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一种基于电加热的导热油系统及其关键零部件的加工工艺设计【8张图纸】【优秀】

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一种基于电加热的导热油系统及其关键零部件的加工工艺设计【8张图纸】【优秀】.rar

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关键词：: 一种基于加热导热油系统及其关键症结枢纽零部件加工工艺设计图纸优秀优良

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一种基于电加热的导热油系统及其关键零部件的加工工艺设计

41页 22000字数+说明书+任务书+开题报告+外文翻译+工艺卡+工艺过程卡+8张CAD图纸【详情如下】

dn20机械加工工艺卡.doc

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dn20机械加工工艺过程卡.doc

dn20毛坯.dwg

dn20法兰盘.dwg

DN50机械加工工艺卡.doc

DN50机械加工工艺工序卡.doc

DN50机械加工工艺过程卡.doc

DN50毛坯.dwg

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DN65机械加工工艺卡.doc

DN65机械加工工艺工序卡.doc

DN65机械加工工艺过程卡.doc

DN65毛坯图.dwg

DN65法兰.dwg

一种基于电加热的导热油系统及其关键零部件的加工工艺设计开题报告.doc

一种基于电加热的导热油系统及其关键零部件的加工工艺设计论文.doc

任务书.doc

外文翻译--机床加工介绍.doc

导热油-装配图.dwg

计划周记进度检查表.xls

部件图.dwg

摘要

　　　了解流体传动的基本原理和接头的设计，同时运用机械专业知识，设计该系统中关键零部件的机械加工工艺。通过对电热油炉工作原理和电热油炉的使用及管理的了解，设计电加热导热油系统的整体装配图。根据所知的生产数据以及系统的运行要求，选用合理的零件进行装配。充分利用导热油系统，通过不断地技术改进和提高，来提高工厂的生产效益。同时对其关键零部件法兰盘进行机械加工工艺的分析，不同尺寸的法兰其加工余量是不同的，要根据法兰的大小正确的选取，保证零件加工的合理性。制定不同的工艺路线，通过对比选择合理的工艺路线。在确定加工余量后，根据加工工序的背吃刀量确定切削的进给量。粗取切削速度，计算出机床的主轴转速并选取机床的实际转速参数，算出实际切削速度。在法兰盘与管道的连接中，焊接也起了决定性作用，为了达到更好的焊接效果，需要对焊接填充材料进行选择。

关键词：导热油系统；工艺路线；切削用量；焊接

摘要II

AbstractIII

目录V

1 绪论1

1.1 课题研究的意义1

1.2 课题研究的目的1

1.3 课题研究的范围1

1.4 达到的技术要求1

1.5 课题研究的内容1

1.5.1 加热器本体2

1.5.2 电加热导热油系统的特点2

2 整体设计3

2.1 整个系统里主要用到以下零部件4

3 部件的选用与设计5

3.1 高温法兰闸阀的选用5

3.2 导热油泵的选用5

3.3 压力表7

3.3.1 压力表的分类7

3.3.2 压力表的选用7

3.3.3 压力表的安装与日常维护8

3.4 加热熔器DN3008

3.5 电加热管芯的选用8

3.5.1 法兰电加热管8

3.5.2 法兰电加热管的特点9

3.6 止回阀的选用9

3.7 针型阀的选用10

3.8 防爆热电阻的选用10

3.9 过滤器的选用11

3.10 膨胀节的选用11

4 法兰盘的设计及制造工艺13

4.1 机加工工艺规程的步骤及原则13

4.2 法兰盘零件的分析14

4.2.1 法兰的作用14

4.2.2 零件的工艺分析14

4.3 工艺规程设计15

4.3.1 确定毛坯的制造形式15

4.3.2 基面的选择15

4.3.3 制定工艺路线15

4.3.4 机械加工余量、工序尺寸及毛坯尺寸的确定16

4.3.5 确定切削用量19

5 系统的管道焊接与装配29

5.1 焊接工艺的重要性29

5.2 焊接过程的物理本质29

5.3 焊接方法30

5.4 装配工艺规程30

5.4.1 装配的精度30

5.4.2 装配工艺规程的设计步骤31

6 结论与展望33

6.1 结论33

6.2 展望33

致谢34

参考文献35

1 绪论

1.1 课题研究的意义

　　　随着科学技术的进步和工业生产的发展，有机热载体炉得到了不断的发展和应用。虽然有机热载体炉的工作压力比较低，但是炉内热传导液温度高，且大多热传导液具有易燃易爆的特性，一旦在运行中发生泄漏，将会引起火灾、爆炸等事故，这样不仅有很重大的财产损失，严重的甚至会造成人员伤亡。因此，对有机热载体炉的安全运行和管理，必须高度重视，防患于未然。电热油炉作为一种直接的热能供给方式，已成为一种基础且关键的工业及民用设施。随着全球经济的快速增长，工业发展及城市建设步伐的不断加快，为电热产业带来了无限商机。　

1.2 课题研究的目的

　　　更加详细的了解电热油炉，熟悉它的工作原理，为电热油炉的发展做铺垫。了解电热油炉的使用和管理，充分利用导热油系统，通过不断地技术改进和提高，来提高工厂的生产效益。

1.3 课题研究的范围

　　　电热油炉的很多部分都是焊接起来的，因此整个电热油炉的加工工艺规程中，焊接工艺在这个系统里起着举足轻重的作用，焊接的出错可能导致整个系统的失效，甚至引发整个系统的爆炸。电热油炉的机加工工艺规程中，除了焊接工艺，系统里其他很多零部件是机加工出来的，零件的大小，尺寸，都有明确的要求。电热油炉也分各种型号，所以并不是所有的电热油炉零件都通用。

　　　系统的运行都是各个零部件组合在一起协同作用，所以正确地把各个零件组合起来是保障电加热系统稳定运行的充分条件，零件组装错误会导致系统的失效。电热油炉的电加热管芯因为是热油炉，所以他是用来传递热量的，那么用什么加热，如何加热很关键。加热管芯要考虑到电阻丝，氧化镁粉。油管法兰盘的工艺设计，这个系统密封性必须要严实，不然这个系统会漏油，从而热量也就损失了。使整个系统的效率下降，而浪费更多的资源。为了保障这个系统的长久运行，测温元件则能测量整个系统的温度，从而能更准确的利用系统。

1.4 达到的技术要求

　　　可在较低的运行压力下，获得较高的工作温度，有效降低管线和锅炉的工作压力。热传导效率高、热损失小，升温快、降温慢。温度控制精确，受热相对均匀。成倍延长设备使用寿命。闭式循环和开式操作均安全可靠。节约能耗约50%左右，对大气烟尘排放减少一半。节油节水节电，对于沙漠缺水、高寒地区、缺电地区推广价值高。

1.5 课题研究的内容

　　　电热式油加热器（电热油炉）是一种新型、节能、能提供高温热能的工业设备。供热原理：以电热升温，采用导热油作传热介质；在闭路循环系统中通过泵使热载体强制循环，在低压、高温状态下运行，直接释放热量，从而达到了提供热源的目的。经用热设备卸载后，重新通过循环泵，回到加热器，再吸收热量，传递给用热设备，如此周而复始，实现热量的连续传递，使被加热物体温度升高，达到加热的工艺要求。将热能输送给用热设备后，继加热→循环→再加热→再循环的特种工业油炉。

1.5.1 加热器本体?

　　　1、加热器本体由锅炉钢结构组成，内胆经特殊防锈处理，外部采用耐高温涂料保护。

　　　2、电加热器内采用“分层、逐节加热”技术成果。可以完全消除加热器内的“死角”，从而使重油在电加热器内循环流动，使重油受热均匀，不在容器内因停滞而产生结焦，从而消除因“死角”内的油品过热而产生的碳化和结焦。

　　　3、热交换采用国外最新的多管、大面积换热结构。特粗三相单端出线电热元件与被加热的重油不直接接触，使换热管表面与被加热重油之间的温差大大降低，避免了重油的碳化现象。

4、电热元件采用远红外辐射技术，大大提高了传热效率，同时又降低了换热管的表面温度，从而进一步防止了油品因在换热管表面的局部过热而产生碳化和

一种基于电加热的导热油系统及其关键零部件的加工工艺设计.gif

内容简介：: 英文原文Machine from the early egyptians pedal cars and John Wilkinson boring machine development. They provide rigid support for the workpiece and cutting tool and can precisely control their relative position and relative velocity. Basically speaking, the metal cutting refers to the woven form a sharpen tools from ductile workpiece surface to remove a narrow metal. Chip is abandoned product, compared with other artifacts chip is shorter, but not for the thickness of the cutting part have some increase. Geometry on the surface of the workpiece depends on the shape of the tool and the machining tool path in the process of operation. Most of the manufacturing process to produce different geometric shapes of parts. If a rough workpiece on the center shaft rotation and tool cutting surface parallel to the center of rotation, a rotating surface is created, this operation is called turning. If a hollow pipe in the same way, surface processing, this operation is called boring. When changing diameter evenly and produced a conical surface, this is known as a taper turning. If the radius of cutter contact point to change the movement way, then an outline like a ball of artifacts produced; Or if the workpiece is enough short and support is very rigid, so forming tool relative to the axis of rotation normal feed can generate an outer surface, short conical or cylindrical surface can also be formed. Flat surfaces are often needed, they can by the cutting tool relative to the axis of rotation of the radial cutting contact point. When planing for larger artifacts easier to fix knives positioned below the cutting tool and workpiece. Tool can reciprocating feed. Forming surface can be generated through the molding tooling. Using double groove drill to drill deep is the hole diameter hole of 5 to 10 times. Bit rotation and workpiece rotating cutting blade and the relative motion between the workpiece is an important factor. When milling a rotary tool with lots of cutting edges in contact with the workpiece, workpiece relative tool movement slowly. Flat or forming surface according to the shape of the geometry of the cutting tool and the way of feed may be produced. Can produce horizontal or vertical shaft rotate and can progress to in any of the three coordinate directions. Through a variety of machining operations remove the number and speed of the materials is huge, as in the large turning processing, or tiny, such as grinding and super precision machining only the highs were removed. One machine tools to perform three major function: 1. It supports workpiece or jig and tool (2) it provides relative motion for the workpiece and tool 3. In each case provide a range of feeding and in the speed of up to 4-32 kinds of choices. Speed, feed and cutting depth is the processing of the three variables. Other measure is tapping and cutting tool materials, coolant and geometry, of tools to remove metal speed and the power needed to rely on these variables. Cutting depth, feed and the cutting speed is a metal processing working procedure must be established in the mechanical parameter. Both impact force to remove the metal, power and speed. Cutting speed can be defined as the rotating speed when the week record surface relative to any instant radiating the spread of the needle, or the distance of two adjacent grooves. Cutting depth is into the depth and the depth of the groove. All processing operations including turning, boring can be categorized as rough machining, finish machining or semi finishing. Is processed as quickly as possible and effective to remove a large number of materials, and left a small part of the workpiece material used in finish machining. Finishing for artifacts for the size, shape and surface accuracy. Sometimes, semi-finishing leave schedule for finishing a certain amount of material, it is prior to finish machining. Generally speaking, the longer the workpiece at the same time by one or two lathe center support. Taper hole, the so-called central hole, on both ends of the artifacts of the drill is suitable for lathe center - usually along the axis of the cylindrical workpiece. Artifacts near for side frame is usually supported by the tailstock center, near the main bearing that comprised of main bearing center support or by jaw clamping. This approach can be strong to artifacts and can be smoothly will force to the workpiece; Auxiliary support provided by the chuck of the workpiece to reduce cutting chatter of the trend, if we can carefully and accurately with the method of chuck supporting artifacts, you can obtain accurate results. Between the two centers supporting artifacts can be very accurate results. One end of the workpiece has been processing, then the workpiece can be turned. On a lathe processing at the other end, center hole as accurate positioning and carry the workpiece weight and resist the bearing surface of cutting force. When the workpiece is removed from the lathe for any reason, center hole will be accurately to make back to work on the lathe or another lathe or a cylindrical grinding machine. Is not permitted to chuck and workpiece clamp on the main bearing lathe center. The first thought is, however, a quick method of adjust the chuck on the workpiece, but because it is not allowed in the chuck clamping is also supported by the lathe center is not possible. Provided by the lathe center adjustment will not be able to continue and claw plate can be damaged by pressure center hole and lathe center, even the lathe main spindle. Floating claw discs for the above statement provides an exception, it almost completely used in high production, the chuck is the real work driver and not for the same purposes such as three jaw, common used four jaw chuck. As produced in the shape of a kind of method, all machining is the most commonly used in the process of manufacturing and is one of the most important method. Machining process is a process generated shape, in this process, drivers device on the parts of some material in the form of a chip has been removed. Although in some occasions, the workpiece without support, use of mobile equipment to machining, but most of the mechanical processing is through the supporting artifacts and supporting tools and equipment to complete. Small volume, low cost. Machining in manufacturing, there are two applications. Is casting, forging and working pressure, each special shape, even a part, is almost always have higher mould cost. The shape of the weld depends largely on the raw materials. By using the total cost high but no special tooling equipment, processing is possible; Starting from almost any form of raw materials, as long as the external dimensions large enough, the arbitrary shape of material design. So when production processing is the preferred method, one or several parts during mass production, even design logically lead to the casting parts, forging or stamping products. High precision and surface accuracy. Mechanical processing of the second application is based on the possible high precision and surface accuracy. If mass production on the rest of the process, a lot of low volume parts will produce low but acceptable tolerance. Many, on the other hand, the shape of the parts is produced by some of the large deformation process in general, and only in selected with very high precision surface processing. The paint process, for example, is seldom produce any way other than mechanical processing and followed by a small hole on the pressure after the operation can be processed. Basic tool when cutting the work fully description method has four factors: cutting tool geometry, cutting speed and cutting depth. Cutting tools must be made of proper material; It must have a certain strength, roughness, hardness and resistance to fatigue. Cutting tool geometry described by the surface and Angle of each cutting operation is correct. Cutting speed is refers to the cutting edge through the speed of working face, it has been said by number of feet per minute. For machining efficiency, cutting speed relative to the combination of special work must have the appropriate size. In general, harder the workpiece, the less speed. Feed is the rate of tool into the workpiece. When the workpiece or tool rotation and feeding unit is inch per revolution. As it moves, a tool or workpiece reciprocating feed unit is inch time, overall, in other similar cases, feed and the cutting speed is inversely proportional to. Ins in cutting speed, cutting tool into the workpiece distance said, when it refers to cutting the width of the chip or the linear cutting chip thickness. When rough machining cutting depth is greater than finishing cutting depth. Heat generated during the metal cutting operations in the main and second deformation area and the results led to the complex temperature in the cutting tool, workpiece and chip. A typical isothermal first as shown, it can be seen that, as predicted, when the workpiece material through the main deformation, cut less, has a very large temperature gradient across the whole width of the chip. When the second chip deformation area and a short distance to reach maximum temperature. Because almost all the work is completed in metal cutting is converted into heat, can be predicted to increase removal per unit volume of metal cutting temperature will increase energy consumption. So before all the other parameters constant, Angle greaten, remove less energy per unit volume of metal and the cutting temperature. When considering the increasing lack of chip thickness and speed, the situation is more complicated. Cutting thickness tends to increase greatly influence the heat to the workpiece, tool, and can make the chip to stay in a fixed amount, at the same time, the change of cutting temperature will be small, but increase the cutting speed can reduce the heat is passed to the workpiece, at the same time, this will increase the main deformation of the chip temperature rise. In addition, the second deformation zone is relatively small, will raise the temperature in the deformation zone. Cutting parameters of other changes almost does not affect the removal of energy consumption per unit volume and the cutting temperature. So has shown that even small changes in cutting temperature has significant influence on tool wear rate, from cutting data to estimate the cutting temperature is appropriate. The most direct the most accurate method to detect high speed steel tools, trent gave details of the temperature distribution in the high speed steel tools. The technology is data detection based on high speed steel cutting tools and related to the microscopic changes of thermal history. Trent has describes the measurement of the temperature of cutting and processing a wide range of temperature distribution of workpiece when high speed steel tools. Using scanning electron microscope (sem) to study the fine scale microstructure change, the technology has been further developed. This technology is also used to study the high speed steel single point cutting tool and the temperature distribution of twist drill, Brittle fracture has been handled, tool wear there are basically three types. After the blade wear, boundary wear and the surface of the knife before wear. Blade wear occurred in the main cutting edge and the cutting edge. Main cutting edges is responsible for removing a lot of metal, which adds to the cutting force and temperature, if left unchecked will lead to the vibration of the cutting tool and workpiece, it can not efficiently cutting again. Cutting edge decide the size and surface accuracy, the sword of the wear and tear can lead to a large number of products after the surface precision of poor. According to actual cutting condition, the main causes of the cutting tool is unavailable work ahead of time on the surface of the knife wear very big, this led to an unacceptable part. Because of the stress distribution of a tool, just started sliding, sliding region of the friction between the chip and achieve maximum, the friction force is zero. So abrasive wear occurred in this area, the chip with more wear in and adjacent to the area, it is more than adjacent to it. This led to the local pitting on the surface of the cutting tool and some distance to the surface, this surface is usually part of the circular arc form. In many ways, and based on the actual cutting condition, boundary wear compared with the knife after surface is a less serious wear and tear, thus grinding blunt knife surface wear is a relatively common standards. Then, because of the author suggests that along with the increase of cutting speed, the addition of surface temperature increase more than the knife surface, due to temperature change seriously affect the wear rate of any type, boundary wear usually occurs in the case of high cutting speed. Cutter and cutting face contact place, the work surface wear than along the residual wear at the end of the worn surface areas is more obvious. This is because the local effects such as is not cutting face by the previous cutting, oxidation scale, formed by high temperature caused by work hardening. This partial wear generally associated with boundary wear, sometimes very serious. Despite Nick will not seriously affect the tool cutting performance, notch is tend to be more deep, if continue to cutting tools are likely to rupture. If any form of gradual wear and tear to make dramatic continue to exist, the tool will face a catastrophic failure, such as cutting tools cannot be cut again, in a good situation, workpiece scrapped, the worst, may cause damage to the machine tools. For carbide cutting tools and various types of wear, in the event of a catastrophic failure before using the longest service life limit. But for high speed steel cutting tool wear is uneven, has found that when wear to continue and even catastrophic failure, the most meaningful and can copy can be got as a result, of course, in practice, cutting time is far less than the fault time. Catastrophic failure occurs few phenomenon, one of the most common is the cutting force increases suddenly, artifacts appear bright ring, significant increase in noise. Tolerance is the greatest change in component size, basic size is allowed to change the amount limited by the size of the derivative and the tolerance range. Sometimes deviation is only allowed in one direction, it allows the tolerance on the hole or shaft changes without serious impact to cooperate. When changes in tolerances in both directions, known as completely deviation (positive and negative). Deviations are completely separate, and in the basic size of each side will have. Compared with minimum size and maximum size limit of size. Thus, tolerance is defined as the difference between these two sizes. Products have been finished the shape and size, it is often necessary to some type of surface precision is that they can perform their functions as well. In some cases, in order to cut and abrasion resistance, improve the physical properties of the surface material is a must. In many manufacturing processes, product surface dirt, dust, grease, or other harmful substances. Mixture composed of different materials, different ways of processing the same material, may need some special surface treatment to provide a uniform appearance. Surface polishing treatment can sometimes become a handler in the middle. Prior to plating process, for example, cleaning and polishing is often essential. Some cleaning procedures are used to improve matching parts of surface smoothness, also in order to remove the burrs, which is harmful in the later use. Another important reason for surface polishing treatment is anticorrosion protection in all kinds of environment. Protection type mainly depends on the expected exposure, and fully considering the protection material and economic factor. In the early days of the project, as far as possible close to matching parts processing to the required size, the mating part to similar size and finish machining, and constantly to other parts to match with it, until they get the ideal relationship. If not convenient at the time of processing will a parts another parts suitable, is the final work is by the bench sitting on the bench, scraping cooperate parts until the ideal cooperation, so as a machinists literal meaning J, it is obvious that the two parts are still together and M have to change, must once again to cooperate. In these days, we want to buy a substitute for the bad parts, and it functions normally do not need scraping and other modification process. When a component can be used to replace another same size and material specifications of the parts, then we call these parts can be interchangeable. Swap system can reduce the production cost, usually for an expensive operation is not necessary, it is beneficial to customers when needed to replace abrasive parts. In production task workpiece in the fixture is fixed, fixed several steps necessary to an artifact. The first step is to determine the position of the workpiece on the fixture, considering the raw surface and the work characteristics. After that, the fixed surface must be selected. In determining the location of the workpiece is fixed on the fixed, and add the necessary force and moment, secure the necessary working characteristics. Finally, necessary to transfer the position or modular fixture element to consider, or assembly, the workpiece firmly fixed on the jig. Through such a program, working procedure and process card, fixture assembly can be automatically. Structure modeling task is to produce a number of stable plane combination, so that in the plane of the clamping force will lead to stable workpiece and fixture. Traditionally, this task can be - machine dialogue is almost completely automated way of choose and employ persons to complete. Man - machine dialogue is in an automated way to determine the fixture structure model has the advantage of fixture design can be organized and planning, reduce the design personnel, shorten the research cycle and better working conditions. In short, it can successfully achieve significantly improved fixture production efficiency and economic benefits. 中文译文机床是从早期的埃及人的脚踏动力车和约翰威尔金森的镗床发展而来的。它们为工件和刀具提供刚性支撑并可以精确控制它们的相对位置和相对速度。基本上讲，金属切削是指一个磨尖的锲形工具从有韧性的工件表面上去除一条很窄的金属。切屑是被废弃的产品，与其它工件相比切屑较短，但对于未切削部分的厚度有一定的增加。工件表面的几何形状取决于刀具的形状以及加工操作过程中刀具的路径。大多数加工工序产生不同几何形状的零件。如果一个粗糙的工件在中心轴上转动并且刀具平行于旋转中心切入工件表面，一个旋转表面就产生了，这种操作称为车削。如果一个空心的管子以同样的方式在内表面加工，这种操作称为镗孔。当均匀地改变直径时便产生了一个圆锥形的外表面，这称为锥度车削。如果刀具接触点以改变半径的方式运动，那么一个外轮廓像球的工件便产生了；或者如果工件足够的短并且支撑是十分刚硬的，那么成型刀具相对于旋转轴正常进给的一个外表面便可产生，短锥形或圆柱形的表面也可形成。平坦的表面是经常需要的，它们可以由刀具接触点相对于旋转轴的径向车削产生。在刨削时对于较大的工件更容易将刀具固定并将工件置于刀具下面。刀具可以往复地进给。成形面可以通过成型刀具加工产生。使用双刃槽钻钻深度是钻孔直径5-10倍的孔。不管是钻头旋转还是工件旋转，切削刃与工件之间的相对运动是一个重要因数。在铣削时一个带有许多切削刃的旋转刀具与工件接触，工件相对刀具慢慢运动。平的或成形面根据刀具的几何形状和进给方式可能产生。可以产生横向或纵向轴旋转并且可以在任何三个坐标方向上进给。通过各种加工工序去除材料的数量和速度是巨大的，正如在大型车削加工，或者是极小的如研磨和超精密加工中只有面的高点被除掉。一台机床履行三大职能：1.它支撑工件或夹具和刀具2.它为工件和刀具提供相对运动3.在每一种情况下提供一系列的进给量和一般可达4-32种的速度选择。速度，进给量和切削深度是经济加工的三大变量。其他的量数是攻丝和刀具材料，冷却剂和刀具的几何形状，去除金属的速度和所需要的功率依赖于这些变量。切削深度，进给量和切削速度是任何一个金属加工工序中必须建立的机械参量。它们都影响去除金属的力，功率和速度。切削速度可以定义为在旋转一周时速度记录面相对任何瞬间呈辐射状扩散的针，或是两个相邻沟槽的距离。切削深度是进入的深度和沟槽的深度。所有的加工工序包括车削，镗孔可以被归类为粗加工，精加工或半精加工。精加工是尽可能快而有效的去除大量材料，而工件上留下的一小部分材料用于精加工。精加工为工件获得最后尺寸，形状和表面精度。有时，半精加工为精加工留下预定的一定量的材料，它是先于精加工的。一般来说，较长的工件同时被一个或两个车床中心支撑。锥形孔，所谓的中心孔，两端被钻的工件适于车床中心-通常沿着圆柱形工件的轴线。工件接近为架的那端通常由尾架中心支撑，在靠近主轴承的那端由主轴承中心支撑或由爪盘夹紧。这种方法可以牢固的加紧工件并且能顺利地将力传给工件；由卡盘对工件提供的辅助支撑减少切削时发生的颤振趋势，如果能小心准确地采用卡盘支撑工件的方法，则可以得到精确的结果。在两个中心之间支撑工件可以得到非常精确的结果。工件的一端已被加工，那么工件便可车削了。在车床上加工另一端，中心孔充当精确定位面和承载工件重量和抵制切削力的支撑面。当工件由于任何一原因从车床上移除后，中心孔将准确地使工件回到这个车床上或另一个车床上或一个圆柱磨床上。工件不允许被卡盘和车床中心夹在主轴承上。然而首先想到的是一个快速调整卡盘上工件的方法，但这是不允许的因为在由卡盘夹持的同时也由车床中心支撑是不可能的。由车床中心提供的调整将不能持续并且爪盘的压力会损坏中心孔和车床中心，甚至是车床主轴。浮动的爪盘为上述陈述提供了一个例外，它几乎完全使用在高生产工作上，这些卡盘是真正的工作驱动者并且不为同样的目的如普通的三爪，四爪卡盘使用。作为产生形状的一种方法，机械加工是所有制造过程中最普遍使用的而且是最重要的方法。机械加工过程是一个产生形状的过程，在这过程中，驱动装置使工件上的一些材料以切屑的形式被去除。尽管在某些场合，工件无支承情况下，使用移动式装备来实现加工，但大多数的机械加工是通过既支承工件又支承刀具的装备来完成。小批量，低成本。机械加工在制造业上有两个应用。是铸造，锻造和压力工作，产生每一个特殊形状，甚至一个零件，几乎总有较高的模具成本。焊接的形状很大程度上取决于原材料。通过利用总成本高但没有特殊模具的设备，加工是有可能的；从几乎任何形式的原材料开始，只要外部尺寸足够大，由任意材料设计形状。因此加工是首选的方法，当生产一个或几个零件甚至在大批量生产时，零件的设计在逻辑上导致铸造，锻造或冲压制品。高精度，表面精度。机械加工的第二个应用是基于可能的高精度和表面精度的。如果在其他工序中大批量生产，很多低量零件会产生出低的但可接受的公差。另一方面，许多零件由一些大变形过程产生一般的形状，并且只在具有很高精度的选定面加工。举例来说，内线流程是很少产生任何方式以外的其他机械加工并且紧接着压力操作后零件上的小洞可能被加工。在切削时基本工具工作的关系充分描述的方法有4个因素：刀具几何形状，切削速度和切削深度。刀具必须由适当的材料做成；它必须有一定的强度，粗糙度，硬度和抗疲劳度。刀具几何形状由面和角度描述，对每一种切削操作都是正确的。切削速度是指切削刃通过工作面的速度，它已每分钟通过的英尺数表示。对于加工效率，切削速度相对于特殊工作组合必须具有适当规模。一般来讲，工件越硬，速度越小。进给是刀具进入工件的速率。当工件或刀具旋转时，进给量的单位是英寸每转。当刀具或工件往复移动时，进给量的单位是英寸没次，总的来说，在其他相似情况下进给量与切削速度成反比。切削速度用英寸表示，是刀具进入工件的距离表示的，它是指车削时屑片的宽度或是直线切削时屑片的厚度。粗加工时切削深度比精加工的切削深度大。在金属切削作业中热量产生于主要和第二变形区而这些结果导致了复杂温度遍布于刀具，工件和屑片。一个典型的等温先如图所示，它可以看出正如预测的，当工件材料经历主要变形，被减切时，有一个非常大温度梯度遍布于屑片的整个宽度。当第二变形区的屑片还有一小段距离就达到了最大温度。因为几乎所有的工作都以金属切削转化为热量而完成，可以预测去除每一单位体积的金属所增加的能量消耗将会提高切削温度。因此在所有其他参数不变，前角变大时，将减少去除每单位体积金属的能量和切削温度。当考虑到增加未形成屑片的厚度和速度

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