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AC=alternative current交流AGV=Automated Guided Vehicle自动导引小车AGVS= Automated Guided Vehicle System自动导引小车系统AMT=advanced manufacturing technology先进制造技术ANSI=American National Standards Institute美国国家标准协会APT=Automatically Programmed Tools自动数控程序BOM=Bill of Material物料清单CAA=Computer Aided Analysis Process计算机辅助分析过程CAD=Computer-Aided Design计算机辅助设计CADD=Computer-Aided Design Drafting计算机辅助设计制图CAE=computer aided engineering计算机辅助工程CAM=Computer-Aided Manufacturing计算机辅助制造CAIT=computer aided testing and inspection计算机辅助实验与检测CAPP=Computer Aided Process Planning计算机辅助工艺设计CHP=chemical Polishing 化学抛光CIM=Computer integrated manufacturing计算机集成制造CBN=Cubic Boron Nitride立方氮化硼CMM=Coordinate Measuring Machine三坐标测量机CNC=computer numerical control电脑数字控制DC=direct current直流DNC=Direct Numerical Control直接数字控制DOF=degrees of freedom自由度DXF=data exchange format数据交换格式ECM=Electrochemical Machining电解加工EBM=Electron beam machining电子束加工EDM=Electrical Discharge Machining电火花加工EGM= enhanced graphics module增强型图形模组FA=factory automation工厂自动化FDM=Fused Deposition Modelling熔融沉积成型FEA=Finite element analysis有限元分析FMC=flexible manufacturing component柔性制造单元FMS=Flexible Manufacturing System柔性制造系统Finite-element有限元Four-bar linkage四连杆机构GNC=graphical numerical control图形数控GT=Grease Trap润滑脂分离器HPM=hard-part machining硬态切削HSS=High-Speed-Steel高速钢IGES=initial graphic exchange specification初始图形交换规则ISO=International Standardization Organization国际标准组织IT=International Tolerance(grade)国际公差JIT=Just in Time准时生产LBM=Laser beam machining激光切削加工LED=light-emitting diode发光二级管LMC=least material condition最小实体状态LOM=Laminated Object Manufacturing叠层实体制造技术MMC=maximum material condition最大实体状态MATL=material材料MC=machining center加工中心NC=Numerical Control数字控制NMP=Nontraditional Manufacturing Processes特种加工技术PCB=printed circuit boards印刷电路板PLC=Programmable Logic Controller PLC控制PKW=parallel kinematics machine并联机床QTY=quantity required需求数量RGV=rail guided vehicle有轨自动导引小车RPM=Rapid Prototype Manufacturing快速成型技术SL= Stereo Lithography光固化成型SLA=Stereo Lithography Apparatus立体印刷技术/光固化立体造型SLS=Selective Laser Sintering选择性激光烧结USM=Ultrasonic Machining超声波加工VNC=voice numerical control声音控制WEDM=Wirecut Electrical Discharge Machining电火花线切割加工WJM/C=water-jet machining/cutting水射流切削3D PRINT 3D打印一、将下列单词译成汉语Mechanism（机械，机构，机构学）configuration（外形，构造，结构）displacement（位移）velocity（速度）acceleration（加速度）gear（齿轮）sprocket（链轮）pulley（带轮）kinematician /dynamics（运动/动力学，力学）kinematician（运动）cam凸轮camshaft凸轮轴accuracy精度dependability可靠性pulley滑轮flywheel飞轮crank曲柄sprocket链轮axle心轴spindle主轴clutche离合器brake制动shaper牛头刨床planer龙门刨pulley皮带轮flywheel飞轮spindle轴clutche离合器crank曲柄sprocket链轮axle车轴brake制动warpage配气机构coolant冷却剂二、将下列词组译成汉语kinematic chain（运动链）skeleton diagram（草图，示意图，简图）Gear system/Cam system（齿轮传动系统/凸轮系统）uniform motion/nonuniform motion（匀速运动/非匀速运动）nonlinear motion（非线性运动）kinematic analysis（运动分析）schematic diagram（运动简图）textile machinery（纺织机械）Kinematic design/ kinematic syntheses（运动设计/运动合成）machinedesign（机械设计）Gear trains/ Cam mechanisms（轮系，齿轮传动链/凸轮机构）dynamic force/inertia force/ static force（动力/惯性力/静力）relative velocity/ absolute velocity（相对速度/绝对速度）angular acceleration/ tangential acceleration/ centripetalacceleration/ velocity vector（角加速度/切向加速度/向心加速度/速度矢量）binary link/ ternary link（二杆组/三杆组）the basecircle（基圆）the pitch curve（啮合曲线）the contact force（接触力）the intermittent motion （间歇运动）the common normal（公法线）the conjugate profiles（共轭齿廓）the cycloidal profiles （摆线齿形）the involute profiles （渐开线齿形）the spurgear（直齿轮）the herringbone gears（双螺旋齿轮）the face gear（端面齿轮）the radial distance （径向距离）the addendumcircle（齿顶圆）The tooth thickness（齿厚）the tooth space（齿间隙）the cap screws（螺钉）the setscrews（固定螺丝钉）theengineering graphics（工程力学）mechanical design（机械设计）the installation techniques（安装技术）the bolted joint（螺栓连接）the hardened washers（强化垫圈）the fatigue resistance（抗疲劳强度）the modulus of elasticity（弹性模量）theantifriction bearing（减摩轴承）the rolling bearing（滚动轴承）the rolling contact （滚动接触）the sliding contact（滑动触电）the corrosion resistance（抗腐蚀性）the machining tolerances（加工公差）the fatigue loading （疲劳载荷）the radial loads（径向负荷）the thrust loads逆负荷the ball bearing球轴承the roller bearing滚子轴承the single-row bearings单沟轴承thedouble-row bearing双沟轴承the needle bearing滚针轴承the bearing life轴承寿命The rating life额定寿命the axis of rotation旋转轴The helix angle螺旋角a right-hand helix 右旋a left-hand helix左旋an involute helicoids螺旋面an involute curve渐开线theshaft centerlines轴中心线worm gear蜗轮the hypoid gear准双曲面齿轮right angle直角worm gearing蜗杆传动the lead angle导角shaftangle轴线角度bending load弯曲载荷tension load张力负荷compression load压缩负载torsional load扭转负荷the bending moment弯矩the bending stress弯曲应力the shot peening喷丸法the actuating force工作力the coefficient of friction摩擦系数Anelectromagnetic coil电磁线圈the magnetic circuit磁路the design specifications中国设计规范the industrial engineering工业工程the machining industry加工行业the machine shops机器商店machine tool机床angular displacements角位移The electric motor电机transmission Linkage传输连接the cutting force切削力the static loads静态负荷the dynamic loads动态载荷the grinding wheel砂轮lubricating oil润滑油the cutting fluids切削液protective guards防护装置the cutting tool刀具the range of feeds进给量enginelathes普通车床turret lathes六角车床the boring machine镗床the drilling machines钻床the milling machines铣床the broachingmachines绞孔机；拉床the sawing machines锯床the cylindrical grinder外圆磨床the centreless grinders无心磨床the surface grinders平面磨床the chemical milling铣削the ultrasonic machining超声波加工a toolholder刀架a compound rest复式刀架the feed screw丝杆the feed rod光杆The feed box进给箱power feed进给the full depth大切削深度thread cutting螺纹切削a chasing dial螺纹指示盘the forward stroke冲程the return stroke回程the clapper box摆动刀架thehydraulic shaper液压牛头刨床the universal machines通用机械universal joints万向节Tracer milling仿形铣the master pattern模型the acceleration of gravity重力加速度conducting material导电材料non-conducting material绝缘材料三、将下列短语译成汉语1.Plane and spatial linkages（平面和空间连杆）2.constrained kinematic chain/unconstrained kinematic chain（约束运动链/非约束运动链）3.closed-loop linkage（闭环运动链）4.four-bar linkage（四连杆机构）5.slider-crank (or crank and slider) mechanism（曲柄滑块机构）6.internal combustion engine（内燃机）7.the kinematic analysis of mechanisms（机构运动分析）8.degree of freedom of the mechanism（机构自由度）9.kinematic analysis process /kinematic synthesis process（运动分析步骤/运动合成步骤）10.input angular velocity（输入角速度）11.input angular acceleration（输入角加速度）12.automatic packaging machinery（自动包装机）13.cam-contour dimensions/cam-follower diameters（凸轮轮廓尺寸/凸轮从动件直径）14.mechanical analog computer（机构模拟计算机）15.dead-center position（死点位置）16.crank-rocker linkage/double-rocker linkage/double-crank (drag-link) linkage（曲柄摇杆机构/双摇杆机构/双曲柄机构）17.maximum force component/ resulting output force or torque（最大的力量组成/输出的最大力或力矩）18.output motion variables/input motion variable（输出运动变量/输入运动变量）19.absolute angular positions（绝对角位置）20.velocity polygon method（速度的多边形的方法）21.instantaneous center method/instant center method（瞬心法/即时瞬心法）22.inertia-force analysis of mechanisms and machines（机构和机器的惯性力分析）23.one and the same coordinate system /inertia frame of reference（惯性参考系）24.systematic design of mechanisms（机械设计的系统）25.cam-contour dimensions/cam-follower diameters（凸轮轮廓尺寸/凸轮从动件直径）26.disk or plate translating (two-dimensional or planar) 盘形传动凸轮（两维的，即平面的）27.cylindrical (three-dimensional or spatial) cams圆柱形凸轮（三维的，即空间的）机构28.a radial (in-line) translating roller follower一个对心直动滚子从动件29.a constant angular velocity ratio旋转角速度的比例30.a constant torque ratio一个恒转矩比31.Nonlinear angular velocity ratios非线性角速度比率32.the parallel helical gear平行斜齿轮33.the crossed helical gear交叉斜齿轮34.the straight bevel gear直锥齿轮35.the spiral bevel gear弧齿锥齿轮36.the skew bevel gear大角度斜交锥齿轮37.the hexagon head screws六角头螺钉38.the fillister head screws槽头螺钉39.the flat head screws 平头螺钉40.the hexagon socket head screws内六角沉头螺钉。
5.1 IntroductionConventional 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、锻压和铸造工艺相比，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 LatheTurning 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。
英文资料Limits and TolerancesThe breakage of the machine spare parts ,generally always from the surface layer beginning of .The function of the product ,particularly its credibility and durable ,be decided by the quantity of spare parts surface layer to a large extent. Purpose that studies the machine to process the surface quantity be for control the machine process medium various craft factor to process the surface quantity influence of regulation, in order to make use of these regulations to control to process the process, end attain to improve the surface quantity, the exaltation product use the function of purpose .The machine processes the surface quantity to use the influence of the function to the machine(A) The surface quantity to bear to whet the sexual influence1.Rough degree of surface to bear to whet the sexual influenceA just process vice-of two contact surfaces of good friction, the first stage is rough only in the surface of the peak department contact ,the actual contact area is much smaller than theoretical contact area, in contact with each other the peak of the units have very great stress, to produce actual contact with the surface area of plastic deformation, deformation and peak between the Department of shear failure, causing serious wear.Parts wear may generally be divided into three stages, the initial stage of wear and tear, normal wear and tear all of a sudden intense phase of stage wear.Parts of the surface roughness of the surface wear big impact. In general the smaller the value of surface roughness, wear better. However, surface roughness value is too small, lubricants difficult to store, contact between the adhesive-prone elements, wear it to increase. Therefore, the surface roughness of a best value, the value and parts of the work related to increased work load, the initial wear increased, the best rough surface is also increased.2.Cold Working hardening the surface of the wear resistanceProcessing the Cold Work hardening the surface of the friction surface layer of metal microhardness increase, it will generally improve the wear resistance. Cold Working but not a higher degree of hardening, wear resistance for the better, because too much will lead to hardening of the Cold Working excessive loose organization ofmetal, even a crack and peeling off the surface of the metal, declined to wear resistance.(B)The surface quality of the impact of fatigue strengthMetal hand alternating loads of fatigue after the damage occurred in parts often Chilled layer below the surface and, therefore parts of the surface quality of fatigue very influential.1.Surface roughness on the impact of fatigue strengthIn alternating load, the surface roughness of the Au-site easily lead to stress concentration, a fatigue crack, the higher the value of surface roughness, surface traces of Yu Shen Wen, Wen at the end of the radius smaller, anti-fatigue damage at the end of the more capacity Worse.2.Residual stress, fatigue Cold Work hardening of the impactResidual stress on the impact of large parts fatigue. Surface layer of residual stress fatigue crack will expand and accelerate the fatigue damage the surface layer and the residual stress can prevent fatigue crack growth, delaying the formation of fatigue damage.(C)The surface quality of the corrosion resistance of the impactParts of the corrosion resistance to a large extent depends on the surface roughness. The higher the value of surface roughness, Au Valley accumulate on the more corrosive substances. Corrosion resistance of the more worse.Surface layer of residual stress will produce stress corrosion cracking, lower parts of the wear-resistance, and the residual stress is to prevent stress corrosion cracking.(D) The surface quality with qualityRough surface will affect the value of the size of the co-ordination with the surface quality. The gap with rough value will increase wear and tear, increased space, with the requirements of the destruction of nature. For Fit, the assembly part of the process of convex surface-crowded peak times, the actual reduction of the surplus and reduce the support of the connection between the strength.DimensioningThe design of a machine includes many factors other than those of determining the loads and stresses and selecting the proper materials. 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 andfamiliarity with manufacturing processes are needed before one can become conversant with all phases of production drawings.Drawings should be carefully checked to see that the dimensioning is done in a manner that will be most convenient and understandable to the production departments. It is obvious that a drawing should be made in such a way that it has one and only one interpretation. In particular, shop personnel should not be required to make trigonometric or other involved calculations before the production machines can be set up.Dimensioning is an involved subject and long experience is required for its mastery.Tolerances must be placed on the dimensions of a drawing to limit the permissible variations in size because it is impossible to manufacture a part exactly to a given dimension. Although small tolerances give higher quality work and a better operating mechanism, the cost of manufacture increases rapidly as the tolerances are reduced, as indicated by the typical curve of Fig 14.1. It is therefore important that the tolerances be specified at the largest values that the operating or functional considerations permit.Tolerances may be either unilateral or bilateral. In unilateral dimensioning, one tolerance is zero, and all the variations are given by the other tolerance. In bilateral dimensioning, a mean dimension is used which extends to the midpoint of the tolerance zone with equal plus and minus variations extending each way from this dimension.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, 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. However, some companies do not use blanket notes on the supposition that if each dimension is considered individually, wider tolerance 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.Dimension and ToleranceIn dimensioning a drawing, the numbers placed in the dimension lines represent dimension that are only approximate and do not represent any degree of accuracy unless so stated by the designer.To specify a degree of accuracy, it is necessary to add tolerance figures to the dimension. Tolerance is the amount of variation permitted in the part or the total variation allowed in a given dimension. A shaft might have a nominal size of 2.5 in. (63.5mm), but for practical reasons this figure could not be maintained in manufacturing without great cost. Hence, a certain tolerance would be added and , if a variation of ±0.003 in.(±0.08mm) could be permitted, the dimension would be stated 2.500±0.003(63.5±0.008mm).Dimensions given close tolerances mean that the part must fit properly with some other part. Both must be given tolerances in keeping with the allowance desired, the manufacturing processes available, and the minimum cost of production and assembly that will maximize profit. Generally speaking, the cost of a part goes up as the tolerance is decreased. If a part has several or more surfaces to be machined, the cost can be excessive when little deviation is allowed from the nominal size.Allowance, which is sometimes confused with tolerance, has an altogether different meaning.It is the minimum clearance space intended between mating parts and representsthe condition of tightest permissible fit. If a shaft, size 1.4980.0000.003+-, is to fit a hole ofsize 1.5000.0030.000+-, the minimum size hole is 1.500 and the maximum size shaft is 1.498.Thus the allowance is 0.002 and the maximum clearance is 0.008 as based on the minimum shaft size and maximum hole dimension.Tolerances may be either unilateral or bilateral. Unilateral tolerance means that any variation is made in only one direction from the nominal or basic dimension.Referring to the previous example, the hole is dimensioned 1.5000.0030.000+-, whichrepresents a unilateral tolerance. If the dimensions were given as 1.500±0.003, the tolerance would be bilateral; that is , it would vary both over and under the nominal dimension. The unilateral system permits changing the tolerance while still retaining the same allowance or type of fit. With the bilateral system, this is not possible without also changing the nominal size dimension of one or both of the two mating parts. In mass production, where mating parts must be interchangeable, unilateral tolerances are customary. To have an interference or fore fit between mating parts, the tolerances must be such as to create a zero or negative allowance.Tolerances Limits and FitsThe drawing must be a true and complete statement of the designer’s expr essed in such a way that the part is convenient to manufacture. Every dimension necessary to define the product must be stated once and repeated in different views. Dimensions relating to one particular feature, such as the position and size of hole, where possible, appear on the same view.There should be no more dimensions than are absolutely necessary, and no feature should be located by more than one dimension in any direction. 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.Dimensions that affect the function of the part should always be specified and not left as the sum or other dimensions. If this is not done, the total permissible variation on that dimension will form the sum or difference of the other dimensions and their tolerance, and this with result in these tolerances having to be made unnecessarily tight. The overall dimension should always appear.All dimensions must be governed by the general tolerance on the drawing unless otherwise stated. Usually, such a tolerance will be governed by the magnitude of the dimension. Specific tolerances must always be stated on dimensions affecting or interchangeability.A system of tolerances is necessary to allow for the variations in accuracy that are bound to occur during manufacture, and still provide for interchangeability and correct function of the part.A tolerance is the difference in a dimension in order to allow for unavoidable imperfections in workmanship. The tolerance range will depend on the accuracy of the manufacturing organization, the machining process and the magnitude of the dimension. The greater the tolerance range is disposed on both sides of the nominal dimension. A unilateral tolerance is one where the tolerance zone is on one side only of the nominal dimension, in which case the nominal dimension may from one of the limits.Limits are the extreme dimensions of the tolerance zone. For example, nominal dimension30mm tolerance 30.0230.000++ limits 30.02530.000Fits depend on the relationship between the tolerance zones of two mating parts,and may be broadly classified into a clearance fit with positive allowance, a transition fit where the allowance may be either positive or negative (clearance or interference) , an interference fit where the allowance is always negative.Type of Limits and FitsThe ISO system of Limits and Fits, widely used in a number of leading metric countries, is considerably more complex than the ANSI system.In this system, each part has a basic size. Each limit of part, high and sign being obtained by subtracting the basic size form the limit in question. The difference between the two limits of size of a part is called the tolerance, an absolute without sign.There are three classes of fits: 1) clearance fits, 2) transition fits ( the assembly may have either clearance or interference ), and 3) interference fits .Either a shaft-basis system or a hole-basis system may be used. For any given basic size, a range of tolerance and deviations may be specified with respect to be line of zero deviation, called the zero line. The tolerance is a function of the basic size and is designated by a number symbol, called the grade-thus the tolerance grade. The position of the tolerance with respect to the zero line also a function of the basic size-is indicated by a letter symbol(or two letter), a capital letter for holes and a lowercase letter for shafts. Thus the specification for a hole and shaft having a basic size of 45mm might be45H8/g7.Twenty standard grades of tolerance are provided, called IT 01,IT 0 ,IT 1-18, providing numerical values for each nominal diameter, in arbitrary steps up to 500mm (for example 0-3,3-6,6-10…, 400-500mm). The value of the tolerance unit, I, for grades 5-16 is=+0.0.001i DWhere i is in microns and D in millimeters.Standard shaft and hole deviations similarly are provided by sets of formulas, However, for practical, both tolerances and deviations are provided in three sets of rather complex tables. Additional tables gives the values for basic sizes above 500mm and for “Commonly Used Shafts and Holes” in two categories ---“General Purpose” and “Fine Mecbanisms and Horology”.中文翻译极限与误差机械零件的破坏，一般总是从表层开始的。
What Is a SketchThe mechanic must not only know how to read the language of the industrial world but must also know how to write it. He must be able to give his own ideas and describe an object to someone else. It is often necessary to make just a part for a machine. However, there is no time to make a drawing of it with instruments, no time either for a draughtsman to make a drawing. Sometimes only one piece of a machine part is to be made and, therefore, it would be inconvenient to have the draughtsman make a mechanical drawing.Sketches are important because they show ideas and dimensions of a machine part. The cleverest idea, however, may result in a great mistake if the sketch is poorly done. We must learn to make clean sketches to be easily read by others as well as by ourselves.Machine ElementsA machine consists of a number of machine elements. The most useful machine element in power transmission is the gear. The gear is virtually a wheel with a number of teeth. Gears must work in pairs. A pair of gears with different number of teeth will increase or decrease the speed of rotationPulleys and belts are very common in power transmission. They can also change speeds on machine tools. Gears or pulleys rotate on shafts. Theshaft must rest in bearings. Sometimes there may be couplings between shafts. We may use clutches to start or stop shaft motion.Some machine elements may be very large. Others may be very small. However, each of them plays a part in the construction of a machine.Cutting ToolsThe metal cutting tool separates chips from the workpiece in order to cut the part to the desired shape and size. There is a great variety of metal cutting tools. Each of them is designed to perform a particular job or a group of metal cutting operations in an efficient manner. For example, a twist drill is designed to drill a hole which has a particular size, while a turning tool may be used to turn a variety of cylindrical shapes.There are three basic types of metal cutting tools: single-point tools, multiple-point tools, and abrasives. A single-point metal cutting tool has a single cutting edge and is used for turning, boring, shaping, and planning. The most common machine tool that employs the single-point cutting tool is the engine lathe. Multiple-point tools have two or more cutting edges such as drills, reamers, and milling cutters. The cutting edge is that part of the tool where cutting is actually done. Grinding wheels are an example of abrasive cutting tools. Each grinding wheel hasa lot of abrasive grains which act as very small cutting tools.Limits and TolerancesMachine parts are manufactured so they areinterchangeable. In other words, each part of a machineor mechanism is made to a certain size and shape so itwill fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part inthe correct way. It is not only impossible, but alsoimpractical to make many parts to an exact size. This isbecause machines are not perfect, and the tools becomeworn. A slight variation from the exact size is alwaysallowed. The amount of this variation depends on the kindof part being manufactured. For example, a part might bemade 6 inches long with a variation allowed of 0.003( three thousandths ) inches above and below this size.Therefore the part could be 5.997 to 6.003 inches and stillbe the correct size. These are known as the limits. Thedifference between upper and lower limits is called the tolerance.When the tolerance is in both directions from the basic size, it is known as a bilateral tolerance ( plus and minus ). Sometimes the limit is allowed in only one direction. This is known as unilateral tolerance. For example, a hole may have to be 2 inches minus 0.000 inches, or plus 0.005 inches. This means that the hole must not be smaller than 2 inches, but can be as large as 2.005 inches.Surface FinishWithin recent years a great deal of attention has been given to the invesigation of the surface texture produced by various machining and finish operations, and, although we have not yet reached the stage when surface finish requirements can be specified and produced just as it is possible for a given dimension, information is being built up which may in the end bring this about.If a machine surface is reproduced to a large enough magnification it will be found to have a wevy profile, the character and shape of the waves varying for different machining methods. Equipment is now available which will produce an enlarged contour of a surface by traversing a needle-like probe over it, the instrument at the same time plotting on a chart a greatly magnified reproduction of the up-and-down movement of the probe with its longitudinal traverse.。
机械工程专业英语》参考译文高等学校机械设计制造及其自动化专业新编系列教材(供教师及学生使用)黄运尧黄威司徒忠李翠琼武汉理工大学出版社目录编译者的话………………………………第1章材料和热加工…………………第1课机械学的基本概念…………第2课塑性理论的基本假设………第3课有限元优化的应用…………第4课金属…………………………第5课金属和非金属材料…………第6课塑料和其他材料……………第7课模具的寿命和失效…………第8踩冷加工和热加工……………第9踩铸造…………………………第10课制造中的金属成形工艺…第11课缎选………………………第12课锻造的优点和工作原理…第13课焊接………………………第14课热处理……………………第二章机构和机器原理……………。
第15课机构介绍…………………。
第16课运动分析…………………．第l7课运动的综合………………—第18课凸轮和齿轮………………—第19课螺纹件，紧固件和联接件—第20课减(耐)摩擦轴承…………＊第2l课斜齿轮、蜗杆蜗轮和锥齿轮第22课轴、离合器和制动器……—第三章机床………第23课机床基础第24课车床……第25课牛头刨、钻床和铣床…………第36课磨床和特种金属加工工艺……第四章切削技术和液压“………………第27课加工基础………………………第28课基本的机械加工参数…………第29课切削参数的改变对温度的影响第30课刀具的磨损…………第31课表面稍整加工机理…第32课极限和公差…………“第33课尺寸控制和表面桔整”第34课自动央具设计………“第36课变速液压装置……………—…………—策37课电液伺服系统…………。
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第五章机械电子技术………………………………第38课专家系统……。
…………………………第3D课建筑机器人………………………………第40课微机为基础的机器人模拟………………第41课机器人学的定义和机器入系统…………第42课微型计算机基础(1)……………………第43课微型计算机基础(x)……………………第44课可编程控制器……………………………第45课CAD／CAM计算机辅助设计与制造…第46课计算机数控和直接数控，CNC和DNC第47课加工过程的数控—………………………第48课柔性制造系统……………—……………第仍课交互式编程系统…………………………第50课在振动分析方面的计算机技术…………策51课压力传感器………………………………第52课反馈元件…………………—……………第53课现代按制理论概述………………………第54课管理上采取了新的措施—来自福持汽第六章英文科技文献和专利文献的查阅…………6．1 常见科技文献及其查阅………………………6．2 专利文献概述…………………………………第七章英文科拉论文写作…………………………7．1 标题与摘要写法………………………………7．2 正文(body)的组织与写法…………………7．3 致谢、附录及参考文献………………—……参考文献………………………………………………第1章材料和热加工机械学的基本概念功是力乘以该力作用在物体上佼物体移动的距离。
一单位1、What is the difference——cans. 合金与纯金属的区别是什么？纯金属是在元素周期表中占据特定位置的元素。
例如电线中的铜和制造烹饪箔及饮料罐的铝。
Alloys contain ——gold and nickel.合金包罗不止一种金属元素。
合金的性质能通过改变其中存在的元素而改变。
金属合金的例子有：不锈钢是一种铁、镍、铬的合金，以及金饰品通常含有金镍合金。
2、Why——mass-to-volume ratio. 为什么要使用金属和合金？许多金属和合金具有高密度，因此被用在需要较高质量体积比的场所。
Some metal ——are durable.某些金属合金，例如铝基合金，其密度低，可用于航空航天以节约燃料。
许多合金还具有高断裂韧性，这意味着它们能经得起打击并且是耐用的。
3、The atomic bonding ——electrical wires. 金属的原子连结对它们的特性也有影响。
在金属内部，原子的外层阶电子由所有原子共享并能随处自由移动。
由于电子能导热和导电，所以用金属可以制造好的烹饪锅和电线。
It is impossible ——pass through.因为这些阶电子吸收到达金属的光子，所以透过金属不可能看得见。
没有光子能通过金属。
4、Some of —resistance.高熔点、低密度、高强度、高刚度、高硬度、高耐磨性和抗腐化性是陶瓷和玻璃的一些有用特性。
Many ceramics —brittle.许多陶瓷都是电和热的良绝缘体。
某些陶瓷还具有一些特殊性能：有些是磁性质料，有些是压电质料，另有些特殊陶瓷在极低温度下是超导体。
陶瓷和玻璃都有一个主要的缺点：它们容易破碎。
5、An optical fiber —damage. 光导纤维有三层：焦点由高纯度玻璃制成，该玻璃是高折射指数光传输质料；中间层为低折射指数玻璃，是掩护焦点玻璃外貌不被擦伤和完整性不被破坏的所谓覆层，外层是聚合物护套，用于掩护光导纤维不受损。
DimensioningThe design of a machine includes many factors other than those of determining the loads and stresses and selecting the proper materials. 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 phase s of production drawings. [1]Drawings should be carefully checked to see that the dimensioning is done in a manner that will be most convenient and understandable to the production departments. It is obvious that a drawing should be made in such a way that it has one and only one interpretation. In particular, shop personnel should not be required to make trigonometric or other involved calculations before the production machines can be set up. [2]Dimensioning is an involved subject and long experience is required for its mastery. [3]Tolerance s must be placed on the dimensions of a drawing to limit the permissible variation s in size because it is impossible to manufacture a part exactly to a given dimension. Although small tolerances give higher quality work and a better operating mechanism, the cost of manufacture increases rapidly as the tolerances are reduced, as indicated by the typical curve of Fig 14.1. It is therefore important that the tolerances be specified at the largest values that the operating or functional considerations permit.Tolerances may be either unilateral or bilateral. In unilateral dimensioning, one tolerance is zero, and all the variations are given by the other tolerance. In bilateral dimensioning, a mean dimension is used which extends to the midpoint of the tolerance zone with equal plus and minus variations extending each way from this dimension.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. 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. [4] 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. [5] In any event it is very important that a drawing be free from ambiguities and be subject only to a single interpretation.Dimension and ToleranceIn dimensioning a drawing, the numbers placed in the dimension lines represent dimension that are only approximate and do not represent any degree of accuracy unless so stated by the designer. [6] To specify a degree of accuracy, it is necessary to add tolerance figure s to the dimension. Tolerance is the amount of variation permitted in the part or the total variation allowed in a given dimension. A shaft might have a nominal size of 2.5 in. (63.5 mm), but for practical reasons this figure could not be maintain ed in manufacturing without great cost. Hence, a certain tolerance would be added and, if a variation of±0.003 in. (±0.08 mm) could be permitted, the dimension would be stated 2.500±0.003 (63.5±0.08 mm).Dimensions given close tolerance s mean that the part must fit properly with some other part. Both must be given tolerances in keeping with the allowance desired, the manufacturing processes available, and the minimum cost of production and assembly that will maximize profit. Generally speaking, the cost of a part goes up as the tolerance is decreased. If a part has several or more surfaces to be machined, the cost can be excessive when little deviation is allowed from the nominal size. Allowance, which is sometimes confused with tolerance, has an altogether different meaning. [7] It is the minimum clearance space intended between mating parts and represents the condition of tightest permissible fit. If a shaft, size, is to fit a hole of size l.500±， the minimum size hole is l. 500 and .1000.0003.0+-498the maximum size shaft is l. 498. Thus the allowance is 0. 002 and the maximum clearance is 0.008 as based on the minimum shaft size and maximum hole dimension. Tolerances may be either unilateral or bilateral. Unilateral tolerance means that any variation is made in only one direction from the nominal or basic dimension. Referring to the previous example, the hole is dimensioned l.500±, which represents a unilateral tolerance. If the dimensions were given as l.500±0.003, the tolerance would be bilateral; that is, it would vary both over and under the nominal dimension. The unilateral system permits changing the tolerance while still retain ing the same allowance or type of fit. With the bilateral system, this is not possible without also changing the nominal size dimension of one or both of the two mating pats. In mass production, where mating parts must be interchangeable, unilateral tolerances are customary. To have an interference or force fit between mating parts, the tolerances must be such as to create a zero or negative allowance. Tolerances， Limits and FitsThe drawing must be a true and complete statement of the designer’s requirements expressed in such a way that the part is convenient to manufacture. Every dimension necessary to define the product must be stated once only and not repeated in different views. Dimensions relating to one particular feature, such as the position and size of a hole, should, where possible, appear on the same view.There should be no more dimensions than are absolutely necessary, and no feature should be located by more than one dimension in any direction. [8] 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 mark ed for reference. Such dimensions are not govern ed by general tolerances. [9]Dimensions that affect the function of the part should always be specified and not left as the sum or difference of other dimensions. If this is not done, the total permissible variation on that dimension will form the sum or difference of the other dimensions and their tolerances, and this will result in these tolerances having to be made unnecessarily tight. [10] The overall dimension should always appear. All dimensions must be governed by the general tolerance on the drawing unless otherwise stated. Usually, such a tolerance will be governed by the magnitude of the dimension. Specific tolerances must always be stated on dimensions affecting function or interchangeability.A system of tolerances is necessary to allow for the variations in accuracy that are bound to occur during manufacture, and still provide for interchangeability and correct function of the part.A tolerance is the difference in a dimension in order to allow for unavoidable imperfections in workmanship. The tolerance range will depend on the accuracy of the manufacturing organisation, the machining process and the magnitude of the dimension. The greater the tolerance range, the cheaper the manufacturing process.A bilateral tolerance is one where the tolerance range is disposed on both sides of the nominal dimension. A unilateral tolerance is one where the tolerance zone is on one side only of the nominal dimension, in which case the nominal dimension may form one of the limits.Limits are the extreme dimensions of the tolerance zone. For example, nominal dimension30 mm tolerance ± limits ±Fits depend on the relationship between the tolerance zones of two mating parts, and may be broadly classified into a clearance fit with positive allowance, a transition fit where the allowance may be either positive or negative (clearance or interference), an interference fit where the allowance is always negative. Type of Limits and FitsThe ISO System of Limits and Fits, widely used in a number of leading metric countries, is considerably more complex than the ANSI system.In this system, each part has a basic size. Each limit of size of a part, high and low, is defined by its deviation from the basic size, the magnitude and sign being obtained by subtracting the basic size from the limit in question. The difference between the two limits of size of a part is called the tolerance, an absolute amount without sign.There are three classes of fits: 1) clearance fits, 2) transition fits (the assembly may have either clearance or interference), and 3) interference fits. Either a shaft-basis system or a hole-basis system may be used. For any given basic size, a range of tolerances and deviations may be specified with respect to the line of zero deviation, called the zero line. The tolerance is a function of the basic size and is designated by a number symbol, called the grade——thus the tolerance grade. The position of the tolerance with respect to the zero line also a function of the basic size——is indicated by a letter symbol (or two letters), a capital letter for holes and a lowercase letter for shafts. Thus the specificationfor a hole and shaft having a basic size of 45mm might be 45 H8/g7.Twenty standard grades of tolerances are provided, called IT 01, IT 0, IT l - 18, providing numerical values for each nominal diameter, in arbitrary steps up to 500 mm (for example 0 - 3, 3 - 6, 6 - 10, …, 400 - 500 mm). [11] The value of the tolerance unit, i, for grades 5 - 16 isi = ……where i is in microns and D in millimeters.Standard shaft and hole deviations similarly are provided by sets of formulas, however, for practical application, both tolerances and deviations are provided in three sets of rather complex tables. Additional tables give the values for basic sizes above 500 mm and for “Commonly Used Shafts and Holes” in two categories ——“General Purpose” and “Fine Mechanisms and Horology”.。
