數(shù)控專業(yè)外文翻譯--鋸削

1、<p><b>　　[英文資料]</b></p><p><b>　　.Sawing</b></p><p>　　Sawing is the parting of material by using metal disks, blades, bands, or abrasive disks as the cutting tools. S

2、awing a piece from stock for further machining is called cutoff sawing, while shaping of forming a piece is referred to as contour sawing.</p><p>　　Machine sawing of metal is performed by five types of saws

3、or processes: hacksawing, babd sawing, cold sawing, friction sawing, and abrasive sawing.</p><p>　　Hacksaws are used principally as cutoff tools. The toothed blade, held in tension, is reciprocated across th

4、e workpiece. A vise holds the stock in position. The blade is fed into the work by gravity or spring. Sometimes a mechanical or hydraulic feed is used. Automatic machines, handling bar-length stock, are used for continuo

5、us production.</p><p>　　Band saws cut rapidly and are suited for either cutoff or contour sawing. The plane in which the blade operates classifies the machine as being either vertical or horizontal. Band saw

6、s are basically a flexible endless band of steel running over pulleys or wheels. The band has teeth on one side and is operated under tension. Guides keep it running true. The frame of the horizontal type is pivoted to a

7、llow positioning of the workpiece in the vise. Horizontal machines are used for either straight o</p><p>　　Cold sawing is principally a cutoff operation. The blade is a circular disk with cutting teeth on it

8、s periphery. Blades range in size from a few inches to several feet in diameter. The cutting teeth may be cut into the periphery of the disk or they may be inserts of a harder material. The blade moves into the stock wit

9、h a positive feed. Stock is positioned manually in some cold-sawing machines, while other models are equipped for automatic cycle sawing.</p><p>　　Friction sawing is a rapid process used to cut steel as well

10、 as certain plastics. This process is not satisfactory for cast iron and nonferrous metals. Cutting is done as the high-speed blade wipes the metal from the kerf after softening it with frictional heat. Circular alloy-st

11、eel blades perform cutoff work, thile frictional band saws do both cutoff and contour sawing. Circular blades are frequently cooled by water or air. Circular blades are adcanced into the work, thile thick work-pieces req

12、</p><p>　　Abrasive sawing is a cutoff process using thin rubber or bakelite bonded abrasive disks. In addition to steel, other materials such as nonferrous metals, ceramics, glass, certain plastics, and hard

13、 rubber are cut by this method. Cutting is done by the abrasive action of the grit in the disk.</p><p>　　Abrasive disks are operated either wet or dry. For heavy cutting a cooling agent is generally used. Th

14、e workpiece is firmly held while the wheel traverses through it. Machines are made in manually operated and automatic models.</p><p><b>　　Drilling</b></p><p>　　Holes are one of the m

15、ost common features in products manufactured today. There-fore, drilling and other related processes and tools are extremely important. Holes as small as 0.005in.may be drilled using special techniques. On the other hand

16、 , holes larger than 2 to 2in. in diameter are seldom drilled, because other processes and techniques are less expensive.</p><p>　　The twist drill (shown in Fig.12-3) is the most common type of drill. The sh

17、ank of the drill is held by the machine tool, which in turn imparts an rotary motion. This shank of the drill is held by the machine tool. Which in turn imparts a rotary motion. This shank may be straight or tapered. The

18、 body of the drill is typically made up of two spiral grooves known as flutes, which are defined by a helix angle that is generally about 30ºbut can vary depending on the material properties of the workpi</p>

19、<p>　　Complex hole configurations may often be called for; these include multiple diameters, chamfers, countersinks, and combinations of these, as illustrated in Fig.12-4. In each of these cases in is possible to m

20、ake special combination drills that can produce the configurations shown in a single operation. Although expensive, they can be economically justified for sufficient volume.</p><p>　　The flat chisel edge, wh

21、ich can “walk” on the surface of the workpiece, and the long , slender shaft and body of the twist drill, which can deflect, make it difficult to machine holes to tight tolerances. A combination center drill and counters

22、ink can be used to accurately start a hole, owing to its small web thickness and its tendency to deflect only very small amounts (because of a relatively large diameter-to-length ratio) . Truing of the hole to make it st

23、raight is accomplished by boring. Re</p><p>　　The feed rate of a drill is normally proportional to its diameter, because it depends on the volume of chips the flutes can handle. However the feed is independe

24、nt of the cutting speed, which is a function of the tool-work combination. A rule of thumb would give a feed rate as approximately d/65,so that a 3/4-in.-diameter drill would have a feed rate of about 0.012 in. /rev. Alt

25、hough the hole wall tends to support the drill when the hole depth exceeds three times the drill diameter, there is a t</p><p>　　Most drills are made from high –speed steel because of its relatively low cost

26、 and ease of manufacture. Some types of carbide drills are now available commercially. The demands of numerically controlled machine tools have led to the development of drills that will produce pore precise holes and th

27、at will originate a hole in line with the centerline of the drill-press spindle. Drills that have heavier webs, less stickout, double margins, and are ground with a spiral point help meet these new dema</p><p&

28、gt;<b>　　Reaming</b></p><p>　　Reaming is a machining process for enlarging, smoothing and/ or accurately sizing existing holes by means of means of multiedge fluted cutting tools (reamers) . As th

29、e reamers and / or workpiece is rotated and advanced relative to each other, chips are produced to remove relatively small amounts of material from the hole wall. Reaming may be performed on the same type of machines use

30、d for drilling.</p><p>　　Accuracy of the hole and quality of finish produced by reaming depends primarily upon the condition of the starting bole, rigidity of the machine and fixture, correct speeds and feed

31、s, a suitable and properly applied cutting fluid, and precise resharpening of dull tools.</p><p>　　Since stock removal is small and must be uniform in reaming , the starting holes (drilled or otherwise produ

32、ced) must have relatively good roundness, straightness, and finish. Reamers tend to follow the existing centerline of the hole being reamed, and in limited instances it may be necessary to bore the holes prior to reaming

33、 to maintain required tolerances. With the proper conditions and operating parameters, reaming can produce close tolerances and smooth finishes.</p><p><b>　　Reamers</b></p><p>　　Area

34、mer is a rotary cutting tool, generally of cylindrical or conical shape, intended for enlarging and finishing holes to accurate dimensions. It is usually equipped with two or more peripheral channels or flutes, either pa

35、rallel to its axis or in a right– or left-hand helix as required. Those with helical flutes provide smooth shear cutting, are less subject to chatter, and produce a better finish. The flutes form cutting teeth and provid

36、e channels for removing the chips.</p><p>　　Kinds of Reamers</p><p>　　Reamers are made in many different forms, including solid and inserted-blade types, adjustable and nonadjustable; they are a

37、vailable for either manual operation (hand reamers) or for machine use (chucking reamers). Materials from which cutting elements of most production reamers are made include high-speed steeland cemented carbides. of most

38、production reamers are made include high-speed steel and cemented carbides.</p><p>　　Carbide reamers These tools are being used increasingly because of their linger life, improved accuracy, and resistance.&

39、lt;/p><p>　　Bore reamers These tools combine boring and reaming in a single operation to minimize problems with respect to hole size, straightness, and finish. Single-point bore reamers, for use in applicat

40、ions for which guide bushings can be used, have a single-point cutting edge on the end of the tool, followed by a reaming section. Multipoint bore reamers are available for applications for applications for which bushing

41、s cannot be used.</p><p>　　Coolant-fed reamers These tools, having means (usually internal passages) for directing coolant to the cutting edges, offer advantages for some applications, particularly when re

42、aming blind holes. In such applications, reduced friction and temperatures at the reamer /workpiece interface decrease wear and lengthen tool life. In some cases, feeds and speeds can be increased and improved accuracies

43、 and smoother finishes obtained. The initial cost of coolant-fed reamers is higher , but increased p</p><p>　　Reamer Holders/ Drivers</p><p>　　Reamers are commonly held and driven by three-jaw c

44、hucks, straight sleeves and setscrews, and, for taper shanks, sleeves or sockets. Reamers with adapters for quick-change chucks are used for production applications.</p><p>　　When reamers must guide themselv

45、es into previously made holes, they require gloating holders to maintain alignment. There are several types of floating holders. Some permit angular float, others permit a parallel (axial) float, and still others permit

46、both angular and parallel float.</p><p>　　Floating holders have some limitations. If the reamer axis is vertical, floating reamer drives often do a good job of correcting for small amounts of misalignment. W

47、hen the workpieces rotate, however, as is the case on screw machines, lathes, and some other machine tools, floating holders are sometimes inadequate. This is because relatively large amounts of misalignment are often fo

48、und on these machines and because the weight of the reamer and holder tend to push the tool into an off-center posi</p><p>　　Some full floating holders, which compensate for both angular and parallel misalig

49、nment, are equipped with springs or other components to counterbalance the mass of the holder. A floating holder cannot generally operate both vertically and horizontally and still correct for both angular and parallel m

50、isalignment. Application details (vertical or horizontal operation and rotating or stationary tool) should be specified when a floating holder is ordered.</p><p>　　Workholding for Reaming</p><p>

51、;　　Jig design and the use of bushings for reaming are essentially the same as for drilling. Major functions of the jigs and bushings are accurate locating, supporting, and securing of the workpieces, and precise guiding

52、of the tools. A difference for reaming is that closer tolerances are generally required on both the jigs and bushings.</p><p>　　Operating Parameters for Reaming</p><p>　　Factors that must be est

53、ablished for efficient and economical reaming include the proper cutting speed, feed rate, and cutting fluid to be used Other important considerations are resharpening the reamers and troubleshooting the operations.</

54、p><p><b>　　[ 譯文如下 ] </b></p><p><b>　　鋸削</b></p><p>　　鋸削是利用金屬圓鋸、鋸條、帶鋸或砂輪作為切削工具將材料分開。從原料上鋸下一塊供進(jìn)一步加工稱為切斷鋸，而將這塊毛坯成形或成型稱為仿形鋸。</p><p>　　機(jī)械金屬鋸削有5種類型的鋸或工藝完

55、成；弓鋸、帶鋸、冷鋸、摩擦聚合砂輪鋸。</p><p>　　弓鋸條主要用作切割工具。帶齒的鋸條被拉緊，來回穿過工件。一只臺鉗固定住原料。鋸條通過重力或彈力向工件進(jìn)給。有時(shí)使用機(jī)械或液壓機(jī)給。處理長棒料的自動鋸機(jī)用于連續(xù)生產(chǎn)。</p><p>　　帶鋸切割快速，適合于切斷鋸或仿形鋸。鋸條工作的平面把鋸機(jī)分為立式和臥式。帶鋸基本上就是一根在滑輪或輪子上運(yùn)轉(zhuǎn)的柔性環(huán)狀鋼帶。帶的一側(cè)有齒，在拉緊的

56、狀態(tài)下工作。導(dǎo)軌保持其精確運(yùn)轉(zhuǎn)。臥式鋸機(jī)的機(jī)架是鉸鏈的，用來給臺鉗的工件定位。臥式鋸機(jī)即可用于直切也可用于角切。支撐工件的工作臺和位于鋸條直立部分的寬的工作導(dǎo)槽是立式帶鋸適合于仿形工件。高速運(yùn)轉(zhuǎn)的帶鋸常常用作摩擦鋸。</p><p>　　冷鋸主要是一道切斷工序。鋸條是一個(gè)周邊帶齒的圓盤，鋸條的尺寸從直徑幾英寸到幾英尺。切削齒可以是在圓盤周邊切出也可是嵌入的堅(jiān)硬材料。鋸條利用機(jī)械進(jìn)給切入原料。在一些冷鋸機(jī)中，原料有

57、工人定位，而裝備其他型號鋸機(jī)可進(jìn)行自動循環(huán)切削。</p><p>　　摩擦鋸是用于切割鋼和某些塑料的快速工藝。這一工藝不適于鑄鐵和有色金屬。切割是利用摩擦熱軟化切口后由高速鋸條擦掉。圓形合金鋼鋸條進(jìn)行切斷作業(yè)，而摩擦帶鋸鋸可切斷鋸也可仿形鋸。圓形鋸條通常用水或空氣冷卻。圓形鋸條向工件內(nèi)切入，而厚的工件在帶鋸上進(jìn)行摩割切割是需要機(jī)動工作臺進(jìn)給。</p><p>　　砂輪鋸是一種使用薄的橡膠或

58、樹脂結(jié)合劑制成的沙輪作切斷工具。除鋼外，其他材料如有色金屬、陶瓷、玻璃、有些塑料和硬橡膠都有此法切斷。切斷是通過砂輪上沙粒的摩擦作用完成的。</p><p>　　砂輪即可濕式工作，又可干式工作。對于厚金屬切割一般要用冷卻劑。當(dāng)砂輪橫穿工件是應(yīng)被牢牢固定。鋸既有人工操縱機(jī)型和自動機(jī)型。</p><p><b>　　鉆削</b></p><p>　

59、　孔是目前制造的產(chǎn)品的一個(gè)最為常見的特征。因此，鉆削和其他相關(guān)工藝及刀具極為重要。小至0.005英寸的孔可以使用專門技術(shù)進(jìn)行鉆削。另一方面，直徑大至2到21/2英寸的孔很少鉆削，因?yàn)槠渌に嚭图夹g(shù)花費(fèi)更低。</p><p>　　麻花鉆（如圖12-3所示）示最普通類型的鉆頭。鉆頭的柄部通過機(jī)床固定，機(jī)</p><p>　　圖12-3 麻花鉆的幾何形狀</p><p>

60、　　床進(jìn)而施加旋轉(zhuǎn)運(yùn)動。柄部可以是直的或錐形的。典型的鉆的刀體有兩個(gè)被稱為鉆溝的螺旋槽組成，鉆溝由螺旋角規(guī)定范圍，螺旋角一般為30º左右，但是可以根據(jù)工件材料特性而變化。鉆頭（見圖12-3）的頂端一般構(gòu)成一個(gè)118º的角，而且包括一個(gè)10º的后角和橫刃。橫刃是平的，其腹部厚度約為鉆頭直徑的0.015倍。由于橫刃在與工件結(jié)合前能在工件表面“行走”,因此橫刃會引起孔的定位問題。對于脆性材料，使用小于118

61、86;的鉆頭頂角；而對于韌性材料使用較大的頂角和較小的間隙角。</p><p>　　有可能經(jīng)常需要復(fù)雜的孔型；這些孔型，如圖12-4所示，包括多直徑、多倒角、多埋頭孔以及這些形式的組合。在每種情況中，又可能制作專用組合鉆頭再一次作業(yè)中制造出所示的孔型。雖然價(jià)格昂貴，但對于足夠數(shù)量來講已經(jīng)被證明會相當(dāng)經(jīng)濟(jì)。</p><p>　　圖12-4 有專用鉆頭加工的內(nèi)表面</p>&l

62、t;p>　　可以在工件表面行走的平的橫刃以及可以撓曲的細(xì)長軸和刀柄，使加工精密公差的孔變得困難。組合式的中心鉆和錐形擴(kuò)孔，由于其較小的腹部厚度合非常小的撓曲（因?yàn)榫哂邢鄬^大的經(jīng)長比），可以用于精確的開始一個(gè)孔。擴(kuò)孔完成對孔的平整以使其變直。鉸孔產(chǎn)生更好的表面光潔度和更精確的尺寸。</p><p>　　鉆頭的進(jìn)給速度通常與其直徑成比例，以為他取決于鉆溝所能處理的切屑量。然而，進(jìn)給獨(dú)立于切削速度，切削速度是刀

63、具-工件組合的函數(shù)。經(jīng)驗(yàn)法則給出的進(jìn)給速度約為d/65,因此，一個(gè)直徑3/4英寸的鉆頭應(yīng)有的進(jìn)給速度約為一次回轉(zhuǎn)0.012英寸。雖然當(dāng)孔的深度超過3倍的鉆頭直徑時(shí)孔壁有支撐鉆頭的傾向，但是也有發(fā)生彎曲的傾向，因此進(jìn)給速度應(yīng)減小。</p><p>　　大多數(shù)鉆頭由高速鋼制造，因此其成本相對較低和易于制造?，F(xiàn)在在市場上可以買到一些類型的應(yīng)制合金鉆頭。對于數(shù)控車床的需要已經(jīng)導(dǎo)致了用以制造更加精密的孔和開始一個(gè)與鉆床主軸

64、中心線成一條直線的鉆頭的發(fā)展。鉆頭具有較大的腹部、較少的懸臂以及雙刃帶，而且使用一個(gè)有助于滿足這些需要的螺尖接合表面。</p><p><b>　　鉸削</b></p><p>　　鉸削是一種利用多刃槽切削刀具對已經(jīng)存在的孔進(jìn)行擴(kuò)大、平滑或精確確定尺寸的加工工藝。當(dāng)鉸刀或工件旋轉(zhuǎn)并相對進(jìn)給時(shí)，就會產(chǎn)生切屑從孔壁取出相對較少量的材料。鉸削可以在同一型號的鉆削機(jī)床上進(jìn)行。

65、</p><p>　　鉸削產(chǎn)生的孔精度和精加工質(zhì)量主要取決于起始孔的情況、機(jī)床和夾具的剛性、正確的速度合進(jìn)給量、適合的并恰當(dāng)使用的切削液以及鈍刀具的重新精確磨快。</p><p>　　由于鉸削的切削率較小而且必須均勻，起始孔（鉆的或由其他方式制造的）必須具有相對較好的圓度、平直度和光潔度。鉸刀傾向于沿已經(jīng)鉸出的孔的中心線而行，而且在有限的場合可能需要在鉸削之前進(jìn)行鏜孔來維持所需的公差。利用

66、合適的條件和工作參數(shù)，鉸削可以產(chǎn)生精密公差和光潔表面。</p><p><b>　　鉸刀</b></p><p>　　鉸刀是一種旋轉(zhuǎn)的切削刀具，一般是柱型或錐形，用于擴(kuò)孔和精整孔至精確尺寸。鉸刀通常裝有兩個(gè)或更多外圍通道或凹槽，即可平行于其軸線也可以根據(jù)需要右或左螺旋。那些帶有提供光滑的剪切式切斷的螺旋槽的鉸刀很少受到振動，因此產(chǎn)生較好的光潔度。凹槽形成了切削齒并提供

67、除屑的通道。</p><p><b>　　鉸刀的種類</b></p><p>　　鉸刀被做成多種形式：包括整體式和刀片嵌入式 、可調(diào)或不可調(diào)的；它即可用于手工作業(yè)（手鉸刀）也可供機(jī)器用（機(jī)用鉸刀）。用于制造大多數(shù)生產(chǎn)用鉸刀的切削元件的材料，又高速鋼和硬質(zhì)合金。</p><p>　　硬質(zhì)合金鉸刀 由于壽命更長而且精度和阻力的到了提高，這類刀

68、具正日益廣泛使用。</p><p>　　鏜孔鉸刀 這類刀具將鏜削和鉸削組合在一次作業(yè)中來提高孔的尺寸、平直度和光潔度的加工精度問題。在使用導(dǎo)向襯套的應(yīng)用中所用的單刃鏜孔鉸刀，在刀具的后段有一個(gè)單刃切削刃，再后是鉸削段。多刃鏜孔鉸刀用于不能使用襯套的加工中。</p><p>　　供給冷卻液的鉸刀 這類刀具帶有向切削刃導(dǎo)引冷卻液的裝置（通常是內(nèi)部通道），對于某些應(yīng)用有優(yōu)勢，尤其

69、當(dāng)鉸削盲孔時(shí)。在這樣的應(yīng)用中，在鉸刀/工件的界面處降低的摩擦和溫度，因而減少了磨損并延長了刀具壽命。在一些情況下，可以提高進(jìn)給量和速度并且能提高精度和光潔度。使用冷卻液的鉸刀的初始成本較高，但是生產(chǎn)率和質(zhì)量的提高常常使之在經(jīng)濟(jì)上令人滿意。</p><p><b>　　鉸刀夾頭/傳動裝置</b></p><p>　　鉸刀通常有三爪卡盤、直襯套和固定螺釘和傳動；而對于錐病

70、鉸刀，用的是襯套何套筒。帶有快卸卡盤聯(lián)結(jié)其的鉸刀用于生產(chǎn)中。</p><p>　　當(dāng)鉸刀必須將自身導(dǎo)入前先加工的孔內(nèi)，它需要浮動夾頭來保持對正。有幾種類型的浮動夾頭。有些允許角度浮動，其它允許平行（軸向）浮動，還有的既允許角度浮動也允許平行浮動。</p><p>　　浮動夾頭有一些局限性。如果鉸刀軸線是垂直的，浮動鉸刀裝置常常可以很好的修正少量的不對正。然而，當(dāng)工件向在螺紋車削機(jī)、車床和一

71、些其它機(jī)床上那樣旋轉(zhuǎn)時(shí)，浮動夾頭有時(shí)并不適合。這是因?yàn)樵谶@種機(jī)器上常發(fā)現(xiàn)有相對較大的不對正而且鉸刀和夾頭的重量往往將刀具推到偏心的位置。</p><p>　　有些可以補(bǔ)償角度和平行不對正的完全浮動夾頭裝有用于平衡夾頭質(zhì)量的彈簧或其他零件。浮動夾頭一般不能既垂直有水平工作而仍可修正角度和平行不對正。應(yīng)用細(xì)節(jié)（垂直或水平工作以及旋轉(zhuǎn)或固定的刀具）應(yīng)該在定制浮動夾頭時(shí)確定。</p><p>&l

72、t;b>　　鉸削的工件夾持</b></p><p>　　鉸削夾具設(shè)計(jì)和襯套的使用基本上于鉆削的相同。夾聚合襯套的主要功能是對工件精確定位、支撐和固定以及對刀具精確引導(dǎo)。鉸削的差異在于夾具和襯套一般都需要鉸精確的公差。</p><p><b>　　鉸削的工作參數(shù)</b></p><p>　　必須確定的用于高效經(jīng)濟(jì)鉸削的因素包括適