒結爐。一般有兩個加熱區，第一個去除潤滑劑，第二個溫度更高的區域讓粉末微粒之間擴散并結合。

A range of atmospheres, including vacuum, are used to sinter different materials depending on their chemical compositions.As an example, precise atmosphere control allows iron/carbon materials to be produced with specific carbon compositions and mechanical properties.根據不同材料的化學成分，燒結的環境包括真空狀態也各不相同。例如精確的環境控制可使鐵/碳材料生成特殊碳化物和機械性能。

The density of the component can also change during sintering, depending on the materials and the sintering temperature.These dimensional changes can be controlled by an understanding and control of the pressing and sintering parameters，根據材料和燒結溫度的不同，零件的密度在燒結過程中也會改變。因為尺寸的變化可以通過了解并調節擠壓及燒結參數進行控制，and components can be produced with dimensions that need little or no rectification to meet the dimensional tolerances.Note that in many cases all of the powder used is present in the finished product, scrap losses will only occur when secondary machining operations are necessary.所以零件尺寸幾乎無需校正就能滿足尺寸公差。可以看到在很多情況下所有使用的粉末都包含在制成品中，廢料損失僅產生于需要輔助機加工時。Hot Isostatic Pressing

Powders are usually encapsulated in a metallic container but sometimes in glass.The container is evacuated, the powder out-gassed to avoid contamination of the materials by any residual gas during the consolidation stage and sealed-off.熱均衡擠壓

粉末通常封裝在金屬容器內有時也裝在玻璃容器內。把容器抽真空，粉末抽氣是為了防止材料在合成階段和密封時被殘留氣體污染。

It is then heated and subjected to isostatic pressure sufficient to plastically deform both the container and the powder.再加熱并施加均衡壓力足以使容器和粉末都塑性變形。

The rate of densification of the powder depends upon the yield strength of the powder at the temperatures and pressures chosen.At moderate temperature the yield strength of the powder can still be high and require high pressure to produce densification in an economic time.粉末致密率取決于該粉末在選定溫度和壓力下的屈服強度。中等溫度下粉末的屈服強度仍然較高，因此需要較高壓力使其在經濟時間內致密化。

Typical values might be 1120℃ and 100MPa for ferrous alloys.By pressing at very much higher temperatures lower pressures are required as the yield strength of the material is lower.Using a glass enclosure atmospheric pressure(15psi)is used to consolidate bars and larger billets.對鐵合金典型的數值為1120℃和100MPa。由于很高溫度下材料的屈服強度較低，因此只需較低壓力就能擠壓。采用玻璃容器時可用大氣壓力(15psi)合成棒料和較大坯段。

The technique requires considerable financial investment as the pressure vessel has to withstand the internal gas pressure and allow the powder to be heated to high temperatures.因為壓力容器必須經受住內氣壓并允許粉末加熱到較高溫度，所以這種技術需要相當可觀的資金投入。

As with cold isostatic pressing only semi-finished products are produced, either for subsequent working to smaller sizes, or for machining to finished dimensions.此工藝與采用冷均衡擠壓一樣只能生產半成品，可以通過后續加工至較小尺寸，也能用機加工到最終尺寸。Hot Forging(Powder Forging)

Cold pressed and sintered components have the great advantage of being close to final shape(near-net shape), but are not fully dense.Where densification is essential to provide adequate mechanical properties, the technique of hot forging, or powder forging, can be used.熱鍛(粉末鍛造)

冷擠壓和燒結零件主要優點是接近最終形狀(近似純形)，但不是充分致密的。當為了提供足夠的機械性能而致密化是必須時，可以采用熱鍛或粉末鍛造技術。

In powder forging an as-pressed component is usually heated to a forging temperature significantly below the usual sintering temperature of the material and then forged in a closed die.This produces a fully dense component with the shape of the forging die and appropriate mechanical properties.在粉末鍛造中，壓制零件一般加熱到遠低于該材料通常燒結溫度的鍛造溫度，然后在閉模中鍛造。這能生產具有鍛模形狀和合適機械性能的充分致密零件。

Powder forged parts generally are not as close to final size or shape as cold pressed and sintered parts.These results from the allowances made for thermal expansion effects and the need for draft angles on the forging tools.Further, minimal machining is required but when all things are considered this route is often very cost-effective.粉末鍛造零件通常不像冷擠壓和燒結零件那樣接近最終尺寸或形狀。這是由于為熱膨脹效應而設置允差以及在鍛模上需要拔模斜角所致。此外還需少量機加工，但全面考慮這種方法通常還是很劃算的。Metal Injection Moulding(MIM)

Injection moulding is very widely used to produce precisely shaped plastic components in complex dies.As injection pressures are low it is possible to manufacture complex components, even some with internal screw threads, by the use of side cores and split tools.金屬注塑成型(MIM)

注塑成型被很廣泛地用于在復雜模具中生產形狀精確的塑料零件。注塑壓力較低使得制作復雜零件成為可能，通過采用側面型芯和分離工具甚至可以帶有內螺紋。

By mixing fine, typically less than 20 μm diameter, spherical metal powders with thermoplastic binders, metal filled plastic components can be produced with many of the features available in injection moulded plastics.After injection moulding, the plastic binder material is removed to leave a metal skeleton which is then sintered at high temperature.將細小(直徑一般小于20μm)球形金屬粉末與熱塑性粘合劑混合，能生產具有多數注塑成型塑料特征的金屬充滿塑料零件。注塑成型后，去除塑料粘合材料剩下金屬骨架，然后在高溫下燒結。

Dimensional control can be exercised on the as-sintered component as the injected density is sensibly uniform so shrinkage on sintering is also uniform.燒結零件可以實現尺寸控制，因為注塑密度明顯均勻，所以燒結收縮也是均勻的。

Shrinkage can be large, due to both the fine particle size of the powders and the substantial proportion of polymer binder used.由于所用粉末細小微粒的尺寸和聚合物粘合劑的真實比例，收縮可以比較大。

? Features

特征

? For high tolerance parts, a sintering part is put back into a die and repressed.In genera this makes the part more accurate with a better surface finish.? 對較大公差的零件，燒結后可放回模具重新擠壓。一般而言這會使零件更精確同時具有更好的表面光潔度。? A part has many voids that can be impregnated.One method is to use an oil bath.Another method uses vacuum first, then impregnation.? 零件有許多可供填充的空間。一種方法是采用油浴。另一種方法是先抽真空然后再充滿。

? A part surface can be infiltrated with a low melting point metal to increase density, strength, hardness, ductility and impact resistance.? Plating, heat treating and machining operations can also be used.? 零件表面能被低熔點金屬滲透以增大密度、強度、硬度、延展性和抗沖擊能力。? 仍然可以進行電鍍、熱處理和機加工作業。? Advantages

優點

? Good tolerances and surface finish ? Highly complex shapes made quickly ? Can produce porous parts and hard to manufacture materials(e.g.cemented oxides)? 良好的公差和表面光潔度 ? 高度復雜的形狀能快速制作

? 能制作多孔零件和難以加工材料(如粘結氧化物)? Pores in the metal can be filled with other materials/metals ? Surfaces can have high wear resistance ? Porosity can be controlled ? Low waste ? Automation is easy ? 金屬中的氣孔可用其它材料/金屬填充 ? 表面能具有較高的耐磨性 ? 孔隙率可以控制 ? 較低損耗 ? 容易自動化

? Physical properties can be controlled ? Variation from part to part is low ? Hard to machine metals can be used easily ? No molten metals ? 物理性能可以控制 ? 零件之間的變化較小

? 難以機加工的金屬能被容易使用 ? 無需熔化金屬

? No need for many/any finishing operations ? Permits high volume production of complex shapes ? Allows non-traditional alloy combinations ? Good control of final density ? 不需要很多/任何修整作業

? 允許加工復雜形狀的大體積產品 ? 允許非傳統合金結合 ? 對最終密度能很好地控制 ? Disadvantages

缺點

? Metal powders deteriorate quickly when stored improperly ? Fixed and setup costs are high ? Part size is limited by the press and compression of the powder used ? 如果存放不當金屬粉末質量很快降低 ? 安裝和調整的成本較高

? 零件尺寸受壓力機和所用粉末壓縮的限制

? Sharp corners and varying thickness can be hard to produce ? Non-moldable features are impossible to produce

? 銳角和變厚度較難加工

? 不適合模壓的東西不可能生產

Injection molding(Fig.6.1)is the predominant process for fabrication of thermoplastics into finished forms, and is increasingly being used for thermosetting plastics, fiber-filled composites, and elastomers.注塑成型(圖6.1)是將熱塑性塑料制成最終形狀的主要工藝，并且越來越多地用于熱硬化性塑料、纖維填充合成物和人造橡膠。

It is the process of choice for tremendous variety of parts ranging in weight from 5g to 85kg.It is estimated that 25% of all thermoplastics are injection molded.它是重量范圍為5g到85kg極大一類零件可選用的工藝。估計所有熱塑性塑料中有25%是采用注塑成型的。If newer modifications, such as reaction injection molding, and the greatly increased rate of adoption of plastics as substitutes for metals are considered, it is likely that the worldwide industrial importance of injection molding will continue to increase.如果考慮到新近的改進(例如反作用注塑成型)和采用塑料替代金屬的高增長率，注塑成型在世界范圍的工業重要性很可能將繼續增加。

Currently, probably close to half of all major processing units is injection molding machines.In 1988, a dollar sale of new injection molding machinery in the U.S.was approximately 65% of total major polymer machinery sales volume;this included 4,600 injection molding units.當前，大概所有主要處理設備的近一半是注塑成型機。1988年，美國新的注塑成型機械銷售約占全部主要聚合物機械銷售量的65%，其中包括4,600臺注塑成型設備。

The machines and their products are ubiquitous and are synonymous with plastics for many people.這類機械和它們的產品普遍存在，對許多人來說與塑料是同義的。

A reciprocating screw injection molding machine combines the functions of an extruder and a compressive molding press.往復螺旋注射成型機把壓出機和成型壓力機的功能結合起來。

It takes solid granules of thermoplastic resin, melts and pressurizes them in the extruder section, forces the melt at high velocity and pressure through carefully designed flow channels into a cooled mold, then ejects the finished part(s), and automatically recycles.把熱塑性塑料樹脂的固體顆粒在壓出部分融化并增壓，迫使其高速融化并通過仔細設計的流動通道進入冷卻模具，噴射成最終零件，然后自動再循環。

This machine is a descendant of the plunger type “stuffing machine” patented by the Hyatt brothers in 1872 to mold celluloid.In 1878, the Hyatts developed the first multicavity mold, but it was not until 1938 that Quillery(France)patented a machine incorporating a screw to plasticize the elastomer being molded.這種機械是1872年Hyatt兄弟獲得專利權的融化賽璐珞的活塞型“填充機”的派生物。1878年Hyatt兄弟開發了第一個多槽模具，但直到1938年Quillery(法國)才發明了用螺旋增塑人造橡膠并使其成型的一體化機械。

In 1956, Ankerwerk Nuremberg commercialized the modern reciprocating screw injection molding machine for thermoplastics.Today, over 50 machine manufacturers are listed in Modern Plastics Encyclopedia, offering machines to the U.S.market ranging from 2 to 6,000 tons clamping capacity.1956年，Ankerwerk Nuremberg使用于熱塑性塑料的現代往復螺旋注塑成型機商業化。今天，已有超過50家制造商列入現代塑料制品百科全書，能為美國市場提供壓制能力從2到6,000噸的機械。

(A machine with a 10,000-ton capacity has been built to mold 264-gallon HDPE trash containers.)A host of suppliers of auxiliary equipment, molds, instruments, and controls service this major segment of the polymer industry.(一臺能力為10,000噸用于成型264加侖高密度聚乙烯垃圾箱的機械也已制成)。許多輔助設備、模具、儀器和控制系統供應商在為聚合物工業的這一主要部分服務。

Injection molding is particularly worthy of intensive study because it combines many areas of interest extrusion, mold design, rheology, sophisticated hydraulic and electronic controls, robotic accessories, design of complex products, and, of course, the integration of materials science and process engineering.注塑成型對深入研究很有價值，因為它結合了許多重要領域，如擠壓、模具設計、流變學、完備的液壓和電子控制、機器人配件、復雜產品的設計，當然還有材料科學與加工工程的綜合。

The objectives of injection molding engineers are simple enough: to obtain minimum cycle time with minimum scrap, to attain specified product performance with assurance, to minimize production costs due to downtime or any other reasons, and to steadily increase in expertise and competitiveness.注塑成型工程師的目標很簡單：在最少廢料的情況下取得最小循環時間，在有保證的情況下獲得指定產品性能，將由停工或其它原因產生的生產成本最小化，還有穩定地增加專門知識和競爭力。

Profit margins for custom injection molders are said to be generally skimpy;an established way to improve profits is to be selected for more demanding, higher margin jobs that demand the highest level of efficiency and competence.傳統的注塑成型機利潤盈余據說一般是不足的；為了更多需求及更高盈余工作需要選擇一種改善利潤的確定方法，它要求最高水平的效率和能力。

This text will concentrate on the reciprocating screw machine for thermoplastics, which has largely replaced the older reciprocating plunger types except for very small-capacity machines.本文將集中論述熱塑性塑料用的往復螺旋機，除了小容量機械外它已在很大程度上取代了較老的往復活塞式機械。

? Injection Molding Materials 注塑成型材料

It is not possible to injection-mold all polymers.Some polymers like PTFE(Poly-tetra-fluoro-ethylene), cannot be made to flow freely enough to make them suitable for injection molding.要注塑成型所有聚合物是不可能的。像聚四氟乙烯之類的聚合物就不能自由流動得足以適合注塑成型。Other polymers, such as a mixture of resin and glass fiber in woven or mat form, are unsuitable by their physical nature for use in the process.In general, polymers which are capable of being brought to a state of fluidity can be injection-molded.其它聚合物，例如樹脂和編織的或墊子形的玻璃纖維的混合物，由于它們的物理性質不適合使用此工藝。一般而言，能進入流動狀態的聚合物都可以注塑成型。

The vast majority of injection molding is applied to thermoplastic polymers.This class of materials consists of polymers which always remain capable of being softened by heat and of hardening on cooling, even after repeated cycling.注塑成型的絕大多數都用于熱塑性聚合物。這類材料由具有加熱軟化、冷卻硬化甚至可重復循環能力的聚合物組成。

This is because the long-chain molecules of the material always remain as separate entities and do not form chemical bonds to one another.An analogy car, be made to a block of ice that can be softened(i.e.turned back to liquid), poured into any shape cavity, and then cooled to become a solid again.這是由于這類材料的長鏈分子總是保持分離的實體并不相互形成化學連結。一輛由冰塊制成的模擬汽車，可以融化(即轉化為液態)，倒入任何形狀的空腔，然后冷卻重新變成固體。

This property differentiates thermoplastic materials from thermosetting ones.In the latter type of polymer, chemical bonds are formed between the separate molecule chains during processing.In this case the chemical bonding referred to as cross linking is the hardening mechanism.這個特性將熱塑性材料與熱硬化性材料區分開。后者在加工過程中分離的分子鏈之間形成化學連結。在此情況下作為交聯的化學連結是硬化機制。

In general, most of the thermoplastic materials offer high impact strength, corrosion resistance, and easy processing with good flow characteristics for molding complex designs.Thermoplastics are generally divided into two classes: namely crystalline and amorphous.一般而言，大多數熱塑性材料具有較高的抗沖擊強度、耐腐蝕性以及良好流動性使其容易加工而適于復雜成型設計。熱塑性塑料通常分為兩類：即結晶質的和非結晶質的。

Crystalline polymers have an ordered molecular arrangement, with a sharp melting point.Due to the ordered arrangement at molecules, the crystalline polymers reflect most incidents light and generally appear opaque.結晶質聚合物具有規則的分子排列及明顯的熔點。由于規則的分子排列，結晶質聚合物能反射大多數特定光線并一般表現為不透明的。

They also undergo a high shrinkage or reduction in volume during solidification.Crystalline polymers usually are more resistant to organic solvents and have good fatigue and wear-resistant properties.Crystalline polymers also generally are denser and have better mechanical properties than amorphous polymers.它們在固化過程中收縮較大或體積減少較多。結晶質聚合物通常多能抵御有機溶劑并具有良好的抗疲勞和磨損特性。結晶質聚合物通常也比非結晶質聚合物更致密并且具有更好的機械性能。

The main exception to this rule is polycarbonate, which is the amorphous polymer of choice for high quality transparent moldings, and has excellent mechanical properties.其中主要例外是聚碳酸酯，它是可選用做高質量透明注塑件的非結晶質聚合物，并具有卓越的機械性能。

The mechanical properties of thermoplastics, while substantially lower than those of metals, can be enhanced for some applications through the addition of glass fiber reinforcement.This takes the form of short-chopped fibers, a few millimeters in length, which are randomly mixed with the thermoplastic resin.就本質而言，熱塑性塑料的機械性能低于金屬，但可以通過加入玻璃纖維強化予以增強來適應某些運用。常用幾毫米長的短碎纖維隨機地與熱塑性樹脂混合。

The fibers can occupy up to one third of the material volume to considerably improve the material strength and stiffness.The negative effect of this reinforcement is usually a decrease in impact strength and an increase in abrasiveness.纖維可占材料體積的三分之一以極大改善材料的強度和硬度。這種加強的負作用通常是抗沖擊強度降低及磨損性增加。

The latter also has an effect on processing since the life of the mold cavity is typically reduced from about 1,000,000 parts for plain resin parts to about 300,000 for glass-filled parts.后者對加工過程也有影響，因為模具腔的壽命從典型的普通樹脂零件大約1,000,000件減少到玻璃纖維填充樹脂零件的約300,000件。

Perhaps the main weakness of injection-molded parts is the relatively low service temperatures to which they can be subjected.Thermoplastic components can only rarely be operated continuously above 250℃, with an absolute upper service temperature of about 400℃.注塑成型零件的主要缺點或許是它們能承受的工作溫度相對較低。熱塑性塑料零件只有很少能連續運行在250℃以上，其絕對最高工作溫度約為400℃。

The temperature at which a thermoplastic can be operated under load can be defined qualitatively by the heat deflection temperature.This is the temperature at which a simply supported beam specimen of the material, with a centrally applied load, reaches a predefined deflection.熱塑性塑料帶載運行溫度可從質量上定義為熱偏差溫度。這是中心承載的該材料簡支梁達到預定偏差的溫度。The temperature value obviously depends upon the conditions of the test and the allowed deflection and for this reason, the test values are only really useful for comparing different polymers.其溫度值明顯取決于試驗條件和允許偏差，因此對比較不同的聚合物而言只有試驗數據是真正有用的。

? Cycle of Operation 作業循環

The reciprocating screw injection molding machine is considered as consisting of two halves: a fixed injection side, and a movable clamp side.往復螺旋注塑成型機被認為由兩部分組成：一個固定注塑端和一個活動夾具端。

The injection side contains the extruder that receives solid resin in pellet or granular form and converts it into a viscous liquid or melt that can be forced through the connecting nozzle, spine, and runners to the gates that lead into the mold cavities.注塑端包含壓出機，它接受小球或粒狀的固體樹脂，然后將其轉化為粘性液體或稱為融化，再強迫其通過連接噴嘴、中心和澆道到閘道進入模具腔。

The mold is tightly clamped against injection pressure and is cooled well below the melt temperature of the thermoplastic.When the parts in the cavities have cooled sufficiently the mold halves are opened at the mold parting plane and the parts ejected by a knockout system drop into a receiving bin below.模具被緊緊地夾住以抵抗注塑壓力，并在熱塑性塑料的融化溫度以下很好地冷卻。當模腔內的零件充分冷卻，剖分模在模具分模面處打開，推出系統將零件推出落入下面的接收容器內。

This summarizes the overall cycle, but leaves out much vital detail that is necessary for understanding the process.However, with this introduction, it is possible to understand the advantages and disadvantages of the process.這概述了整個循環，但省略了許多對理解此工藝所必需的很重要細節。然而通過本介紹，了解這種工藝的優缺點仍是可能的。

? Effects of Process Variables on Orientation

加工變量對方向性的影響

In injection molding, any variation in processing that keeps the molding resin hot throughout filling allows increased relaxation and, therefore, decreased orientation.Some of the steps that can be taken to reduce orientation are as follows.在注塑成型時，整個填料過程始終保持成型樹脂高溫的任何加工變化都會增加松弛作用而減少方向性。下面是可以用于減少方向性的若干措施。

? Faster injection(up to a point): less cooling during filling, hence a thinner initial frozen layer, lower viscosity due to shear thinning;better flow to corners;and less

crystallinity all favor lower subsurface orientation.The primary effect is that the gate will freeze more quickly.At that point, orientation stops and relaxation starts.? 較快注塑(到點)：在填料過程中冷卻較少，因此初始固化層較薄，由于剪應變稀少而粘性較低；能較好地流到角落；結晶度較小；所有這些促成表面下的方向性也較低。主要效果是閘道將較快固化。這樣使得方向性停止產生而松弛作用開始增加。

? Higher melt and mold temperatures: lower melt viscosity, easier filling, and greater relaxation favor reduced orientation.? Reduced packing time and pressure: overpacking inhibits relaxation processes.? 較高的融化和成型溫度：融化粘性較低，更容易填充，較大松弛作用促成方向性減少。? 減少擠壓時間和壓力：過度擠壓會抑制松弛過程。

? Reduced gate size: larger gates take longer to freeze off and permit increased orientation.? 減小閘道尺寸：閘道越大則固化時間越長并會使方向性增加。

Excessively high injection speed can cause high surface orientation and increase susceptibility to stress cracking.For example, moldings that are to be electroplated, and will be subject to acid solutions during plating, must be made using very slow injection speeds to minimize surface orientation.過高的注塑速度會引起較高的表面方向性及增加應力破裂的敏感性。例如，要電鍍的注塑件在電鍍時會經受酸溶液，必須采用很低的注塑速度制造以使表面方向性最小化。

On the other hand, the transverse motion component of the melt front in most moldings can cause transverse subsurface orientation superimposed on the primary orientation, giving a desirable biaxial orientation effect.另一方面，大多數注塑件的融化前部橫向運動部分能導致在主要方向性上有層理的表面下橫向方向性，產生需要的雙軸方向性效應。

Orientation can be seriously increased by obstructions to flow during filling of the cavity.Flow around an obstruction causes a decrease in melt front speed and leads to high local viscosity and reduced relaxation.This is also likely to occur near the end of the filling phase if gating is inadequate.在填充模腔時流動受到阻礙會極大地增加方向性。圍繞障礙物流動使融化前部的速度下降并產生較高的局部粘性而減少松弛作用。如果閘道不適當，這也很可能發生在接近填充結束階段。

The molder must recognize the dangers of excessive fill speed, insufficient injection pressure, excessive melt temperature, and inadequate packing.These dangers are weighed against the opposing effects on orientation discussed above.注塑工必須認識過快填充速度、不足注塑壓力、過高融化溫度和不充分擠壓的危害性。這些危害性要與上述方向性的反向效應相權衡。

Thicker parts delay cooling and increase relaxation time and tend to result in lower orientation.Thicker parts also tend to warp less.Therefore, a minimum wall thickness can be established by experience for various shapes, materials, and process combinations.較厚零件會延遲冷卻并且增加松弛時間，趨向于導致較低的方向性。較厚零件也有助于減少翹曲。因此，對各種形狀、材料和工藝組合能通過經驗來確定最小壁厚。

Lower molecular weight and broader molecular weight distribution in thermoplastics favor lower orientation and reduced internal stress in moldings.在熱塑性塑料中較小的分子量以及較寬泛的分子量分布促成方向性減少同時降低注塑件中的內應力。

The skin thickness ratio is affected by process variables in the same way as one would predict for the orientation;that is, it decreases as the melt or mold temperatures and cavity pressure increases.Tensile strength and stiffness increase as skin thickness ratio increases.Microscopic examination thus provides another way of studying the process efficiently.外殼厚度比受加工變量影響的方式與方向性預測一樣；也就是它能隨融化或成型溫度及模腔壓力的增加而減少。拉伸強度和硬度隨外殼厚度比增加而增加。因而顯微鏡檢查提供了有效研究該工藝的另一方法。

? Advantages

優點

1.High production rates.For example, a CD disk can be produced with a 10~12s cycle in high melt flow index PC.1.高生產率：例如，一張CD盤在高融體流動指數生產控制中只需10~12s一個循環就能生產出來。

2.Relatively low labor content.One operator can frequently take care of two or more machines, particularly the moldings are unloaded automatically onto conveyors.2.相對較少的工作內容：一個操作者經常可以照看兩臺以上機械，尤其是當成品能自動卸到輸送機上時。

3.Parts require little or no finishing.For example, flash can be minimized and molds can be arranged to automatically separate runners and gates from the part itself.4.Very complex shapes can be formed.Advances in mold tooling are largely responsible.3.零件幾乎不需要修整：例如，飛邊可以最小化并且模具能被設計成自動將澆道和閘道從零件本身分離。

4.非常復雜的形狀也能成型：模具的進步很大程度上是可靠的。

5.Flexibility of design(finishes, colors, inserts, materials).More than one material can be molded through co-injection.Foam core materials with solid skins are efficiently produced.Thermosetting plastics and fiber-reinforced shapes are injection molded.5.設計的靈活性(光潔度、顏色、插入物、材料)：通過復合注塑可以成型多于一種材料。可以高效地生產帶有固體外殼的泡沫型芯材料。熱硬化性塑料和纖維加強形狀都可以注塑成型。

6.Minimum scrap loss.Runners, gates, and scrap can usually be reground.Recycled thermoplastics can be injection molded.6.廢料損失最小化：澆道、閘道和廢料通常可以重新研磨。循環熱塑性塑料可以注塑成型。

7.Close tolerances are obtainable.Modern microprocessor controls, fitted to precision molds, and elaborate hydraulics, facilitate tolerances in the 0.1% range on dimensions and weights(but not without a high level of operational skills in constant attendance).7.能得到接近的公差：現代微處理器控制、合適的精密模具和精心制作的液壓設備使得尺寸和重量的公差保持在0.1% 的范圍內(但不是沒有在持續照看時的高水平操作技能)。

8.Makes best use of the unique attributes of polymers, such as flow ability, light weight, transparency, and corrosion resistance.This is evident from the number and variety of molded plastic products in everyday use.8.充分利用聚合物諸如流動能力、重量輕、透明和耐腐蝕等獨特屬性：從日常使用成型塑料產品的數量和種類就能明顯看到。

? Disadvantages and Problems 缺點和問題

1.High investment in equipment and tools requires high production volumes.2.Lack of expertise and good preventive maintenance can cause high startup and running costs.1.較高的設備和模具投資需要較高生產量才合算。

2.缺少專門技術和良好的預防性維修會導致較高的啟動和運行成本。

3.Quality is sometimes difficult to determine immediately.For example, post-mold warpage may render parts unusable because of dimensional changes that are not completed for weeks or months after molding.3.質量有時難以馬上確定。例如，成型后的翹曲會導致零件不能用，因為在成型后幾星期甚至幾個月尺寸變化都不能完成。

4.Attention is required on many details requiring a wide variety of skills and cross-disciplinary knowledge.5.Part design sometimes is not well suited to efficient molding.4.對許多需要廣泛多樣性技能和交叉學科知識的細節必須加以注意。

5.零件設計有時不能很好地適應有效率的成型。

6.Lead time for mold design, mold manufacture and debugging trials is sometimes very long.6.模具設計、模具制造和調試試驗這些先導工作有時要花費很長時間。

The importance of machining processes can be emphasised by the fact that every product we use in our daily life has undergone this process either directly or indirectly.(1)In USA, more than $100 billions are spent annually on machining and related operations.機加工過程的重要性可通過日常生活使用的每件產品都直接或間接經歷這一過程的事實來強調。

(1)在美國，每年花在機加工及其相關作業上的費用都多于千億美元。

(2)A large majority(above 80%)of all the machine tools used in the manufacturing industry have undergone metal cutting.(3)An estimate showed that about 10 to 15% of all the metal produced in USA was converted into chips.(2)用于制造業的全部機床中的大多數(多于80%)都經歷過金屬切削。

(3)有估計顯示美國生產的所有金屬中約10到15%轉變成了切屑。

These facts show the importance of metal cutting in general manufacturing.It is therefore important to understand the metal cutting process in order to make the best use of it.這些事實說明了金屬切削在常規制造中的重要性。因此了解金屬切削過程以充分利用它是重要的。

A number of attempts have been made in understanding the metal cutting process and using this knowledge to help improve manufacturing operations which involved metal cutting.在了解金屬切削過程并運用這些知識幫助改善與金屬切削有關的制造作業方面已經做了許多努力。

A typical cutting tool in simplified form is shown in Fig.7.1.The important features to be observed are follows.典型切削刀具的簡化形式如圖7.1所示。要注意的重要特征如下。

1.Rake angle.It is the angle between the face of the tool called the rake face and the normal to the machining direction.Higher the rake angle, better is the cutting and less are the cutting forces, increasing the rake angle reduces the metal backup available at the tool rake face.1.前角：它是被稱為前傾面的刀具面與垂直機加工方向的夾角。前角越大，則切削越好且切削力越小，增加前角可以減少刀具前傾面上產生的金屬阻塞。

This reduces the strength of the tool tip as well as the heat dissipation through the tool.Thus, there is a maximum limit to the rake angle and this is generally of the order of 15°for high speed steel tools cutting mild steel.It is possible to have rake angles at zero or negative.但這會和減少通過刀具散發的熱量一樣減少刀尖強度。因此前角有一最大限制，用高速鋼刀具切削低碳鋼通常為15°。前角取零度或負值也是可能的。

2.Clearance angle.This is the angle between the machined surface and the underside of the tool called the flank face.The clearance angle is provided such that the tool will not rub the machined surface thus spoiling the surface and increasing the cutting forces.A very large clearance angle reduces the strength of the tool tip, and hence normally an angle of the order of 5~6°is used.2.后角：這是機加工面與被稱為后側面的刀具底面夾角。后角使刀具不產生會損壞機加工面的摩擦和增加切削力。很大的后角會削弱刀尖的強度，因此一般采用5~6°的后角。

The conditions which have an important influence on metal cutting are work material, cutting tool material, cutting tool geometry, cutting speed, feed rate, depth of cut and cutting fluid used.對金屬切削有重要影響的條件有工件材料、刀具材料、刀具幾何形狀、切削速度、進給率、切削深度和所用的切削液。

The cutting speed, v, is the speed with which the cutting tool moves through the work material.This is generally expressed in metres per second(ms-1).切削速度v指切削刀具經過工件材料的移動速度。通常用米每秒(ms-1)表示。

Feed rate, f, may be defined as the small relative movement per cycle(per revolution or per stroke)of the cutting tool in a direction usually normal to the cutting speed direction.Depth of cut, d, is the normal distance between the unmachined surface and the machined surface.進給率f可定義為每循環(每轉或每行程)切削刀具在通常為垂直于切削速度方向的次要相對運動。

切削深度d是未加工面與已加工面之間的垂直距離。

? Chip Formation 切屑的形成

Metal cutting process is a very complex process.Fig.7.2 shows the basic material removal operation schematically.金屬切削過程是一個很復雜的過程。圖7.2用圖的形式顯示了基本材料去除作業。

The metal in front of the tool rake face gets immediately compressed, first elastically and then plastically.This zone is traditionally called shear zone in view of fact that the material in the final form would be removed by shear from the parent metal.在刀具前傾面前的金屬直接受到壓縮，首先彈性變形然后塑性變形。考慮到最終形狀中的材料是通過剪切從母體金屬去除的，此區域傳統上稱為剪切區。

The actual separation of the metal starts as a yielding or fracture, depending upon the cutting conditions, starting from the cutting tool tip.Then the deformed metal(called chip)flows over the tool(rake)face.金屬的實際分離始于屈服或斷裂(視切削條件而定)，從切削刀尖開始。然后變形金屬(稱為切屑)流過刀具(前傾)面。If the friction between the tool rake face and the underside of the chip(deformed material)is considerable, then the chip gets further deformed, which is termed as secondary deformation.The chip after sliding over the tool rake face is lifted away from the tool, and the resultant curvature of the chip is termed as chip curl.如果刀具前傾面與切屑(變形金屬)底面之間的摩擦相當大，那么切屑進一步變形，這也叫做二次變形。滑過刀具前傾面的切屑被提升離開刀具，切屑彎曲的結果被稱為切屑卷。

Plastic deformation can be caused by yielding, in which case strained layers of material would get displaced over other layers along the slip-planes which coincide with the direction of maximum shear stress.屈服能導致塑性變形，在這種情況下材料變形層沿著與最大剪應力方向一致的滑移面被其它層所取代。

A chip is variable both in size and shape in actual manufacturing practice.Study of chips is one of the most important things in metal cutting.As would be seen later, the mechanics of metal cutting are greatly dependent on the shape and size of the chips produced.在實際加工過程中切屑的尺寸和形狀都是變化的。對切屑的研究是金屬切削最重要的事情之一。如同后面將要看到的那樣，金屬切削力學極大地依賴于所產生切屑的形狀和尺寸。

Chip formation in metal cutting could be broadly categorised into three types:(Fig.7.3)

(1)Discontinuous chip

(2)Continuous chip

(3)Continuous chip with BUE(Built up edge)

金屬切削中的切屑形成可以寬泛地分成三個類型(圖7.3)：

(1)間斷切屑

(2)連續切屑

(3)帶切屑瘤的連續切屑

Discontinuous Chip.The segmented chip separates into short pieces, which may or may not adhere to each other.Severe distortion of the metal occurs adjacent to the face, resulting in a crack that runs ahead of the tool.間斷切屑：分段的切屑分散成小碎片，既可能相互附著也可能不相互附著。在靠近切削面處發生金屬的劇烈變形，導致在運動刀具前方金屬層產生裂縫。

Eventually, the shear stress across the chip becomes equal to the shear strength of the material, resulting in fracture and separation.With this type of chip, there is little relative movement of the chip along the tool face, Fig.7.3a.最后，橫過切屑的剪切應力與材料的剪切強度相等，造成斷裂和分離。生成這類切屑時，切屑沿刀具面幾乎沒有相對運動，見圖7.3a。

Continuous chip.The continuous chip is characterized by a general flow of the separated metal along the tool face.There may be some cracking of the chip, but in this case it usually does not extend far enough to cause fracture.連續切屑：連續的切屑一般具有分離金屬沿刀具面流動的特征。切屑可能有一些破裂，但在這種情況下切屑通常不會延長到足以引起斷裂。

This chip is formed at the higher cutting speeds when machining ductile materials.There is little tendency for the material to adhere to the tool.The continuous chip usually shows a good cutting ratio and tends to produce the optimum surface finish, but it may become an operating hazard, Fig.7.3b.這種切屑形成于用較高切削速度機加工有延展性的材料時。材料幾乎沒有粘附刀具的傾向。連續切屑通常具有良好的切削率和趨向于產生最適宜的表面光潔度，但可能成為操作的危險之源，見圖7.3b。

Continuous with a built-up edge.This chip shows the existence of a localized, highly deformed zone of material attached or “welded” on the tool face.帶切屑瘤的連續切屑：這種切屑顯示了粘合或“焊接”在刀具面上材料局部高度變形區的存在。

Actually, analysis of photomicrographs shows that this built-up edge is held in place by the static friction force until it becomes so large that the external forces acting on it cause it to dislodge, with some of it remaining on the machined surface and the rest passing off on the back side of the chip, Fig.7.3c.實際上，對顯微照片的分析顯示這種切屑瘤受到靜摩擦力抑制直至它變得大到作用在它上面的外力使其移動，一些留在機加工表面上而另一些延伸到切屑的背面，見圖7.3c。

? Shear Zone

剪切區

There are basically two schools of thought in the analysis of the metal removal process.One school of thought is

that the deformation zone is very thin and planar as shown in Fig.7.4a.The other school thinks that the actual deformation zone is a thick one with a fan shape as shown in Fig.7.4b.在對金屬去除過程的分析中主要存在兩種思想學派。一種思想學派認為變形區如圖7.4a所示那樣非常薄而平坦。另一學派則認為真實變形區象圖7.4b所示那樣為一厚的帶有扇形的區域。

Though the first model(Fig.7.4a)is convenient from the point of analysis, physically it is impossible to exist.This is because for the transition from undeformed material to deform to take place along a thin plane, the acceleration across the plane has to be infinity.雖然第一種模型(圖7.4a)從分析的角度看是方便的，但實際上是不可能存在的。這是由于未變形的材料沿著剪切面發生變形，而且越過剪切面的加速度無窮大。

Similarly the stress gradient across the shear plane has to be very large to be practical.同樣在實際運用中越過剪切面的應力梯度必須很大才行。

In the second model(Fig.7.4b)by making the shear zone over a region, the transitions in velocities and shear stresses could be realistically accounted for.在第二種模型(圖7.4b)中讓剪力區分布于一個范圍，速度和剪應力的轉變能說明得更符合實際。

The angle made by the shear plane with the cutting speed vector, Φ is a very important parameter in metal cutting.Higher the shear angle better is the cutting performance.From a view of the Fig.7.4a, it can be observed that a higher rake angles give rise to higher shear angles.由剪切面和切削速度矢量形成的角度Φ在金屬切削中是一個十分重要的參數。剪切角越大，切削作業越好。從圖7.4a觀察，可以看到較大的前角能增大剪切角。

? Cutting Tool Materials 切削刀具材料

Various cutting tool materials have been used in the industry for different applications.A number of developments have occurred in the current century.在工業中為了不同的應用可以使用各種各樣的切削刀具材料。在最近的百年里產生了許多進展。

A large variety of cutting tool materials has been developed to cater to the variety of materials used in these programmes.Before we discuss the properties of these materials, let us look at the important characteristics expected of a cutting tool material.多種切削刀具材料被開發出來以滿足這些方案中使用材料的多樣性。討論這些材料性能之前，先看一下作為切削刀具材料應具備哪些重要特性。

1.Higher hardness than that of the workpiece material being machined, so that it can penetrate into the work material.2.Hot hardness, which is the ability of the material to retain its hardness at elevated temperatures in view of the high temperatures existing in the cutting zone.1.硬度要比被切削工件材料高，這樣它才能進入工件材料。

2.熱硬度，即材料由于存在于切削區的高溫而升溫時仍能保持其硬度的能力。

3.Wear resistance—The chip-tool and chip-work interfaces are exposed to such severe conditions that adhesive and abrasion wear is very common.The cutting tool material should therefore have high abrasion resistance to improve the effective life of the tool.3.耐磨性—切屑-刀具與切屑-工件的接觸界面處于如此嚴酷的狀態，粘附和磨損是很普遍的。因此切削刀具材料應具有高耐磨性以提高刀具的有效壽命。

4.Toughness—Even though the tool is hard, it should have enough toughness to withstand the impact loads that come in the beginning of cut or force fluctuations due to imperfections in the work material.This requirement is going to be more useful for the interrupted cutting, e.g.milling.4.韌性—雖然刀具是堅硬的，但也應有足夠的韌性以經受住沖擊載荷，這些載荷來自于切削的開始或由于工件材料的缺陷而產生的作用力波動。這個要求對如銑削之類的間斷切削更有用。

5.Low friction—The coefficient of friction between the chip and tool should be low.This would allow for lower wear rates and better chip flow.5.低摩擦系數—切屑與刀具間的摩擦系數應當較低。這會使磨損率較小及切屑流動更好。

6.Thermal characteristics—Since a lot of heat is generated at the cutting zone, the tool material should have higher thermal conductivity to dissipate this heat in the shortest time, otherwise the tool temperature would become high, reducing its life.6.熱特性—因為大量的熱產生在切削區，刀具材料應當具有較高的熱傳導性以在最短的時間內散發熱量，否則刀具溫度會升高，壽命會減少。

All these characteristics may not be found in a single tool material.Improved tool materials have been giving a better cutting performance.所有這些特性不可能存在于單一刀具材料中。改進的刀具材料已經被賦予較好的切削性能。

? Surface Finish

表面光潔度

Machining operations are utilized in view of the better surface finish that could be achieved by it compared to other manufacturing operations.由于機加工能獲得比其它制造作業更好的表面光潔度，所以機加工作業具有實用價值。

Thus it is important to know what would be the effective surface finish that can be achieved in a machining operation.The surface finish in a given machining operation is a result of two factors: 因而了解能在機加工作業中獲得怎樣的實際表面光潔度是重要的。給定機加工作業中的表面光潔度是兩個因素共同作用的結果：

(1)the ideal surface finish, which is a result of the geometry of the manufacturing process which can be determined by considering the geometry of the machining operation, and(2)the natural component, which is a result of a number of uncontrollable factors in machining, which is difficult to predict.(1)理想的表面光潔度，是通過考慮機加工作業的幾何體系所決定的制造工藝幾何學的結果，和(2)自然要素，即在機加工中一些難以預測的不可控因素作用的結果。Ideal Surface Finish in Turning

The actual turning tool used would have a nose radius in place of the sharp tool point, which modifies the surface geometry as shown in Fig.7.5a.If the feed rate is very small, as is normal in finish turning, the surface is produced purely by the nose radius alone as shown in Fig.7.5.車削中的理想表面光潔度

實際使用的車削刀具有一個刀尖半徑取代鋒利刀尖，它將表面幾何形狀加工為如圖7.5a所示。如果進給率很小，象精車中很正常的那樣，工件表面則完全是由刀尖半徑單獨產生的，如圖7.5所示。

For the case in Fig.7.5, the surface roughness value is to be

Ra=8f2/(18R√3)

Where: Ra is the surface roughness value

R is the nose radius

f is the feed rate

對圖7.5這種情況，表面粗糙度值為

Ra=8f2/(18R√3)式中：Ra是表面粗糙度值

R是刀尖半徑

f是進給率

The above are essentially geometric factors and the values represent an ideal situation.The actual surface finish obtained depends to a great extent upon a number of factors such as:

上述基本為幾何要素，其值代表了理想情況。而實際獲得的表面光潔度很大程度上還取決于下列一些因素：(1)the cutting process parameter, speed, feed and depth of cut(2)the geometry of the cutting tool(3)application of cutting fluid(4)work and tool material characteristics(5)rigidity of the machine tool and the consequent vibrations.(1)切削工藝參數、速度、進給和切削深度(2)切削刀具的幾何形狀(3)切削液的運用

(4)工件和刀具的材料特性

(5)機床的剛度及其伴隨發生的振動

The major influence on surface finish is exerted by the feed rate and cutting speed.As the feed decreases, from the above equations, we can see that the roughness index decreases.對表面光潔度產生主要影響的是進給率和切削速度。從上述公式可以看到，隨著進給的減少，粗糙度指標會降低。

Similarly as the cutting speed increases, we have better surface finish.Thus while making a choice of cutting process parameters for finish, it is desirable to have high cutting speed and small feed rates.同樣隨著切削速度的增大，能得到較好表面光潔度。因此在為光潔度而選擇切削工藝參數時，采用較高的切削速度和較小的進給率是適當的。

? Cutting Fluids

切削液

The functions of cutting fluids(which are often erroneously called coolants)are: ? To cool the tool and workpiece ? To reduce the friction

切削液(經常誤稱為冷卻液)的功能如下：

? 冷卻刀具和工件 ? 減少摩擦

? To protect the work against rusting ? To improve the surface finish ? To prevent the formation of built-up edge ? To wash away the chips from the cutting zone ? 保護工件不生銹 ? 改善表面光潔度 ? 防止切屑瘤的形成 ? 從切削區沖掉切屑

However, the prime function of a cutting fluid in a metal cutting operation is to control the total heat.This can be done by dissipating the heat generated as well as reducing it.The mechanisms by which a cutting fluid performs these functions are: cooling action and lubricating action.然而，在金屬切削作業中切削液的主要功能是控制總熱量。這可通過既散發又減少所產生的熱量來達到。切削液實現這些功能的機理是：冷卻作用和潤滑作用。

Cooling action.Originally it was assumed that cutting fluid improves the cutting performance by its cooling properties alone.That is why the name coolant was given to it.冷卻作用：最初設想切削液僅僅是通過冷卻特性來改善切削作業。這也是它曾被稱為冷卻液的原因。

Since most of the tool wear mechanisms are thermally activated, cooling the chip tool interface helps in retaining the original properties of the tool and hence prolongs its life.由于大多數刀具的磨損機理都是由熱引起的，冷卻切屑刀具接觸界面有助于保持刀具的原有特性，從而延長其使用壽命。

However, a reduction in the temperature of the workpiece may under certain conditions increase the shear flow stress of the workpiece, thereby decreasing tool life.It has been shown through a number of investigations that cooling in fact is one of the major factors in improving the cutting performance.可是工件溫度的降低在特定條件下會增加工件的剪切流動應力，從而降低刀具壽命。通過一些研究已經表明實際上冷卻只是改善切削作業的主要因素之一。

Lubricating action.The best improvement in cutting performance can be achieved by the lubricating action since this reduces the heat generated, thus reducing the energy input to the metal cutting operation.潤滑作用：切削作業的最大改善可通過潤滑作用來達到，由于它減少了熱量的產生因而減少了金屬切削作業的能量輸入。

However, if the cutting fluid is to be effective, it must reach the chip tool interface.But it is not easy to visualize how it is accomplished in the case of a continuous turning with a single point turning tool, specially when the chip-tool contact pressure is as high as 70 MPa.可是，如果要使切削液起作用就必須讓它到達切屑刀具接觸界面。但如何在采用單尖刀具連續車削的場合尤其是切屑-刀具接觸壓力高達70MPa時實現并非易事。

Merchant thought that minute asperities existed at the chip-tool interface and the fluid was drawn into the interface by the capillary action of the interlocking network of these surface asperities.Merchant認為：在切屑與刀具接觸界面上存在微小的粗粒，切削液通過這些表面的微小粗粒組成連鎖的網絡的毛細管被吸入到切屑與刀具的接觸界面上。

Grinding is a manufacturing process that involves the removal of metal by employing a rotating abrasive wheel.The latter simulates a milling cutter with an extremely large number of miniature cutting edges.磨削是通過采用旋轉磨輪去除金屬的制造工藝。磨輪用非常大量的微型切削刃模仿銑刀進行切削。

Generally, grinding is considered to be a finishing process that is usually used for obtaining high-dimensional accuracy and better surface finish.Grinding can be performed on flat, cylindrical, or even internal surfaces by employing specialized machine tools, which are referred to as grinding machines.一般而言，磨削被認為是一種通常用于獲得高尺寸精度和較好表面光潔度的精加工作業。磨削通過采用被稱為磨床的特殊機床能在平面、圓柱面甚至內表面上進行。

Obviously, grinding machines differ in construction as well as capabilities, and the type to be employed is determined mainly by the geometrical shape and nature of the surface to be ground, e.g., cylindrical surfaces are ground on cylindrical grinding machines.顯然，磨床根據結構和功能的不同有所區別，使用何種形式的磨床主要取決于被磨削表面的幾何形狀和物理性質。例如，圓柱面在外圓磨床上磨削。

? Type of Grinding Operations 磨削作業的類型

1.Surface grinding.As the name surface grinding suggests, this operation involves grinding of flat or plane surfaces.Fig.8.1 indicates the two possible variations, either a horizontal or vertical machine spindle.1.表面磨削：就像其名稱暗示的那樣，表面磨削和平面磨削直接有關。圖8.1表示了兩種可能的變化：臥式磨床主軸或立式磨床主軸。

In the first case(horizontal spindle), the machine usually has a planer-type reciprocating table on which the workpiece is held.However, grinding machines with vertical spindles can have either a planer type table like that of the horizontal-spindle machine or a rotating worktable.在第一種情況(臥式主軸)，臥式磨床通常具有安裝工件的刨床式往復工作臺。而立式主軸磨床既可以像臥式主軸磨床那樣具有刨床式工作臺也可以具有旋轉工作臺。

Also, the grinding action in this case is achieved by the end face of the grinding wheel(Fig.8.1b), contrary to the case of horizontal-spindle machines, where the workpieces ground by the periphery of the grinding wheel.而且在這種情況下，磨削動作是通過砂輪端面完成的(圖8.1b)，這與通過砂輪周邊磨削工件的臥式主軸磨床正好相反。

Fig.8.1a and b also indicate the equations to be used for estimating the different parameters of the grinding operation, such as the machining time and the rate of metal removal.圖8.1a和b同時簡述了用于估計諸如加工時間和金屬去除率之類的磨削作業不同參數的方程式。

During the surface-grinding operations, heavy workpieces are either held in fixtures or clamped on the machine table by strap clamps and the like, whereas smaller workpieces are usually held by magnetic chucks.在平面磨削時，重的工件用夾具固定或用壓板等夾緊在磨床工作臺上，而小的工件則通常是用電磁卡盤固定的。2.Cylindrical grinding.In cylindrical grinding, the workpiece is held between centers during the grinding operation, and the wheel rotation is the source and cause for the rotary cutting motion, as shown in Fig.8.2.In fact, cylindrical grinding can be carried out by employing any of the following methods: 2.圓柱面磨削：在圓柱面磨削中，作業時工件支撐在兩頂尖之間，砂輪轉動是導致回轉切削運動的動力源，如圖8.2所示。實際上，圓柱面磨削能通過采用下列任意方法來實現：

(1)The transverse method, in which both the grinding wheel and the workpiece rotate and longitudinal linear feed is applied to enable grinding of the whole length.The depth of cut is adjusted by the cross feed of the grinding wheel into the workpiece.(1)橫向方法：這種方法中砂輪與工件均旋轉且采用線性縱向進給以保證能磨削整個長度。切削深度通過改變砂輪對工件的橫向進給來進行調整。

(2)The plunge-cut method, in which grinding is achieved through the cross feed of the grinding wheel and no axial feed is applied.As you can see, this method can be applied only when the surface to be ground is shorter than the width of the grinding wheel used.(2)插入-切削方法：這種方法通過砂輪的橫向進給完成磨削而不采用軸向進給。正如料想的那樣，這種方法只在要磨削表面比所用砂輪寬度短時才使用。

(3)The full-depth method, which is similar to the transverse method except that the grinding allowance is removed in a

single pass.This method is usually recommended when grinding short rigid shafts.(3)全深度方法：這種方法除了一次加工就能去除磨削余量外其它與橫向方法相同。這種方法通常在磨削較短剛性軸時推薦使用。

Internal grinding.Internal grinding is employed for grinding relatively short holes, as shown in Fig.8.3.The workpiece is held in a chuck or a special fixture.Both the grinding wheel and the workpiece rotate during the operation and feed is applied in the longitudinal direction.內表面磨削：內表面磨削用于相對較短的孔，如圖8.3所示。工件安裝在卡盤或特殊夾具上。作業時砂輪和工件都回轉并且采用縱向進給。

Any desired depth of cut can be obtained by the cross feed of the grinding wheel.A variation from this type is planetary internal grinding, which is recommended for heavy workpieces that cannot be held in chucks.通過砂輪的橫向進給能得到任意所需的切削深度。這種方法的一個變體是行星式內表面磨削，當工件較重不能用卡盤固定時推薦使用。

In that case, the grinding wheel not only spins around its own axis but also rotates around the centerline of the hole that is being ground.在這種情況下，砂輪不但繞自身軸線回轉，同時還繞被磨削孔的中心線旋轉。

Centerless grinding.Centerless grinding involves passing a cylindrical workpiece, which is supported by a rest blade, between two wheels, i.e., the grinding wheel and the regulating or feed wheel.無心磨削：無心磨削用于加工圓柱形工件，工件由托板支撐，在兩輪即砂輪和調節或進給輪之間通過去。The grinding wheel does the actual grinding, while the regulating wheel is responsible for rotating the workpiece as well as generating the longitudinal feed.This is possible because of the frictional characteristics of that wheel, which is usually made of rubber-bonded abrasive.砂輪完成實際磨削，而調節輪負責旋轉工件和產生縱向進給。由于調節輪通常用橡膠粘結的磨料制成，其摩擦特性使這成為可能。

As can be seen in Fig.8.4, the axis of the regulating wheel is tilted at a slight angle with the axis of the grinding wheel.Consequently, the peripheral velocity of the regulating wheel can be resolved into two components, namely, workpiece rotational speed and longitudinal feed.正如在圖8.4中所看到的那樣，調節輪的軸與砂輪軸傾斜一個微小角度。因此調節輪的圓周速度可以分解為兩個分量，即工件回轉速度和縱向進給。

These can be given by the following equations:

Vworkpiece＝Vregulating wheel×cosα

Axial feed＝Vregulating wheel×c×sinα

Where c is a constant coefficient to account for the slip between the workpiece and the regulating wheel(c=0.94~0.98).其值可由下列公式給出：

V工件＝V調節輪×cosα

軸向進給＝V調節輪×c×sinα

式中c是考慮工件和調節輪之間滑動的恒定系數(c=0.94~0.98)。

The velocity of the regulating wheel is controllable and is used to achieve any desired rotational speed of the workpiece.The angleαis usually taken from 1°to 5°and the larger the angle, the larger the longitudinal feed would be.調節輪的速度是可控的并被用于實現工件任意所需的轉動速度。α角通常取1到 5°，這角度越大則縱向進給也將越大。

Whenαis taken as 0°, i.e., the two axes of the grinding and regulating wheels are parallel, there is no longitudinal feed of the workpiece.當α取0°時，即砂輪和調節輪軸線平行時，則工件沒有縱向進給。

? Grinding Wheels 砂輪

Grinding wheels are composed of abrasive grains having similar size and a binder.The actual grinding process is performed by the abrasive grains.Pores between the grains within the binder enable the grains to act as separate single-point cutting tools.砂輪由具有相近尺寸的磨料顆粒和粘合劑組成。實際磨削作業由磨粒完成。在粘合劑中磨粒之間的孔隙使磨粒能象獨立的單刃切削刀具一樣工作。

These pores also provide space for the generated chips, thus preventing the wheel from clogging.In addition, pores assist the easy flow of coolants to enable efficient and prompt removal of the heat generated during the grinding process.這些孔隙同時還為產生的切屑提供空間以防砂輪堵塞。另外孔隙幫助冷卻液容易流動，從而使在磨削作業中產生的熱量能有效而迅速地散發。

Grinding wheels are identified based on their shape and size, kind of abrasive, grain size, binder, grade(hardness), and structure.砂輪根據它們的形狀和尺寸、磨料的類型、磨粒的大小、粘合劑、等級(硬度)和結構組織來分類。

Shape and size of grinding wheels.Grinding wheels differ in shape and size, depending upon the purpose for which they are to be used.Various shapes are shown in Fig.8.5 and include the following types:

砂輪的形狀和尺寸：根據砂輪的用途，它們的形狀和尺寸是不同的。各種形狀如圖8.5所示，其中包括： 1)Straight wheels used for surface, cylindrical, internal, and centerless grinding.2)Bevelled-face or tapered wheels used for grinding threads, gear teeth, and the like.3)Straight recessed wheels for cylindrical grinding and facing.1)用于表面、圓柱面、內部和無心磨削的直輪。2)用于磨削螺紋、齒輪輪齒之類的斜面或錐形輪。3)用于圓柱面和端面磨削的直凹輪。

4)Abrasive disks for cutoff and slotting operations.(thickness 0.02 up to 0.2in.(0.5 to 5mm)).5)Cylinders, straight cups, and flaring cups are used for surface grinding with the end face of the wheel.4)用于切斷和開槽作業的砂輪片(其厚度從0.02到0.2英寸(0.5到5毫米))。5)用其端面進行表面磨削的圓柱、直杯及外展杯狀砂輪。

The main dimensions of a grinding wheel are the outside diameter D, the bore diameter d, and the height H.These dimensions vary widely, depending upon the grinding process for which the wheel is to be used.砂輪的主要尺寸有外徑D、孔徑d和厚度H。根據采用砂輪的磨削工藝，這些尺寸變化很大。

Kind of abrasive.Grinding wheels can be made of natural abrasives such as quartz, emery, and corundum or of industrially prepared chemical compounds such as aluminum oxide or silicon carbide(known as carborundum).磨料的類型：砂輪可以由象石英、金剛砂、剛玉之類的自然磨料制成，或者由象氧化鋁或碳化硅(也稱人造金剛砂)之類的工業制備的化學化合物制成。

Generally, silicon carbide grinding wheels are used when grinding low-tensile-strength materials like cast iron, whereas aluminum oxide wheels are employed for grinding high-strength metals such as alloy steel, hardened steel, and the like.當磨削象鑄鐵類低拉伸強度材料時，一般采用碳化硅砂輪，而磨削合金鋼、淬火鋼等高強度金屬則要用氧化鋁砂輪。

Grain size of abrasive used.As you may expect, the grain size of the abrasive particles of the wheel plays a fundamental role in determining the quality of ground surface obtained.所用磨粒的尺寸：正如料想的那樣，砂輪磨粒的尺寸對決定所得磨削表面的質量起著根本的作用。

The finer the grains, the smoother the ground surface is.Therefore, coarse-grained grinding wheels are used for roughing operations, whereas fine-grained wheels are employed in final finishing operations.磨粒越細，磨削表面越光滑。所以，粗粒砂輪用于粗加工，而細粒砂輪則用于最后精加工。

The grade of the bond.The grade of the bond is actually an indication of the resistance of the bond to pulling off the abrasive grains from the grinding wheel.Generally, wheels having hard grades are used for grinding soft materials and vice versa.粘結體的等級：粘結體的等級實際上是其抵抗將磨粒從砂輪上拉脫的指標。一般而言，具有較硬等級的砂輪用于磨削較軟材料，反之亦然。

If a hard-grade wheel were to be used for grinding a hard material, the dull grains would not be pulled off from the bond quickly enough, thus impeding the self-dressing process of the surface of the wheel and finally resulting in clogging of the wheel and burns on the ground surface.如果較硬等級的砂輪用于磨削較硬材料，磨鈍的磨粒將不能足夠快地脫離粘結體，這會妨礙砂輪表面的自修復，最終導致砂輪的堵塞并在被磨表面留下灼斑。

In fact, the cutting properties of all grinding wheels must be restored periodically by dressing with a cemented carbide roller or a diamond tool to give the wheel the exact desired shape and remove all worn abrasive grains.實際上，所有砂輪的磨削性能都必須定期地通過使用硬質合金滾輪或金剛石修整器修整而被恢復，以求很準確地把砂輪加工成要求的形狀，并去除已磨鈍的磨粒。

Structure.Structure refers to the amount of void space between the abrasive grains.When grinding softer metals, larger void space are needed to facilitate the flow of the removed chips.結構組織：結構組織與磨粒間的空隙量有關。當磨削較軟金屬時，需要較大的空隙以便去除切屑的流動。

The binder.Abrasive particles are bonded together in many different ways.These include bond, silicate, rubber, resinoid, shellac, and oxychloride.Nevertheless, the bond is the most commonly used one.粘合劑：磨粒可用多種不同方法粘結在一起。其中包括粘合劑、硅酸鹽、橡膠、樹脂、蟲膠和氯氧化物。然而，粘合劑是最常用的。

In fact, the standard marking system is employed for distinguishing grinding wheels, by providing all the preceding parameters in a specific sequence.在實際生產中，為了區分砂輪采用標準標注系統，通過用一特定順序將所有上述參數都表示出來。

? Lapping 研磨

Lapping is a finishing operation used on flat and cylindrical surfaces.The lap, shown in Fig.9.1a, is usually made of cast iron, copper, leather, or cloth.研磨是一種用于平面和圓柱面的精加工作業。研具，如圖9.1a所示，通常用鑄鐵、銅、皮革或布制成。The abrasive particles are embedded in the lap, or they may be carried through slurry.Depending on the hardness of the workpiece, lapping pressures range from 7kPa to 140kPa(1 to 20 psi).研磨微粒嵌入研具內，或者可以通過液體攜帶。根據工件硬度，研磨壓力可在7kPa到140kPa(1到20psi)范圍中取。

Lapping has two main functions.Firstly, it produces a superior surface finish with all machining marks being removed from the surface.Secondly, it is used as a method of obtaining very close fits between mating parts such as pistons and cylinders.研磨有兩個主要作用。首先，它通過去除所有機加工痕跡能產生較好的表面光潔度。其次，它能用作獲得像活塞與氣缸之類配件間過盈配合的方法。

The lapped workpiece surface may look smooth but it is actually filled with microscopic peaks, valleys, scratches and pits.Few surfaces are perfectly flat.Lapping minimizes the surface irregularities, thereby increasing the available contact area.研磨后的工件表面可能看似平滑，其實布滿著微觀峰、谷、劃痕和凹陷。幾乎沒有表面是完全平整的。研磨使表面不規則最小化，因而增加了有效接觸面積。

The drawing in Fig.9.1a shows two surfaces.The upper one is how a surface might look before lapping and the lower one after lapping.Lapping removes the microscopic mountain tops and produces relatively flat plateaus.Entire microscopic mountain ranges may need to be ground down in order to increase the available contact area.圖9.1a上顯示了兩個表面。上面是研磨前表面可能的外觀模樣而下面則是研磨后的模樣。研磨去除了微觀峰頂從而產生相對平坦的平臺。整個微觀山脈范圍都需要磨去以增加有效接觸面積。

Production lapping on flat or cylindrical pieces is done on machines such as those shown in Fig.9.1b and 9.1c.Lapping is also done on curved surfaces, such as spherical objects and lenses, using specially shaped laps.研磨平面或圓柱面工件的生產過程是在如圖9.1b和9.1c那樣的機器上完成的。研磨也可采用特殊成型研具在諸如球形物體和透鏡之類的曲面上進行。

? Polishing

拋光

Polishing is a process that produces a smooth, lustrous surface finish.Two basic mechanisms are involved in the polishing process:(a)fine-scale abrasive removal, and(b)softening and smearing of surface layers by frictional heating during polishing.拋光是生成平滑、有光澤表面光潔度的工藝。拋光工藝涉及兩種基本機理：(a)精細等級磨粒去除，和(b)在拋光中通過摩擦生熱軟化并抹光表面層。Electropolishing

Electropolishing is an electrochemical process similar to, but the reverse of, electroplating.The electropolishing process smoothes and streamlines the microscopic surface of a metal object.Mirror-like finishes can be obtained on metal surfaces by electropolishing.電解拋光

電解拋光是一種與電鍍相似的電化學工藝，但過程與電鍍正好相反。電解拋光工藝使金屬物體的微觀表面平

滑和簡單化。通過電解拋光能在金屬表面得到鏡面光潔度。

In electropolishing, the metal is removed ion by ion from the surface of the metal object being polished.Electrochemistry and the fundamental principles of electrolysis(Faraday’s Law)replace traditional mechanical finishing techniques.在電解拋光中，金屬是逐個離子地從被拋光金屬物體表面去除的。電化學和電解基本原理(Faraday定理)取代了傳統的機械精加工技術。

In basic terms, the object to be electropolished is immersed in an electrolyte and subjected to a direct electrical current.The object is maintained anodic, with the cathodic connection being made to a nearby metal conductor.用基本術語說，要電解拋光的物體被浸沒在電解液中并且通上直流電。該物體為陽極，陰極連接到附近的金屬導體上。

Smoothness of the metal surface is one of the primary and most advantageous effects of electropolishing.During the process, a film of varying thickness covers the surface of the metal.This film is thickest over micro depressions and thinnest over micro projections.金屬表面的平滑是電解拋光主要的和最有優勢的效應之一。在此過程中，一變化著厚度的膜覆蓋在金屬表面上。該膜在微觀凹陷處最厚而在微觀凸出處最薄。

Electrical resistance is at a minimum wherever the film is thinnest, resulting in the greatest rate of metallic dissolution.Electropolishing selectively removes microscopic high points or “peaks” faster than the rate of attack on the corresponding micro-depressions or “valleys”.電阻在膜最薄處最小，導致最大金屬分解率。電解拋光選擇性地去除微觀高點或“峰” 快于對相應微觀凹陷處或“谷”的侵蝕速率。

Stock is removed as metallic salt.Metal removal under certain circumstances is controllable and can be held to 0.0001 to 0.0025 mm.原材料以金屬鹽的形式被去除。在特定環境下金屬的去除是可控的并且保持在0.0001 到0.0025mm范圍內。Chemical Mechanical Polishing

Chemical mechanical polishing is becoming an increasingly important step in the fabrication of multi-level integrated circuits.Chemical mechanical polishing refers to polishing by abundant slurry that interacts both chemically and mechanically with the surface being polished.化學機械拋光

化學機械拋光正在多層集成電路制造領域成為日益重要的步驟。化學機械拋光是指大量拋光液與被拋光表面產生化學和機械作用的拋光。

During the chemical mechanical polishing process, a rotating wafer is pressed face down onto a rotating, resilient polishing pad while polishing slurry containing abrasive particles and chemical reagents flows in between the wafer and the pad.在化學機械拋光過程中，旋轉晶片面向下壓在旋轉、有回彈力的拋光襯墊上，而同時含有研磨微粒和化學反應物的拋光液流過晶片與襯墊之間。

The combined action of polishing pad, abrasive particles and chemical reagents results in material removal and polishing of the wafer surface.Chemical mechanical polishing creates flat, damage-free on a variety of brittle materials and it is used extensively on silicon wafers in the manufacture of integrated circuits.拋光襯墊、研磨微粒和化學反應物的共同作用導致晶片表面的材料去除并拋光。化學機械拋光可使多種易碎材料平整且不受損害，因此在集成電路制造中被廣泛地用在硅晶片上。

Chemical mechanical polishing is a complicated multiphase process.It mainly includes the following two dynamics.First, the active component in polishing slurry reacts with the atoms of the wafer, and the process is chemical reaction step with oxidation-reductive reaction.化學機械拋光是一種復雜的多相工藝。它主要包括下列兩個動態過程：第一，拋光液中活性成分與晶片的原子發生反應，這是帶有氧化-還原反應的化學反應步驟。

The second step is the process of desorption, that is to say, the resultants gradually separate from the wafer surface and new surface is exposed to polishing slurry.If chemical reactive rate is smaller, the total removal rate of the wafer is also small;furthermore, the surface degree of finish is not good.第二步是解吸附過程，即反應產物逐漸從晶片表面分離并將新表面暴露給拋光液。如果化學反應速率較小，晶片的總去除率也較小，而且表面光潔程度不夠好。

On the contrary, even if chemical reaction is very rapid, but desorption is very slow, the total removal rate is not good.Because resultants connot separate from the wafer surface, the active component in the polishing slurry cannot expose and react with the atoms on the new surface, which holds up chemical reaction.與之相反，即使化學反應很快，但解吸附很慢，則總去除率也不夠好。因為反應產物不能從晶片表面分離，拋光液中活性成分就不能暴露并與新表面上的原子起反應，這會抑制化學反應。

The balance and compositive effects of two steps decide the total removal rate and its surface degree of finish.這兩個步驟的平衡與合成效應決定了總去除率和表面光潔程度。

The processes of surface engineering, or surface treatments, tailor the surfaces of engineering materials to:(1)control friction and wear,(2)improve corrosion resistance,(3)change physical property, e.g., conductivity, resistivity, and reflection,(4)alter dimension,(5)vary appearance, e.g., color and roughness,(6)reduce cost.進行表面工程或表面處理的目的是：(1)控制摩擦和磨損，(2)改善抗腐蝕性，(3)改變物理性能，例如，傳導率、電阻系數和反射率，(4)修改尺寸，(5)變更外觀，例如顏色和粗糙程度，(6)降低成本。

Common surface treatments can be divided into two major categories: treatments that cover the surfaces and treatments that alter the surfaces.通常的表面處理可以分為兩個主要類型：覆蓋表面的處理和改變表面的處理。

? Covering the Surface 覆蓋表面

The treatments that cover the surfaces include organic coatings and inorganic coatings.覆蓋表面的處理包括有機涂層和無機涂層。

The inorganic coatings perform electroplatings, conversion coatings, thermal sprayings, hot dippings, furnace fusings, or coat thin films, glass, ceramics on the surfaces of the materials.無機涂層有電鍍、轉化層、熱噴涂、熱浸漬、熔爐熔融、或在材料表面涂上薄膜、玻璃、陶瓷。

Electroplating is an electrochemical process by which metal is deposited on a substrate by passing a current through the bath.電鍍是一種在電鍍槽通上電流使金屬沉淀在基體上的電化學過程。

Usually there is an anode(positively charged electrode), which is the source of the material to be deposited;the electrochemistry which is the medium through which metal ions are exchanged and transferred to the substrate to be coated;and a cathode(negatively charged electrode)which is the substrate to be coated.通常有一個陽極(正電極)，是要沉淀材料的來源；電化學反應是使金屬離子交換并遷移到要覆蓋基體上的中間過程；以及一個陰極(負電極)，即要覆蓋的基體。

Plating is done in a plating bath which is usually a non-metallic tank(usually plastic).The tank is filled with electrolyte which has the metal, to be plated, in ionic form.電鍍在通常為非金屬容器(一般是塑料)的電鍍槽中進行。該容器裝滿了含有離子態被鍍金屬的電解液。

The anode is connected to the positive terminal of the power supply.The anode is usually the metal to be plated(assuming that the metal will corrode in the electrolyte).For ease of operation, the metal is in the form of nuggets and placed in an inert metal basket made out non-corroding metal(such as titanium or stainless steel).陽極與電源正極相連。陽極通常為被鍍金屬(假定該金屬能在電解液中腐蝕)。為了操作容易，該金屬呈固體小塊形式并置于由抗腐蝕金屬(如鈦或不銹鋼)制成的惰性金屬筐內。

The cathode is the workpiece, the substrate to be plated.This is connected to the negative terminal of the power supply.The power supply is well regulated to minimize ripples as well to deliver a steady predictable current, under varying loads such as those found in plating tanks.陰極是工件，即要鍍的基體，連接到電源的負極。很好地調節電源使波動最小化并在載荷變化情況(如同電鍍容器中看到的那樣)下提供穩定的可預知電流。

As the current is applied, positive metal ions from the solution are attracted to the negatively charged cathode and deposit on the cathode.As a replenishment for these deposited ions, the metal from the anode is dissolved and goes into the solution and balances the ionic potential.一旦通上電流，來自溶液的正的金屬離子被吸引到帶負電的陰極并沉淀在其上。作為這些沉淀離子的補充，來自陽極的金屬被溶解并進入溶液平衡離子勢能。

Thermal spraying process.Thermal spraying metal coatings are depositions of metal which has been melted immediately prior to projection onto the substrate.The metals used and the application systems used vary but most applications result in thin coatings applied to surfaces requiring improvement to their corrosion or abrasion resistance properties.熱噴涂工藝：熱噴涂金屬涂層是金屬熔化后立即投射到基體上形成的金屬沉積層。所用的金屬和應用系統都可以變化，但大多數應用都是在要求改善抗腐蝕或耐磨性能的表面涂上薄層。

Thermal spray is a generic term for a broad class of related processes in which molten droplets of metals, ceramics, glasses, and/or polymers are sprayed onto a surface to produce a coating, to form a free-standing near-net-shape, or to create an engineered material with unique properties.熱噴涂是用于很大一類相關工藝的一個通用術語，噴涂到表面產生涂層的熔化小滴可以是金屬、陶瓷、玻璃和/或聚合物，形成獨立的近似純形或產生具有獨特性能的設計材料。

In principle, any material with a stable molten phase can be thermally sprayed, and a wide range of pure and composite materials are routinely sprayed for both research and industrial applications.Deposition rates are very high in comparison to alternative coating technologies.大體上，有穩定熔化狀態的任何材料都可以熱噴涂，范圍寬闊的純凈和合成材料一般都能噴涂用于研究及工業目的。其沉積率與可供選擇的涂層技術比較是很高的。

Deposit thickness of 0.1 to 1mm is common, and thickness greater than 1cm can be achieved with some materials.沉淀厚度普遍為0.1到1mm，對某些材料則沉淀厚度可以達到1cm以上。

The process for application of thermal spray metal is relatively simple and consists of the following stages.(1)Melting the metal at the gun.(2)Spraying the liquid metal onto the prepared substrate by means of compressed air.熱噴涂金屬的應用工藝相對簡單并由下列階段組成：(1)在噴槍內熔化金屬。

(2)通過壓縮空氣將液態金屬噴涂在準備好的基體上。(3)Molten particles are projected onto the cleaned substrate.There are two main types of wire application available today namely arc spray and gas spray.(3)熔化微粒投射在清潔過的基體上。

現在有兩種主要的金屬絲應用類型可選用，也就是電弧噴涂和氣體噴涂。

ARC—A pair of wires are electrically energized so that an arc is struck across the tips when brought together through a pistol.Compressed air is blown across the arc to atomise and propel the autofed metal wire particles onto the prepared workpiece.電弧噴涂—當一對金屬絲通過手持噴槍連到一起時，通上電橫過其末端劃燃電弧。壓縮空氣吹過電弧使其霧化并驅使自動送料金屬絲微粒到準備好的工件上。

GAS—In combustion flame spraying the continuously moving wire is passed through a pistol, melted by a conical jet of burning gas.The molten wire tip enters the cone, atomises and is propelled onto the substrate.氣體噴涂—連續移動的金屬絲在燃燒火焰噴射中通過手持噴槍，并被燃燒氣體的錐形噴嘴所熔化。熔化后的金屬絲頂端進入錐體霧化并驅使其到基體上。

Thin-Film Coatings.Physical Vapor Deposition(PVD)and Chemical Vapor Deposition(CVD)are two most common types of thin-film coating methods.薄膜涂層：物理蒸發沉淀(PVD)和化學蒸發沉淀(CVD)是兩種最常見薄膜涂層方法的類型。

PVD coatings involve atom-by-atom, molecule-by-molecule, or ion deposition of various materials on solid substrates in vacuum systems.物理蒸發沉淀涂層涉及到在真空裝置內各種各樣的材料原子緊靠原子、分子緊靠分子或離子沉淀于固態基體上。

Thermal evaporation uses the atomic cloud formed by the evaporation of the coating metal in a vacuum environment to coat all the surfaces in the line of sight between the substrate and the target.It is often used in producing thin, 0.5μm, decorative shiny coatings on plastic parts.熱蒸發利用涂層金屬在真空環境中蒸發形成的微粒子霧將基體和靶材之間可見范圍內所有表面覆蓋。在塑料零件上生成較薄(0.5μm)的、裝飾性的、有光澤的涂層時常常用到它。

The thin coating, however, is fragile and not good for wear applications.The thermal evaporation process can also coat a very thick, 1mm, layer of heat-resistant materials, such as MCrAIY—a metal, chromium, aluminum, and yttrium alloys, on jet engine parts.然而，這種薄涂層是易碎的并不適合用于磨損場合。熱蒸發工藝也能在噴氣發動機零件上覆蓋很厚(1mm)的耐熱材料涂層，例如MCrAIY—一種金屬、鉻、鋁和釔合金。

Sputtering applies high-technology coatings such as ceramics, metal alloys, organic and inorganic compounds by connecting the workpiece and the substance to a high-voltage DC power supply in an argon vacuum system.反應濺射法通過在氬真空設備中連接工件和具有特定成分的材料到高壓直流電來應用諸如陶瓷、金屬合金、有機和無機化合物之類的高技術涂層。

The plasma is established between the substrate(workpiece)and the target(donor)and transposes the sputtered off target atoms to the surface of the substrate.等離子區形成于基體(工件)和靶材(原料物質)之間并將被濺射的靶材原子轉移到基體的表面上。

When the substrate is non-conductive, e.g., polymer, a radio-frequency(RF)sputtering is used instead.Sputtering can produce thin, less than 3μm(120μin), hard thin-film coatings, e.g., titanium nitride(TIN)which is harder than the hardest metal.如果基體不導電，例如聚合物，則采用射頻(RF)濺射代替。反應濺射法可以生成較薄(小于3μm(120μin))的、堅硬薄膜涂層，像比最硬金屬還硬的氮化鈦(TIN)。

Sputtering is now widely applied on cutting tools, forming tools, injection molding tools, and common tools such as punches and dies, to increase wear resistance and service life.現在反應濺射法已被廣泛應用于切削刀具、成型工具、注射模具和諸如沖頭和沖模之類的通用器具，以增強其耐磨性和使用壽命。

CVD is capable of producing thick, dense, ductile, and good adhesive coatings on metals and non-metals such as glass and plastic.Contrasting to the PVD coating in the “line of sight”, the CVD can coat all surfaces of the substrate.化學蒸發沉淀能在金屬和像玻璃和塑料之類的非金屬上生成較厚的、致密的、有延伸性的和帶良好粘性的涂層。與物理蒸發沉淀在“可見范圍”對比，化學蒸發沉淀能將基體的所有表面都覆蓋。

Conventional CVD coating process requires a metal compound that will volatilize at a fairly low temperature and decompose to a metal when it contacts with the substrate at higher temperature.常規的化學蒸發沉淀涂層工藝需要一種容易在相當低溫度下揮發并且在較高溫度下與基體接觸時能分解成純金屬的金屬化合物。

The most well known example of CVD is the nickel carbonyl(NiCO4)coating as thick as 2.5mm(0.1in.)on glass windows and containers to make them explosion or shatter resistant.最為人熟知的化學蒸發沉淀例子是在玻璃窗和容器上鍍厚為2.5mm(0.1in.)的羰基鎳(NiCO4)涂層使它們能抵抗爆裂或破碎。

Diamond CVD coating process is introduced to increase the surface hardness of cutting tools.However, the process is done at the temperatures higher than 700℃(1300℉)which will soften most tool steel.為增加切削刀具表面硬度引入了鉆石化學蒸發沉淀涂層工藝。可是此工藝要在高于700℃(1300℉)的溫度下才能實現，這溫度會軟化大多數工具鋼。

Thus, the application of diamond CVD is limited to materials which will not soften at this temperature such as cemented carbides.因而鉆石化學蒸發沉淀的應用受到材料限制，要求材料在此溫度下不軟化例如硬質合金。

Plasma-Assisted CVD coating process can be performed at lower temperature than diamond CVD coatings.This CVD process is used to apply diamond coatings or silicon carbide barrier coatings on plastic films and semiconductors, including the state of the art 0.25μm semiconductors.等離子體輔助化學蒸發沉淀涂層工藝可以在比鉆石化學蒸發沉淀涂層低的溫度下操作。這種化學蒸發沉淀用于在塑料膜和半導體(包括人工0.25μm半導體的情況)上覆蓋鉆石涂層或碳化硅隔離涂層。

? Altering the Surfaces 改變表面

The treatments that alter the surfaces include hardening treatments, high-energy processes and special treatments.改變表面的處理包括淬火處理、高能加工和特殊處理。

High-energy processes are relatively new surface treatment methods.They can alter the properties of surfaces without changing the dimension of the surface.Common high-energy processes, including electron beam treatment, ion implantation, and laser beam treatment, are briefly discussed as follows:

高能加工是相對較新的表面處理方法。它們能在不改變表面尺寸的情況下改變表面性能。通用的高能加工包括電子束處理、離子注入和激光束處理簡要討論如下：

Electron beam treatment.Electron beam treatment alters the surface properties by rapid heating—using electron beam and rapid cooling—in the order of 106℃/see in a very shallow region, 100μm, near the surface.This technique can

also be used in hardfacing to produce “surface alloys”.電子束處理：電子束處理在靠近表面很淺(100μm)的區域通過用電子束快速加熱并以106℃/秒等級快速冷卻來改變表面性能。這種技術也被用于表面硬化產生“表面合金”。

Ion implantation.Ion implantation uses electron beam or plasma to impinge gas atoms to ions with sufficient energy, and embed these ions into atomic lattice of the substrate, accelerated by magnetic coils in a vacuum chamber.The mismatch between ion implant and the surface of a metal creates atomic defects that harden the surface.離子注入：離子注入采用電子束或等離子體通過真空室內磁性線圈加速以足夠的能量將氣體原子撞擊為離子，并把這些離子嵌入基體的原子點陣中。離子注入和金屬表面之間的錯配產生了硬化表面的原子瑕疵。

Laser beam treatment.Similar to electron beam treatment, laser beam treatment alters the surface properties by rapid heating and rapid cooling in a very shallow region near the surface.It can also be used in hardfacing to produce “surface alloys”.激光束處理：與電子束處理類似，激光束處理通過在靠近表面很淺的區域快速加熱和快速冷卻來改變表面性能。它也可以用于表面硬化產生“表面合金”。

The results of high-energy processes are not well known or very well controlled.But the preliminary results look promising.Further development is needed in high-energy processes, especially in implant dosages and treatment methods.高能加工的結果不能充分地了解或很好地控制。但初步結果看來是有前途的。高能加工需要進一步的開發，特別是注入劑量和處理方法。

? The Lathe and Its Construction 車床及其結構

A lathe is a machine tool used primarily for producing surfaces of revolution and flat edges.車床是主要用于生成旋轉表面和平整邊緣的機床。

Based on their purpose, construction, number of tools that can simultaneously be mounted, and degree of automation, lathes-or, more accurately, lathe-type machine tools can be classified as follows: 根據它們的使用目的、結構、能同時被安裝刀具的數量和自動化的程度，車床—或更確切地說是車床類的機床，可以被分成以下幾類：

(1)Engine lathes(2)Toolroom lathes(3)Turret lathes(4)Vertical turning and boring mills(5)Automatic lathes(6)Special-purpose lathes(1)普通車床(2)萬能車床(3)轉塔車床(4)立式車床(5)自動車床(6)特殊車床

In spite of that diversity of lathe-type machine tools, they all have common features with respect to construction and principle of operation.These features can best be illustrated by considering the commonly used representative type, the engine lathe.Following is a description of each of the main elements of an engine lathe, which is shown in Fig.11.1.雖然車床類的機床多種多樣，但它們在結構和操作原理上具有共同特性。這些特性可以通過普通車床這一最常用的代表性類型來最好地說明。下面是關于圖11.1所示普通車床的主要部分的描述。

Lathe bed.The lathe bed is the main frame, involving a horizontal beam on two vertical supports.It is usually

made of grey or nodular cast iron to damp vibrations and is made by casting.車床床身：車床床身是包含了在兩個垂直支柱上水平橫梁的主骨架。為減振它一般由灰鑄鐵或球墨鑄鐵鑄造而成。

It has guideways to allow the carriage to slide easily lengthwise.The height of the lathe bed should be appropriate to enable the technician to do his or her job easily and comfortably.它上面有能讓大拖板輕易縱向滑動的導軌。車床床身的高度應適當以讓技師容易而舒適地工作。

Headstock.The headstock is fixed at the left hand side of the lathe bed and includes the spindle whose axis is parallel to the guideways(the slide surface of the bed).The spindle is driven through the gearbox, which is housed within the headstock.主軸箱：主軸箱固定在車床床身的左側，它包括軸線平行于導軌的主軸。主軸通過裝在主軸箱內的齒輪箱驅動。

The function of the gearbox is to provide a number of different spindle speeds(usually 6 up to 18 speeds).Some modern lathes have headstocks with infinitely variable spindle speeds, which employ frictional ,electrical ,or hydraulic drives.齒輪箱的功能是給主軸提供若干不同的速度(通常是6到18速)。有些現代車床具有采用摩擦、電力或液壓驅動的無級調速主軸箱。

The spindle is always hollow, i.e., it has a through hole extending lengthwise.Bar stocks can be fed through that hole if continuous production is adopted.主軸往往是中空的，即縱向有一通孔。如果采取連續生產，棒料能通過此孔進給。

Also, that hole has a tapered surface to allow mounting a plain lathe center.The outer surface of the spindle is threaded to allow mounting of a chuck, a face plate, or the like.同時，此孔為錐形表面可以安裝普通車床頂尖。主軸外表面是螺紋可以安裝卡盤、花盤或類似的裝置。

Tailstock.The tailstock assembly consists basically of three parts, its lower base, an intermediate part, and the quill.The lower base is a casting that can slide on the lathe bed along the guideways, and it has a clamping device to enable locking the entire tailstock at any desired location, depending upon the length of the workpiece.尾架：尾架總成基本包括三部分，底座、尾架體和套筒軸。底座是能在車床床身上沿導軌滑動的鑄件，它有一定位裝置能讓整個尾架根據工件長度鎖定在任何需要位置。

The intermediate part is a casting that can be moved transversely to enable alignment of the axis of the tailstock with that of the headstock.The third part, the quill, is a hardened steel tube, which can be moved longitudinally in and out of the intermediate part as required.尾架體為一能橫向運動的鑄件，它可以調整尾架軸線與主軸箱軸線成一直線。第三部分，套筒軸是一淬硬鋼管，它能根據需要在尾架體中縱向進出移動。

This is achieved through the use of a handwheel and a screw, around which a nut fixed to the quill is engaged.The hole in the open side of the quill is tapered to enable mounting of lathe centers or other tools like twist drills or boring bars.The quill can be locked at any point along its travel path by means of a clamping device.這通過使用手輪和螺桿來達到，與螺桿嚙合的是一固接在套筒軸上的螺母。套筒軸開口端的孔是錐形的，能安裝車床頂尖或諸如麻花鉆和鏜桿之類的工具。套筒軸通過定位裝置能沿著它的移動路徑被鎖定在任何點。

The carriage.The main function of the carriage is mounting of the cutting tools and generating longitudinal and/or cross feeds.It is actually an H-shaped block that slides on the lathe bed between the headstock and tailstock while being guided by the V-shaped guideways of the bed.大拖板：大拖板的主要功能是安裝刀具和產生縱向和/或橫向進給。它實際上是一由車床床身V形導軌引導的、能在車床床身主軸箱和尾架之間滑動的H形滑塊。

The carriage can be moved either manually or mechanically by means of the apron and either the feed rod or the lead screw.大拖板能手動或者通過溜板箱和光桿(進給桿)或絲桿(引導螺桿)機動。

When cutting screw threads, power is provided to the gearbox of the apron by the lead screw.In all other turning operations, it is the feed rod that drives the carriage.The lead screw goes through a pair of half nuts, which are fixed to the rear of the apron.在切削螺旋時，動力通過絲桿提供給溜板箱上的齒輪箱。在其余車削作業中，都由光桿驅動大拖板。絲桿穿過一對固定在溜板箱后部的剖分螺母。

When actuating a certain lever, the half nuts are clamped together and engage with the rotating lead screw as a single nut, which is fed, together with the carriage, along the bed.When the lever is disengaged, the half nuts are released and the carriage stops.當開動特定操作桿時，剖分螺母夾在一起作為單個螺母與旋轉的絲桿嚙合，并帶動拖板沿著床身提供進給。當操作

桿脫離時，剖分螺母釋放同時大拖板停止運動。

On the other hand, when the feed rod is used, it supplies power to the apron through a worm gear.The latter is keyed to the feed rod and travels with the apron along the feed rod, which has a keyway extending to cover its whole length.另一方面，當使用光桿時則通過蝸輪給溜板箱提供動力。蝸輪用鍵連接在光桿上，并與溜板箱一起沿光桿運動，光桿全長范圍開有鍵槽。

A modern lathe usually has a quick-change gearbox located under the headstock and driven from the spindle through a train of gears.It is connected to both the feed rod and the lead screw and enables selecting a variety of feeds easily and rapidly by simply shifting the appropriate levers.現代車床一般在主軸箱下裝備快速變換齒輪箱，通過一系列齒輪由主軸驅動。它與光桿和絲桿連接，能容易并快速地通過簡單轉換適當的操作桿選擇各種進給。

The quick-change gearbox is employed in plain turning, facing and thread cutting operations.Since that gearbox is linked to the spindle, the distance that the apron(and the cuttingtool)travels for each revolution of the spindle can be controlled and is referred to as the feed.快速變換齒輪箱可用于普通車削、端面切削和螺旋切削作業中。由于這種齒輪箱與主軸相連，主軸每轉一圈溜板箱(和切削刀具)運動的距離能被控制，這距離就可以被認為是進給。

? Lathe Cutting Tools 車床切削刀具

The shape and geometry of the lathe tools depend upon the purpose for which they are employed.車床刀具的形狀和幾何參數取決于它們的使用目的。

Turning tools can be classified into two main groups, namely, external cutting tools and internal cutting tools.Each of these two groups include the following types of tools: 車削刀具可以分為兩個主要組別，即外部切削刀具和內部切削刀具。這兩組中的每一組都包括以下類型刀具：

Turning tools.Turning tools can be either finishing or rough turning tools.Rough turning tools have small nose radii and are employed when deep cuts are made.車削刀具：車削刀具可以是精車刀具或粗車刀具。粗車刀具刀尖半徑較小，用于深切削。

On the other hand, finishing tools have larger nose radii and are used for obtaining the final required dimensions with good surface finish by making slight depths of cut.Rough turning tools can be right-hand or left-hand types, depending upon the direction of feed.They can have straight, bent, or offset shanks.而精車刀具刀尖半徑較大，用于通過微量進刀深度來獲得具有較好表面光潔度的最終所需尺寸。粗車刀具按其進給方向可以是右手型的或是左手型的。它們可以有直的、彎的或偏置的刀桿。

Facing tools.Facing tools are employed in facing operations for machining plane side or end surfaces.There are tools for machining left-hand-side surfaces and tools for right-hand-side surfaces.Those side surfaces are generated through the use of the cross feed, contrary to turning operations, where the usual longitudinal feed is used.端面刀具：端面刀具用在端面作業中加工平板側面或端部表面，也有加工左右側表面之分。與一般采用縱向進給的車削作業相反，那些側表面通過采用橫向進給產生。

Cutoff tools.Cutoff tools, which are sometimes called parting tools, serve to separate the workpiece into parts and/or machine external annular grooves.切斷刀具：切斷刀具，有時也稱為分割刀具，用于將工件分割成若干部分和/或加工外部環形槽。

Thread-cutting tools.Thread-cutting tools have either triangular, square, or trapezoidal cutting edges, depending upon the cross section of the desired thread.Also, the plane angles of these tools must always be identical to those of the thread forms.螺紋切削刀具：螺紋切削刀具根據所需螺紋的橫截面，有三角形的、矩形的或梯形的切削刃。同時，這些刀具的平面角必須始終與螺紋形狀的平面角保持一致。

Thread-cutting tools have straight shanks for external thread cutting and are of the bent-shank type when cutting internal threads.車外螺紋的螺紋切削刀具為直刀桿，而車內螺紋的螺紋切削刀具則是彎刀桿。

Form tools.Form tools have edges especially manufactured to take a certain form, which is opposite to the desired shape of the machined workpiece.成形刀具：成形刀具有專門制成特定形狀的刀刃，這種刀刃形狀與被加工工件所需外形正好相反。

An HSS tool is usually made in the form of a single piece, contrary to cemented carbides or ceramic, which are made in the form of tips.The latter are brazed or mechanically fastened to steel shanks．

高速鋼刀具通常以單件形式制造，而硬質合金或陶瓷刀具則以刀尖形式制造。后者用銅焊或機械方法固定于鋼質刀桿上。

Fig.11.2 indicates an arrangement of this latter type, which includes the carbide tip, the chip breaker, the pad, the clamping screw(with a washer and a nut), and the shank.圖11.2所示為機械式固定布置方式，它包括了硬質合金刀尖、斷屑槽、襯墊、卡裝螺桿(帶有墊圈和螺母)及刀桿。As the name suggests, the function of the chip breaker is to break long chips every now and then, thus preventing the formation of very long twisted ribbons that may cause problems during the machining operation.顧名思義，斷屑槽的功能就是不時地折斷長切屑，以防形成很長的可能會在機加工操作中引起問題的纏繞切屑條。The carbide tips(or ceramic tips)can have different shapes, depending upon the machining operations for which they are to be employed.The tips can either be solid or with a central through hole, depending on whether brazing or mechanical clamping is employed for mounting the tip on the shank.硬質合金刀尖(或陶瓷刀尖)根據采用它們的機加工操作，可以有不同的形狀。根據將刀尖裝配在刀桿上是通過用銅焊還是機械卡裝，刀尖可以是實心的或是帶有中心通孔的。

? Lathe Operations 車床操作

In the following section, we discuss the various machining operations that can be performed on a conventional engine lathe.在下面這節中，要討論的是能在傳統普通車床上進行的各種機加工作業。

It must be borne in mind, however, that modern computerized numerically controlled lathes have more capabilities and can do other operations, such as contouring, for example.Following are conventional lathe operations.然而，必須記住現代計算機數控車床具有更多的功能并且可以進行其它操作，例如仿型。下面是傳統車床的操作。

Cylindrical turning.Cylindrical turning is the simplest and the most common of all lathe operations.A single full turn of the workpiece generates a circle whose center falls on the lathe axis;this motion is then reproduced numerous times as a result of the axial feed motion of the tool.圓柱面車削：圓柱面車削是所有車床操作中最簡單也是最普通的。工件旋轉一整圈產生一個圓心落在車床主軸上的圓；由于刀具的軸向進給運動這種動作重復許多次。

The resulting machining marks are, therefore, a helix having a very small pitch, which is equal to the feed.Consequently, the machined surface is always cylindrical.所以，由此產生的機加工痕跡是一條具有很小節距的螺旋線，該節距等于進給。因此機加工表面始終是圓柱形的。

The axial feed is provided by the carriage or the compound rest, either manually or automatically, whereas the depth of cut is controlled by the cross slide.軸向進給通過大拖板或復式刀架手動或自動提供，然而切削深度則由橫向滑板控制。

In roughing cuts, it is recommended that large depths of cuts(up to 0.25in.or 6mm, depending upon the workpiece material)and smaller feeds would be used.On the other hand, very fine feeds, smaller depths of cut(less than 0.05in, or 0.4mm), and high cutting speeds are preferred for finishing cuts.粗車中，推薦使用較大切削深度(根據工件材料可達0.25英寸或6毫米)和較小進給。另一方面，精車則最好采用很小的進給、較小的切削深度(小于0.05英寸或0.4毫米)和較高的切削速度。

Facing.The result of a facing operation is a flat surface that is either the whole end surface of the workpiece or an annular intermediate surface like a shoulder.During a facing operation, feed is provided by the cross slide, whereas the depth of cut is controlled by the carriage or compound rest.端面車削：端面車削操作的結果是將工件整個端部表面或者像軸肩之類的中間環形表面加工平整。在端面車削操作中，進給由橫向滑板提供，而切削深度則通過大拖板或復式刀架控制。

Facing can be carried out either from the periphery inward or from the center of the workpiece outward.It is obvious that the machining marks in both cases take the form of a spiral.端面車削既可以從外表面向內切削也可以從工件中心往外切削。很明顯在這兩種情況下機加工痕跡都是螺線形式。Usually, it is preferred to clamp the carriage during a facing operation, since the cutting force tends to push the tool(and, of course, the whole carriage)away from the workpiece.In most facing operations, the workpiece is held in a chuck or on a face plate.通常在端面車削作業時習慣于采用夾住大拖板，這是因為切削力傾向于將刀具(當然包括整個大拖板)推離工件。在大多數端面車削作業中，工件被支撐在卡盤或花盤上。

Groove cutting.In cut-off and groove-cutting operations, only cross feed of the tool is employed.The cut-off and grooving tools, which were previously discussed, are employed.開槽：在切斷和開槽操作中，刀具只有橫向進給。要采用前面已經討論過的切斷和開槽刀具。

Boring and internal turning.Boring and internal turning are performed on the internal surfaces by a boring bar or suitable internal cutting tools.If the initial workpiece is solid, a drilling operation must be performed first.The drilling tool

is held in the tailstock, and the latter is then fed against the workpiece.鏜孔和內部車削：鏜孔和內部車削通過鏜桿或合適的內部切削刀具在內表面進行。如果初始工件是實心的，則必須首先進行鉆孔作業。鉆孔刀具安裝在尾架上，然后對著工件進給。

Taper turning.Taper turning is achieved by driving the tool in a direction that is not parallel to the lathe axis but inclined to it with an angle that is equal to the desired angle of the taper.Following are the different methods used in taper-turning practice:

錐面車削：錐面車削通過沿著與車床主軸不平行而傾斜成一個等于錐面所需角度的方向進刀來實現。下面是在實際錐面車削中采用的不同方法：

(1)Rotating the disc of the compound rest with an angle equal to half the apex angle of the cone.Feed is manually provided by cranking the handle of the compound rest.This method is recommended for taper turning of external and internal surfaces when the taper angle is relatively large.(1)將復式刀架盤旋轉一個等于圓錐體頂角一半的角度。通過搖動復式刀架操縱柄手動提供進給。當錐角相對較大時切削外錐面和內錐面推薦使用這種方法。

(2)Employing special form tools for external, very short, conical surfaces.The width of the workpiece must be slightly smaller than that of the tool, and the workpiece is usually held in a chuck or clamped on a face plate.In this case, only the cross feed is used during the machining process and the carriage is clamped to the machine bed.(2)對很短的外錐面采用特殊的成型刀具。工件的寬度必須略小于刀具的寬度，并且工件通常由卡盤支撐或夾緊在花盤上。在這種情況下，機加工作業時只有橫向進給而大拖板則夾緊在床身上。

(3)Offsetting the tailstock center.This method is employed for external taper turning of long workpieces that are required to have small taper angles(less than 8°).The workpiece is mounted between the two centers;then the tailstock center is shifted a distance S in the direction normal to the lathe axis.(3)偏移尾架頂尖。對需要較小錐角(小于8°)的較長工件外錐面車削采用這種方法。工件安裝于兩頂尖之間；然后將尾架頂尖朝垂直于車床主軸方向移動一距離S。

(4)Using the taper-turning attachment.This method is used for turning very long workpieces, when the length is larger than the whole stroke of the compound rest.The procedure followed in such cases involves complete disengagement of the cross slide from the carriage, which is then guided by the taper-turning attachment.(4)采用錐面車削附加裝置。這種方法用于車削很長的工件，其長度大于復式刀架的整個行程。在這種場合下要遵循的步驟是將橫向滑板完全脫離大拖板，然后通過錐面車削附加裝置進行引導。

During this process, the automatic axial feed can be used as usual.This method is recommended for very long workpieces with a small cone angle, i.e., 8°through 10°.在此作業中，能照常使用自動軸向進給。對具有較小錐角(即8°到10°)的很長工件推薦采用這種方法。

Thread cutting.When performing thread cutting, the axial feed must be kept at a constant rate, which is dependent upon the rotational speed(rpm)of the workpiece.The relationship between both is determined primarily by the desired pitch of the thread to be cut.螺紋切削：在螺紋切削作業時，軸向進給必須保持恒定速率，這取決于工件的轉速(rpm)。兩者之間的關系基本上由被切削螺紋所需的節距決定。

As previously mentioned, the axial feed is automatically generated when cutting a thread by means of the lead screw, which drives the carriage.When the lead screw rotates a single revolution, the carriage travels a distance equal to the pitch of the lead screw.如前所述，當依靠驅動大拖板的絲桿切削螺紋時軸向進給是自動產生的。絲桿旋轉一圈，大拖板就行進等于絲桿節距的一段距離。

Consequently, if the rotational speed of the lead screw is equal to that of the spindle(i.e., that of the workpiece), the pitch of the resulting cut thread is exactly equal to that of the lead screw.因此如果絲桿的旋轉速度等于心軸的轉速(即工件的轉速)，生成切削螺紋的節距就正好等于絲桿的節距。

The pitch of the resulting thread being cut therefore always depends upon the ratio of the rotational speeds of the lead screw and the spindle: Pitch of the lead screw/ Desired pitch of workpiece=rpm of the workpiece/rpm of lead screw=spindle-to-carriage gearing ratio.所以被切削生成螺紋的節距總是取決于絲桿和心軸的轉速比：絲桿的節距/工件所需節距=工件轉速/絲桿轉速=心軸到大拖板的傳動比。

This equation is useful in determining the kinematic linkage between the lathe spindle and the lead screw and enables proper selection of the gear train between them.這公式在決定車床心軸和絲桿之間的運動學關系時很有用，并且提供了正確挑選它們之間輪系的方法。

In thread cutting operations, the workpiece can either be held in the chuck or mounted between the two lathe

centers for relatively long workpieces.The form of the tool used must exactly coincide with the profile of the thread to be cut, i.e., triangular tools must be used for triangular threads, and so on.在螺紋切削作業中，工件既能支撐于卡盤中，對相對較長的工件也能安裝在兩個車床頂尖之間。使用的刀具外形必須正好與要切削螺紋的輪廓一致，即三角形刀具必須用于三角形螺紋等等。

Knurling.Knurling is mainly a forming operation in which no chips are produced.It involves pressing two hardened rolls with rough filelike surfaces against the rotating workpiece to cause plastic deformation of the workpiece metal.滾花：滾花主要是一種不產生切屑的成型操作。它使用兩個帶有粗銼式表面的淬火滾輪壓在旋轉的工件上使工件金屬產生塑性變形。

Knurling is carried out to produce rough, cylindrical(or conical)surfaces, which are usually used as handles.Sometimes, surfaces are knurled just for the sake of decoration;there are different types of patterns of knurls from which to choose.滾花用于生成粗糙的圓柱(或圓錐)面，通常用來作手柄。有時表面滾花只為裝飾之故；有不同的滾花圖案類型可供選擇。

? Cutting Speeds and Feed 切削速度和進給

The cutting speed, which is usually given in surface feet per minute(SFM), is the number of feet traveled in the circumferential direction by a given point on the surface(being cut)of the workpiece in 1 minute.切削速度，通常用每分鐘表面英尺給出，就是一分鐘內工件(被切削)表面給定點在圓周方向上行進的英尺數。The relationship between the surface speed and rpm can be given by the following equation:

SFM=πDN Where D=the diameter of the workpiece in feet N=the rpm 表面速度與轉速之間的關系可以用下式給出：

SFM=πDN 式中

D=用英尺表示的工件直徑 N=轉速

The surface cutting speed is dependant primarily upon the material being machined as well as the material of the cutting tool and can be obtained from handbooks, information provided by cutting tool manufacturers, and the like.表面切削速度主要由被切削材料和切削刀具材料決定，可以從手冊、切削刀具生產商提供的資料及類似的東西上查取。

Generally, the SFM is taken as 100 when machining cold-rolled or mild steel, as 50 when machining tougher metals, and as 200 when machining softer materials.For aluminum, the SFM is usually taken as 400 or above.There are also other variables that affect the optimal value of the surface cutting speed.一般而言，SFM當機加工冷軋或低碳鋼時取100，機加工較堅韌的金屬時取50，而機加工較軟材料時取200。對鋁而言，SFM通常可取400以上。也還存在其它一些變量影響表面切削速度的最佳值。

These include the tool geometry, the type of lubricant or coolant, the feed, and the depth of cut.As soon as the cutting speed is decided upon, the rotational speed(rpm)of the spindle can be obtained as follows:

N=SFM/(πD)其中包括刀具形狀、潤滑劑或冷卻液的類型、進給和切削深度。切削速度一旦確定，心軸轉速(rpm)就能按下式得到：

N=SFM/(πD)

The selection of a suitable feed depends upon many factors, such as the required surface finish, the depth of cut, and the geometry of the tool used.Finer feeds produce better surface finish, whereas higher feeds reduce the machining time during which the tool is in direct contact with the workpiece.合適進給的選擇取決于許多因素，例如所需表面光潔度、切削深度和所用刀具的幾何形狀。進給越小生成的光潔度越好，而在刀具與工件直接接觸時進給越大則可以減少機加工時間。

Therefore, it is generally recommended to use high feeds for roughing operations and finer feeds for finishing operations.Again, recommended values for feeds, which can be taken as guidelines, are found in handbooks and in information booklets provided by cutting tool manufacturers.所以對粗車一般推薦使用較大進給，而精車則用較小進給。再者，作為指導方針的進給推薦值可以從手冊和切削刀具生產商提供的資料小冊子上找到。

? Drilling and Drills 鉆削和鉆頭

Drilling involves producing through or blind holes in a workpiece by forcing a tool, which rotates around its axis, against the workpiece.鉆削就是通過迫使繞自身軸線旋轉的切削刀具進入工件而在其上生成通孔或盲孔。

Consequently, the range of cutting from that axis of rotation is equal to the radius of the required hole.In practice, two symmetrical cutting edges that rotate about the same axis are employed.因此，從旋轉軸線開始的切削范圍等于所需孔的半徑。實際上，使用的是兩條圍繞相同軸線旋轉的對稱切削刃。

Drilling operations can be carried out by using either hand drills or drilling machines.The latter differ in size and construction.Nevertheless, the tool always rotates around its axis while the workpiece is kept firmly fixed.This is contrary to drilling on a lathe.鉆削作業既能采用手鉆也能采用鉆床來實現。鉆床在尺寸和結構上雖有差別，然而始終都是切削刀具圍繞自身軸線旋轉、工件穩固定位的形式。這正好與在車床上鉆孔相反。Cutting Tool for Drilling Operation

In drilling operations, a cylindrical rotary-end cutting tool, called a drill, is employed.The drill can have either one or more cutting edges and corresponding flutes, which can be straight or helical.用于鉆削作業的切削刀具

在鉆削作業中，要用到被稱為鉆頭的圓柱形回轉端切削刀具。鉆頭可以有一條或多條直的或是螺旋狀的切削刃以及相應的出屑槽。

The function of the flutes is to provide outlet passages for the chips generated during the drilling operation and also to allow lubricants and coolants to reach the cutting edges and the surface being machined.Following is a survey of the commonly used drills.出屑槽的功能是給鉆削作業中產生的切屑提供排出通道，并允許潤滑劑和冷卻液到達切削刃和正在被加工的表面。下面是常用鉆頭的概述。

Twist drill.The twist drill is the most common type of drill.It has two cutting edges and two helical flutes that continue over the length of the drill body, as shown in Fig.12.1.The drill also consists of a neck and a shank that can be either straight or tapered.麻花鉆：麻花鉆是最常用的鉆頭類型。它有兩條切削刃和兩條沿鉆頭體全長連續的螺旋狀出屑槽，如圖12.1所示。麻花鉆還包括鉆頸和鉆柄，鉆柄可以是直的也可以是錐形的。

In the latter case, the shank is fitted by the wedge action into the tapered socket of the spindle and has a tang, which goes into a slot in the spindle socket, thus acting as a solid means for transmitting rotation.錐形鉆柄通過楔入動作安裝在主軸的錐形軸孔中，鉆柄上還有柄舌插入主軸軸孔中的插槽，從而作為傳遞轉動的可靠方法。

On the other hand, straight-shank drills are held in a drill chuck that is, in turn, fitted into the spindle socket in the same way as tapered shank drills.另一方面，直柄鉆頭用鉆頭卡盤夾住，接下來鉆頭卡盤則象錐形鉆柄鉆頭一樣安裝在主軸軸孔內。

As can be seen in Fig.12.1, the two cutting edges are referred to as the lips, and are connected together by a wedge, which is a chisel-like edge.The twist drill also has two margins, which enable proper guidance and locating of the drill while it is in operation.如圖12.1所示，兩條切削刃就是鉆唇，通過鑿子狀邊緣的楔形體連在一起。麻花鉆還有兩條導向邊，用于作業中鉆頭的正確導向和定位。

The tool point angle(TPA)is formed by the two lips and is chosen based on the properties of the material to be cut.The usual TPA for commercial drills is 118°, which is appropriate for drilling low-carbon steels and cast irons.兩條鉆唇形成鉆頂角，并根據被鉆削材料的性能來選取其大小。商品化鉆頭的鉆頂角一般為118°，這適用于鉆削低碳鋼和鑄鐵。

For harder and tougher metals, such as hardened steel, brass and bronze, larger TPAs(130°or 140°)give better performance.The helix angle of the flutes of the commonly used twist drills ranges between 24°and 30°.When drilling copper or soft plastics, higher values for the helix angle are recommended(between 35°and 45°).對于更硬更韌的金屬，諸如淬火鋼、黃銅和青銅，更大的鉆頂角(130°或140°)才能有更好的效果。麻花鉆常用的出屑槽螺旋角范圍為24°到 30°。鉆削紫銅或軟塑料時，推薦采用更大的螺旋角(35°到45°)。

Twist drills are usually made of high-speed steel, although carbide-tipped drills are also available.The sizes of twist drills used in industrial practice range from 0.01 up to 3.25 in.(i.e., 0.25 up to 80 mm).雖然也有硬質合金刀尖的鉆頭，麻花鉆一般用高速鋼制成。工業實際中使用的麻花鉆尺寸范圍為0.01到3.25英寸(即0.25到80毫米)。

Core drills.A core drill consists of the chamfer, body, neck, and shank, as shown in Fig.12.2.This type of drill may have either three or four flutes and equal number of margins, which ensure superior guidance, thus resulting in high machining accuracy.空心鉆：空心鉆包括斜面、鉆頭體、鉆頸和鉆柄，如圖12.2所示。這類鉆頭可以有三條或四條出屑槽及相同數量的保證良好導向的導向邊，這樣使得加工有高精度。

It can also be seen in Fig.12.2 that a core drill has flat end.The chamfer can have three or four cutting edges or lips, and the lip angle may vary between 90°and 120°.在圖12.2中同樣能看到，空心鉆具有平坦的端部。斜面可以有三或四條切削刃或鉆唇，并且鉆唇角可以在90°到120°之間變化。

Core drills are employed for enlarging previously made holes and not for originating holes.This type of drill is characterized by greater productivity, high machining accuracy, and superior quality of the drilled surfaces.空心鉆用于擴大已有的孔而不是打孔。這類鉆頭具有較大生產率、高加工精度和優良鉆削表面質量的特性。

Gun drills.Gun drills are used for drilling deep holes.All gun drills are straight-fluted, and each has a single cutting edge.A hole in the body acts as a conduit to transmit coolant under considerable pressure to the tip of the drill.深孔鉆：深孔鉆用于鉆深孔。所有深孔鉆都是直出屑槽的，并且均為單切削刃。鉆頭體中有個孔作為導管在相當大的壓力下將冷卻液傳送到鉆頭頂端。

There are two kinds of gun drills, namely, the center-cut gun drill used for drilling blind holes and the trepanning drill.The latter has a cylindrical groove at its center, thus generating a solid core, which guides the tool as it proceeds during the drilling operation.深孔鉆有兩種類型，即用于鉆盲孔的中心切削深孔鉆和套孔鉆。后者在其中心有一圓柱形溝槽，這樣能生成整體芯在鉆孔作業過程中引導鉆頭。

Spade drills.Spade drills are used for drilling large holes of 3.5 in.(90mm)or more.Their design results in a marked saving in cost of the tool as well as a tangible reduction in its weight, which facilitates its handling.Moreover, this type of drill is easy to grind.扁平鉆：扁平鉆用于鉆削3.5英寸(90毫米)或更大的大孔。其設計使得鉆頭成本明顯節省、重量切實減輕，重量輕又使操作更方便。此外這種鉆頭容易磨利。

? Milling and Milling Cutter 銑削和銑刀

Milling is a machining process that is carried out by means of a multiedge rotating tool known as a milling cutter.銑削是采用被稱為銑刀的多刃旋轉刀具完成的機加工作業。

In this process, metal removal is achieved through combining the rotary motion of the milling cutter and linear motions of the workpiece simultaneously.Milling operations are employed in producing flat, contoured and helical surfaces as well as for thread-and gear-cutting operation.在此工藝中，金屬去除是通過銑刀的旋轉運動和工件的直線運動的組合實現的。銑削作業既可用于生成平面、輪廓面和螺旋面，也可用于切削螺紋和齒輪。

Each of the cutting edges of a milling cutter acts as an individual single-point cutter when it engages with the workpiece metal.Therefore, each of those cutting edges has appropriate rake and relief angles.在銑刀切削工件金屬時，銑刀的每條切削刃都象一單獨的單刃刀具一樣作用。所以每條切削刃都適當的前后角。

Since only a few of the cutting edges are engaged with the workpiece at a time, heavy cuts can be taken without adversely affecting the tool life.In fact, the permissible cutting speeds and feeds for milling are three to four times higher than those for turning or drilling.由于同一時間只有部分切削刃切削工件，因此可以在對刀具壽命沒有不利影響的情況下承擔重型切削。事實上，銑削允許的切削速度和進給比車削或鉆削高三到四倍。

Moreover, the quality of the surfaces machined by milling is generally superior to the quality of surfaces machined by turning, shaping, or drilling.此外，由銑削加工的表面質量通常優于車削、刨削或鉆削加工的表面質量。

A wide variety of milling cutters is available in industry.This, together with the fact that a milling machine is a very versatile machine tool, makes the milling machine the backbone of a machining workshop.工業上可采用的銑刀類型眾多。連同銑床是極通用機床的事實，使得銑床成為機加工車間的支柱。

As far as the direction of cutter rotation and workpiece feed are concerned, milling is performed by either of the following two methods.至于涉及到銑刀轉動的方向和工件的進給，銑削可以通過下列兩種方法之一進行。

Up milling(conventional milling).In up milling the workpiece is fed against the direction of cutter rotation, as shown in Fig.12.3a.As we can see in that figure, the depth of cut(and consequently the load)gradually increases on the successively engaged cutting edges.逆銑(傳統銑削)：在逆銑中，工件逆著銑刀轉動的方向進給，如圖12.3a所示。就像在此圖中能看到的那樣，切削深度(及作為結果的載荷)隨著切削刃持續進入切削而逐漸增加。

Therefore, the machining process involves no impact loading, thus ensuring smoother operation of the machine tool and longer tool life.The quality of the machined surface obtained by up milling is not very high.Nevertheless, up milling is commonly used in industry, especially for rough cuts.所以，這種工藝沒有沖擊載荷，從而保證了機床的較平穩運行和較長壽命。通過逆銑所得機加工表面質量不是很高。然而逆銑仍經常被用在工業上，尤其是粗切削時。

Down milling(climb milling).As can be seen in Fig.12.3b, in down milling the cutter rotation coincides with the direction of feed at the contact point between the tool and the workpiece.It can also be seen that the maximum depth of cut is achieved directly as the cutter engages with the workpiece.順銑(同向銑削)：如同在圖12.3b中看到的那樣，在順銑時刀具與工件之間接觸點上銑刀旋轉與進給方向一致。還可以看到當刀具進入工件切削時直接達到最大切削深度。

This results in a kind of impact, or sudden loading.Therefore, this method cannot be used unless the milling machine is equipped with a backlash eliminator on the feed screw.The advantages of this method include higher quality of the machined surface and easier clamping of workpieces, since the cutting forces act downward.這會導致一種沖擊，或突然加載。因此，這種方法只有當銑床在進給螺栓上配備間隙消除器時才采用。這種方法的優點包括機加工表面質量較高和工件由于切削力向下作用而較容易夾緊。Types of Milling Cutters

There is a wide variety of milling cutter shapes.Each of them is designed to perform effectively a specific milling operation.銑刀的類型

銑刀的形狀類型很多。其中每種都是為有效進行特定的銑削作業而設計的。

Generally, a milling cutter can be described as a multiedge cutting tool having the shape of a solid of revolution, with the cutting teeth arranged either on the periphery or on an end face or on both.Following is a quick survey of the commonly used types of milling cutters.通常，銑刀可以被描述為具有旋轉實體形狀并將切削齒安裝在周邊或一到兩個端面上的多刃切削刀具。下面是常用銑刀類型的快速綜覽。

Plain milling cutter.A plain milling cutter is a disk-shaped cutting tool that may have either straight or helical teeth, as shown in Fig.12.4a.This type is always mounted on horizontal milling machines and is used for machining flat surfaces.平面銑刀：平面銑刀是一種盤狀切削刀具，它可以具有直齒或螺旋齒，如圖12.4a所示。這類銑刀總是安裝在臥式銑床上，用于機加工平面。

Face milling cutter.A face milling cutter is also used for machining flat surfaces.It is bolted at the end of a short arbor, which is in turn mounted on a vertical milling machine.Fig.12.4b indicates a milling cutter of this type.端面銑刀：端面銑刀也可用于機加工平面。它用螺栓固定在短刀桿的端部，而短刀桿則依次安裝于立式銑床上。圖12.4b顯示了這類銑刀。

Plain metal slitting saw cutter.Fig.12.4c indicates a plain metal slitting saw cutter.we can see that it actually involves a very thin plain milling cutter.平面金屬開槽鋸刃銑刀：圖12.4c顯示了一種平面金屬開槽鋸刃銑刀。可以看到它其實是一種很薄的平面銑刀。

Side milling cutter.A side milling cutter is used for cutting slots, grooves, and splines.As shown in Fig.12.4d, it is

第四篇：機械工程英語翻譯（范文模版）

車床及其結構

車床是主要用于生成旋轉表面和平整邊緣的機床。

根據它們的使用目的、結構、能同時被安裝刀具的數量和自動化的程度，車床—或更確切地說是車床類的機床，可以被分成以下幾類：(1)普通車床(2)萬能車床(3)轉塔車床(4)立式車床(5)自動車床(6)特殊車床

雖然車床類的機床多種多樣，但它們在結構和操作原理上具有共同特性。這些特性可以通過普通車床這一最常用的代表性類型來最好地說明。下面是關于圖11.1所示普通車床的主要部分的描述。

車床床身：車床床身是包含了在兩個垂直支柱上水平橫梁的主骨架。為減振它一般由灰鑄鐵或球墨鑄鐵鑄造而成。

它上面有能讓大拖板輕易縱向滑動的導軌。車床床身的高度應適當以讓技師容易而舒適地工作。

主軸箱：主軸箱固定在車床床身的左側，它包括軸線平行于導軌的主軸。主軸通過裝在主軸箱內的齒輪箱驅動。

齒輪箱的功能是給主軸提供若干不同的速度(通常是6到18速)。有些現代車床具有采用摩擦、電力或液壓驅動的無級調速主軸箱。

主軸往往是中空的，即縱向有一通孔。如果采取連續生產，棒料能通過此孔進給。同時，此孔為錐形表面可以安裝普通車床頂尖。主軸外表面是螺紋可以安裝卡盤、花盤或類似的裝置。

尾架：尾架總成基本包括三部分，底座、尾架體和套筒軸。底座是能在車床床身上沿導軌滑動的鑄件，它有一定位裝置能讓整個尾架根據工件長度鎖定在任何需要位置。尾架體為一能橫向運動的鑄件，它可以調整尾架軸線與主軸箱軸線成一直線。第三部分，套筒軸是一淬硬鋼管，它能根據需要在尾架體中縱向進出移動。這通過使用手輪和螺桿來達到，與螺桿嚙合的是一固接在套筒軸上的螺母。套筒軸開口端的孔是錐形的，能安裝車床頂尖或諸如麻花鉆和鏜桿之類的工具。套筒軸通過定位裝置能沿著它的移動路徑被鎖定在任何點。

大拖板：大拖板的主要功能是安裝刀具和產生縱向和/或橫向進給。它實際上是一由車床床身V形導軌引導的、能在車床床身主軸箱和尾架之間滑動的H形滑塊。大拖板能手動或者通過溜板箱和光桿(進給桿)或絲桿(引導螺桿)機動。

在切削螺旋時，動力通過絲桿提供給溜板箱上的齒輪箱。在其余車削作業中，都由光桿驅動大拖板。絲桿穿過一對固定在溜板箱后部的剖分螺母。當開動特定操作桿時，剖分螺母夾在一起作為單個螺母與旋轉的絲桿嚙合，并帶動拖板沿著床身提供進給。當操作桿脫離時，剖分螺母釋放同時大拖板停止運動。

另一方面，當使用光桿時則通過蝸輪給溜板箱提供動力。蝸輪用鍵連接在光桿上，并與溜板箱一起沿光桿運動，光桿全長范圍開有鍵槽。現代車床一般在主軸箱下裝備快速變換齒輪箱，通過一系列齒輪由主軸驅動。它與光桿和絲桿連接，能容易并快速地通過簡單轉換適當的操作桿選擇各種進給。

快速變換齒輪箱可用于普通車削、端面切削和螺旋切削作業中。由于這種齒輪箱與主軸相連，主軸每轉一圈溜板箱(和切削刀具)運動的距離能被控制，這距離就可以被認為是進給。? 車床切削刀具

車床刀具的形狀和幾何參數取決于它們的使用目的。

車削刀具可以分為兩個主要組別，即外部切削刀具和內部切削刀具。這兩組中的每一組都包括以下類型刀具：

車削刀具：車削刀具可以是精車刀具或粗車刀具。粗車刀具刀尖半徑較小，用于深切削。

而精車刀具刀尖半徑較大，用于通過微量進刀深度來獲得具有較好表面光潔度的最終所需尺寸。粗車刀具按其進給方向可以是右手型的或是左手型的。它們可以有直的、彎的或偏置的刀桿。

端面刀具：端面刀具用在端面作業中加工平板側面或端部表面，也有加工左右側表面之分。與一般采用縱向進給的車削作業相反，那些側表面通過采用橫向進給產生。

切斷刀具：切斷刀具，有時也稱為分割刀具，用于將工件分割成若干部分和/或加工外部環形槽。

螺紋切削刀具：螺紋切削刀具根據所需螺紋的橫截面，有三角形的、矩形的或梯形的切削刃。同時，這些刀具的平面角必須始終與螺紋形狀的平面角保持一致。車外螺紋的螺紋切削刀具為直刀桿，而車內螺紋的螺紋切削刀具則是彎刀桿。

成形刀具：成形刀具有專門制成特定形狀的刀刃，這種刀刃形狀與被加工工件所需外形正好相反。

高速鋼刀具通常以單件形式制造，而硬質合金或陶瓷刀具則以刀尖形式制造。后者用銅焊或機械方法固定于鋼質刀桿上。

圖11.2所示為機械式固定布置方式，它包括了硬質合金刀尖、斷屑槽、襯墊、卡裝螺桿(帶有墊圈和螺母)及刀桿。顧名思義，斷屑槽的功能就是不時地折斷長切屑，以防形成很長的可能會在機加工操作中引起問題的纏繞切屑條。

硬質合金刀尖(或陶瓷刀尖)根據采用它們的機加工操作，可以有不同的形狀。根據將刀尖裝配在刀桿上是通過用銅焊還是機械卡裝，刀尖可以是實心的或是帶有中心通孔的。? 車床操作

在下面這節中，要討論的是能在傳統普通車床上進行的各種機加工作業。

然而，必須記住現代計算機數控車床具有更多的功能并且可以進行其它操作，例如仿型。下面是傳統車床的操作。

圓柱面車削：圓柱面車削是所有車床操作中最簡單也是最普通的。工件旋轉一整圈產生一個圓心落在車床主軸上的圓；由于刀具的軸向進給運動這種動作重復許多次。所以，由此產生的機加工痕跡是一條具有很小節距的螺旋線，該節距等于進給。因此機加工表面始終是圓柱形的。

軸向進給通過大拖板或復式刀架手動或自動提供，然而切削深度則由橫向滑板控制。粗車中，推薦使用較大切削深度(根據工件材料可達0.25英寸或6毫米)和較小進給。另一方面，精車則最好采用很小的進給、較小的切削深度(小于0.05英寸或0.4毫米)和較高的切削速度。

端面車削：端面車削操作的結果是將工件整個端部表面或者像軸肩之類的中間環形表面加工平整。在端面車削操作中，進給由橫向滑板提供，而切削深度則通過大拖板或復式刀架控制。

端面車削既可以從外表面向內切削也可以從工件中心往外切削。很明顯在這兩種情況下機加工痕跡都是螺線形式。

通常在端面車削作業時習慣于采用夾住大拖板，這是因為切削力傾向于將刀具(當然包括整個大拖板)推離工件。在大多數端面車削作業中，工件被支撐在卡盤或花盤上。

開槽：在切斷和開槽操作中，刀具只有橫向進給。要采用前面已經討論過的切斷和開槽刀具。

鏜孔和內部車削：鏜孔和內部車削通過鏜桿或合適的內部切削刀具在內表面進行。如果初始工件是實心的，則必須首先進行鉆孔作業。鉆孔刀具安裝在尾架上，然后對著工件進給。

錐面車削：錐面車削通過沿著與車床主軸不平行而傾斜成一個等于錐面所需角度的方向進刀來實現。下面是在實際錐面車削中采用的不同方法：(1)將復式刀架盤旋轉一個等于圓錐體頂角一半的角度。通過搖動復式刀架操縱柄手動提供進給。當錐角相對較大時切削外錐面和內錐面推薦使用這種方法。

(2)對很短的外錐面采用特殊的成型刀具。工件的寬度必須略小于刀具的寬度，并且工件通常由卡盤支撐或夾緊在花盤上。在這種情況下，機加工作業時只有橫向進給而大拖板則夾緊在床身上。

(3)偏移尾架頂尖。對需要較小錐角(小于8°)的較長工件外錐面車削采用這種方法。工件安裝于兩頂尖之間；然后將尾架頂尖朝垂直于車床主軸方向移動一距離S。

(4)采用錐面車削附加裝置。這種方法用于車削很長的工件，其長度大于復式刀架的整個行程。在這種場合下要遵循的步驟是將橫向滑板完全脫離大拖板，然后通過錐面車削附加裝置進行引導。

在此作業中，能照常使用自動軸向進給。對具有較小錐角(即8°到10°)的很長工件推薦采用這種方法。

螺紋切削：在螺紋切削作業時，軸向進給必須保持恒定速率，這取決于工件的轉速(rpm)。兩者之間的關系基本上由被切削螺紋所需的節距決定。

如前所述，當依靠驅動大拖板的絲桿切削螺紋時軸向進給是自動產生的。絲桿旋轉一圈，大拖板就行進等于絲桿節距的一段距離。

因此如果絲桿的旋轉速度等于心軸的轉速(即工件的轉速)，生成切削螺紋的節距就正好等于絲桿的節距。

所以被切削生成螺紋的節距總是取決于絲桿和心軸的轉速比：絲桿的節距/工件所需節距=工件轉速/絲桿轉速=心軸到大拖板的傳動比。

這公式在決定車床心軸和絲桿之間的運動學關系時很有用，并且提供了正確挑選它們之間輪系的方法。

在螺紋切削作業中，工件既能支撐于卡盤中，對相對較長的工件也能安裝在兩個車床頂尖之間。使用的刀具外形必須正好與要切削螺紋的輪廓一致，即三角形刀具必須用于三角形螺紋等等。

滾花：滾花主要是一種不產生切屑的成型操作。它使用兩個帶有粗銼式表面的淬火滾輪壓在旋轉的工件上使工件金屬產生塑性變形。

滾花用于生成粗糙的圓柱(或圓錐)面，通常用來作手柄。有時表面滾花只為裝飾之故；有不同的滾花圖案類型可供選擇。

? Cutting Speeds and Feed切削速度和進給

切削速度，通常用每分鐘表面英尺給出，就是一分鐘內工件(被切削)表面給定點在圓周方向上行進的英尺數。

表面速度與轉速之間的關系可以用下式給出： SFM=πDN 式中

D=用英尺表示的工件直徑

N=轉速

表面切削速度主要由被切削材料和切削刀具材料決定，可以從手冊、切削刀具生產商提供的資料及類似的東西上查取。

一般而言，SFM當機加工冷軋或低碳鋼時取100，機加工較堅韌的金屬時取50，而機加工較軟材料時取200。對鋁而言，SFM通常可取400以上。也還存在其它一些變量影響表面切削速度的最佳值。

其中包括刀具形狀、潤滑劑或冷卻液的類型、進給和切削深度。切削速度一旦確定，心軸轉速(rpm)就能按下式得到： N=SFM/(πD)合適進給的選擇取決于許多因素，例如所需表面光潔度、切削深度和所用刀具的幾何形狀。進給越小生成的光潔度越好，而在刀具與工件直接接觸時進給越大則可以減少機加工時間。

所以對粗車一般推薦使用較大進給，而精車則用較小進給。再者，作為指導方針的進給推薦值可以從手冊和切削刀具生產商提供的資料小冊子上找到。

Unit 1 1中央控制單元（CPU）的功能是控制所有系統部件的運行和對數據進行數字的或是邏輯的操作。為了完成上述功能，CPU由以下兩個單元組成 2． 控制單元

． 數字邏輯單元

3控制單元通過程序指令來協調大量的特種操作，這些操作包括接受輸入計算機的數據，并決定和是以何種方法來處理這些數據。控制單元能指揮數字邏輯單元的操作，他把數據發送給ALU來告訴ALU根據這些數據該運行什么功能，并且在哪里把結果存儲下來。控制單元完成上述操作的能力基于其安裝了一個具有儲存與記憶功能的總控程序機構。

4數字邏輯單元運行諸如加減比較之類的操作。這些操作是根據數據以二進制的形式表現出來的。在指示了確定的條件下，邏輯部也可以用來改變命令執行的次序。此外，邏輯部分還具有編輯或清除數據等功能。

5控制單元和數字邏輯單元都是得用寄存器來完成他們的功能的，計算機寄存器是一個可以接收短暫存儲，轉移數據的小記憶裝置。根據計算機能力的不同，寄存器能建立出相應的字節數的字長。每個詞的字節數從4到64不等！

Unit 2 生產設備的數字控制

（1）數控是程序控制的自動化，在數字控制系統中，設備通過數字，字母和符號來編碼，以一種合適的格式為每一個特定的零件

或工件定義一個程序指令集。當工件變化時，程序也變化，改變程序的能力也就是適合中小批量生產。寫一個新程序比改變大量生

產設備要容易的多。

（2）基本結構：數控系統由下面三部分組成：1.控制程序；2.機器控制單元；3.加工設備。三部分的基本關系，由圖2.1 所示。程序輸入到控制單元由送入的程序來引導加工設備控制。（3）指導程序是一步步詳細的指導加工設備的指令。通常指令把主軸上刀具相對于安裝工具的工作臺定位。更多先進的說明包括

主軸的轉速，加工工具的選擇及其功能。程序刻在合適的介質中，提交到機器控制單元中，在過去幾十年中，最常用的介質是一英

寸寬的打孔紙帶。由于打孔紙帶的廣泛使用，NC 有時也叫紙帶控制，然而這是現代數控使用的誤稱。現在進入使用更多的是磁帶

和軟盤。（4）機器控制單元（MUC）由電子和控制硬件組成，機器控制單元可以讀出和執行指令程序，可以自動改變加工工具和其他加工 設備。

（5）執行單元是數控系統的第三基礎部分，執行原件是有效執行工作的原件，最常見的數控例子其中的一個加工操作，加工設備 由工作臺和主軸組成，就像用電動機來驅動一樣。加工設備由控制單元來驅動控制系統的類型。

控制系統的類型

（6）數控有2 種基本類型，點對點式和輪廓式控制，點對點式控制也稱定位控制，每個軸都是通過絲杠單獨驅動，根據加工類型

不同，加工速度也不一樣。機器開始以最大速度運行來減少非加工時間，但當他達到數據定義的位置時，機器開始減速。因此在一

個操作中，如鉆或沖孔操作先定位在加工。在鉆或沖孔之后，迅速收起工具移動到另一個位置重復此操作。從一個位置移到另一個

位置是非常重要的，要遵循一個原則，從效率上考慮只要時間最短即可。點對點系統主要用于鉆，沖孔，直銑操作中。

（7）輪廓式也就是連續路徑式系統，定位和切削同時按不同速度來控制，由于刀具在指定路線運動同時切削，因此速度和運動的

同步控制是非常重要的。輪廓式系統常用于車床銑床磨床焊接設備和加工中心。

（8）沿著路徑的運動或以增量差補是幾個基本方式的一個，在所有的差補中，要控制刀具的回轉中心定位，補償可以以不同直徑

及刀具磨損，在數控程序中進行改寫。

（9）有一些已形成差補方案來處理數控系統中連續路徑和加工系統產生的問題包括： 1.線性差補；2.圓弧差補；3.螺旋線差補；4.拋物線差補；5.立體差補（10）每一種差補程序都允許程序源產生加工指令，適用于相對少的輸入參數的直線或曲線路徑。儲存在數控單元中的模塊預算指 引工具沿計算出的路徑運動。

（11）線性差補是最基本的差補方法，用于連續路徑的數控系統中。兩軸和三軸線性差補路線在實際中有時會分辨出的，但在概念

上他們是一樣的，程序源要明確指定直線的起點和缺點及沿直線的進給率。差補需計算兩軸或三軸的進給速率以達到設定的進給速 度。

（12）線性差補用來差補圓是不合適的因為程序源需要明確指定線段部分（線段數量）和各自的終點來大約模擬圓弧。圓弧差補法

已形成他允許程序編程的路徑，使用圓弧只要給定以下參數，圓弧終點坐標，圓心坐標，半徑和刀具沿圓弧路徑的走刀方向。圓弧

差補也是由許多小的直線段來實現的，但這些小線段的參數由差補模塊來計算出來的，而不是程序員設定的。切削是沿著每一小線

段一個一個的進行以產生光滑曲線路徑。圓弧差補的局限性是圓弧路徑所在平面是由數控系統中兩軸所決定的平面。

（13）螺旋線差補結合了環形差補兩軸在第三軸上做線性運動這樣來定義空間三維螺旋路徑。（14）拋物線差補和立方差補法通過高次高程來實現自由曲線。這通常需要有強的計算能力，正因如此，他不如直線差補和環形差 補常見。他們主要用于汽車工業中具有自由風格的車身面，而這是線性差補和圓弧差補不能精確容易得到的。（15）數控技術運用于數控機床，這是數控的主要應用。現在主要用于商業。我們仍討論數控系統特別是金屬數控車床。數控車床技術

（16）種加工過程都可以在設計的專門車床上來實現加工。在車床上車削，在鉆床上鉆，在銑床上加工。有幾種類型的磨削方法也

要有相應種類的磨床。被設計的數控磨床可以進行下列加工包括：1.鉆加工；2.銑床立式和臥式主軸；3.車床臥式主軸和立式主軸；

4.臥式和立式鏜床；5.仿形銑床；6.平面磨和圓柱磨

（17）除了上述幾種機械加工方法，數控機床可用于其他金屬加工過程包括：用于薄片板的金屬板上沖孔的沖壓機，用于薄片金屬 彎曲的折彎機。

（18）數控技術的介入到機加工對機床的設計和運用有著顯著的影響。數控影響之一在程序控制下切削金屬的時間與傳統手動機床__ 大得多。所以對于一些零件如主軸驅動主軸絲杠磨損更快，這些零件要設計成持續時間長的。第二，增加電子控制單元后設備成本

也隨之增加，因此需要更高的利用率。取代傳統手工操作的一班制，數控機床通常采用兩班或三班制來獲得更多的回報。數控機床 的設計中減少了非操作過程的時間如裝卸工件和換刀時間。第三，增加的勞動成本由人工成本變為設備成本。考慮到人工操作的角

色，角色由技術熟練的工人控制，工件生產的每一個過程變為只控制裝卸換刀和清除碎屑和類似的操作，這樣一個工人可以同時操

作兩臺或三臺車床，機床的角色和功能也改變了。數控需要設計成高度自動化具有需要在不同車床加工幾種操作聯合在一起一定加 工的能力，這些變化是通過一種新型車床在數控技術存在之前是不存在的，他豐富了數控加工中心

（19）加工中心是在20 世紀50 年代發展起來的具有在程序控制下在一個工件上一次裝夾完成幾種不同的加工能力的機床。加工中

心能完成銑，鉆，鉸屑，攻絲，鏜，車端面及一些類似機加工工作。另外數控加工中心的典型特征包括以下方面：

（20）(1)自動換刀能力: 多種機加工工作一位著需要多種刀具。刀具貝安裝在刀庫或多刀刀庫中。當一把刀需要被調換時，多刀

刀座自動旋轉到相應的位置上。自動化的換刀機構。在程序控制下進行，把主軸上需換下的刀和多刀刀座上的刀調換。

（21）(2)工件的自動定位: 大多數加工中心都可以使工件沿著主軸旋轉因此允許刀具達到工件的四個表面。

（22）(3)托架滑動裝置（平板架）: 加工中心另一個特點是有兩個或多個獨立拖板每個拖板都可以調整在刀具上。在加工過程中，一個拖板在刀具的前部，另一個拖板在遠離主軸的安全位置。這樣當機床正在加工當前的零件時。操作人員就可以從上一個工作循

環中卸下最終加工好的零件，同時加緊毛坯用于下一個工作循環。

（23）加工中心可以分為立式和臥式。這是參照機床主軸方向來劃分的。立式加工中心具有軸線相對工作臺垂直的主軸，臥式車床 的主軸軸線是水平方向的。這種區別通常會導致在這些加工中心加工的零件類型不同。立式加工中心用于以上進刀的平面工作。臥 式加工中心用于立體形狀，刀具在立體側面可以進刀。一臺數控臥式加工中心，例子如圖2.2 所示，具有上面提到的一些特征。

（24）加工中心的成功應用導致了其他類似金屬加工機床的發展。例如：在車削中心，把車削加工設計成一個高度自動化萬能機床

可以完成車削，刨，鉆，螺紋加工和類似的操作

DNC AND CNC（25）數控的發展在分批生產和小批量生產中有著重要意義，從技術和商業角度來說都有著重要意義。數控有兩方面的提高和擴展，包括：1.直接數據控制；2.計算機數字控制（26）直接數據控制

直接數據控制定義為一個制造系統，一定數量的機床有一臺計算機通過直接硬件連線實時控制。相應的磁帶播放機忽略在直接數控

中，這樣就消除系統中最不可靠的環節。不用磁帶播放機而用電腦信息傳給車床。原則上說一臺計算機可以控制100 臺獨立機器

（DNC 系統在1970 年稱為可控制26 臺機床）直接數控（DNC）電腦設計成在需要的時候提供指令給每一臺機床，當機床需要控

制指令時，計算機立即發送指令給機床。

（27）圖2.3 說明了DNC 的基本配置。這個系統包括4 部分：

1.中央計算機；2.大量內存，用于存放數控程序；3.通信線；4.機床刀具

（28）計算機從海量內存中取出部分程序指令送入到需要的獨立機床中。相應的計算機也接受機床反饋信息。這種雙工的信息流在

實時控制加工系統中出現意味著每臺機床需要指令的請求能立即得到回應。類似的，計算機必須總是要準備要接受信息和進行回應。

DNC 系統顯著特點是：可以實時控制大量機床。更具機器數量和所需的計算機程度化。有時需要使用衛星計算機如圖2.4 所示。衛

星計算機是更小的計算機，可以分擔中央計算任務，減輕其負擔。每臺衛星控制幾臺機床。零件加工指令程序由計算機接受，儲存

在內存中。當需要時衛星計算機發送指令程序到每個獨立機床中。來自機床的反饋數據在電腦中央存儲接受之前存儲在衛星內存中。（29）計算機數字控制

由于DNC 技術的介入，在計算機技術上得到了很大的發展。計算機在尺寸和成本顯著減少的同時，計算機的能力卻有很大的提高。

在數控中，這些發展使得由硬件布置的MCU（）變為數字電腦控制的控制單元。最早，小型機在1970 年使用。隨著計算機進一步

小型化，小型機被當今的微型機取代。

（30）計算機控制也是一種數字控制，它采用微型計算機作為控制單元。由于數字電腦用于CNC 和DNC 中，只近似區分兩種類

型。有三個區分原則： 1）.DNC 電腦接受和發送指令數據都是來自許多機器，CNC 電腦控制只是一個機器或多個機器。

2）.DNC 電腦占有一個位置通過控制來實現機器的旋轉。CNC 電腦要非常靠近車床。3）.DNC 軟件的發展不經可以控制生產設備的每個單獨零件，還可以在生產堅固性方面提供主要控制信息。CNC 的提高可以提 高特殊車床的能力。（31）電腦數控系統的大體配置如圖2.5 所示。如圖中所示，最初進入控制器的是磁帶播放機。這樣，CNC 的外部系統與傳統的NC機相似。然而CNC 中的程序使用方法是不同的。Unit 3 數控編程

數控編程由一系列方向構成，這些方向導致數控車床執行某種操作，加工是最常用的進程。數控車床編程由內部編程部門來完成，在車間里，或者從外部源購買。編程還可以手動或者在計算機輔助下來完成。

程序包括指令和命令。幾何指令涉及刀具和工件間的相對移動。進程指令涉及主軸速度，進給以及道具等。行動指令涉及插值的類型以及刀具或者工作臺的緩慢和快速移動。切換命令涉及到開/關冷卻液供給狀況，主軸旋轉，主軸方向，換刀，工件進給，夾具固定等等。（1）手工編程。手工編程包括根據部分工程圖紙首先算出刀具，工件以及工作臺的尺寸關系，繼而決定執行的操作和工序。那么一個包括執行特定操作所需必要信息的程序表就準備好了，例如刀具切削，主軸轉速，進給，切削深度，切削液，以及刀具或者工件間的相對位置或者移動。根據這些信息，部分程序就準備好了。通常一個紙帶首先被準備好用于試用和調試程序。根據紙帶被使用多久，紙袋通常用更耐用的聚酯薄膜制成。

手工編程可以由那些具有特定制造工藝知識和能夠理解，閱讀以及更改部分程序的人來完成。因為他們熟悉機床刀具和工藝流程，熟練的機械師可以做一些手工編程的編程培訓。然而，所涉及的工作是乏味的，費時的，因此不合算。手工編程大多數用于簡單的點對點應用上。

（2）計算機輔助編程。計算機輔助編程是一種涉及到特殊符號的編程語言，這種語言可以決定角點的坐標，刀口以及工件的表面。編程語言是與計算機通信的方式并且涉及到符號字符。編程員用這種語言描述加工零件，而由計算機將零件程序轉換為數控機床的執行指令。許多種商業應用上的語言有多種多樣的特點和應用。第一種被使用的是類似于英語語句的語言，它在十九世紀五十年代末被開發出來并被稱為APT語言。這種語言，由于它多種多樣的擴展形式，一直是最廣泛的用于點對點和連續路徑編程的語言。

復雜的工件現在使用基本的繪圖進行制造，計算機輔助制造程序。刀具的路徑是在類似于一個CAD程序的大量的繪圖環境下制造出來的。這種機器代碼由程序自動生成。

在生產開始之前，程序應該被校驗，還有就是通過一個顯示器觀看工藝流程的模仿或者使用廉價的材料（例如鋁，木頭，石蠟，或者是塑料）制作工件，而不是使用指定用于已加工零件的真實材料。

計算機輔助編程有以下幾個優于人工方式的重要優點。

比較容易使用的符號語言

縮短了編程時間。編程是一種容納了大量關于機械特點和工藝變量數據的一種能力，例如動力，速度，進給，刀具形狀，刀具形狀改變的補給量，刀具磨損，偏轉，以及冷卻液的使用。

減少了在人工編程中出現人為錯誤的可能性。

因為編程時所需更少的時間，降低了成本。

編程語言的使用不僅導致更高的工件質量而且考慮到了機械指令的更加快速發展。另外，模擬可以在遠程計算機的終端設備上運行，這就確保了程序按照既定來運行。這種方法可以防止昂貴的機器由于調試程序產生不必要的占用。

選擇某一種數控機床編程語言主要取決于以下幾個因素：

生產設施人員的專業水平級別

工件的復雜程度

設備的外形以及計算機的應用 涉及編程的時間及費用

因為數控涉及有關工件材料和加工參數的數據插入，編程必須由有制造業的相關方面知識的操作工和程序員來完成。在生產開始之前，程序應該被校驗，還有通過一個CRT屏幕來觀察工藝流程的模擬或者用廉價的材料制造工件，例如鋁，木頭或者塑料，而不是使用指定用于已加工零件的真實材料。

數控編程語言

自從1956念麻省理工學院的初步研究數控編程系統以來大概有超過100種的數控編程語言已經被開發出來了。大多數語言開發用于特殊的需求和機械并且它們沒有經受住時間的考驗。然而，相當多的語言在今天一直被使用。在本小節，我們回顧一下那些被普遍認為是重要的語言。

APT(自動編程工具)，APT語言是麻省理工學院研發的關于數控機床控制編程系統的成果。它的研發開始于1956年六月，它第一次用于生產是在1959年左右。幾天它是在美國應用最廣泛的語言。雖然第一次打算作為一種輪廓語言。APT現在的版本可用于定位和持續路徑的編程而且可用于多達五個基準軸的持續路徑編程。

AUTOSPOT(用于定位工具的自動系統)。這個程序有IBM研發，在1962年第一次被引進用于PTP編程。AUTOSPOT現在的版本也可應被用于修證輪廓。

COMPACT II。這種語言是來自于制造數據系統的封裝。（MDSI公司），在安阿伯，密歇根州的一家公司。數控機床控制編程的許多特點于SPLIT相似。MDSI公司將COMPACT II系統租賃給以分時為依據的用戶。這種程序通過使用遠程終端把程序傳送給MDSI公司的計算機，有計算機轉向產生數控的紙帶。

ADAPT（APT的改編版本）。多種編程語言直接依據于APT程序。這些語言之一便是ADAPT，它是在空軍合同下由IBM公司研發的。這種語言意圖提供許多APT的特點但是用于小型計算機。ADAPT不如APT一樣強大，但是能夠被用于定位和修改輪廓工作的程序。

EXAPT(APT的擴展子集)。這種語言是由德國研發的。，開始于1964年之間，以APT語言為依據。有三個版本：EXAPT I ——被設計應用于定位（鉆削和直切銑）。EXAPT II——被設計用于車削，還有EXAPT III—被設計用于限制輪廓的操作。EXAPT最重要的一個特點是嘗試自動地計算最佳進給量和進給速度。

APT不僅僅是一種數控語言；它也是一種以APT聲明為依據執行計算來。生成切割位置的計算機程序。

在APT語言中聲明有四種類型：

幾何聲明。這些定義好的幾何元素包括了工作組。它們有時也叫做定義聲明。后處理程序聲明。這些聲明用于特殊的機械工具和控制系統。它們用于指定進給量和進給速度而且精確了機械的其他特點。

輔助聲明。這些不同種類的聲明常用作定義工件，刀具，以及公差等等。

銑床和車床的CNC編程于其他機械編程工藝是相似的；它需要對編程語言有一個透徹的理解。這種用作銑床和車床NC的語言通常被稱為G代碼。這些工序通常用于銑床機械和機加工中心，提供了一些G代碼使用的經典例子，因為它包括大約了NC操作中的75%。下面編程和工藝的五類用于銑床NC編程。（下轉P114）自動化編程的人工指南

NC機械編程采用兩種形式：人工編程以及在CAM軟件支持下的代碼生成。例3-1是一個人工編程的例子。它以銑削零件圖為開始，編程者設計一些能夠驅動切削刀具沿著預期路徑運行的G代碼工序。CAM生成的NC代碼為了使目標機械工具能夠直接轉換為零件圖送給G代碼程序運行在已選擇的機械上，從而使用一個后處理程序。CAM軟件和后處理程序分成兩類。類型之一，專業CAM和簡潔CAM，它是獨立的，并且吸收了所有主要CAM供應商的繪圖文件。第二種類型，是被CAD供應商研發的，它集成了CAD程序和運行，作為集成CAD / CAM設計軟件的一部分

Unit 4 機加工與切削加工中心

（1）這篇文章介紹了計算機控制的機械刀具設計的能力和較大的發展，就想我們知道的機加工和切削加工中心，這些機器有其他

機器工具沒有的柔性和多功能性，應此他們作為加工工具第一選擇。機加工與切削加工中心

（2）需要注意的是每臺機器他的自動化程度有多高，都要設計一種基本的加工樣式就像所展示的那樣，在制造過程中不同的表面 是用不同的加工方法加工的，（3）例如，如圖4.3 所示，銑、端面車削、鏜、鉆、鉸孔、切絲來獲得額定的公差要求及最終表面精度。

（4）習慣性的加工過程的執行，始于工件的移動從一把加工刀具到另一把加工刀具直至所有的加工完成，這是一種切實可行的制

造方法，并具有高度的自動化。這就是生產流水線的原理。最常見的是應用于高容量或大批量的生產，生產流水線是由幾種加工刀 具按一定的次序排列組成的，諸如自動發動機模塊這樣的工件從一個加工地點到另一個加工地點，并且在每一個加工中心都運用特

有的加工方式進行加工，工件會被輸送到下一個機器進行下一個加工。

（5）有這樣一些產品或加工方法，他們的生產路線是不可行或不經濟的，特別是當這些種類的產品在加工時需要迅速轉換加工方

法。一個重要的概念，在20 世紀50 年代末期得到發展，那就是機加工中心。一個機加工中心就是運用計算機控制的刀具在工件的

不同表面和不同的方向上進行切削操作的能力，通常說工件是不動的，而切削工具進行旋轉，比如銑和鉆操作。

（6）機加工中心的發展暗示著計算機控制的機器刀具之間關系的進步。如數字控制的車床加工中心擁有兩個轉臺帶動幾把切削刀 具進行車削，端面車削，鏜孔和切螺紋。

（7）工件在加工中心里是被安放在托盤上或模塊上，那樣可以被移動并且可以進行不同方向的旋轉和定位，在進行特殊的切削過

程完成后，工件不需要移動到另一臺機器進行鉆孔，鉸孔，攻絲之類的附加加工。換句話說，工件和機器是被置于工件上的。

（8）當所有的加工工作完成后，托盤會自動離開已加工工件，并且另一個托盤運用自動托盤變速器將工件進行定位和加工。所有 的傳動機構都有計算機控制，并且托盤定位器有10-30 秒的循環時間，托盤臺能夠使得多級托盤更好的服務于加工中心，工具同樣

能夠被裝備到不同的自動化部件中，諸如上料與下料機構。

（9）加工中心裝備了可變程序的自動刀具變換器，依賴于這樣的設計多達200 把切削刀具能夠被貯存在刀庫，刀鼓，刀鏈（工具

庫），輔助工具庫能夠更好的為一些特殊加工中心提供更好的切削道具，這些刀具可以自動的任意選擇到達機械主軸的最短路線，刀具交換臂是一個普通的設計機構，他可以旋轉來拾取特殊的工具（每一個工具有他自己的刀桿）和他在主軸上的位置。

（10）刀具通過直接連接在刀具夾持口上的編碼標簽、條形碼或記憶芯片來標識。一次換刀時間在5-10 秒鐘，對于小的刀具可以

少于1-2 秒，對于重達110 公斤的刀具可以達到30 秒，刀具變換器的設計趨勢趨向于運用簡單的原理提高換刀的時間。

（11）加工中心同時裝備有工具的檢驗臺，他可以給計算機數字控制提供信息對于在換刀和刀具磨損時的誤差提供補償。接觸試探

針可以自動裝入工具夾持口中以確定工件的參考平面，以便對刀具設置進行選擇并對加工的工件在線檢測。

（12）圖4.6 所示的一些表面可以被聯系起來，他們的相對位置可以被確立并儲存在計算機軟件的數據庫中，這些數據稍后可被用

于編寫刀具工作路徑的程序同時對刀具的長度和直徑進行補償，又可以為預先加工刀具的磨損提供補償。

機加工與切削加工中心的種類

（13）盡管這里有不同種類的刀具設計在加工中心中，兩種最基本的種類垂直主軸和水平主軸；大部分的機器擁有上述兩種軸線的

能力，在加工中心中最大的切削刀具的尺寸可以繞工具一周，就像我們知道的工具包絡，這個術語第一次應用在與工業機器人的聯 系上。

（14）垂直主軸加工中心或是水平主軸加工中心都是為了適用在工件具有深腔的平面上執行加工工藝，如鑄型和模具制造。一個垂

直主軸的加工中心類似于一個垂直主軸銑床。刀庫在圖示的左側并且所有的加工方法和傳動機構通過位于右側的計算機控制托盤進 行定位和修改。

（15）因為在加工中心中由于推力的作用方向是向下的，機器具有高的剛度，并在對于加工部分有較好的精確補償，這些機器通常 比水平主軸的機器便宜些。

（16）水平主軸的加工中心或水平機加工中心是為了適用于高大工件的表面加工的需求。托盤可以在不同的軸線（如圖4.3 所示）上旋轉來進行不同種類的有角定位。

（17）水平主軸加工的另一個范疇是車削加工，是用特殊機床進行計算機控制的車削加工。一個三轉動架的計算機數字控制的車削

加工如圖4.8 所示，這個機器是由兩個水平主軸和三個轉動架以及不同的切削刀具設計而成的來執行一些旋轉工件的加工。

（18）萬能加工中心同時裝備了垂直主軸和水平主軸的機器，他們具有不同種類的特色，并且具有加工所有表面的能力（垂直的、水平的、斜的）。機加工中心的特征和能力

（19）下面是加工中心的大部分特征：

a．他們有能力有效的，經濟的并且擁有重復的高精度的尺寸的能力來處理不同型號的磨具的能力。公差的范圍在正負0.0025mm。

b．這些機器是萬能的，擁有多達6 條線性的有角傳動的軸線并且有能力快速的從一種加工方式向另一種加工方式轉變來滿足不同 種類的加工刀具和有效的減小地板空間。

c．裝載工作和卸載工作，轉換刀具，矯正，故障尋找所需的時間正在減少，應此生產能力提高，減少實驗的需求尤其是對于熟練

實驗的要求并且生產成本降到最低。

d．他們可以高速的自動化并相對地緊湊，應此一個工作人員可以在同一時間照顧到兩臺或更多的機器。

e．加工機器裝備了刀具調節監測裝置為了檢測出工具的磨損與破裂，又可以探測工具磨損的補償和工具調位。

f．前處理和后處理的矯正和工件加工監測在加工中心的功能。

（20）加工中心可應用于更廣闊范圍的不同種類型號和特征，并且他們的成本范圍從5 萬到100 萬甚至更高。典型容量范圍可達

75KW，并且最小軸轉速通常在4000-8000rpm 范圍里，一些可以達到75000rpm，還用于小補償切削的特殊應用。一些托盤具有支

撐重達7000kg 工件的能力，通常高的容量用于特殊的應用當中。

（21）現在大部分機器有一個標準組件的基準構造，應此不同種類的外圍裝備和附件可以被安裝并且和修改不同種類產品的修改要

求。（22）因為加工中心的高生產能力，大量的切削會產生并且必須被收集起來應此一些需要一些可用于切削收集處理的設計，就像圖 示所舉例那樣，兩個在橫軸加工中心截面圖底部的切削傳送帶這些特殊的加工傳送帶是螺旋形或螺桿型，他們沿著導槽收集切削并

且將他們輸送到收集點，另一條系統會選用鏈式傳送帶。刀具的選擇

（23）加工中心能夠有能力需求有效的花費可以說進行有效的成本控制，他們通常不得不每天做至少兩次移動，所以他們必須有效

并且可以連續調整在加工中心中產品的購買需求，因為他們固定的多功能性，但是加工中心可用于及時的制造大范圍的特殊產品。

（24）種類的選擇和加工中心的尺寸依賴于以下幾種因素。a．產品的種類，尺寸和模具的復雜性。

b．加工方法的種類及執行方式和切削工具的需求次數。c．精確補償的需求。d．生產速率的需求。

（25）盡管多功能性是選取加工中心的一個關鍵因素，我們必須考慮到權衡高成本高精度需求和比較在運用傳統加工工具制造相同 產品時的成本。

第五篇：機械工程英語翻譯

Part2

Unit 12

Nanomaterial and Micro-machine

納米材料和微型機器

Nanomaterial

納米材料

Nanomaterials and nanotechnolology have become a magic word in modern society.納米材料和納米技術已成為現代社會一個具有魔幻色彩的詞匯。Nanomaterials represent today’s frontier in the development of novel advanced materials and present great promises and opportunities for a new generation of materials with improved and tailorable properties for applications in sensors, optoelectronics, energy storage, separation and catalysis.納米材料代表了當今新型先進材料發展的前沿，為具有各種改良的、能按照人們各種要求進行“定制”的性能的新一代材料，在傳感器、光電子學、儲能、分離和催化劑技術等方面提供了廣闊的應用前景。So nanomaterials are considered as a great potential in the 21th century

because of their special properties in many fields such as optics, electronics, magnetic, mechanics, and chemistry.因此納米材料被視為21世紀具有巨大的潛力的一種材料，因為在很多領域如光學、電子學、磁學、力學和化學他們的特殊性質。

These uinque properties are attractive for various high performance applications.這些特殊的性質對于各種不同高性能的應用程序 來說具有很大的吸引力。

Exampeples include wear-resistant surfaces, low temperature sinterable high-strength ceramics, and magnetic nanocomposites.例如耐磨的表層以及在低溫環境下 具有高張力的陶瓷和磁力納米復合材料。

Nanostructured materials present great promises and opportunities for a new generation of materials of materials with improved and marvelous properties.納米結構的材料為新一代具有改良的非凡的性能的材料提供了廣闊的前景。

It is appropriate to begin with a brief introduction to the history of the subject.在這里簡單介紹一下納米材料的歷史。

Scientific work on this subject can be traced back over 100 years.在這方面的科學研究可以追溯得到100多年以前。

In 1861 the British chemist Thomas Graham coined the term “colloid” to describe a solution contion containing 1 to 100 nm diameter particles in suspension.在1961年，英國化學家格雷姆首次用“膠體”這個術語來描述一種含有直徑為1~100nm的微小懸浮顆粒的溶液。

Around the turn of century, such famous scientists as Rayleigh, Maxwell, and Einstein studied colloids.大約在20世紀末20世紀初的時候，一些有名的科學家如雷利,麥克斯韋和愛因斯坦開始研究膠體。

In 1930 the Langmuir-Blodgett method for developing monolayer films was developed.1930年，單分子薄膜的狼繆爾布羅杰特方法形成。

By 1960 Uyeda had used electron microscopy and diffraction to study individual particles.到1960年Uyeda 已經用電子顯微鏡檢查法以及衍射來研究單個粒子。At about the same time, arc, plasma, and chemical flame furnaces were employed to produce submicron particles.幾乎是同一時間 電弧，單離子體和化學反射爐已經用于生產亞微米粒子了。

Magnetic alloy particles for use in magnetic tapes were produced in 1970.1970年磁力合金粒子已經運用于磁帶中了。

By1980, studies were made on clusters containing fewer than 100 atoms.到1980年，已有很多人開始對含有不到100個原子的原子團進行了研究。In1985,a team led by Smalley and Kroto found spectroscopic evidence that C60 clusters were unusually stable.在1985年，一個由斯莫利和克羅托領導的科研小組通過光譜分析證實了C60原子團具有不同尋常的穩定性。

In1991, Lijima reported studies of graphitic carbon tube filaments.1991年，Lijima 也報道了有關石墨碳管狀絲材的研究情況。

Research on nanomaterials has been stimulated by their technological applications.關于納米材料的研究是在他們的技術的應用引起的。

The first technological uses of these materials were as catalysts and pigments.這些納米材料的第一次技術使用是催化劑和天然色素運用。

The large surface area to volume ratio increases the chemical activity.大面積的體積比增加到化學活動上。

Because of this increased activity, there are significant cost advantages in fabricating catalysts from nanomaterials.正因為這些增加的研究，從納米材料上制造催化劑才有了巨大的成本優勢。

The properties of some single-phase materials can be improved by preparing them as nanostructurs.一些單相的材料的性能還可以通過納米結構來優化。

For example, the sintering temperature can be decreased and the plasticity increased on single-phase, structural ceramics by reducing the grain size to several nanometers.例如，降低燃燒溫度，把顆粒大小縮小幾個納米，可以單相的提升建筑陶瓷的可塑性。

Multiphase nanostructured materials have displayed novel behavior resulting from the small size of the individual phases.由單個顆粒的小型體積，多相的納米結構材料已經展示了非比尋常的性質。

In microelectronics, the need for faster switching times and ever larger integration has motivated considerable effort to reduce the size of electronic components.在微電子學中，對快速轉換時間和更大規模的集成電路的需要在減小電子元件尺寸的工作起到了很大的作用

Increasing the component density increased the difficulty of satisfying cooling requirements and reduces the allowable amount of energy released on switching between states.而增加器件密度又會增加必須滿足冷卻條件以及減少開關狀態轉換是所允許的最大能量釋放的難度。

It would be ideal if the switching occurred with the motion of a single electron.在單電子的移動時開關是最理想的狀態。

One kind of single-electron device is based on the change in the Coulombic energy（庫倫能）when an electron is added or removed from a particle.當從一個粒子中增加或較少一個電子的時候，一種單電子裝置是以庫倫能的變化為基礎的。

For a nanoparticle this energy change can be large enough that adding a single electron will effectively block the flow of other electrons.對于納米粒子來說，這個能量的變化因增加單個電子有效的限制其他電子的流動而充分。

In addition to technology, nanomaterials are also interesting systems for basic scientific investigations.除了技術，納米材料的基本科學調查也是有趣的系統。For example , small particles display deviations偏差 from bulk 體積solid behavior such as reductions in the melting temperature and changes(usually reductions)in the lattice parameter.（網狀參數）

例如微粒材料和塊狀材料會呈現出不同的性能，比如其熔點降低和晶格參數變小。

The changes in the lattice parameter observed for metal and semiconductor particles result from the effect of the surface stress, while the reduction in the melting temperature results from the effect of the surface free energy.金屬和半導體粒子觀察來的晶狀參數變化是來自于表面的壓力，而熔點的降低是來自于表層的自由能的作用。

By studying the size dependence of the properties of particles, it is possible to find the critical length scales at which particles behave essentially as bulk matter.通過研究微粒性能的數量相關性，有可能發現微粒像塊狀材料性能的臨界尺度。

Generally, the physical properties of a nanoparticle approach bulk values for particles containing more than a fen hundred atoms.一般說來，納米粒子如果達到包含有幾百個原子的大小時，其物理性能就會接近塊體材料。

New techniques have been developed recently that have permitted researchers to produce larger quantities of other nanomaterials.發展的新技術已經被研究學者用于發掘納米材料的更多的性能了。Each fabrication technique has its own set of advantages and disadvantages.每項制造技術都有其優缺點。

Chemical techniques are very versatile in that they can be applied to nearly all materials(ceramics, semiconductors, and metals)and can usually produce a large amount of materials.化學技術是通用的，它可以運用到陶瓷，半導體以及金屬等所有種材料中，還可以用來生產大量的其他材料。

A difficulty with chemical processing is the need to find the proper chemical reactions and processing conditions for each material.化學處理的困難是需要找到合適每種材料的化學反應以及反應條件。

The ability to characterize nanomaterials has been increased greatly by the invention of the scanning tunneling microscope(STM)and other proximal probes such as the atomic force microscope(AFM), the magnetic force microscope, and the optical near-field microscope.因為掃描隧道電子顯微鏡以及源自顯微鏡和磁力顯微鏡等類似儀器的發明，人們對納米的特點的認知能力又大大增強了。STM has been used to carefully place atoms on surfaces to write bits using a small number of atoms.STM

（掃描隧道電子顯微鏡）技術一般用來將少量的單個原子小心地“搬運”到某些材料得的表面來書寫二進制數碼。

It has also been employed to construct a circular arrangement of metal atoms on an insulating surface and hence a nano-scale electronic component is fabricated.它還可以用來在絕緣表面將金屬原子擺放成一個環狀圖形，從而制造出納米尺寸的電子器件。

Other new instruments and improvements of existing instruments are increasingly becoming important tools for characterizing surface of films, biological materials, and nanomatirials.其他新的工具和現有工具的改善已經成為顯現薄膜表層，生物材料以及納米材料的主要手段。

The development of nanoindentors and the improved ability to interpret resulting from nanoindentation measurements have increased our ability to study the mechanical properties of nanostructured materials.納米材料的發展以及改良的納米技術的測量能力的展現增強了我們去研究納米結構材料的性能的能力。

Improved high-resolution electron microscopes and modeling of the electron microscope images have improved our knowledge of the structure of the particles and the interphase region between particles in consolidated nanomaterials.改良的高分辨率的電子顯微鏡以及 電子顯微鏡圖像的模型提高了我們對粒子的結構以及在加固的納米材料的分裂區間的認識。

Micro-machine 微型機器 Introduction 介紹

From the beginning, mankind seems instinctively to have desired large machines and small machines.從一開始，人類似乎就本能地有一種想制造“大機器”和“小機器”的愿望。

That is , “large” and “small” in comparison with human －scale.這里的所謂“大”和“小”是相對人類本身的尺寸而言的。

Machines larger than human are powerful allies in the battle against the fury of nature;smaller machines are loyal partners that do whatever they are told.比人體大的機器將稱成為人類同暴虐無情的自然界作斗爭的得力幫手，而那些小機器則只能乖乖聽從人類的命令，讓干什么就干什么。

If we compare the facility and technology of manufacturing larger machines, common sense tells us that the smaller machines are easier to make.如果我們將生產大型機器的設備和技術相比，常識告訴我們小型機器更容易制造。

Nevertheless, throughout the history of technology, larger machines have always stood out.盡管如此，整個技術的歷史，較大型機器一直很突出。

The size of the restored models of the water-mill invented by Vitruvius in the Roman Era, the windmill of the Middle Ages,and the steam engine invented by Watt is overwhelming.維特魯維在羅馬時代發明恢復模型尺寸大小的水車，中世紀的風車，和瓦特發明的蒸汽機是勢不可擋的。

On the other hand, smaller machines in history of technology are mostly tools.另一方面，小型機器的科技歷史大部分是工具。

If smaller machines are easier to make, a variety of such machines existed，but until modern times ,no significant small machines existed except for guns and clocks.如果小型機器相對容易制造，那么會存在一系列這樣的機器，但直到現代，沒有重要的小機器存在除了槍和鬧鐘外。

This fact may imply that smaller machines were actually more difficult to make.這樣的事實可能暗示較小機器事實上是更難制造。

Of course, this does not mean simply that it was difficult to make a small machine;it means that it was difficult to invent a small machine that would be significant to human beings.當然，這并不簡單意味著制造一個小機器是很困難的；而是意味著創造一個小機器是困難的，那將對人類是重要的。

Some people might say that mankind may not have wanted smaller machines.一些人可能會說人類可能不需要較小型機器。

This theory, however, does not explain the recent popularity of palm-size mechatronics products.然而，這一理論并不能解釋最近流行的手掌大小的機電一體化產品。

The absence of small machines in history may be due to the extreme difficulty in manufacturing small precision parts.歷史上小機器的缺乏可能是由于制造高精度小部件極度困難。The dream of the ultimate small machine, or micro-machine, was first depicted in detail about 30 years ago in the 1966 movie “Fantastic Voyage.”

最終的小機器或微型的夢想，首次被描述在詳細介紹30年前在1966年的“奇妙的航行”科幻電影中。

At the time, the study of micro-machining of semiconductors had already begun.那時候，半導體的微細加工的研究已經開始。

Therefore, manufacturing minute mechanisms through micro-machining of semiconductors would have been possible.然而，通過半導體的微加工制造分鐘的機制是有可能的。

There was, however, a wait of over 20 years before the introduction of electrostatic motors and gears made by semiconductor micro-machining.然而，有等待超過20年引進的半導體微細加工制成的靜電馬達和齒輪。

Why didn’t the study of micro-machining and the dream of micro-machines meet earlier?

為什么不把微加工的研究和微型機械的夢想早一點接觸呢? A possible reason for this is as follows.一個可能的原因如下。

In addition to micro-machining, the development of micro-machines requires a number of technologies including materials, instrumentation, control, energy, information processing, and design.此外微加工，微型機器的發展需要許多科技技術包括物材、儀器儀表、控制、能源、信息處理和設計。

Before micro-machine research and development can be started, all of these technologies must reach a certain level.在微型機器研究和發展開始前，所有這些技術必須達到一定水平。In other words, the overall technological level, as a whole, must reach a certain critical point, but it hadn’t reached that point 40 years ago.換句話說，整體技術水平，作為一個整體，必須達到一定的臨界點，但在40年以前是達不到這一點。

Approximately 20 years after “Fantastic Voyage ,”the technology level for micro-machines finally reached a critical point.大約在科幻電影《奇妙的航行》上映后20年，微型機械的技術終于達到一個相當水平。

Micro-motors and micro-gears made by semiconductor micromachining were introduced at about that time, triggering the research on development of micro-machines.用半導體加工技術制造出的微型電動機和微型齒輪機構開始在那時候出現，從而刺激了微型機械的研究和發展。

Micromachines as Gentle Machine 微電機作為溫和的機器

The most unique feature of a micro-machine is , of course, its small size.Utilizing its tiny dimensions , a micro-machine can perform tasks in a revolutionary way that would be impossible for conventional machines.當然，它的體積小的微型機器的最獨特的功能。利用其微小的尺寸，微機器可以一種革命性的方式，執行傳統的機器不可能的任務。That is , micro-machines do not affect the object or the environment as much as conventional machines do.也就是說，相比傳統機器，微型機器可以盡可能多的不影響它的對象或環境。

Micro-machines perform their tasks gently.This is a fundamental difference between micro-machines and conventional machines.微型機器可以柔和的執行他們的任務。這是微型機器和常規機器之間的根本區別。

The medical field holds the highest expectations for benefits from this feature of micro-machines.在醫療領域擁有最高期望得益于微型機器的特點。

Diagnosis and treatment will change drastically from conventional methods, and “Fantastic Voyage” may no longer be a fantasy.診斷和治療將從傳統方法上發生急劇變化，同時“神奇之旅”可能不再是一個幻想。

If a micro-machine can gently enter a human body to treat illnesses, humans will be freed from painful surgery and uncomfortable gastro-camera testing.如果一個微型機器可以輕輕地進入人體，以治療疾病，人類將擺脫痛苦的手術和不舒服的胃腸相機測試。

Furthermore, if micro-machines can halt the trend of ever-increasing size in medical equipment, it could slow the excess growth and complexity of medical technology, contributing to the solving of serious problems with high medical costs for citizens.此外，如果微型機器可以控制醫療設備日益增加大尺寸，它可能會放緩醫療技術過剩的增長和復雜性，從而促使公民高額的醫療費用問題得到解決。

Micro-electronics and mechatronics 微型電子和機電一體化

The concept of micro-machines and related technologies is still not adequately unified, as these are still at the development stage.微型機器和相關技術的概念，還沒有充分統一，因為這是仍處于發展階段。

The micro-machines and related technologies are currently referred to by a variety of different terms.目前，微型機器及其相關技術涉及許多不同術語。

In the United States, the accepted them is “Micro Electro Mechanical Systems”(MEMS);in Europe, the term “Microsystems Technology”(MST)is common, while the term “micro-engineering” is sometimes used in Britain.在美國，“微機電系統”（MEMS）是被接受的，在歐洲通常叫“微系統技術”（MST）而在英國它被稱作“微型工程”。Meanwhile in Australia “Micro-machine”.與此同時它在澳大利亞被稱作“微型機器”。

The most common term if it is translated into English is "micro-machine” in Japan.最常見到術語，在日本它如果被翻譯成英文是“微型機器”。

However “Micro-robot” and “Micro-mechanism are also available case by case.但是“微型機器人”和微觀機制“也是到處可見的。

The evolution of machines and micromachines 機器和微型機器的發展

Many researchers see micro-machines as the ultimate in mechatronics , developed out of machine systems.許多研究人員把微型機器看作是機電一體化最終開發的系統。Ever since the Industrial Revolution, machine systems have grown larger and larger in the course of their evolution.自從工業革命以來，機器系統在其演化過程中已經越來越大。Only very recently has evolution in the opposite direction begun, with the appearance of mechatronics.最近機電一體化的外觀次啊開始在反方向的演變。

Devices such as video cameras, tape recorders, portable telephones, portable copiers which at one time were too large to put one’s arms around , now fit on the palm of one’s hand.設備，如攝像機，錄音機，便攜式電話，便攜式復印機，曾經太大以至于拿起來就是身邊的武器，現在適合放在也個人的手上。

Miniaturization through mechatronics has resulted mainly from the development of electronic controls and control software for machine systems, but the changes to the structural parts of machine systems have been minor compared to those in the control systems.機械電子技術的發展帶來的結構微型化主要是機械系統中電子控制技術和控制軟件發展的結果。但機械系統結構部件的發展變化與控制系統的技術發展還是無法相比。

The next target in miniaturization of machine systems is miniaturization of the structural parts left untouched by present mechatronics.機械系統微型化的下一個目標是當前電子技術尚未觸及到的結構部件的微型化。

These are the micro-machines which are seen as the ultimate in mechatronics.這就是所謂被視為機械電子學終極發展目標的微型機械

Seen in this light, the aim of micro-machines can be expressed as follows: 由此看來，微型機器的目的，可以表示如下

“Micro-machines are autonomous machines which can be put on a fingertip, composed of parts the smallest sized of which is a few dozen micrometers.”

微型機器是可以放在指尖上的自動機器，它的組成部分最小的尺寸是幾十微米。

That is, since micro-machines which can be put on a fingertip have to perform operations in spaces inaccessible to humans, they are required to be autonomous and capable of assessing situations independently, as are intelligent robots.也就是說，既然要小到可以放在指尖上的微型機械完成那些由于空間位置限制人類而無法實行的操作，這些微型機械就應該具有”自治“能力，也就是說它們就像那些智能機器人一樣，可以多所處的工作環境獨，立做出判斷。

To achieve this kind of functionality, a large number of parts must be assembled in a confined space.要實現這種功能，大量的部件必須組裝在一個密閉空間內。

This factor determines the size of the smallest parts, and given the resolution of micro-machining systems, a target size of several dozen micrometers should be achievable.這個因素決定了組成部分的最小尺寸，由于微加工系統的解決，目標在幾十微米大小是可以實現。