【机械类文献翻译】机床
【机械类文献翻译】多用途组合机床
英文原文Multi-purpose aggregate machine-tool timeRegarding the multi-purpose aggregate machine-tools, in the industrial field has many names to describe it, like “the multitasking installment”, “the multi-purpose engine beds”, “the multi-procedure production system” and so on, it may be called the processing domain truly the nova, may reduce the cost, the simplified disposition, and has maintained in the US territory produces. Inthe past only then used the duty which many machine operations could complete, now may concentrate to an engine bed on processes completes.As a result of market demand's unceasing change, the product life cycle is reducing unceasingly, today's market more intense demand multitasking installment concept. Carries out the fine profit management when the entire production environment, compared to having not concentrated the components processing to a machine on completes a finer profit.Some tradition's manufacturing industry manufacturer thought that the multi-purpose aggregate machine-tools are too complex,very difficult to find the appropriate operators also the difficult problem innovates on the spot on the insufficiency for the metal working Basic principle and in the Production workshop related new engine bed use solution aspect training.Intuition type technical controlThe equipment use “carries off the quantity of heat” the type design, has different material which the lathe bed, the steeliness straight line rolling guide, on the steeliness revolving tool box saddle, the equipment uses, all these combine make an engine bed together. These with the thermal conductivity, the volume expansion are related. All different size's thing can by the different speed growth.As a result of this reason, needs to make the hot friendly engine bed, with the aim of knowing gives off heat the weak point in where, can compensate through the reasonable engine bed design. The part is the entire journey movement. The engine bed glide produces rubs and transform hotly. The machining produces the hot filings fall to the different place, the refrigerant can mix in the entire process in which. Will present the different temperature province continually on the cutting tool, will therefore also have many things to have the influence to the thermostability. The cutting tool technology turned the multi-purpose aggregate machine-tools has had the milling and cutting power “the versatile machine”.According to the material introduced that the most remarkable characteristic is in these engine bed whole has the intuition. The anti-collision preservation technology was already mature, in certain circumstances, even if uses the manual operation pattern, can also avoid the occurrence which collides. Because the control software has the very good intuition, the user operation friendly degree unceasingly is also enhancing. Believe the multi-purpose aggregate machine-tools by its survivability world-wide in the more different processing scenes.The off-line programming optimization and the NC automatic control system's formation already made this technology to be easier to accept, when therefore uses the procedure when the engine bed, does not need to spend many time tune-up procedure and confirmed that some part does not have the question. If components need to provide the high and low two revolving tool box saddle simultaneously to carry on the rough machining, in this kind of situation the programming is quite difficult, because it needs two revolving tool box saddles also to feed. The AdMac system may realize tool rest's automatic programming which simultaneously feeds to these, and can cause the correct main axle speed, the correct feed rate and so on all parameters to realize the synchronization.Okuma Corporation's collision avoidance system design based on actual processing operating mode anti-collision simulation, therefore, if the operator has installed the wrong cutting tool or has established the wrong parameter, the control system will examine and prevents the engine bed to enter the processing condition. Through cooperates with the Siemens, INDEX Corporation may provide the 3D pattern now “the hypothesized engine bed”, has custom-made according to some specific model's engine bed. The result indicated that the simulation processes not only the fabricated parts and the actual end product is similar, is the one-to-one copy simply.The intuition type control interface, the simulation as well as other software technique are progressive, the more Production workshops have opened wide the front door to the multi-purpose aggregate machine-tools, but if does not have the corresponding knowledge to train and to solve the question creativity, the manufacturer is also very difficult to realize and the full use advanced engine bed flexibility aspect superiority. The work which does to the machine are more, the machine will be more complex, also needs to have the stronger skill person correspondingly to be able to operate it.If machinist past one day operated 3 engine beds, then he has this kind of multi-purpose engine bed now, might produce more components. More importantly, he may draw support from software's help to cause the production efficiency to be higher, regarding transformation processing components preparation, may also establish the processing craft plan. Because the replacement components need to lower 3 main axles, therefore before replacing the components, the workshop should process as far as possible many components. Regarding the multi-purpose engine beds, the transformation components speed is quick, the production batch of time interval is shorter, the stock is lower, the production efficiency is higher. Can use multi-purpose engine bed's some workshops fully, very quick will discover the post function the unification. Now, a workshop may only use an operator, an adjuster and a programming teacher, in the future these 3 work definitely may do by a person.In the traditional post description the machinist will transit becomes one to adjust engineer, if this engineer the familiar components processing programming, that were also more ideal. Regarding such transformation, training has been simple, so long as trains 1 individual line, but is not 3individuals. Looking from the long views, this will provide to the people the higher post degree of satisfaction. When adjusts engineer to be responsible to process the programming, and pays attention to the components processing personally time the entire process, he completely has become this components control. In addition, but should also makes more effort in the cutting tool choice and the programming aspect, must make any model the multi-purpose aggregate machine-tool to succeed, the workshop needs to provide the skilled machinist, has ability and completes many kinds of operations nimbly. Therefore, crosswise training was at any time in the past more important. Regarded as the milling and the lathe work the different belongs to their time. Regarding personnel who will program, will understand the engine bed and controls it, this will be their ability manifestation.The cutting tool will choose most people not to install the passenger vehicle tire to the race car on, but processed the cutting tool to have such situation. The cutting tool should match with the new engine bed, is conceivably redundant on the new engine bed uses the old cutting tool to the production efficiency influence. In order to match the multi-purpose aggregate machine-tools, the new cutting tool and the cutting tool adapter technology was already developed. At present the industrial field is developing the development the processing cutting tool, may complete the turning on the identical tool rest, boring and drills truncates the processing, is only processes the phase to differ from regarding the work piece angle. The processing operates the difference even confuses is unclear. The new processing cutting tool may complete the milling and the turning. The machinery automation technology first starts from the 1920s in the machine manufacture cold finishing production in enormous quantities process to develop the application, after in the 60s, to adapt the market demand and the change, for the enhancement machine-building industry to the market nimble rapid reaction's ability, starts to establish the variable automation production system,namely revolves the computer technology the flexible automation. It is in the manufacture system invariable or in the change small situation, the machinery equipment either production management process through the automatic detection, the information processing, the analysis judgment realizes the anticipated operation or some kind of process automatically, and can from make one kind of components to transform automatically to makes another kind of different components. The social practice proved that under this kind of definition's manufacture system automation and the contemporary majority enterprises are not actually accommodating. The contemporary society also not in the science and technology, the material and the personnel aspect prepares to realize this automated condition, insists such to do only meets the wasted effort. This kind of situation is not exceptional regarding the separate production method's machine-building industry, the difficulty can bigger.The aggregate machine-tool future development more use transmissions and so on variable speed motor and ball bearing guide screw,will simplify structure, the reduction production metre; Uses the numerical control system and the headstock, the jig automatic replacement system, enhancesthe craft controllability; As well as integrates the flexible manufacture system and so on.中文译文多用途组合机床对于多功能组合机床，在工业领域有许多名字来描述它，如“多任务处理装置”，“多功能机床”，“多工序生产系统”等，它确实可称为加工领域的新星，可降低成本，简化配置，和一直保持在美国本土生产。
【机械类文献翻译】车床与铣削加工
附件1：外文资料翻译译文车床与铣削加工车床用与车外圆、端面和镗孔等加工的机床叫车床。
车削很少在其他种类的机床上进行，某些机床不能像车床那样方便地进行车削加工。
由于车床除了用于车外圆外还能用于镗孔、车端面、钻孔和铰孔，车床的多功能性可以使工件在一次定位安装中完成多种加工。
这就是在生产中普遍使用各种车床比其他种类的机床都要多的原因。
很早就已经有了车床。
现代车床可以追溯到大约17世纪，那时亨利·莫德斯利发明了一种具有丝杠的车床。
这种车床可以控制工具的机械进给。
聪明的英国人还发明了一种把主轴和丝杠相连接的变速装置，这样就可以切削螺纹。
车床的主要部件：床身、主轴箱组件、尾架组件、拖板组件、变速齿轮箱、丝杠和光杠床身是车床的基础件。
它通常是由经过正火处理的灰铸铁或者球墨铸铁制成，它是一个坚固的刚性框架，所有其他主要部件都安装在床身上。
通常在床身上面有内外两组平行的导轨。
一些制造厂生产的四个条导轨都采用倒“V”形，而另一些制造厂则将倒“V”形导轨和平面导轨相结合。
由于其他的部件要安装在导轨上或在导轨上移动，导轨要经过精密加工，以保证其装配精度。
同样地，在操作中应该小心，以避免损伤导轨。
导轨上的任何误差，常常会使整个机床的精度破坏。
大多数现代车床的导轨要进行表面淬火处理，以减小磨损和擦伤，具有更大的耐磨性。
主轴箱安装在床身一端内导轨的固定位置上。
它提供动力，使工件在各种速度下旋转。
它基本上由一个安装在精密轴承中的空心主轴和一系列变速齿轮，通过变速齿轮，主轴可以在许多种转速下旋转。
大多数车床有8—18种转速，一般按等比级数排列。
在现代车床上只需扳动2～4个手柄，就能得到全部挡位的转速。
目前发展的趋势是通过电气的或机械的装置进行无级变速。
由于车床的精度在很大程度上取决于主轴，因此主轴的结构尺寸较大，通常安装在紧密配合的重型圆锥滚子轴承或球轴承中。
主轴中有一个贯穿全长的通孔。
主轴孔的大小是车床的一个重要尺寸，因为当工件通过主轴孔供料时，它确定了能够加工棒料毛坯的最大外径尺寸。
【机械类文献翻译】车床2
外文翻译车床车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。
车削很少在其他种类的机床上进行，而且任何一种其他机床都不能像车床那样方便地进行车削加工。
由于车床还可以用来钻孔和铰孔，车床的多功能性可以使工件在一次安装中完成几种加工。
因此，在生产中使用的各种车床比任何其他种类的机床都多。
车床的基本部件有：床身、主轴箱组件、尾座组件、溜板组件、丝杠和光杠。
床身是车床的基础件。
它能常是由经过充分正火或时效处理的灰铸铁或者球墨铁制成。
它是一个坚固的刚性框架，所有其他基本部件都安装在床身上。
通常在床身上有内外两组平行的导轨。
有些制造厂对全部四条导轨都采用导轨尖朝上的三角形导轨（即山形导轨），而有的制造厂则在一组中或者两组中都采用一个三角形导轨和一个矩形导轨。
导轨要经过精密加工以保证其直线度精度。
为了抵抗磨损和擦伤，大多数现代机床的导轨是经过表面淬硬的，但是在操作时还应该小心，以避免损伤导轨。
导轨上的任何误差，常常意味着整个机床的精度遭到破坏。
主轴箱安装在内侧导轨的固定位置上，一般在床身的左端。
它提供动力，并可使工件在各种速度下回转。
它基本上由一个安装在精密轴承中的空心主轴和一系列变速齿轮(类似于卡车变速箱)所组成。
通过变速齿轮，主轴可以在许多种转速下旋转。
大多数车床有8~12种转速，一般按等比级数排列。
而且在现代机床上只需扳动2~4个手柄，就能得到全部转速。
一种正在不断增长的趋势是通过电气的或者机械的装置进行无级变速。
由于机床的精度在很大程度上取决于主轴，因此，主轴的结构尺寸较大，通常安装在预紧后的重型圆锥滚子轴承或球轴承中。
主轴中有一个贯穿全长的通孔，长棒料可以通过该孔送料。
主轴孔的大小是车床的一个重要尺寸，因此当工件必须通过主轴孔供料时，它确定了能够加工的棒料毛坯的最大尺寸。
尾座组件主要由三部分组成。
底板与床身的内侧导轨配合，并可以在导轨上作纵向移动。
底板上有一个可以使整个尾座组件夹紧在任意位置上的装置。
【机械类文献翻译】关于数控车床
英文原文On the NC latheCNC machine tool numerical control machine tools (Computer numerical control machine tools) abbreviation, is provided with a program control system of automatic machine tools. The logic control system can deal with the control code or other symbolic instruction specified program, and decoding the digital code, said information carrier, through the numerical control device input. After processing by CNC device control signals, control the machine movements, by drawing the shape and size requirements, will be automatically processed by the parts.Features: CNC machine tool operation and monitoring of all completed in the numerical control unit, it is the brain of CNC machine tools. Compared with the general machine tools, CNC machine tools has the following characteristics:● the processing object adaptability, adapt to the characteristics of mold products such as a single production, provide the appropriate processing method for die and mould manufacturing;● high machining accuracy, proce ssing with stable quality;● can coordinate linkage, processing complex shape parts;● machining parts change, only need to change the program, can save the preparation time of production;● the machine itself high precision, rigidity, can choose the amoun t of processing good, high productivity (3~5 times as common machine);The machine is a high degree of automation, reducing labor intensity;● conducive to the production management modernization. The use of CNC machine tools and the standard code of digital information processing, information transmission, the use of computer control method, has laid the foundation for the integration of computer aided design, manufacturing and management;● on the operators of higher quality, higher demands for the repair of the technical staff;● high reliability.Composition: CNC machine tools in general by the input medium, man-machine interactive equipment, CNC equipment, feed servo drive system, spindle servo drive system, the auxiliary control device, feedback apparatus and adaptive control device etc.. [4] in NC machining, NC milling processing is the most complex, need to solve most problems. NC programming of NC line in addition to CNC milling, cutting, CNC EDM, CNC lathe, CNC grinding, each with its owncharacteristics, servo system is the role of the motion signal is converted into the machine moving parts from the numerical control device of pulse. Concrete has the following parts: the structure of CNC machine tools.Driver: he is driving parts of CNC machine tools, actuator, including spindle drive unit, feeding unit, spindle motor and feed motor. He through the electric or electro-hydraulic servo system to realize the spindle and feed drive under the control of numerical control device. When several feed linkage, can complete the positioning, processing line, plane curve and space curve.The main performance(1) the main dimensions.(2) the spindle system.(3) feed system.(4) tool system.(5) electrical. Including the main motor, servo motor specifications and power etc..(6) cooling system. Including the cooling capacity, cooling pump output.(7) dimensions. Expressed as length * width * height.Development trend of CNC lathe:High speed, precision, complex, intelligent and green is the general trend in the development of CNC machine tool technology, in recent years, made gratifying achievements in practicality and industrialization. Mainly in the:1 machine tool composite technology to further expand with the CNC machine tool technology, composite processing technology matures, including milling - car compound, car milling compound, car - boring - drill - gear cutting compound, composite grinding, forming, composite processing, precision and efficiency of machining is greatly improved. "One machine is a processing factory", "one card, complete processing" concept is being accepted by more people, the development of compound processing machine tool is the trend of diversified.Intelligent technology 2 CNC machine tools have a new breakthrough, in the performance of NC system has been reflected more. Such as: automatically adjust the interference anti-collision function, after the power of workpiece automatically exit safety power-off protection function, machining parts detection and automatic compensation function of learning, high precision machining parts intelligent parameter selection function, process automatic elimination of machine vibration functions into the practical stage, intelligent upgrade the function of machine and quality.The 3 robots enable flexible combination of flexible combination of higher efficiency of robot and the host are widely used, make flexible line more flexible, extending the function, flexible line shorten further, more efficient. Robot and machining center, milling composite machine, grinder, gear processing machine tool, tool grinding machine, electric machine, sawing machine, punching machine, laser cutting machine, water cutting machine etc. various forms of flexible unit and flexible production line has already begun the application.4 precision machining technology has the machining precision of CNC metal cutting machine tools from the yarn in the original (0.01mm) up to micron level (0.001mm), some varieties has reached about 0.05 μ M. Micro cutting and grinding machining of ul tra precision CNC machine tools, precision can reach about 0.05 μ m, shape precision can reach about 0.01 μ M. Special processing precision by using optical, electrical, chemical, energy can reach nanometer level (0.001 μ m). By optimizing the design of ma chine tool structure, machine tool parts of ultra precision machining and precision assembly, using high precision closed loop control and temperature, vibration and other dynamic error compensation technology, improve the geometric accuracy of machine tool processing, reduce the shape of error, surface roughness, and into the submicron, nano super finishing tiThe 5 functional component to improve the performance of functional components are at a high speed, high precision, high power and intelligent direction, and obtain the mature application. A full digital AC servo motor and drive device, high technology content of the electric spindle, linear motor, torque motor, linear motion components with high performance, application of high precision spindle unit and other function parts, greatly improving the technical level of CNC machine tools.The feed drive system of CNC lathe:Effect of feed drive system,The feed drive system of CNC machine tools will be received pulse command issued by the numerical control system, and the amplification and conversion machine movements carry the expected movement.Two, the feeding transmission system requirementsIn order to guarantee the machining accuracy of NC machine tool is high, the feed drive system of transmission accuracy, sensitivity high (fast response), stable work, high stiffness and friction and inertia small, service life, and can remove the transmission gap.Category three, feed drive system1, stepping motor servo systemGenerally used for NC machine tools.2, DC servo motor servo systemPower is stable, but because of the brush, the wear resulting in use need to change. Generally used for middle-grade CNC machine tools.3, AC servo motor servo systemThe application is extremely widespread, mainly used in high-end CNC machine tools.4, the linear motor servo systemNo intermediate transmission chain, high precision, the feed speed, no length limit; but the poor heat dissipation, protection requirements are particularly high, mainly used for high-speed machine.Driving component four, feed system1, the ball screw nut pairNC machining, the rotary motion into linear motion, so the use of screw nut transmission mechanism. NC machine tools are commonly used on the ball screw, as shown in Figure 1-25, it can be a sliding friction into rolling friction, meet the basic requirements of the feed system to reduce friction. The transmission side of high efficiency, small friction, and can eliminate the gap, no reverse air travel; but the manufacturing cost is high, can not lock, size is not too big, generally used for linear feed in small CNC machine tool.2, rotary tableIn order to expand the scope of the process of NC machine tools, CNC machine tools in addition to make linear feed along the X, Y, Z three coordinate axes, often also need a circumferential feed movement around Y or Z axis. Circular feed motion of CNC machine tools in general by the rotary table to realize, for machining center, rotary table has become an indispensable part of.Rotary table of commonly used CNC machine tools in the indexing table and NC rotary table.(1) indexing tableIndexing table can only finish dividing movement, not circular feed, it is in accordance with the instructions in the NC system, when indexing will work together with the workpiece rotation angle. When indexing can also use manual indexing. Provisions of indexing table is generally only rotary angle (such as 90, 60 and 45 degree).(2) NC rotary tableNC rotary table appearance similar to the indexing table, but the internal structure and function is not the same. The main function of the NC rotary table is based on the numerical control devicesends command pulse signal, complete circumferential feed movement, various arc processing and surface processing, it can also be graduation work.3, guideRail is an important part of feed drive system, is one of the basic elements of the structure of machine tool, rigidity, precision and accuracy of NC machine tool which determines to a large extent retention. At present, guide the NC machine tool are sliding rail, rolling guideway and hydrostatic guideway.(1) sliding guideSliding guide rail has the advantages of simple structure, easy manufacture, good stiffness, vibration resistance and high performance, widely used in CNC machine tools, the use of most metal plastic form, known as the plastic guide rail, as shown in figure 1-26.On characteristics of the plastic sliding guide: friction characteristic is good, good wear resistance, stable movement, good manufacturability, low speed.(2) rolling guideRolling guide is placed in the rail surface between the ball, roller or needle roller, roller, the rolling friction instead of sliding surface of the guide rail between wipe.Rolling guide rail and the sliding rail, high sensitivity, small friction coefficient, and the dynamic, static friction coefficient is very small, so the motion is uniform, especially in the low speed movement, the stick-slip phenomenon is not easy to occur; high positioning accuracy, repeatability positioning accuracy is up to 0.2 μ m; traction force is small, wear small, portable in movement; good precision, long service life. But the vibration of rolling guide, high requirements on protection, complicated structure, difficult manufacture, high cost.Automatic tool changer:One, the function of automatic tool changerAutomatic tool changing device can help save the auxiliary time of CNC machine tools, and meet in an installation completed procedure, step processing requirements.Two, on the requirement of automatic tool changerNumerical control machine tool for automatic tool changer requirement is: tool change quickly, time is short, high repetitive positioning accuracy, tool storage capacity is sufficient, small occupation space, stable and reliable work.Three, change the knife form1, rotary cutter replacementIts structure is similar to the ordinary lathe turret saddle, according to the processing of different objects can be designed into square or six angle form, consists of the NC system sends out the instruction to the rotary cutter.2, the replacement of the spindle head tool changeThe spindle head pre-loaded required tools, in order to machining position, the main motor is switched on, drives the cutter to rotate. The advantage of this method is that eliminates the need for automatic clamping, cutting tool, clamping and cutting tool moving and a series of complex operation, reduce tool change time, improveThe ATC reliability.3, the use of changing toolThe processing required tools are respectively arranged in the standard tool, adjust the size of the machine after certain way add to the knife, the exchange device from the knife and the spindle take knife switch.Four, the tool switching deviceAutomatic tool change device, device for knife library and the main shaft transmission and handling tool for tool exchange device. Tool exchange often have two kinds: mechanical hand tool exchange and by relative motion of knife and machine tool spindle exchange tool (knife to spindle forThe knife or the spindle motion to the knife knife tool change position), the mechanical hand tool change is most common.Five, the knifeThe knife is one of the most important parts in automatic tool changer, have great influence on the overall design of NC machine tool and its capacity, layout and structure.1, the capacity of the tool storageA number of knife inventory cutters, generally depending on the processing requirements. The capacity of small knife, can not meet the processing needs; capacity is too large, will make the knife database size, covers an area of large, tool selection process for a long time, and the knife library utilization rate is low, the structure is too complex, causing great waste. 2, the knife typeGenerally, the chain disc and drum type knife several.Disc cutter tool was circular arrangement, low utilization of space, size is not large but simple structure.Chain magazine compact structure, large capacity, link shape can also be random bed made of various forms and flexible layout, but also will change the cutter location prominent for tool change, widely used.Drum type or lattice type knife, covers an area of small, compact structure, large capacity, but cutter selection, tool movements are complicated, for centralized knife system for FMS.3, tool selectionOften order tool selection and random selection tool two.The order of tool selection is before processing, the processing required tools to process sequence of insert knife knife, order not wrong, processing adjust knife in order. The work piece changes, the need to reset the tool sequence, the operation is simple, and the processing tool with a workpiece can not be repeated use.A knife is the cutting tool has its own code, optional and can be repeatedly used in processing, also do not put in the fixed knife, knife, the knife is convenient.Technology file is the guiding file workers during processing, process scheme is reasonable, not only affect the efficiency of NC machining, and will directly affect the machining quality. Therefore, before NC programming, NC machining process follows the process of certain principles and combined with the characteristics of CNC lathe seriously and develop in detail the good parts.In the CNC lathe processing parts, should according to the principle of dividing process concentrated, in a fixture as far as possible to complete the most or even all of the surface processing. Part positioning, according to the structure of different shapes, usually cylindrical, face or end clamping, and strive to design basis, process reference and programming the unification datum.The main contents are: analysis of NC machining technology of part drawings, clear processing content; determination method, workpiece on lathe the surface processing sequence and tool feed line and cutting tools, fixtures and cutting the amount of choice.Analysis, part drawing processIn the machining process planning of parts, first of all to carry on in-depth analysis to the processing object. For NC turning process should consider the following aspects:1 reading part drawing, analysis of geometric conditions of part contourIn turning process of manual programming, to calculate each node coordinates; in automatic programming, to define the components outline all geometric elements. Therefore, in the analysis of parts should pay attention to:Parts of the map is missing a dimension, the geometric conditions are not sufficient to constitute the part outline, influence;Map location map parts of the ambiguity or dimension is not clear, so that the program can't start;The part drawing geometry given is not reasonable, resulting in mathematical difficulties.The part drawing dimensioning methods should adapt to the characteristics of CNC lathe processing, should size or directly given coordinate dimension with the same standard.2 dimensional accuracy requirementsAnalysis of the pattern of parts size precision requirements, to determine whether achieve the turning process, and determine the process method to control the dimension precision.In the analysis process, but also can convert some dimensions such as size, incremental and absolute size and dimension chain calculation. In the use of NC lathe turning parts, average value of components often required size and maximum and minimum limit of size size as the basis of programming.3 shape and position accuracy requirementsPattern of parts tolerance of shape and location given is important foundation to ensure the parts precision. When machining parts, to determine the location reference and measurement reference according to the requirements, can also carry out some technical processing according to the special needs of CNC lathe parts, in order to control effectively the shape and position accuracy.4 requirements of surface roughnessSurface roughness is an important requirement of micro precision parts of the surface, but also the reasonable selection of NC lathe, cutting tools and cutting the amount determined on the basis of.5 material and heat treatment requirementsThe part drawing on material and heat treatment given requirements, is the choice of cutter, CNC lathe, cutting the amount determined on the basis of model.Determination of two and fixture, clamping scheme selectionDivision 1.(1) according to the tool used by the process division can improve machining efficiency.(2) can keep the NC lathe machining according to the rough, finishing process division adopted this approach accuracy.The 2 part is determined and the fixture clamping scheme selectionThe CNC lathe parts mounting method is the same with the ordinary lathe, universal fixture should try to choose the existing clamping, and attention should be paid to reduce clamping times, as far as possible in one clamping parts can put all to processing surface processing. Datum location should be coincident with the design reference, in order to reduce the positioning error effect on the dimensional accuracy.CNC lathe with chuck with three jaws to clamp workpiece; shaft parts can also be used to support the tailstock center. Due to the NC lathe spindle speed is very high, for the convenience of the workpiece clamping, the use of hydraulic high-speed power chuck, because it is in the production plant has passed the strict balanced, with a high speed (the speed limit is 4000 ~ 6000rpm), high clamping force (the maximum force is 2000 ~ 8000N), high precision, convenient adjusting claw, a through hole long service life, etc.. By adjusting the pressure of oil cylinder, which can change the clamping force, the special needs of holding various thin-walled workpiece deformation and easy to meet.Deformation of slender shaft processing to reduce stress, improve the machining accuracy, as well as in processing the shaft with hole workpiece inner hole, the hydraulic automatic centering central frame, the centering precision can reach 0.03 mm.Three, determine the processing order and feed routeDetermination of 1 processing sequenceIn the process of NC machine tool, as the processing object is complicated, especially the shape and position of the myriads of changes curve, with the influence of different materials, different from that of the bulk and other factors, in the formulation of the processing sequence of specific parts, should make a concrete analysis and distinction, flexible processing. Only in this way, can the processing order of the rational, so as to achieve excellent quality, high efficiency and low cost objective.(1) the coarse to fineIn order to improve production efficiency and ensure the precision parts processing quality, in the cutting process, should arrange the roughing process, in a relatively short period of time, the finishing before machining allowance amount of removed, at the same time as much as possible to meet the precision machining allowance uniformity requirements.When the roughing process arrangement is finished, and then arrange the semi-finish machining and finish machining for the knife after the. Among them, arrange the semi-finishing aims, when after the rough machining allowance of uniformity can not meet the precision requirement, canarrange the semi-finish machining as a transitional process, in order to make the finishing allowance is small and uniform.In the arrangement of a knife or blade finish machining process of the part, the final contour should be the last knife and continuous processing. At this time, the cutting tool and cutter location to consider appropriate, try not to arrange the cut and cut out or tool change and pause in a continuous contour, so as to avoid sudden changes of cutting force caused by elastic deformation, resulting in smooth connection defects, surface scratch shape mutation or retention tool mark profile.(2) to nearly far after processing, reduce air travel timeHere said the far and near, is according to the processing site relative to the size of the knife point distance. In general, especially in the rough, usually arranged from near the site of the first processing tool, tool bit far from site after processing, in order to shorten tool moving distance, reduce air travel time. For turning, the first after the far past helps maintain the rough orsemi-finished parts of the rigid, improve the cutting condition.(3) and crossOn both the inner surface (inner type cavity), and outer surface of machined parts, the processing sequence arrangement, should be done before and after surface rough machining, inner and outer surface finishing. Must not be parts of a portion of the surface (the inner or outer surface) after machining, processing and other surface (inner or outer surface).(4) surface of first principlesSurface is used as a fine benchmark priority should be processed, because the surface of locating datum is more precise, clamping error is smaller. For example, shaft parts processing, always first machining center hole, and then to the center hole for precision machining surface and surface.The principle is not immutable and frozen, for some special cases, you need to take a flexible scheme.Determination of processing feed line 2The feed line is the tool relative to the workpiece in the whole movement process, it not only includes the steps of content, but also reflect the step sequence. One of the feed line is the basis of programming.Determine the processing route must keep the size precision and surface quality of machining parts, then consider the numerical calculation is simple, knife route as short as possible, higher efficiency. Because of the feed line finishing is basically along the contour sequence, therefore the determination of feed line focus is to determine the feed line rough machining and air travel. The following will analyze:(1) the relationship between processing route and machining allowanceIn the CNC lathe is not to popularize the use of conditions, the general should be a roughcast margin too much, especially with forging, casting hard layer cushion placed in ordinary lathe. If must use NC lathe machining, should pay attention to the flexible program. The first cutting processing must arrange some subroutine to margin too much site.(2) the tool cut, cut outThe processing of CNC machine tools, to arrange the tool cut, cut out the route, the tangent direction to make the tool along the outline of the cut, cut out.(3) to determine the shortest route for emptyDetermine the shortest tool path, in addition to rely on a lot of practical experience, should be good at analysis, if necessary, supplemented by some simple calculations.(4) determine the cutting feed shortestCutting feed route is short, can effectively improve the production efficiency, reduce the tool wear. In the cutting feed route arrangement the rough or semi-finished, it shall also take into account to be rigid and processing parts processing technology requirements, do not care for this and lose that.Four, to determine the cutting parametersCNC programming, the programmer must determine the cutting parameters of each process, and instructions in the form of written procedures. Cutting parameters including spindle speed, depth of cut and feed speed. For the different processing methods, selection of cutting parameters for different needs. Principle of selection of cutting parameters is: to ensure the accuracy and surface roughness of the parts processing, give full play to the tool cutting performance, guarantee a reasonable tool life and give full play to the performance of the machine tool, to maximize the productivity, reduce the cost of.To determine the 1 spindle speed(1) determine the spindle speed of light carSpindle speed should be based on the allowable cutting speed and workpiece diameter selection, the calculation formula is as followsN=1000v/ (d)Type V -- the cutting speed (M / min), determined by the tool life.N -- the spindle speed (R / min);D -- or the diameter of cutter and workpiece diameter (mm).Spindle speed calculation n finally depends on the machine specifications selecting machine or close to the speed of.(2) the car threaded spindle speedIn thread cutting, the lathe spindle speed will be thread pitch (or lead) factors affecting size, driving motor movements frequency characteristics and thread interpolation operation speed, the different NC systems, recommended the spindle speed range of different options. Spindle speed as most ordinary lathe CNC system recommended threading:N ≤ 1200/p-KType P -- pitch or lead the thread (mm);K -- the insurance factor, usually taken as 80;N -- the spindle speed, rpm.To determine the 2 feed speedThe feed velocity is an important parameter in the CNC machine tool cutting, mainly according to the machining accuracy and surface roughness value selection of parts and tool, workpiece material properties. The maximum speed limit by the performance of machine tool stiffness and feed system.To determine the feed speed is the principle:(1) when the workpiece quality requirements can be guaranteed, in order to improve the production efficiency, can choose the higher feed rate. 100 ~ 200mm / min range selection.(2) in cutting, machining deep hole or processing of high-speed steel cutting tool, should choose a lower feeding rate, generally in the 20 ~ 50mm / min range selection.(3) when processing high precision and surface roughness values is small, the feed rate should be smaller, the range of 20~50mm/min selection.(4) the tool to air travel, especially to zero distance, can be set to the highest feed speed setting of the machine tool CNC system.To determine the depth of the 3The cutting depth was decided according to machine tool, workpiece and cutting tool rigidity, stiffness in the permit conditions, should as far as possible back an amount equal to the machining allowance of the workpiece, thus reducing the feeding times, improve production efficiency. 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机械外文翻译中英文_机床
附录附录1英文原文Basic Machining Operations and Cutting TechnologyBasic Machining OperationsMachine tools have evolved from the early foot-powered lathes of the Egyptians and John Wilkinson's boring mill. They are designed to provide rigid support for both the workpiece and the cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the workpiece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile workpiece in the form of a severely deformed chip. The chip is a waste product that is considerably shorter than the workpiece from which it came but with a corresponding increase in thickness of the uncut chip. The geometrical shape of workpiece depends on the shape of the tool and its path during the machining operation.Most machining operations produce parts of differing geometry. If a rough cylindrical workpiece revolves about a central axis and the tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is produced, and the operation is called turning. If a hollow tube is machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface uniformly varying diameter is called taper turning, if the tool point travels in a path of varying radius, a contoured surface like that of a bowling pin can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed.Flat or plane surfaces are frequently required. They can be generated by radial turning or facing, in which the tool point moves normal to the axis of rotation. In other cases, it is more convenient to hold the workpiece steady and reciprocate the tool across it in a series of straight-line cuts with a crosswise feed increment before each cutting stroke. This operation is called planning and is carried out on a shaper. For larger pieces it is easier to keep the tool stationary and draw the workpiece under it as in planning. The tool is fed at each reciprocation. Contoured surfaces can be produced by using shaped tools.Multiple-edged tools can also be used. Drilling uses a twin-edged fluted tool for holes with depths up to 5 to 10 times the drill diameter. Whether thedrill turns or the workpiece rotates, relative motion between the cutting edge and the workpiece is the important factor. In milling operations a rotary cutter with a number of cuttingedges engages the workpiece. Which moves slowly with respect to the cutter. Plane or contoured surfaces may be produced, depending on the geometry of the cutter and the type of feed. Horizontal or vertical axes of rotation may be used, and the feed of the workpiece may be in any of the three coordinate directions.Basic Machine ToolsMachine tools are used to produce a part of a specified geometrical shape and precise I size by removing metal from a ductile material in the form of chips. The latter are a waste product and vary from long continuous ribbons of a ductile material such as steel, which are undesirable from a disposal point of view, to easily handled well-broken chips resulting from cast iron. Machine tools perform five basic metal-removal processes: I turning, planning, drilling, milling, and grinding. All other metal-removal processes are modifications of these five basic processes. For example, boring is internal turning; reaming, tapping, and counter boring modify drilled holes and are related to drilling; bobbing and gear cutting are fundamentally milling operations; hack sawing and broaching are a form of planning and honing; lapping, super finishing. Polishing and buffing are variants of grinding or abrasive removal operations. Therefore, there are only four types of basic machine tools, which use cutting tools of specific controllable geometry: 1. lathes, 2. planers, 3. drilling machines, and 4. milling machines. The grinding process forms chips, but the geometry of the abrasive grain is uncontrollable.The amount and rate of material removed by the various machining processes may be I large, as in heavy turning operations, or extremely small, as in lapping or super finishing operations where only the high spots of a surface are removed.A machine tool performs three major functions: 1. it rigidly supports the workpiece or its holder and the cutting tool; 2. it provides relative motion between the workpiece and the cutting tool; 3. it provides a range of feeds and speeds usually ranging from 4 to 32 choices in each case.Speed and Feeds in MachiningSpeeds, feeds, and depth of cut are the three major variables for economical machining. Other variables are the work and tool materials, coolant and geometry of the cutting tool. The rate of metal removal and power required for machining depend upon these variables.The depth of cut, feed, and cutting speed are machine settings that must be established in any metal-cutting operation. They all affect the forces, the power, and the rate of metal removal. They can be defined by comparing them to the needle and record of a phonograph. The cutting speed (V) is represented by the velocity of- the record surface relative to the needle in the tone arm at any instant. Feed is represented by the advance of the needle radially inward per revolution, or is the difference in position between two adjacent grooves. The depth of cut is the penetration of the needle into the record or the depth of the grooves.Turning on Lathe CentersThe basic operations performed on an engine lathe are illustrated. Those operations performed on external surfaces with a single point cutting tool are called turning. Except for drilling, reaming, and lapping, the operations on internal surfaces are also performed by a single point cutting tool.All machining operations, including turning and boring, can be classified as roughing, finishing, or semi-finishing. The objective of a roughing operation is to remove the bulk of the material as rapidly and as efficiently as possible, while leaving a small amount of material on the work-piece for the finishing operation. Finishing operations are performed to obtain the final size, shape, and surface finish on the workpiece. Sometimes a semi-finishing operation will precede the finishing operation to leave a small predetermined and uniform amount of stock on the work-piece to be removed by the finishing operation.Generally, longer workpieces are turned while supported on one or two lathe centers. Cone shaped holes, called center holes, which fit the lathe centers are drilled in the ends of the workpiece-usually along the axis of the cylindrical part. The end of the workpiece adjacent to the tailstock is always supported by a tailstock center, while the end near the headstock may be supported by a headstock center or held in a chuck. The headstock end of the workpiece may be held in a four-jaw chuck, or in a type chuck. This method holds the workpiece firmly and transfers the power to the workpiece smoothly; the additional support to the workpiece provided by the chuck lessens the tendency for chatter to occur when cutting. Precise results can be obtained with this method if care is taken to hold the workpiece accurately in the chuck.Very precise results can be obtained by supporting the workpiece between two centers. A lathe dog is clamped to the workpiece; together they are driven by a driver plate mounted on the spindle nose. One end of the Workpiece is mecained;then the workpiece can be turned around in the lathe to machine the other end. The center holes in the workpiece serve as precise locating surfaces as well as bearing surfaces to carry the weight of the workpiece and to resist the cutting forces. After the workpiece has been removed from the lathe for any reason, the center holes will accurately align the workpiece back in the lathe or in another lathe, or in a cylindrical grinding machine. The workpiece must never be held at the headstock end by both a chuck and a lathe center. While at first thought this seems like a quick method of aligning the workpiece in the chuck, this must not be done because it is not possible to press evenly with the jaws against the workpiece while it is also supported by the center. The alignment provided by the center will not be maintained and the pressure of the jaws may damage the center hole, the lathe center, and perhaps even the lathe spindle. Compensating or floating jaw chucks used almost exclusively on high production work provide an exception to the statements made above. These chucks arereally work drivers and cannot be used for the same purpose as ordinary three or four-jaw chucks.While very large diameter workpieces are sometimes mounted on two centers, they are preferably held at the headstock end by faceplate jaws to obtain the smooth power transmission; moreover, large lathe dogs that are adequate to transmit the power not generally available, although they can be made as a special. Faceplate jaws are like chuck jaws except that they are mounted on a faceplate, which has less overhang from the spindle bearings than a large chuck would have.Introduction of MachiningMachining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported workpiece.Low setup cost for small Quantities. Machining has two applications in manufacturing. For casting, forging, and press working, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may he produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining; to start with nearly any form of raw material, so tong as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore .machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or press working if a high quantity were to be produced.Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in press worked parts may be machined following the press working operations.Primary Cutting ParametersThe basic tool-work relationship in cutting is adequately described by means of four factors: tool geometry, cutting speed, feed, and depth of cut.The cutting tool must be made of an appropriate material; it must be strong, tough, hard, and wear resistant. The tool s geometry characterized by planes and angles, must be correct foreach cutting operation. Cutting speed is the rate at which the work surface passes by the cutting edge. It may be expressed in feet per minute.For efficient machining the cutting speed must be of a magnitude appropriate to the particular work-tool combination. In general, the harder the work material, the slower the speed.Feed is the rate at which the cutting tool advances into the workpiece. "Where the workpiece or the tool rotates, feed is measured in inches per revolution. When the tool or the work reciprocates, feed is measured in inches per stroke, Generally, feed varies inversely with cutting speed for otherwise similar conditions.The depth of cut, measured inches is the distance the tool is set into the work. It is the width of the chip in turning or the thickness of the chip in a rectilinear cut. In roughing operations, the depth of cut can be larger than for finishing operations.The Effect of Changes in Cutting Parameters on Cutting TemperaturesIn metal cutting operations heat is generated in the primary and secondary deformation zones and these results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip.Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and the cutting temperatures will reduce. When considering increase in unreformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thickness tends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed; however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip m primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate it is appropriate to indicate how cutting temperatures can be assessed from cutting data.The most direct and accurate method for measuring temperatures in high -speed-steel cutting tools is that of Wright &. Trent which also yields detailed information on temperature distributions in high-speed-steel cutting tools. The technique is based on the metallographic examination of sectioned high-speed-steel tools which relates microstructure changes to thermal history.Trent has described measurements of cutting temperatures and temperature distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron microscopy to study fine-scale microstructure changes arising from over tempering of the tempered martens tic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed -steel single point turning tools and twist drills.Wears of Cutting ToolDiscounting brittle fracture and edge chipping, which have already been dealt with, tool wear is basically of three types. Flank wear, crater wear, and notch wear. Flank wear occurs on both the major and the minor cutting edges. On the major cutting edge, which is responsible for bulk metal removal, these results in increased cutting forces and higher temperatures which if left unchecked can lead to vibration of the tool and workpiece and a condition where efficient cutting can no longer take place. On the minor cutting edge, which determines workpiece size and surface finish, flank wear can result in an oversized product which has poor surface finish. Under most practical cutting conditions, the tool will fail due to major flank wear before the minor flank wear is sufficiently large to result in the manufacture of an unacceptable component.Because of the stress distribution on the tool face, the frictional stress in the region of sliding contact between the chip and the face is at a maximum at the start of the sliding contact region and is zero at the end. Thus abrasive wear takes place in this region with more wear taking place adjacent to the seizure region than adjacent to the point at which the chip loses contact with the face. This result in localized pitting of the tool face some distance up the face which is usually referred to as catering and which normally has a section in the form of a circular arc. In many respects and for practical cutting conditions, crater wear is a less severe form of wear than flank wear and consequently flank wear is a more common tool failure criterion. However, since various authors have shown that the temperature on the face increases more rapidly with increasing cutting speed than the temperature on the flank, and since the rate of wear of any type is significantly affected by changes in temperature, crater wear usually occurs at high cutting speeds.At the end of the major flank wear land where the tool is in contact with the uncut workpiece surface it is common for the flank wear to be more pronounced than along the rest ofthe wear land. This is because of localised effects such as a hardened layer on the uncut surface caused by work hardening introduced by a previous cut, an oxide scale, and localised high temperatures resulting from the edge effect. This localised wear is usually referred to as notch wear and occasionally is very severe. Although the presence of the notch will not significantly affect the cutting properties of the tool, the notch is often relatively deep and if cutting were to continue there would be a good chance that the tool would fracture.If any form of progressive wear allowed to continue, dramatically and the tool would fail catastrophically, i. e. the tool would be no longer capable of cutting and, at best, the workpiece would be scrapped whilst, at worst, damage could be caused to the machine tool. For carbide cutting tools and for all types of wear, the tool is said to have reached the end of its useful life long before the onset of catastrophic failure. For high-speed-steel cutting tools, however, where the wear tends to be non-uniform it has been found that the most meaningful and reproducible results can be obtained when the wear is allowed to continue to the onset of catastrophic failure even though, of course, in practice a cutting time far less than that to failure would be used. The onset of catastrophic failure is characterized by one of several phenomena, the most common being a sudden increase in cutting force, the presence of burnished rings on the workpiece, and a significant increase in the noise level.Mechanism of Surface Finish ProductionThere are basically five mechanisms which contribute to the production of a surface which have been machined. These are:(l) The basic geometry of the cutting process. In, for example, single point turning the tool will advance a constant distance axially per revolution of the workpiecc and the resultant surface will have on it, when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut.(2) The efficiency of the cutting operation. It has already been mentioned that cutting with unstable built-up-edges will produce a surface which contains hard built-up-edge fragments which will result in a degradation of the surface finish. It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds small rake angles and low cutting speeds, besides producing conditions which lead to unstable built-up-edge production, the cutting process itself can become unstable and instead of continuous shear occurring in the shear zone, tearing takes place, discontinuous chips of uneven thickness are produced, and the resultant surface is poor. This situation is particularly noticeable when machining very ductile materials such as copper and aluminum.(3) The stability of the machine tool. Under some combinations of cutting conditions; workpiece size, method of clamping ,and cutting tool rigidity relative to the machine toolstructure, instability can be set up in the tool which causes it to vibrate. Under some conditions this vibration will reach and maintain steady amplitude whilst under other conditions the vibration will built up and unless cutting is stopped considerable damage to both the cutting tool and workpiece may occur. This phenomenon is known as chatter and in axial turning is characterized by long pitch helical bands on the workpiece surface and short pitch undulations on the transient machined surface.(4)The effectiveness of removing swarf. In discontinuous chip production machining, such as milling or turning of brittle materials, it is expected that the chip (swarf) will leave the cutting zone either under gravity or with the assistance of a jet of cutting fluid and that they will not influence the cut surface in any way. However, when continuous chip production is evident, unless steps are taken to control the swarf it is likely that it will impinge on the cut surface and mark it. Inevitably, this marking besides looking.(5)The effective clearance angle on the cutting tool. For certain geometries of minor cutting edge relief and clearance angles it is possible to cut on the major cutting edge and burnish on the minor cutting edge. This can produce a good surface finish but, of course, it is strictly a combination of metal cutting and metal forming and is not to be recommended as a practical cutting method. However, due to cutting tool wear, these conditions occasionally arise and lead to a marked change in the surface characteristics.Limits and TolerancesMachine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so will 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 in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools become worn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For examples part might be made 6 in. long with a variation allowed of 0.003 (three-thousandths) in. above and below this size. Therefore, the part could be 5.997 to 6.003 in. and still be the correct size. These are known as the limits. The difference between upper and lower limits is called the tolerance.A tolerance is the total permissible variation in the size of a part.The basic size is that size from which limits of size arc derived by the application of allowances and tolerances.Sometimes the limit is allowed in only one direction. This is known as unilateral tolerance.Unilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is shown in only one direction from the nominal size. Unilateral tolerancing allow the changing of tolerance on a hole or shaft without seriously affecting the fit.When the tolerance is in both directions from the basic size it is known as a bilateral tolerance (plus and minus).Bilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is split and is shown on either side of the nominal size. Limit dimensioning is a system of dimensioning where only the maximum and minimum dimensions arc shown. Thus, the tolerance is the difference between these two dimensions.Surface Finishing and Dimensional ControlProducts that have been completed to their proper shape and size frequently require some type of surface finishing to enable them to satisfactorily fulfill their function. In some cases, it is necessary to improve the physical properties of the surface material for resistance to penetration or abrasion. In many manufacturing processes, the product surface is left with dirt .chips, grease, or other harmful material upon it. Assemblies that are made of different materials, or from the same materials processed in different manners, may require some special surface treatment to provide uniformity of appearance.Surface finishing may sometimes become an intermediate step processing. For instance, cleaning and polishing are usually essential before any kind of plating process. Some of the cleaning procedures are also used for improving surface smoothness on mating parts and for removing burrs and sharp corners, which might be harmful in later use. Another important need for surface finishing is for corrosion protection in a variety of: environments. The type of protection procedure will depend largely upon the anticipated exposure, with due consideration to the material being protected and the economic factors involved.Satisfying the above objectives necessitates the use of main surface-finishing methods that involve chemical change of the surface mechanical work affecting surface properties, cleaning by a variety of methods, and the application of protective coatings, organic and metallic.In the early days of engineering, the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, until the desired relationship was obtained. If it was inconvenient to offer one part to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit was obtained, the fitter therefore being a 'fitter' in the literal sense. J It is obvious that the two parts would have to remain together, and m the event of one having to be replaced, the fitting would have to be done all over again. In these days, we expect to be able to purchase a replacement fora broken part, and for it to function correctly without the need for scraping and other fitting operations.When one part can be used 'off the shelf' to replace another of the same dimension and material specification, the parts are said to be interchangeable. A system of interchangeability usually lowers the production costs as there is no need for an expensive, 'fiddling' operation, and it benefits the customer in the event of the need to replace worn parts.Automatic Fixture DesignTraditional synchronous grippers for assembly equipment move parts to the gripper centre-line, assuring that the parts will be in a known position after they arc picked from a conveyor or nest. However, in some applications, forcing the part to the centre-line may damage cither the part or equipment. When the part is delicate and a small collision can result in scrap, when its location is fixed by a machine spindle or mould, or when tolerances are tight, it is preferable to make a gripper comply with the position of the part, rather than the other way around. For these tasks, Zaytran Inc. Of Elyria, Ohio, has created the GPN series of non- synchronous, compliant grippers. Because the force and synchronizations systems of the grippers are independent, the synchronization system can be replaced by a precision slide system without affecting gripper force. Gripper sizes range from 51b gripping force and 0.2 in. stroke to 40Glb gripping force and 6in stroke. GrippersProduction is characterized by batch-size becoming smaller and smaller and greater variety of products. Assembly, being the last production step, is particularly vulnerable to changes in schedules, batch-sizes, and product design. This situation is forcing many companies to put more effort into extensive rationalization and automation of assembly that was previouslyextensive rationalization and automation of assembly that was previously the case. Although the development of flexible fixtures fell quickly behind the development of flexible handling systems such as industrial robots, there are, nonetheless promising attempts to increase the flexibility of fixtures. The fact that fixtures are the essential product - specific investment of a production system intensifies the economic necessity to make the fixture system more flexible.Fixtures can be divided according to their flexibility into special fixtures, group fixtures, modular fixtures and highly flexible fixtures. Flexible fixtures are characterized by their high adaptability to different workpieces, and by low change-over time and expenditure.There are several steps required to generate a fixture, in which a workpiece is fixed for a production task. The first step is to define the necessary position of the workpiece in the fixture, based on the unmachined or base pan, and the working features. Following this, a combination of stability planes must be selected. These stability planes constitute the fixture configuration in which the workpiece is fixed in the defined position, all the forces or torques are compensated,。
机械类数控车床外文翻译外文文献英文文献数控
机械类数控车床外文翻译外文文献英文文献数控原文来源：Zhao Chang-ming Liu Wang-ju (CNC Machining Process and equipment, 2002,China)一、摘要Equip the engineering level, level of determining the whole national economy of the modernized degree and modernized degree of industry, numerical control technology is it develop new developing new high-tech industry and most advanced industry to equip (such as information technology and his industry, biotechnology and his industry, aviation, spaceflight, etc. national defense industry) last technology and getting more basic most equipment. Numerical control technology is the technology controlled to mechanical movement and working course with digital information, integrated products of electromechanics that the numerical control equipment is the new technology represented by numerical control technology forms to the manufacture industry of the tradition and infiltration of the new developing manufacturing industry,Keywords:Numerical ControlTechnology, E quipment,industry二、译文数控技术和装备进展趋势及计策装备工业的技术水平和现代化程度决定着整个国民经济的水平和现代化程度，数控技术及装备是进展新兴高新技术产业和尖端工业〔如信息技术及其产业、生物技术及其产业、航空、航天等国防工业产业〕的使能技术和最差不多的装备。
机床工具——机械类外文文献翻译、中英文翻译
机床工具——机械类外文文献翻译、中英文翻译本文旨在对机床工具的相关外文文献进行翻译，并提供中英文对照。
以下是翻译内容：1. 文献标题：Machine Tools in the Manufacturing Industry机床工具在制造业中的应用2. 文献摘要：摘要内容省略3. 引言：引言内容省略4. 机床工具的定义和分类4.1 定义机床工具是指用于加工金属、塑料等材料的机械设备。
它们可以通过切削、打孔、钻孔等方式来改变工件的形状和尺寸。
机床工具在制造业中扮演着重要的角色，是生产加工的关键设备之一。
4.2 分类机床工具根据加工方式和功能可以分为多种类型，包括但不限于：- 钻床：用于钻孔和打孔的机床工具。
- 铣床：用于平面和曲面的加工，常用于零件的修整和切割。
- 车床：用于旋转对称零件的加工，可进行螺纹加工。
- 磨床：用于零件的磨削，获得更高的平滑度和精度。
- 刨床：用于平面的加工，可进行切削和修整。
- 冲床：用于冲压工艺，可用于冲孔和冲剪。
5. 机床工具的应用和发展趋势5.1 应用机床工具广泛应用于制造业的各个领域，包括汽车制造、航空航天、电子设备、家电等。
它们在产品加工、零部件制造和整体生产中起着关键作用。
5.2 发展趋势随着科技的不断进步，机床工具也在不断发展和创新。
以下是一些机床工具的发展趋势：- 数控机床：采用数字控制技术，提高加工效率和精度。
- 智能机床：结合人工智能和自动化技术，实现智能化生产和优化生产流程。
- 柔性机床：具有多功能和快速转换能力，适应不同产品和加工需求。
- 环保机床：注重节能和环境友好，减少废料和排放。
- 精密机床：追求更高的精度和平滑度，满足特殊加工要求。
6. 结论：结论内容省略以上是对机床工具的相关外文文献进行的翻译，提供了中英文对照。
机床工具在制造业中具有重要作用，并且随着科技的发展，机床工具的应用和发展也呈现出新的趋势和特点。
（数控加工）机械类数控外文翻译外文文献英文文献数控
（数控加工）机械类数控外文翻译外文文献英文文献数控NumericalControlOneofthemostfundamentalconceptsintheareaofadvancedmanufacturingte chnologiesisnumericalcontrol(NC).PriortotheadventofNC,allmachinetools weremanualoperatedandcontrolled.Amongthemanylimitationsassociatedwith manualcontrolmachinetools,perhapsnoneismoreprominentthanthelimitation ofoperatorskills.Withmanualcontrol,thequalityoftheproductisdirectlyre latedtoandlimitedtotheskillsoftheoperator.Numericalcontrolrepresentst hefirstmajorstepawayfromhumancontrolofmachinetools.Numericalcontrolmeansthecontrolofmachinetoolsandothermanufacturin gsystemsthoughtheuseofprerecorded,writtensymbolicinstructions.Rathert hanoperatingamachinetool,anNCtechnicianwritesaprogramthatissuesoperat ionalinstructionstothemachinetool,Foramachinetooltobenumericallycontr olled,itmustbeinterfacedwithadeviceforacceptinganddecodingthep2ogramm edinstructions,knownasareader.Numericalcontrolwasdevelopedtoovercomethelimitationofhumanoperato r,andithasdoneso.Numericalcontrolmachinesaremoreaccuratethanmanuallyo peratedmachines,theycanproducepartsmoreuniformly,theyarefaster,andthe long-runtoolingcostsarelower.ThedevelopmentofNCledtothedevelopmentofs everalotherinnovationsinmanufacturingtechnology:1.Electricaldischargemachining.sercutting.3.Electronbeamwelding.Numericalcontrolhasalsomademachinetoolsmoreversatilethantheirmanuallyoperatedpredecessors.AnNCmachinetoolcanautomaticallyproduceawidev arietyofpar4s,eachinvolvinganassortmentofundertaketheproductionofprod uctsthatwouldnothavebeenfeasiblefromaneconomicperspectiveusingmanuall ycontrolledmachinetoolsandprocesses.Likesomanyadvancedtechnologies,NCwasborninthelaboratoriesoftheMas sachusettsInstituteofTechnology.TheconceptofNCwasdevelopedintheearly1 950swithfundingprovidedbytheU.SAirForce.Initsearlieststages,NCmachine swereabletomakestraightcutsefficientlyandeffectively.However,curvedpathswereaproblembecausethemachinetoolhadtobeprogra mmedtoundertakeaseriesofhorizontalandverticalstepstoproduceacurve.The shorteristhestraightlinesmakingupthestep,thesmootheris4hecurve.Eachli nesegmentinthestepshadtobecalculated.Thisproblemledtothedevelopmentin1959oftheAutomaticallyProgrammedT ools(APT)languageforNCthatusesstatementssimilartoEnglishlanguagetodef inethepartgeometry,describethecuttingtoolconfiguration,andspecifythen ecessarymotions.ThedevelopmentoftheAPTlanguagewasamajorstepforwardint hefurtherdevelopmentofNCtechnology.TheoriginalNCsystemwerevastlydiffe rentfromthoseusedpunchedpaper,whichwaslatertoreplacedbymagneticplasti ctape.Atapereaderwasusedtointerprettheinstructionswrittenonthetapefor themachine.Together,all/fthisrepresentedgiantstepforwardinthecontrolo fmachinetools.However,therewereanumberofproblemswithNCatthispointinit sdevelopment.Amajorproblemwasthefragilityofthepunchedpapertapemedium.Itwascomm onforthepapercontainingtheprogrammedinstructionstobreakortearduringam achiningprocess,Thisproblemwasexacerbatedbythefactthateachsuccessivet imeapartwasproducedonamachinetool,thepapertapecarryingtheprogrammedin structionshadtorerunthoughtthereader.Ifitwasnecessarytoproduce100copi esofagivenpart,itwasalsonecessarytorunthepapertapethoughtthereader100 separatetimes.Fragilepapertapessimplycouldnotwithstandtherigorsofshop floorenvironmentandthiskindofrepeateduse.Thisledtothedevelopmentofaspecialmagnetictape.Whereasthepapertape carriedtheprogrammedinstructionsasaseriesofholespunchedinthetape,theT hismostimportantofthesewasthatitwasdifficultorimpossibletochangethein structionsenteredonthetape.Tomakeeventhemostminoradjustmentsinaprogra mofinstructions,itwasnecessarytointerruptmachiningoperationsandmakean ewtape.Itwasalsostillnecessarytorunthetapethoughtthereaderasmanytimes astherewerepartstobeproduced.Fortunately,computertechnologybecomearea lityandsoonsolvedtheproblemsofNC,associatedwithpunchedpaperandplastic tape.Thedevelopmentofaconceptknownasnumericalcontrol(DNC)solvethepaper andplastictapeproblemsassociatedwithnumericalcontrolbysimplyeliminati ngtapeasthemediumforcarryingtheprogrammedinstructions.Indirectnumeric alcontrol,machinetoolsaretied,viaadatatransmissionlink,toahostcompute randfedtothemachinetoolasneededviathedatatransmissionlinkage.Directnumericalcontrolrepresentedamajorstepforwardoverpunchedtapeandplasticta pe.However,itissubjecttothesamelimitationasalltechnologiesthatdependo nahostcomputer.Whenthehostcomputergoesdown,themachinetoolsalsoexperie ncedowntime.Thisproblemledtothedevelopmentofcomputernumericalcontrol.Thedevelopmentofthemicroprocessorallowedforthedevelopmentofprogra mmablelogiccontrollers(PLC)andmicrocomputers.Thesetwotechnologiesallo wedforthedevelopmentofcomputernumericalcontrol(CNC).WithCNC,eachmachi netoolhasaPLCoramicrocomputerthatservesthesamepurpose.Thisallowsprogr Csolvedtheproblems associateddowntimeofthehostcomputer,butitintroducedanotherproblemknow nasdatamanagement.Thesameprogrammightbeloadedontendifferentmicrocompu terswithnocommunicationamongthem.Thisproblemisintheprocessofbeingsolv edbylocalareanetworksthatconnectDigitalSignalProcessorsTherearenumeroussituationswhereanalogsignalstobeprocessedinmanywa ys,likefilteringandspectralanalysis,Designinganaloghardwaretoperformt hesefunctionsispossiblebuthasbecomelessandpractical,duetoincreasedper formancerequirements,flexibilityneeds,andtheneedtocutdownondevelopmen t/testingtime.Itisinotherwordsdifficultpmdesignanaloghardwareanalysis ofsignals.Theactofsamplingansignalintothehatarespecialisedforembeddedsignal processingoperations,andsuchaprocessoriscalledaDSP,whichstandsforDigi talSignalProcessor.TodaytherearehundredsofDSPfamiliesfromasmanymanufacturers,eachonedesignedforaparticularprice/performance/usagegroup.Man yofthelargestmanufacturers,likeTexasInstrumentsandMotorola,offerboths pecialisedDSP’sforcertainfieldslikemotor-controlormodems,andgeneralh igh-performanceDSP’sthatcanperformbroadrangesofprocessingtasks.Devel opmentkitsan`softwarearealsoavailable,andtherearecompaniesmakingsoftw aredevelopmenttoolsforDSP’sthatallowstheprogrammertoimplementcomplex processingalgorithmsusingsimple“drag‘n’drop”methodologies.DSP’smoreorlessfallintotwocategoriesdependingontheunderlyingarch itecture-fixed-pointandfloating-point.Thefixed-pointdevicesgenerallyo perateon16-bitwords,whilethefloating-pointdevicesoperateon32-40bitsfl oating-pointwords.Needlesstosay,thefixed-pointdevicesaregenerallychea per.Anotherimportantarchitecturaldifferenceisthatfixed-pointprocessor stendtohaveanaccumulatorarchitecture,withonlyone“generalpurpose”reg ister,makingthemquitetrickytoprogramandmoreimportantly,makingC-compil ersinherentlyinefficient.Floating-pointDSP’sbehavemorelikecommongene ral-purposeCPU’s,withregister-files.TherearethousandsofdifferentDSP’sonthemarket,anditisdifficulttas kfindingthemostsuitableDSPforaproject.Thebestwayisprobablytosetupacon straintandwishlist,andtrytocomparetheprocessorsfromthebiggestmanufact urersagainstit.The“bigfour”manufacturersofDSPs:TexasInstruments,Motorola,AT&Ta ndAnalogDevices.Digital-to-analogconversionInthecaseofMPEG-Audiodecoding,digitalcompresseddataisfedintotheDS Pwhichperformsthedecoding,thenthedecodedsampleshavetobeconvertedbacki ntotheanalogdomain,andtheresultingsignalfedanamplifierorsimilaraudioe quipment.Thisdigitaltoanalogconversion(DCA)isperformedbyacircuitwitht hesamename&DifferentDCA’sprovidedifferentperformanceandquality,asmea suredbyTHD(Totalharmonicdistortion),numberofbits,linearity,speed,filt ercharacteristicsandotherthings.TheTMS320familyDQPofTexasInstrumentsTheTLS320familyconsistsoffixed-point,floating-point,multiprocesso rdigitalsignalprocessors(D[Ps),andfoxed-pointDSPcontrollers.TMS320DSP haveanarchitecturedesignedspecificallyforreal-timesignalprocessing.Th e’F/C240isanumberofthe’C2000DSPplatform,andisoptimizedforcontrolapp lications.The’C24xseriesofDSPcontrollerscombinesthisreal-timeprocess ingcapabilitywithcontrollerperipheralstocreateanidealsolutionforcontr olsystemapplications.ThefollowingcharacteristicsmaketheTMS320familyth erightchoiceforawiderangeofprocessingapplications:---Veryflexibleinstructionset---Inherentoperationalflexibility---High-speedperformance---Innovativeparallelarchitecture---CosteffectivenessDeviceswithinagenerationoftheTMS320familyhavethesameCPUstructure butdifferenton-chipmemoryandperipheralconfigurations.Spin-offdevicesu senewcombinationsofOn-chipmemoryandperipheralstosatisfyawiderangeofne edsintheworldwideelectronicsmarket.Byintegratingmemoryandperipheralso ntoasinglechip,TMS320devicesreducesystemcostsandsavecircuitboardspace .The16-bit,fixed-pointDSPcoreofthe‘C24xdevicesprovidesanalogdesi gnersadigitalsolutionthatdoesnotsacrificetheprecisionandperformanceof theirsystemperformancecanbeenhancedthroughtheuseofadvancedcontrolalgo rithmsfortechniquessuchasadaptivecontrol,Kalmanfiltering,andstatecont rol.The‘C24xDSPcontrollerofferreliabilityandprogrammability.Analogco ntrolsystems,ontheotherhand,arehardwiredsolutionsandcanexperienceperf ormancedegradationduetoaging,componenttolerance,anddrift.Thehigh-speedcentralprocessingunit(CPU)allowsthedigitaldesignert oprocessalgorithmsinrealtimeratherthanapproximateresultswithlook-upta bles.TheinstructionsetoftheseDSPcontrollers,whichincorporatesbothsign alprocessinginstructionsandgeneral-purposecontrolfunctions,coupledwit htheextensivedevelopmenttimeandprovidesthesameeaseofuseastraditional8 -and16-bitmicrocontrollers.Theinstructionsetalsoallowsyoutoretainyour softwareinvestmentwhenmovingfromothergeneral-purpose‘C2xxgeneration, sourcecodecompatiblewiththe’C2xgeneration,andupwardlysourcecodecompa tiblewiththe‘C5xgenerationofDSPsfromTexasInstruments.The‘C24xarchitectureisalsowell-suitedforprocessingcontrolsignal s.Itusesa16-bitwordlengthalongwith32-bitregistersforstoringintermedia teresults,andhastwohardwareshiftersavailabletoscalenumbersindependent lyoftheCPU.Thiscombinationminimizesquantizationandtruncationerrors,an dincreasesp2ocessingpowerforadditionalfunctions.Suchfunctionsmightinc ludeanotchfilterthatcouldcancelmechanicalresonancesinasystemoranestim ationtechniquethatcouldeliminatestatesensorsinasystem.The‘C24xDSPcontrollerstakeadvantageofansetofperipheralfunctions thatallowTexasInstrumentstoquicklyconfigurevariousseriesmembersfordif ferentprice/performancepointsorforapplicationoptimization.Thislibraryofbothdigitalandmixed-signalperipheralsincludes:---Timers---Serialcommunicationsports(SCI,SPI)---Analog-to-digitalconverters(ADC)---Eventmanager---Systemprotection,suchaslow-voltageandwatchdogtimerTheDSPcontrollerperipherallibraryiscontinuallygrowingandchanging tosuittheoftomorrow’sembeddedcontrolmarketplace.TheTMS320F/C240isthefirststandarddeviceintroducedinthe‘24xserie sofDSPcontrollers.Itsetsthestandardforasingle-chipdigitalmotorcontrol ler.The‘240canexecute20MIPS.Almostallinstructionsareexecutedinasimpl ecycleof50ns.Thishighperformanceallowsreal-timeexecutionofverycomple8controlalgorithms,suchasadaptivecontrolandKalmanfilters.Veryhighsampl ingratescanalsobeusedtominimizeloopdelays.The‘240hasthearchitecturalfeaturesnecessaryforhigh-speedsignalp rocessinganddigitalcontrolfunctions,andithastheperipheralsneededtopro videasingle-chipsolutionformotorcontrolapplications.The‘240ismanufac turedusingsubmicronCMOStechnology,achievingalogpowerdissipationrating.A lsoincludedareseveralpower-downmodesforfurtherpowersavings.Someapplic ationsthatbenefitfromtheadvancedprocessingpowerofthe‘240include: ---Industrialmotordrives---Powerinvertersandcontrollers---Automotivesystems,suchaselectronicpowersteering,antilockbrake s,andclimatecontrol---ApplianceandHVACblower/compressormotorcontrols---Printers,copiers,andotherofficeproducts---Tapedrives,magneticopticaldrives,andothermassstorageproducts---RoboticandCNCmillingmachinesTofunctionasasystemmanager,aDSPmusthaverobuston-chipI/Oandotherp eripherals.Theeventmanagerofthe‘240isunlikeanyotheravailableonaDSP.T hisapplication-optimizedperipheralunit,coupledwiththehighperformanceD SPcore,enablestheuseofadvancedcontroltechniquesforhigh-precisionandhi gh-efficiencyfullvariable-speedcontrolofallmotortypes.Includeintheeve ntmanagerarespecialpulse-widthmodulation(PWM)generationfunctions,suchasaprogrammabledead-bandfunctionandaspacevectorPWMstatemachinefor3-ph asemotorsthatprovidesstate-of-the-artmaximumefficiencyintheswitchingo fpowertransistors.Thereindependentupdowntimers,eachwithit’sowncompareregister,sup portthegenerationofasymmetric(noncentered)aswellassymmetric(centered) PWMwaveforms.Open-LoopandClosed-LoopControlOpen-loopControlSystemsThewordautomaticimpliesthatthereisacertainamountofsophistication inthecontrolsystem.Byautomatic,itgenerallymeansThatthesystemisusually capableofadaptingtoavarietyofoperatingconditionsandisabletorespondtoa classofinputssatisfactorily.However,notanytypeofcontrolsystemhastheau ually,theautomaticfeatureisachievedbyfeed.gthefeedbackstructure,itiscalledanopen-loopsystem,whichisthesimp lestandmosteconomicaltypeofcontrolsystem.inaccuracyliesinthefactthato nemaynotknowtheexactcharacteristicsofthefurther,whichhasadefinitebear ingontheindoortemperature.Thisalcopointstoanimportantdisadvantageofth eperformanceofanopen-loopcontrolsystem,inthatthesystemisnotcapableofa daptingtovariationsinenvironmentalconitionsortoexternaldisturbances.I nthecaseofthefurnacecontrol,perhapsanexperiencedpersoncanprovidecontr olforacertaindesiredtemperatureinthehouse;butidthedoorsorwindowsareop enedorclosedintermittentlyduringtheoperatingperiod,thefinaltemperatureinsidethehousewillnotbeaccuratelyregulatedbytheopen-loopcontrol.Anelectricwashingmachineisanothertypicalexampleofanopen-loopsyst em,becausetheamountofwashtimeisentirelydeterminedbythejudgmentandesti mationofthehumanoperator.Atrueautomaticelectricwashingmachineshouldha vethemeansofcheckingthecleanlinessoftheclothescontinuouslyandturnitse dtoffwhenthedesireddegisedofcleanlinessisreached.Closed-LoopControlSystemsWhatismissingintheopen-loopcontrolsystemformoreaccurateandmoread aptablecontrolisalinkorfeedbackfromtheoutputtotheinputofthesystem.Ino rdertoobtainmoreaccuratebontrol,thecontrolledsignalc(t)mustbefedbacka ndcomparedwiththereferenceinput,andanactuatingsignalproportionaltothe differenceoftheoutputandtheinputmustbesentthroughthesystemtocorrectth eerror.Asystemwithoneormorefeedbackpat(slikethatjustdescribediscalled aclosed-loopsystem.humanbeingareprobablythemostcomplexandsophisticate dfeedbackcontrolsysteminexistence.Ahumanbeingmaybeconsideredtobeacont rolsystemwithmanyinputsandoutputs,capableofcarryingouthighlycomplexop erations.Toillustratethehumanbeingasafeedbackcontrolsystem,letusconsidert hattheobjectiveistoreachforanobjectonaperformthetask.Theeyesserveasas ensingdevicewhichfeedsbackcontinuouslythepositionofthehand.Thedistanc ebetweenthehandandtheobjectistheerror,whichiseventuallybroughttozeroa sthehandreachertheobject.Thisisatypicalexampleofclosed-loopcontrol.However,ifoneistoldtoreachfortheobjectandthenisblindolded,onecanonlyrea chtowardtheobjectbyestimatingitsexactposition.ItisAsantherillustrativ eexampleofaclosed-loopcontrolsystem,showstheblockdiagramoftherudderco ntrolsystemofThebasicalementsandtheblocadiagramofaclosed-loopcontrols ystemareshowninfig.Ingeneral,theconfigurationofafeedbackcontrolsystem maynotbeconstrainedtothatoffig&.Incomplexsystemstheremaybemultitudeof feedbackloopsandelementblocks.数控在先进制造技术领域最根本的观念之壹是数控（NC）。
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钻头和钻床
麻花钻头是一种高效率的刀具，它通常由扁钢锻造后扭转出凹槽，或由圆柱 棒料铣削而成，一般用高速钢制作。高速钢的成本虽然较高，但用它制作的刀具在 耐热性方面要比用普通工具钢制作的刀具好得多。
麻花钻可分做三个主要部分：钻体、钻柄和钻尖。螺旋槽是位于钻头侧面的螺 旋形凹槽，钻头制成两条、三条或四条螺旋槽。带有三条或四条螺旋槽的钻头用于 较小钻头钻孔后继续钻孔的场合，或对已钻好的孔进行扩孔，而不宜在实体坯料上 钻孔。
铣床
铣床是一种当工件向铣刀进给时，铣刀旋转着从工件表面切除金属的机床。铣 刀安装在刀杆上并由衬套或轴套定位。刀杆的一端安装在主轴上，而另一端则可在 安装在刀杆支架的轴承里旋转。
铣刀通常有高速钢制成，有不同的尺寸和形状。铣刀可分为圆柱铣刀、立铣刀 （铣端面）、成形铣刀、角度铣刀、三面刃铣刀、锯片铣刀等。这些铣刀的铣削方 向可能不同，例如，在切削时，它们可以顺时针转动，也可以逆时针转动。
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附件 1：外文资料翻译译文
机床
机床是用于切削金属的机器。工业上使用的机床要数车床、钻床和铣床最为重 要。其它类型的金属切削机床在金属切削加工方面不及这三种机床应用广泛。
车床通常被称为所有类型机床的始祖。为了进行车削，当工件旋转经过刀具时， 车床用一把单刃刀具切除金属。用车削可以加工各种圆柱型的工件，如：轴、齿轮 坯、皮带轮和丝杠轴。镗削加工可以用来扩大和精加工定位精度很高的孔。
螺旋槽主要有四个好处： （1）螺旋槽使钻头的切削刃有正确的前角； （2）螺旋槽可以卷紧切屑，使其占有最小的空间； （3）螺旋槽可以构成若干通道，切屑能借助这些通道从孔内排出； （4）螺旋槽可以使润滑剂顺利地流向切削刃。
刃带（棱边）是螺旋槽切削刃上的狭带。刃带部分实际上是钻头的最大直径处， 它伸展到螺旋槽的全长，它的表面是圆柱体的一部分。紧靠刃带的钻体部分其直径 略小于刃带的直径，减小的直径称做钻体间隙。钻体间隙用来减少钻头和孔壁间的 摩檫，而刃带则用来保证孔的准确尺寸。
毕业设计(论文)外文资料翻译
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English For Electromechanical Engineering
附 件： 1.外文资料翻译译文；2.外文原文。
指导教师评语： 此翻译文章简单介绍了各机床的加工原理，并详细介绍了
各机床的构造，并对方各机床的加工方法法进行了详细的描述， 翻译用词比较准确，文笔也较为通顺，为在以后工作中接触英 文资料打下了基础。
车床的最大部件称为床身，它的两端分别装有床头箱和尾座。床身表面有专门 的导轨，溜板和尾座可以在导轨上滑行。
车床的两个顶尖分别装在两根主轴中：活顶尖装在床头箱主轴中，另一个死顶 尖则装在尾座的主轴中。
车床卡盘用于夹紧工件，其目的在于使工件在车削时不摇晃。通常，安装在床 头箱主轴上的卡盘可具有不同的尺寸和结构。如果工件是一完整的圆，可将其夹紧 在所谓的三爪通用卡盘中，卡盘的三个爪靠转动螺旋机构能同时向中间移动。但是 如果工件系非完整的圆，则应使用四爪相互独立的四爪卡盘。
钻头的一端是钻柄，它被安装在钻套、钻床的主轴或钻夹头中。通常只有锥柄 钻头才带柄舌。
钻床是仅次于车床的最古老的机床，它的发明略迟于车床，它是一种最普通和 最有用的机床。钻床可分为三大类：立式钻床、多轴钻床和摇臂钻床。立式钻床有 三种类型：重型钻床、普通钻床和高速手压台钻。
钻床除了钻孔外，还可完成下列工作：如攻螺纹（加工内螺纹）、铰孔（用绞 刀精加工孔）、尖底锪钻、平底锪钻、镗孔和锪端面等。
车床在车削不同材料和不同直径的工件时，必须以不同的速度运转。装在床头 箱内的齿轮系统能使车床以不同的速度运转。
车床在车削工件前，它的顶尖要对准，即两个顶尖的轴线必须在同一直线上。 为检验车床顶尖的同轴度，可进行一次车削，然后用千分尺测量车削物的两端。 并非所有的工件都必须装夹在车床的两个顶尖之间。短工件的车削可不使用死 顶尖，而是简单的将其适当夹紧在床头箱的主轴上。
钻削是由旋转的钻头完成的。大多数金属的钻削由麻花钻来完成。用来进行钻 削加工的机床称为钻床。铰孔和攻螺纹也归类为钻削过程。铰孔是从已经钻好的孔 上再切除少量的金属。
攻螺纹是在内孔上加工出螺纹，以使螺钉或螺栓旋进孔内。 铣削由旋转的、多切削刃的铣刀来完成。铣刀有多种类型和尺寸。有些铣刀只 有两个切削刃，而有些则有多达三十或更多的切削刃。铣刀根据使用的刀具不同能 加工平面、斜面、沟槽、齿轮轮齿和其它外形轮廓。 牛头刨床和龙门刨床用单刃刀具来加工平面。用牛头刨床进行加工时，刀具在 机床上往复运动，而工件朝向刀具自动进给。在用龙门刨床进行加工时，工件安装 在工作台上，工作台往复经过刀具而切除金属。工作台每完成一个行程刀具自动向 工件进给一个小的进给量。 磨削利用磨粒来完成切削工作。根据加工要求，磨削可分为精密磨削和非精密 磨削。精密磨削用于公差小和非常光洁的表面，非精密磨削用于在精度要求不高的 地方切除多余的金属。
车床
车床是用来从圆形工件表面切除金属的机床，工件安装在车床的两个顶尖之 间，并绕顶尖轴线旋转。车削工件时，车刀沿着工件的旋转轴线平行移动或与工件 的旋转轴线成一斜角移动，将工件表面的金属切除。车刀的这种位移称为进给。车
刀装夹在刀架上，刀架则固定在溜板上。溜板是使刀具沿所需方向进行进给的机构。 用于操纵车床手柄可使车刀实现进给，也可以借助专门的同取决于要加工工件的 类型特点。根据主轴的位置，铣床可分为立式铣床和卧式铣床两大类。铣床可分为 许多种。
根据总体结构的不同，铣床可分为升降台式铣床、专用铣床、龙门铣床；根据 工作台的结构，铣床可分为万能铣床和普通铣床。
铣床主要的零部件有启动手柄、主轴、立柱、升降台、升降螺杆、工作台、分 度台、调速手柄、进给手柄、工作台移动手柄、床身和刀杆支架。