机械工程专业英语_原文翻译

5.1 Introduction Conventional machining is the group of machining operations that use single- or multi-point tools to remove material in the form of chips. Metal cutting involves removing metal through machining operations. Machining traditionally takes place on lathes, drill presses, and milling machines with the use of various cutting tools. Most machining has very low set-up cost compared with forming, molding, and casting processes. However, machining is much more expensive for high volumes. Machining is necessary where tight tolerances on dimensions and finishes are required. 5.1 译文 传统机械加工是一组利用单刃或者多刃刀具以切屑形式去除材料的加工方式。金属切削意味着通过机械加工去除金属。传统的机械加工都是利用不同的刀具在车床、钻床和铣床上进行的。与成型加工、锻压和铸造相比，大多数机械加工的生产准备成本都较低，然而如果是大批量生产，其成本要高得多。当对零件的尺寸公差和光洁度要求较高时，机械加工是很有必要的。 5.2 Turning and Lathe Turning is one of the most common of metal cutting operations. In turning, a workpiece is rotated about its axis as single-point cutting tools are fed into it, shearing away excess material and creating the desired cylindrical surface. Turning can occur on both external and internal surfaces to produce an axially-symmetrical contoured part. Parts ranging from pocket watch components to large diameter marine propeller shafts can be turned on a lathe. Apart from turning, several other operations can also be performed on lathe. axially ['æksiəli] adv.轴向地 symmetrical [si'metrikəl] a. 对称的 cylindrical [si'lindrikl] a.圆柱形的 contoured ['kɔntuəd] a.显示轮廓的，与某种形体轮廓相吻合的 译文: 在金属切削加工操作中，车削是最常见的一种。在车削过程中，工件绕其轴线回转，单刃车刀沿工件进给，切除掉多余的材料，最后形成要求的圆柱形表面。车削可以加工外面和内表面以形成具有轴对称的成形工件。从怀表的零件到大直径的船用螺旋桨轴都可以在车床上加工。 除了车削，还有另外几种加工操作都可以在车床上进行。 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. When boring is done in a lathe, the work usually is held in a chuck or on a face plate. Holes may be bored straight, tapered, or to irregular contours. Boring is essentially internal turning while feeding the tool parallel to the rotation axis of the workpiece. 译文: 利用镗杆或合适的内圆车刀可以进行镗削和车内圆。如果工件毛坯是实心的，首先要钻孔。钻头安装在尾架上，后者向工件进给。如果在车床上进行镗削加工，工件通常装夹在卡盘或者花盘上。镗出的孔可以是直孔、锥孔或者不规则轮廓。当将刀具沿工件的回转轴线平行进给时，镗削实际上就是车内圆。 Facing. Facing is the producing of a flat surface as the result of a tool’s being fed across the end of the rotating workpiece. Unless the work is held on a mandrel, if both ends of the work are to be faced, it must be turned around after the first end is completed and then the facing operation repeated. The cutting speed should be determined from the largest diameter of the surface to be faced. Facing may be done either from the outside inward or from the center outward. In either case, the point of the tool must be set exactly at the height of center of rotation. Because the cutting force tends to push the tool away from the work, it is usually desirable to clamp the carriage to the lathe bed during each facing cut to prevent it from moving slightly and thus producing a surface that is not flat. In the facing of casting or other materials that have a hard surface, the depth of the first cut should be sufficient to penetrate the hard material to avoid excessive tool wear. mandrel ['mændrəl] n.车床心轴 clamp [klæmp] v. 夹紧，夹住 carriage [‘kæridʒ] n.大刀架，拖板 penetrate ['penitreit] v. 穿透，渗透 tool wear 刀具磨损 译文: 车端面可以加工出一个平面，它是当车刀沿回转工件的端面横向进给的结果。除非工件固定在心轴上，如果工件两端都要车端面，必须将一端加工完成后，将工件调头，重复进行车端面加工。车削速度必须由所加工表面的最大直径来决定。车端面可以由外向内也可以由中心向外进行。无论哪种情况，刀尖必须准确地与回转中心对正。由于切削力有将车刀推离工件的趋势，通常最可行的就是在车端面时将拖板卡紧在床身上以避免车刀轻微移动造成加工表面不平整。在对具有硬质表面的铸件或其他材料进行车端面加工时，首次切深要足以穿透硬质材料从而避免过度的刀具磨损。 Parting. Parting is the operation by which one section of a workpiece is severed from the remainder by means of cutoff tool. Because cutting tools are quite thin and must have considerable overhang, this process is less accurate and more difficult. The tool should be set exactly at the height of axis of rotation, be kept sharp, have proper clearance angles, and be fed into the workpiece at a proper and uniform feed rate. remainder [ri'meində]剩余物 ，余数 overhang ['əuvə'hæŋ] vt.悬于...之上 n.伸出;突出 uniform ['ju:nifɔ:m] a.相同的,一致的 n.制服;军服 clearance angles 后角 译文: 切断是一种利用切断刀（割刀）将工件的一部分与其剩余部分脱离的加工方法。由于切断刀非常薄而且处于悬臂状态，因此这种加工方法不太精确而且加工起来常常比较困难。切断刀必须准确地对正回转轴，保持锋利，具有合适的后角，以合适、不变的进给率沿工件进给。 Threading. Threading can be considered as turning since the path to be travelled by the cutting tool is helical. However, there are some major differences between turning and threading. While in turning, the interest is in generating a smooth cylindrical surface, in threading the interest is in cutting a helical thread of a given form and depth which can be calculated from the formulae. 译文: 车螺纹可以看作是车削，只是车刀所形成的加工轨迹是螺旋线。但二者也存在一些不同之处。车削主要考虑能否生成光滑的圆柱形表面，而车螺纹注重的是能否切出具有按公式计算出来的规定形状和深度的螺旋线。 There are two basic requirements for thread cutting. • An accurately shaped and properly mounted tool is needed because thread cutting is a form-cutting operation. The resulting thread profile is determined by the shape of the tool and its position relative to the workpiece. • The second by requirement is that the tool must move longitudinally in a specific relationship to the rotation of workpiece, because this determines the lead of the thread. This requirement is met through the use of the lead screw and the split unit, which provide positive motion of carriage relative to the rotation of spindle form-cutting operation 成形加工 longitudinally [lɔ:ŋdʒi'tju:dinəli] adv.纵向 lead screw 丝杠 split unit 开合机构 译文: 车螺纹有两个基本要求：首先，由于车螺纹是一种成形加工，因此车刀必须具有准确的形状而且要安装合适。所切出的螺纹外形是由车刀形状和它与工件的相对位置决定的。其次，车刀的纵向进给与工件的回转运动具有特定的关系，因此这决定了螺纹的导程。这个条件可以通过采用丝杠和开合机构得到满足，它们可以实现拖板相对于主轴回转运动的精确可靠的运动 1. Engine lathes 普通车床 2. Vertical lathes 立式车床 3. Turret lathes 转塔车床 5. Contouring lathes 仿形车床 6. Universal lathes 万能车床 Lathe bed is foundation of the engine lathe, which heavy, rugged casting is made to support the working parts of the lathe. The size and mass of the bed gives the rigidity necessary for accurate engineering tolerances required in manufacturing. On top of the bed are machined slideways that guide and align the carriage and tailstock, as they are move from one end of the lathe to the other. rugged adj. 健壮，坚固 mass n. 质量 slideways n.导轨 床身是普通车床的基础，它是由沉重而坚固的铸件制作而成的，其目的是为了支撑车床的工作部件。床身的尺寸和质量要使车床具有足够的刚性以保证制造过程中获得所需的工程公差。床身上的导轨可以引导和对准拖板和尾座，使它们可以从车床的一端移动到另一端。 • Headstock is clamped atop the bed at left-hand end of the lathe and contains the motor that drives the spindle whose axis is parallel to the guideways through a series of gears housed within the gearbox. The function of gearbox is to generate a number of different spindle speeds. • atop adv. 在(…)顶上 • gearbox 齿轮箱 床头箱（主轴箱）紧固在床身上面的左端，内装有电机，它通过变速箱内的一组齿轮来驱动主轴转动，主轴的轴线平行于导轨。变速箱的功能是可以产生不同的主轴转速。 • A spindle gear is mounted on the rear of the spindle to transmit power through the change gears to the feeding box that distributes the power to the lead screw for threading or to the feed rod for turning. • on the rear of 在…的尾部 • change gears 挂轮 • lead screw 丝杠 • feed rod 光杠 主轴齿轮安装在主轴的尾部，通过挂轮把动力传递到进给箱，如果是车螺纹，进给箱将动力分配到丝杠上；如果是车削，就将动力分配到光杠上。 • The spindle has a through hole extending lengthwise through which bar stocks can be fed if continuous production is used. The hole can hold a plain lathe center by its tapered inner surface and mount a chuck, a face plate or collet by its threaded outer surface. • taper n.坡度，锥形 v.锥度加工 • collet n.夹头 主轴有一个纵向通孔，如果连续加工棒料，通孔就用来实现棒料的送料。这个通孔具有一个内锥面，可以安装普通车床的中心顶尖。主轴的外表面车有螺纹，可以安装卡盘，花盘或夹头。 Carriage assembly is actually an H-shaped block that sits across the guideways and in front of lathe bed. The function of the carriage is to carry and move the cutting tool longitudinally. It can be moved by hand or by power and can be clamped into position with a locking nut. The carriage is composed of the cross slide, compound rest, tool saddle, and apron. 拖板组件实际上是一个H形的铸件，位于床身的前端并横跨在导轨上。拖板的功能带动刀具纵向移动，这个可以通过手动或者自动完成。利用锁紧螺母可以将其卡紧在所需位置。拖板组件由横拖板，小刀架，刀架鞍板和溜板箱组成。 • The cross slide is mounted on the dovetail guideways on the top of the saddle and it moved back and forth at 90°to the axis of the lathe by the cross slide lead screw. The lead screw can be hand or power activated. • dovetail 燕尾槽 横拖板安装在刀架鞍板上部的燕尾槽导轨上。它利用横拖板丝杠于车床轴线成90度夹角的方向上前后移动。丝杠可以手动或者自动驱动。 • The compound rest is mounted on the cross slide and can be swiveled and clamped at any angle in a horizontal plane. The compound is typically used for cutting chamfers or tapers, but must also be used when cutting thread. The compound rest can only be fed by hand. There is no power to compound rest. The cutting tool and tool holder are secured in the tool post which is mounted directly to the compound rest. • swivel ['swɪvəl] v.旋转 小刀架安装在横拖板上，它可以在水平面内转动或夹紧在任意角度位置。小刀架主要用来倒角和加工锥面，在车削螺纹时也必须用到小刀架。小刀架只能手动进给，没有动力传到小刀架上。刀具和刀夹被卡紧在直接安装在小刀架上的刀座上。 The tool saddle is an H shaped casting mounted on the top of the guideways and houses the cross slide and compound rest. It makes possible longitudinal, cross and angular feeding of the tool bit. • 刀架鞍板是一个安装在导轨上部的H形铸件，容纳有横拖板和小刀架。它可以实现刀尖的纵向、横向和斜向进给。 The apron is attached to the front of the carriage and contains the gears and feed clutches which transmit motion from the feed rod or lead screw to carriage and cross slide. 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. • 溜板箱位于拖板的前端，里面装有齿轮和将运动从光杠或丝杠传递至拖板或横向拖板的进给离合器。当切制螺纹时，动力通过丝杠传递到溜板箱中的变速齿轮箱。在其它车削加工时，依靠光杠来驱动拖板。 • Tailstock is composed of a low base and the movable part of the tail-stock proper, the transverse adjustments being made with a cross screw furnished with a square head. The two parts are hold together by the holding-down bolts which secure the tailstock to the bed. • transverse adj. 横向的，横切的； n. 横轴 • holding-down bolts 压紧螺栓 尾座由底座和尾座体的可移动部件组成。课移动部件的横向调整有带有四方头的横向丝杠来完成。底座和可移动部分通过压紧螺栓连接在一起并将尾座固定在床身上。 6.1 Traditional or conventional machining, such as turning, milling, and grinding etc., uses mechanical energy to shear metal against another substance to create holes or remove material. Non-traditional machining processes are defined as a group of processes that remove excess material by various techniques involving mechanical, thermal, electrical or chemical energy or combinations of these energies but do not use a sharp cutting tool as it is used in traditional manufacturing processes. 传统的或常规的加工，如车削，铣削，磨削等，利用机械能剪金属与另一个物质创造孔或删除材料。非传统加工工艺被定义为一组过程清除多余的材料的各种技术，涉及机械，热，电或化学能源或组合这些能量，但不要用锋利的切割工具，它采用的是传统的制造工艺 [1] Extremely hard and brittle materials arc difficult to be machined by traditional machining processes. Using traditional methods to machine such materials means increased demand for time and energy and therefore increases in costs; in some cases traditional machining may not be feasible. Traditional machining also results in tool wear and loss of quality in the product owing to induced residual stresses during machining. Non-traditional machining processes, also called unconventional machining process or advanced manufacturing processes, are employed where traditional machining processes are not feasible, satisfactory or economical due to special reasons as outlined below: 非常硬脆材料难加工的传统加工过程。用传统方法加工的材料需求增加的时间和精力，因此成本增加；在某些情况下 传统加工可能是不可行的。传统加工也导致刀具磨损质量损失在产品由于加工引起的残余应力。非传统加工工艺，又称为非常规加工过程或先进的制造工艺，采用传统的加工工艺是不可行的，令人满意的或经济由于特殊原因概述如下： 1. Very bard fragile materials difficult to clamp for traditional machining; 很难夹巴德脆性材料加工； 2. When the workpiece is too flexible or slender, 当工件太灵活或纤细， 3. When the shape of the part is too complex; 当形状的部分是太复杂； 4. Parts without producing buns or inducing residual stresses. 无生产面包或诱导残余应力。 Traditional machining can be defined as a process using mechanical (motion) energy. Non-traditional machining utilizes other forms of energy; the three main forms of energy used in non-traditional machining processes are as follows: 传统加工可以被定义为一个过程中使用机械（运动）的能量。特种加工利用其他形式的能量；三种主要形式的能量用于非传统加工工艺如下： 1. Thermal energy; 热能量； 2. Chemical energy-化学能, 3. Electrical energy. 电力能源 Several types of non-traditional machining processes have been developed to meet extra required machining conditions. When these processes are employed properly, they offer many advantages over traditional machining processes. The common non-traditional machining processes are described in the following section. 几种类型的非传统加工工艺已满足 额外所需的加工条件。当这些过程是正确使用，他们提供了许多优势，传统的加工工艺。常见的非传统 加工过程是描述在下面的部分。 6.2 Electrical Discharge Machining (EDM) 电火花加工（电火花） Electrical discharge machining (EDM) sometimes is colloquially referred to as spark machining, spark eroding, burning, die sinking or wire erosion. It is one of the most widely used non-traditional machining processes. The main attraction of EDM over traditional machining processes such as metal cutting using different tools and grinding is that this technique utilizes thermoelectric process to erode undesired materials from the workpiece by a series of rapidly recurring discrete- electrical sparks between workpiece and electrode. 电火花加工（电火花）有时是通俗称为火花机械加工，电火花加工，燃烧，开模或侵蚀。这是一个最 广泛使用的非传统加工工艺。主要景点的电火花加工过传统加工工艺等金属切削用不同的工具和研磨这种技术利用热电过程不受欢迎的材料的侵蚀工件通过一系列的快速离散-电火花加工和电极。 [2] The traditional machining processes rely on harder tool or abrasive material to remove the softer material whereas non-traditional machining processes such as EDM uses electrical spark or thermal energy to erode unwanted material in order to create desired shapes. So, the hardness of the material is no longer a dominating factor for EDM process. 传统的加工工艺很难依靠工具或研磨材料拆下软的材料，而非传统加工工艺如电火花使用电火花或热能量侵蚀有害物质为创造所需的形状。因此，材料的硬度不再是一个主导因素电火花过程。 EDM removes material by discharging an electrical current, normally stored in a capacitor bank, across a small gap between the tool (cathode) and the workpiece (anode) typically in the order of 50 volts/l0 amps. As shown in Fig-6. 1, at the beginning of EDM operation, a high voltage is applied across the narrow gap between the electrode and the workpiece. This high voltage induces an electric field in the insulating dielectric that is present in narrow gap between electrode and workpiece. This cause conducting particles suspended in the dielectric to concentrate at the points of strongest electrical field. When the potential difference between the electrode and the workpiece is sufficiently high ,the dielectric breaks down and a transient spark discharges through the dielectric fluid, removing small amount of material from the workpiece surface. The volume of the material removed per spark discharge is typically in the range of 10-5 to 10-6 mm3. The gap is only a few thousandths of an inch, which is maintained at a constant value by the servomechanism that actuates and controls the tool feed. 电容器组，在一个小的差距之间的工具（阴极）和工件（阳极）通常在50伏特/ 10安培。如在fig-6。1年初，电火花加工经营，高电压应用于缩小之间的差距电极和工件。这种高电压诱导电场绝缘介质是目前在窄间隙的电极与工件之间。这导致导电粒子悬浮介质中的集中点的最大电场。什么时候 电位差的电极与工件之间的足够高，介质崩溃和一个短暂的火花放电通过流体介质，除少量材料从工件表面。体积的 材料去除每火花放电通常范围在10 - 5到10 - 6毫米。差距只有千分之几 7.1 Introduction Quality and accuracy are major considerations in making machine parts or structures. Interchangeable parts require a high degree of accuracy to fit together. With increasing accuracy or less variation in the dimension, the labor and machinery required to manufacture a part is more cost intensive.[l] Any manufacturer should have a thorough knowledge of the tolerances to increase the quality and reliability of 'a manufactured part with the least expense. 质量和精度的主要因素在制造机器零件或结构。零件的互换性要求高精度的配合。随着越来越多的准确性或少变化的尺寸，劳动和机械要求制造一个部分是成本密集。[ 1 ]任何厂商应该有一个透彻的 知识的公差，提高质量和可靠性的一部分用最少的费用。 An engineering drawing must be properly dimensioned in order to convey the designer's intent to the end user. Dimensions of parts given on blueprints and manufactured to those dimensions should be exactly alike and fit properly. Unfortunately, it is impossible to make things to an exact or dimension. Most dimensions have a varying degree of accuracy and a means of specifying acceptable limitations in dimensional variance so that a manufactured part will be accepted and still function. It is necessary that the dimensions, shapes and mutual position of surfaces of individual parts are kept within a certain accuracy to achieve their correct and reliable functioning. Routine production processes do not allow maintenance (or measurement) of the given geometrical properties with absolute accuracy. 工程图纸必须是适当的尺寸来传达设计师的意图最终用户。在图纸和零件尺寸制造这些方面应该是完全一样的，好的。不幸的，这是不可能让事情精确或尺寸。大多数方面有不同的程度的准确性和可接受的限制手段指定尺寸方差，制造部分将被接受和功能仍然。这是必要的尺寸，形状和相互位置的表面上的个别部分被保持在一定的精度，实现正确的和可靠的运作。日常生产过程不允许维持（或测量）的几何性质绝对精度 [2] Actual surfaces of the produced parts therefore differ from实际表面产生不同的部位 ideal surfaces prescribed in drawings. Deviations of actual surfaces are divided into four groups to enable assessment, prescription and checking of the permitted inaccuracy during production: 理想的表面在图纸规定。偏差的实际表面分为四组，使评估，处方和检查的允许误差在生产： 1. Dimensional deviations; 尺寸偏差； 2. Shape deviations; 形状偏差； 3. Position deviations; 位置偏差 4. Surface roughness deviations. 表面粗糙度偏差。 As mentioned above, it is principally impossible to produce machine parts with absolute dimensional accuracy. In fact, it is not necessary or useful. It is quite sufficient that the actual dimension of the part is found between two limit dimensions and a permissible deviation is kept with production to ensure correct functioning of engineering products. The required level of accuracy of the given part is then given by the dimensional tolerance which is prescribed in the drawing. The production accuracy is prescribed with regards to the functionality of the product and to the economy of production as well. The principal factor used to set a tolerance for a dimension should be the function of the feature being controlled by the dimension. Unnecessarily tight tolerances lead to high cost of manufacture resulting from more expensive manufacturing methods and higher reject rates. 如上所述，它主要是不可能产生的机械零件绝对尺寸精度。事实上，它是不必要或有用。这是很充分的 ，零件的实际尺寸是两国之间的极限尺寸和允许偏差是确保正确的运作与生产工程产品。所需的准确度的特定部分给出的尺寸 宽容是在绘图。生产精度是明关于该产品的功能和经济的生产等。本主要用于设置一个公差尺寸应该是功能的特征所控制的尺寸。不必要的紧公差导致成本高制造更昂贵的制造方法和较高的拒绝率。 7 2 Tolerances公差 Tolerance is the total amount that a specific dimension is permitted to vary. It is the difference between the maximum and the minimum limits for the dimension. To understand tolerances, you should understand some of the definitions associated with the determination of a tolerance. These definitions may be generally categorized as relating to size, allowance, or fit. 宽容的总金额，具体尺寸允许有所不同。它是之间的差异最大和最小极限尺寸。到理解公差，你应该了解一些定义与测定误差。这些定义大致可归类为有关大小，补贴，或适合。 Size. The size of an object or its mate is (mown as nominal, basic, or design size. Allowance. The difference between the largest allowable shaft size and the smallest hole diameter is termed as the allowance. [3] The quality of the fit is characterized by the allowance value. 大小。物体的大小或其配偶（割的名义，基本设计，或大小。津贴。之间的差异最大允许轴尺寸和最小的孔直径被称为津贴。[ 3 ]符合质量的特点是津贴的价值。 Fit. clearance, interference, or transition fit refer to how the object 'its ski assembly. 适合的。清除，干扰，或过渡配合指对象“滑雪组件。 To specify the size of an object, we dimension it with a nominal size, basic size, and actual size shown in Fig.7.1. 指定对象的大小尺寸，我们用公称尺寸，基本尺寸，和实际尺寸显示在fig.7.1。 Nominal size (basic size). It is the designation used for general identification and usually expressed in common fractions. It is an exact theoretical size of a part from which limit dimensions are computed. The nominal size of a part should be selected from the preferred dimension series indicated by the national standard.(4J (shown in Fig.7.Ia) limit size. It includes upper limit size and lower limit size which are allowable extreme sizes of a part Fox example, the limits for a hole arc 1500 (lower limit)