中英文翻譯鏜削加工和鏜床

1、英文翻譯原文:(一)boring and boring machinesas carried out on a lathe, boring produces circular internal profiles in hollow work-pieces or on a hole made by drilling or another process, boring is done with cutting tools that are similar to those used in turning. because the boring bar has to reach the full

2、length of the bore, tool deflection and, therefore, maintainance of dimensional accuracy can be a significant problem.the boring bar must be sufficiently stiffthat is, made of a material with high elastic modulus, such as tungsten carbide to minimize deflection and avoid vibration and chatter. borin

3、g bars have been designed with capabilities for damping vibration.although boring operations on relatively small work-pieces. can be carried out on a lathe, boring mills are used for large work-pieces. these machines are either vertical or horizontal, and are capable of performing operations such as

4、 turning, facing, grooving, and chamfering. a vertical boring machine is similar to a lathe but has a vertical axis of work-piece rotation.the cutting tool (usually a single point made of m-2 and m-3 high-speed steel and c-7 and c-8 carbide) is mounted on the tool head, which is capable of vertical

5、movement (for boring and turning) and radial movement (for facing), guided by the cross-rail. the head can be swiveled to produce conical (tapered) surfaces.in horizontal boring machine, the work-piece is mounted on a table that can move horizontally in both the axial and radial directions. the cutt

6、ing tool is mounted on a spindle that rotates in the headstock, which is capable of both vertical and longitudinal movements. drills, reamer, taps, and milling cutters can also be mounted on the machine spindle.boring machine are available with a variety of features. although work-piece diameters ar

7、e generally 1 m-4 m(3ft-12ft),work-piece as large as 20 m(60ft) can be machined in some vertical boring machines. machine capacities range up to 150 kw (200hp).these machines are also available with computer numerical controls, which allow all movements to be programmed. with such controls, little o

8、peraror involvement is required and consistency and productivity are improved. cutting speeds and feeds for boring are similar to those for turning.(for capabilities of boring operations)jig borers are vertical boring machines with high precision bearings. although they are available in various size

9、s and used in tool rooms for making jigs and fixtures, they are now being replaced by more versatile numerical control machines.design considerations for boring. guidelines for efficient and economical boring operations are similar to those for turning. additionally, the following factors should be

10、considered：a. whenever possible, through holes rather than blind holes should be specified.(the term blind hole refers to a hole that does not go though the thickness of the work-piece )b. the greater the length to bore-diameter ratio, the more difficult it is to hold dimensions because of the defle

11、ctions of the boring bar due to cutting forces.c. interrupted internal surfaces should be avoided. （2）fundamentals of machine toolsin many cases products form the primary forming processes must undergo further refinements in size and surface finish to meet their design specifications. to meet such p

12、recise tolerances the removal of small amounts of material is needed. usually machine tools are used for such operation.in the united states material removal is a big business-in excess of $ per year, including material, labor, overhead, and machine-tool shipments, is spent. since 60 percent of the

13、mechanical and industrial engineering and technology graduates have something connection with the machining industry either through sale, design, or operation of machine shops, or working in related industry, it is wise for an engineering student to devote some time in his curriculum to studying mat

14、erial removal and machine tools.a machine tool provides the means for cutting tools to shape a workpiece to required dimensions; the machine supports the tool and the workpiece in a controlled relationship through the functioning of its basic members, which are as follow:(a) bed, structure or frame.

15、 this is the main member which provides a basis for, and a connection between, the spindles and slides; the distortion and vibration under load must be kept to a minimum. (b) slides and sideways. the translation of a machine element (e.g. the slide) is normally achieved by straight-line motion under

16、 the constraint of accurate guiding surfaces (the slideway).(c) spindles and bearings. angular displacements take place about an axis of rotation; the position of this axis must be constant within extremely fine limits in machine tools, and is ensured by the provision of precision spindles and beari

17、ngs.(d) power unit. the electric motor is the universally adopted power unit for machine tools. by suitably positioning individual motors, belt and gear transmissions are reduced to a minimum.(e) transmission linkage. linkage is the general term used to denote the mechanical, hydraulic, pneumatic or

18、 electric mechanisms which connect angular and linear displacements in defined relationship.there are two broad divisions of machining operations:(a) roughing, for which the metal removal rate, and consequently the cutting force, is high ,but the required dimensional accuracy relatively low .(b) fin

19、ishing, for which the metal removal rate, and consequently the cutting force, is low, but the required dimensional accuracy and surface finish relatively high .it follows that static loads and dynamic loads, such as result form an unbalanced grindingwheel, are more significant in finishing operation

20、s than in roughing operations, the degree of precision achieved in any machining process will usually be influenced by the magnitude of the deflections, which occur as a result of the force acting.machine tool frames are generally made in cast iron, although some may be steel casting or mild-steel f

21、abrications. cast iron is chosen because of its cheapness, rigidity, compressive strength and capacity for damping the vibrations set-up in machine operations, to avoid massive sections in castings, carefully designed systems of ribbing are used to offer the maximum resistance to bending and torsion

22、al stresses. two basic types of ribbing are box and diagonal. the box formation is convenient to produce, apertures in walls permitting the positioning and extraction of cores. diagonal ribbing provides greater torsional stiffness and yet permits swarf to fall between the sections; it is frequently

23、used for lathe beds. the slides and slideways of a machine tool locate and guide members which move relative to each other, usually changing the position of the tool relative to workpiece .the movement generally takes the form of translation in a straight line, but is sometimes angular rotation, e.g

24、. tilting the wheel-head of a universal thread-grinding machine to an angle corresponding which the helix angle of the workpiece thread. the basic geometric elements of slides are flat, vee, dovetail and cylinder. these elements may be used separately or combined in various ways according to the app

25、lications . features of slideways are as follows :(a) accuracy of movement. where a slide is to be displaced in a straight line, this line must lie in two mutually perpendicular planes and there must be no slide rotation. the general tolerance for straightness of machine tool slideways is 00.02mm pe

26、r 1000mm; on horizontal surfaces this tolerance may be disposed so that a convex surface results, thus countering the effect of sag of the slideway.(b) means of adjustment. to facilitate assembly, maintain accuracy and eliminate play between sliding members after wear has taken place, a strip is som

27、etimes inserted in slides. this is called a gibstrip. usually, the gib is retained by socket-head screws passing through elongated slots；and is adjusted by grub-screws secured by lock nuts.(c) lubrication. slideways may be lubricated by either of the following systems：1)intermittently through grease

28、 or oil nipples, a method suitable where movements are infrequent and speed low2) continuously e.g. by pumping through a metering valve and pipe-work to the point of application; the film of oil introduced between surfaces by these means must be extremely thin to avoid the slide “floating”if sliding

29、 surfaces were optically flat oil would be squeezed out，resulting in the surfaces sticking. hence in practice slide sillfaces are either grourld using the edge of a cup wheel，or scraped. both processes produee minulte surface depressions，which retainpocket” of oil, and complete separation of the par

30、ts may not occur at all points.(d) protectionto maintain slideways in good order, the following conditions must be met：1) ingress of foreign matter，egswarf，must be prevented. where this is no possible，it is desirable to have a form of slideway，which does not retain swarf，e.g. the inverted vee.2) lub

31、ricating oil must be retainedthe adhesive property of oil for use on vertical or inclined slide surface is important; oils are available which have been specially developed for this purpose. the adhesiveness of oil also preverts it being washed away by cutting fluids3) accidental damage must be prev

32、ented by protective guards譯文:(一)鏜削加工和鏜床像車床加工零件一樣，鏜床能在中空的工件或由鉆削加工或其它工藝所加工的孔上進行內(nèi)輪廓圓的加工。鏜削是由那些類似車削的刀具完成的。因為鏜頭必須達到鏜桿的全長，刀具將發(fā)生彎曲，因此，尺寸精度的保持性成為了一個重大問題。鏜桿必須有足夠的剛度刀桿是由較高彈性模量的材料制造的，比如碳化鎢（硬質(zhì)合金）去減小彎曲和避免搖動和振動。鏜桿被設(shè)計有減振的能力。鏜床既能加工在車床上加工的較小工件，鏜銑床又能加工巨大的工件。這類機械既有立式的又有臥式的并且能夠完成如：車削、車端面、切槽、和倒角。一臺立式的鏜床類似一臺車床，但它有一根垂直的工件

33、旋轉(zhuǎn)軸。刀具（通常用于切削的單獨切削點是由m-2和m-3高速鋼和c-8硬質(zhì)合金制造的）被安裝于能垂直運動（用于鏜削和車削）和徑向運動（用于車端面）并由十字導軌導向的刀頭上。刀頭能夠旋轉(zhuǎn)去加工圓錐形表面。在臥式鏜床上工件被裝夾在能在水平面內(nèi)兩個軸向和徑向上移動的工作臺上，刀具被安裝于能做垂直和縱向兩方向上運動的主軸箱上。鉆頭、鉸刀、螺紋刀和銑刀都能安裝于機床主軸上。鏜床具有許多優(yōu)良的性能，它所加工工件的直徑是1m-4m(3ft-12ft)，工件尺寸達到20m(60ft)的可在專用的立式鏜床上加工。機床功率范圍可達到150kw(200hp)。這些可用于所有運動都能編程的數(shù)字控制加工。利用這些控制，

34、只需要很少的相關(guān)操作，并且穩(wěn)定性和生產(chǎn)率大大提高了。鏜床的切削速度和進給速度和車床比較相似。坐標鏜床是屬于具有較高精度支撐的立式鏜床。盡管它們可用于各類尺寸的工件加工和擁有夾緊合安裝的刀具空間。它們正被多功能的數(shù)控機床取代。鏜床的設(shè)計要求：導軌的效率，類似于車削的經(jīng)濟型操作，另外，應該考慮以下因素：a.無論何時，應盡可能注意是加工通孔而并盲孔。（盲孔系列是指那些沒有穿國工件厚度的孔）b.應該控制徑向進給速率，很難去支撐徑向，因為切削力引起鏜桿的彎曲變形。c.應該避免交叉的內(nèi)表面加工。（2）機床基礎(chǔ)為了滿足規(guī)定的設(shè)計規(guī)格，大多數(shù)情況下初步加工的產(chǎn)品都必須再經(jīng)過進一步的尺寸和表面的精加工。要達到這

35、樣的精確規(guī)定公差的要求，少量材料需要被切除掉，而機床通常就是用于此種操作。在美國，材料切除是一項大業(yè)務每年這方面的支出超過36109美元，包括材料、勞力和機床運輸。60%的機械工程和工業(yè)工程畢業(yè)生都通過貿(mào)易、設(shè)計、機械修理工廠，或通過在相關(guān)行業(yè)工作而與機械工業(yè)密不可分，因而如果他們花費一定的時間精力來學習這個領(lǐng)域中的材料切除和機床技術(shù)的話會是很明智的選擇。機床提供切割工具的方式，以使工件成型，達到規(guī)定的尺寸；此種機器依靠其基礎(chǔ)部件的運作來掌握工具和工件之間的聯(lián)系。其基礎(chǔ)部件的運作如下： 床身、構(gòu)造和框架。這三種主要的部件為錠子和滑移的基礎(chǔ)，并將它們聯(lián)系起來；操作中的變形和震動必須盡量避免。 滑移與滑軌。機械部件（如滑移）的轉(zhuǎn)換通常是通過在精密的指導表面（滑軌）的控制下做直線運動而完成的。 錠子與軸承。角位移是圍繞一個旋轉(zhuǎn)軸線發(fā)生的；這個轉(zhuǎn)軸的位置必須一直處于嚴格精確的限制之中，并由精密錠子