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数控车床 电动 刀架 设计 四工位

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数控车床电动刀架设计【四工位】,数控车床,电动,刀架,设计,四工位

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扬州市职业大学毕业设计（论文）任务书题目名称： 数控车床电动刀架 学 院： 扬州市职业大学 专 业： 机电一体化 姓 名： 浦锦峰 学 号： 0401020329 指导教师： 吴红 二七 年 3 月 18 日一、 毕业设计（论文）的目的与要求：通过本次毕业设计，将微机原理、数控技术、检测技术、零件设计、机械制图等知识贯穿起来，是对学生综合设计能力的一个锻炼，另外数控行业是一个热门的行业，希望能够把握这次设计的机会，多从设计中找到自己的不足，从而能够提高自己。技术要求：1）要求设计一个四工位数控电动刀架2）重复定位精度（mm）0.0053）主轴电机功率(w) 204）电机转速（rpm）1250二、 毕业设计（论文）的内容：1）查阅相关资料，学习机床设计的相关知识，了解电动刀架的基本结构2）确定具体设计方案3）零件草图的绘制4）装配图绘制5）电气部分设计6）图纸打印7）编写毕业论文三、 毕业设计（论文）课题应完成的工作：1）装配图1张2）电气原理图1张3）零件图2张4）盘1张5）外文翻译1份6）毕业设计说明书1份四、毕业设计（论文）进程的安排：序 号设计（论文）各阶段名称日 期备 注1收集相关资料3.143.21交开题报告2学习软件3.224.17学习软件的使用3确定总体方案4.184.20明确设计内容，参数4零件草图4.215.20绘制零件图5装配图5.215.27绘制装配图6生成工程图5.286.4出图7编写毕业论文6.56.12完成论文8910五、应收集的资料及参考文献1、位置检测与数量技术李谋主编；机械工业出版社2、机床数控技术及其应用林奕鸿编著；机械工业出版社3、现代数控机床伺服及检测技术白恩远，王俊元，孙爱国主编；国防工业出版社4、数控实用技术浙江工业大学王贵名编著；机械工业出版社5、数字控制技术与数控机床杨有军主编；机械工业出版社6、电气控制技术弭洪涛，宋宏主编；吉林科学技术出版社7、机电传动控制邓星钟主编；华中科技大学出版社8、机械设计高等教育出版社9、机械零件郑志祥，文天一主编；高等教育出版社10、实用机床设计手册李洪主编；辽宁科学技术出版社六、任务执行日期自 年 月 日起，至 年 月 日止。学 生（签字） 浦锦峰 指导教师（签字） 系 主 任（签字） 扬州市职业大学毕业论文摘要数控车床今后将向中高当发展，中档采用普及型数控刀架配套，高档采用动力型刀架，兼有液压刀架、伺服刀架、立式刀架等品种，预计近年来对数控刀架需求量将大大增加。数控刀架的发展趋势是：随着数控车床的发展，数控刀架开始向快速换刀、电液组合驱动和伺服驱动方向发展。 本部分主要对四工位立式电动刀架的机械设计和应用继电-接触控制系统控制部分的设计。并对以上部分运用AUTOCAD做图，对电动刀架有更直观的了解。最后的提出了对电动刀架提出了意见和措施。关键词 ：数控刀架 ； 电动刀架 ； 四工位 AbstractNumerical control there is in the future lathe to in will develop,the middle-grade to adopt popular numerical control knife rest form a complete set, adopt the motive force type knife rest top-gradly, have such varieties as knife rest of hydraulic pressure , servo knife rest , vertical knife rest ,etc. concurrently, it is estimated that will increase to numerical control knife rest demand greatly in recent years. The development trend of the numerical control knife rest is: With the development of numerical control lathe, numerical control knife rest begin to change one hundred sheets , electric liquid is it urge and urge direction develop while being servo to make up fast. Some originally design and is it continue electricity to use to four worker location vertical electronic machinery of knife rest mainly- exposed to control system control some designs. And use AUTOCAD to pursue to the above part , have an more ocular knowledge of electronic knife rest. The last proposition has put forward the suggestion and measure to the electronic knife rest.Keyword： Numerical control knife rest ； Electronic knife rest ；Four engineering location 7目录绪 论1第1章 数控自动刀架总体介绍21.1 数控自动刀架的设计背景21.2 设计准则21.3 主要技术参数21.4 本章小结3第2章 自动刀架电气说明书42.1 电动刀架系统42.1.1 电动刀架及其工作原理42. 1. 2 电动刀架动作过程42.1.3 技术说明52.1.4 接口注意事项62.1.5 在装调中，可能出选的异常现象及原因62.1.6 PLC控制说明112.2 本章小结14第3章 电动刀架机械说明书153.1 工作原理153.2 刀架动作顺序153.3 步进电机的选用153.4 蜗轮及蜗杆的选用与校核163.4.1 选择蜗杆传动类型163. 4. 2 选择材料163.4.3 按齿面接触疲劳强度设计163.5 蜗杆与蜗轮的主要参数与几何尺寸183. 5. 1 蜗杆183. 5. 2 蜗轮183. 5. 3 校核齿根弯曲疲劳强度183.6 轴的校核与计算193.6.1 画出受力简图193. 6. 2 画出扭矩图193. 6. 3 弯矩图203.7 弯矩组合图203.8 根据最大危险截面处的扭矩确定最小轴径203.9 连轴器的选择213.9.1 类型选择213.9.2 载荷计算213.9.3 型号选择213.10 键联接的类型和尺寸213.11 蜗杆上键的选取与校核223.12 轴承的选用223. 12. 1 轴承的类型223. 12. 2 轴承的游隙及轴上零件的调配233. 12. 3 滚动轴承的配合233.12.4 滚动轴承的润滑233. 12. 5 滚动轴承的密封装置233.13 本章小结23第4章 总结24致谢26参考文献27绪 论数控刀架的发展趋势是：随着数控车床的发展，数控刀架开始向快速换刀、电液组合驱动和伺服驱动方向发展。目前国内数控刀架以电动为主，分为立式和卧式两种。立式刀架有四、六工位两种形式，主要用于简易数控车床；卧式刀架有八、十、十二等工位，可正、反方向旋转，就近选刀，用于全功能数控车床。另外卧式刀架还有液动刀架和伺服驱动刀架。电动刀架是数控车床重要的传统结构，合理地选配电动刀架，并正确实施控制，能够有效的提高劳动生产率，缩短生产准备时间，消除人为误差，提高加工精度与加工精度的一致性等等。另外，加工工艺适应性和连续稳定的工作能力也明显提高：尤其是在加工几何形状较复杂的零件时，除了控制系统能提供相应的控制指令外，很重要的一点是数控车床需配备易于控制的电动刀架，以便一次装夹所需的各种刀具，灵活 方便地完成各种几何形状的加工。数控刀架的市场分析：国产数控车床今后将向中高档发展，中档采用普及型数控刀架配套，高档采用动力型刀架，兼有液压刀架、伺服刀架、立式刀架等品种，近年来需要量可达10001500台。数控刀架的高、中、低档产品市场数控刀架作为数控机床必需的功能部件，直接影响机床的性能和可靠性，是机床的故障高发点。这就要求设计的刀架具有具有转位快，定位精度高，切向扭矩大的特点。它的原理采用蜗杆传动，上下齿盘啮合，螺杆夹紧的工作原理。第1章 数控自动刀架总体介绍1.1 数控自动刀架的设计背景电动刀架是数控车床重要的传统结构数控刀架的高、中、低档产品市场数控刀架作为数控机床必需的功能部件，直接影响机床的性能和可靠性，是机床的故障高发点。随着数控车床的发展，数控刀架开始向快速换刀、电液组合驱动和伺服驱动方向发展。目前国内数控刀架以电动为主，分为立式和卧式两种。立式刀架有四、六工位两种形式，主要用于简易数控车床；卧式刀架有八、十、十二等工位，可正、反方向旋转，就近选刀，用于全功能数控车床。另外卧式刀架还有液动刀架和伺服驱动刀架。在本次设计中我主要负责设计一只四工位立式电动刀架的机械设计和应用继电-接触控制系统控制部分的设计。1.2 设计准则我们的设计过程中，本着以下几条设计准则1） 创造性的利用所需要的物理性能和控制不需要的物理性能2） 判别功能载荷及其意义3） 预测意外载荷4） 创造有利的载荷条件5） 提高合理的应力分布和刚度而重量达到最轻6） 应用基本公式求相称尺寸和最佳尺寸7） 根据性能组合选择材料8） 在储备零件与整体零件之间精心的进行选择9） 进行功能设计以适应制造工艺和降低成本的要求1.3 主要技术参数（1）最大许用力矩（Nm）Mq 100 Mx 200 Ms 100（2）重复定位精度：（mm）0.005（3）电机功率(w) 20（4）电机转速（rpm）12501.4 本章小结初步了解了设计题目（电动刀架）及发展概况，设计背景，对刀架有了一些印象，对整理设计思路 安排设计时间有很好的辅助作用。对一些参数的进行了解同时按准则要求来完成设计。1-1第2章 自动刀架电气说明书2.1 电动刀架系统现结合图2-1来讨论电动刀架的相关问题。 图2-1电气原理图2.1.1 电动刀架及其工作原理电动刀架的机械部分类似于蜗轮机构，实现刀具的抬升、旋转（交换刀具位置）及下降锁紧，这里着重讨论实现上述动作所必须的硬件条件和电路原理。在图2-1中，继电器KA1,KA2实现电动刀架的动作切换控制，主要完成刀架电机的正、反转切换。在刀架旋转过程中，每个工位上的霍尔元件会依次切换为有效状态，系统根据T1,T2,T3及T4状态的变化，可以推断出目前的刀号，并判断是否为当前所选用刀具，一旦符合，则电机反向旋转，锁紧刀具。电动刀架各时序的切换及间隔是系统控制的关键，反向锁紧所用时间取决于电动刀架生产厂家有推荐指标，过长会引起电机发热甚至烧毁。为保证电动刀架安全运动，在电动刀架交流380V进线处加装快速熔断器和热继电器。2. 1. 2 电动刀架动作过程数控系统调刀代码开始执行时，或行动调刀时，首先输出刀架正转信号，使刀架旋转，当接收到指定的刀具的到位信号后，关闭刀架正转信号，延迟50ms时间后，刀架开始反转而进行锁紧，并开始检查锁紧信号，当接收到该信号后，关闭刀架反转信号，延迟时间，并对电机制动。换刀结束。程序转入下一程序段继续执行。如执行扬州市职业大学毕业设计（论文）开题报告题目名称： 数控车床电动刀架 学 院： 扬州市职业大学 专 业： 机电一体化 姓 名： 浦锦峰 学 号： 0401020329 指导教师： 吴红 二七 年 3 月 18 日一、 毕业设计（论文）的目的与要求：通过本次毕业设计，将微机原理、数控技术、检测技术、零件设计、机械制图等知识贯穿起来，是对学生综合设计能力的一个锻炼，另外数控行业是一个热门的行业，希望能够把握这次设计的机会，多从设计中找到自己的不足，从而能够提高自己。技术要求：1）要求设计一个四工位数控电动刀架2）重复定位精度（mm）0.0053）主轴电机功率(w) 204）电机转速（rpm）1250二、 毕业设计（论文）的内容：1）查阅相关资料，学习机床设计的相关知识，了解电动刀架的基本结构2）确定具体设计方案3）零件草图的绘制4）装配图绘制5）电气部分设计6）图纸打印7）编写毕业论文三、 毕业设计（论文）课题应完成的工作：1）装配图1张2）电气原理图1张3）零件图2张4）盘1张5）外文翻译1份6）毕业设计说明书1份四、毕业设计（论文）进程的安排：序 号设计（论文）各阶段名称日 期备 注1收集相关资料3.143.21交开题报告2学习软件3.224.17学习软件的使用3确定总体方案4.184.20明确设计内容，参数4零件草图4.215.20绘制零件图5装配图5.215.27绘制装配图6生成工程图5.286.4出图7编写毕业论文6.56.12完成论文8910五、应收集的资料及参考文献1、位置检测与数量技术李谋主编；机械工业出版社2、机床数控技术及其应用林奕鸿编著；机械工业出版社3、现代数控机床伺服及检测技术白恩远，王俊元，孙爱国主编；国防工业出版社4、数控实用技术浙江工业大学王贵名编著；机械工业出版社5、数字控制技术与数控机床杨有军主编；机械工业出版社6、电气控制技术弭洪涛，宋宏主编；吉林科学技术出版社7、机电传动控制邓星钟主编；华中科技大学出版社8、机械设计高等教育出版社9、机械零件郑志祥，文天一主编；高等教育出版社10、实用机床设计手册李洪主编；辽宁科学技术出版社六、任务执行日期自 年 月 日起，至 年 月 日止。学 生（签字） 浦锦峰 指导教师（签字） 系 主 任（签字） 英文翻译【附】英文原文翻译文献：Five-axis milling machine tool kinematic chain design and analysis作者：E.L.J. Bohez文献出处：International Journal of Machine Tools & Manufacture 42 (2002) 505520翻译页数：Five-axis milling machine tool kinematic chain design and analysis1. IntroductionThe main design specifications of a machine tool can be deduced from the following principles: The kinematics should provide sufficient flexibility inorientation and position of tool and part. Orientation and positioning with the highest possiblespeed. Orientation and positioning with the highest possibleaccuracy. Fast change of tool and workpiece. Save for the environment. Highest possible material removal rate.The number of axes of a machine tool normally refers to the number of degrees of freedom or the number of independent controllable motions on the machine slides.The ISO axes nomenclature recommends the use of a right-handed coordinate system, with the tool axis corresponding to the Z-axis. A three-axis milling machine has three linear slides X, Y and Z which can be positioned everywhere within the travel limit of each slide. The tool axis direction stays fixed during machining. This limits the flexibility of the tool orientation relative to the workpiece and results in a number of different set ups. To increase the flexibility in possible tool workpiece orientations, without need of re-setup, more degrees of freedom must be added. For a conventional three linear axes machine this can be achieved by providing rotational slides. Fig. 1 gives an example of a five-axis milling machine.2. Kinematic chain diagram To analyze the machine it is very useful to make a kinematic diagram of the machine. From this kinematic (chain) diagram two groups of axes can immediately be distinguished: the workpiece carrying axes and the tool carrying axes. Fig. 2 gives the kinematic diagram of the five-axis machine in Fig. 1. As can be seen the workpiece is carried by four axes and the tool only by one axis.The five-axis machine is similar to two cooperating robots, one robot carrying the workpiece and one robot carrying the tool.Five degrees of freedom are the minimum required to obtain maximum flexibility in tool workpiece orientation,this means that the tool and workpiece can be oriented relative to each other under any angle. The minimum required number of axes can also be understood from a rigid body kinematics point of view. To orient two rigid bodies in space relative to each other 6 degrees of freedom are needed for each body (tool and workpiece) or 12 degrees. However any common translation and rotation which does not change the relative orientation is permitted reducing the number of degrees by 6. The distance between the bodies is prescribed by the toolpath and allows elimination of an additional degree of freedom, resulting in a minimum requirement of 5 degrees.3.Literature review One of the earliest (1970) and still very useful introductions to five-axis milling was given by Baughman 1 clearly stating the applications. The APT language was then the only tool to program five-axis contouring applications. The problems in postprocessing were also clearly stated by Sim 2 in those earlier days of numerical control and most issues are still valid. Boyd in Ref. 3 was also one of the early introductions. Beziers book 4 is also still a very useful introduction. Held 5 gives a very brief but enlightening definition of multi-axis machining in his book on pocket milling. A recent paper applicable to the problem of five-axis machine workspace computation is the multiple sweeping using the Denawit-Hartenberg representation method developed by Abdel-Malek and Othman 6. Many types and design concepts of machine tools which can be applied to five-axis machines are discussed in Ref. 7 but not specifically for the five-axis machine. he number of setups and the optimal orientation of the part on the machine table is discussed in Ref. 8. A review about the state of the art and new requirements for tool path generation is given by B.K. Choi et al. 9. Graphic simulation of the interaction of the tool and workpiece is also a very active area of research and a good introduction can be found in Ref. 10.4. Classification of five-axis machines kinematic structure Starting from Rotary (R) and Translatory (T) axes four main groups can be distinguished: (i) three T axes and two R axes; (ii) two T axes and three R axes; (iii) one T axis and four R axes and (iv) five R axes. Nearly all existing five-axis machine tools are in group (i). Also a number of welding robots, filament winding machines and laser machining centers fall in this group. Only limited instances of five-axis machine tools in group (ii) exist for the machining of ship propellers. Groups (iii) and (iv) are used in the design of robots usually with more degrees of freedom added. The five axes can be distributed between the workpiece or tool in several combinations. A first classification can be made based on the number of workpiece and tool carrying axes and the sequence of each axis in the kinematic chain. Another classification can be based on where the rotary axes are located, on the workpiece side or tool side. The five degrees of freedom in a Cartesian coordinates based machine are: three translatory movements X,Y,Z (in general represented as TTT) and two rotational movements AB, AC or BC (in general represented as RR).Combinations of three rotary axes (RRR) and two linear axes (TT) are rare. If an axis is bearing the workpiece it is the habit of noting it with an additional accent. The five-axis machine in Fig. 1 can be characterized by XYABZ. The XYAB axes carry the workpiece and the Z-axis carries the tool. Fig. 3 shows a machine of the type XYZAB, the three linear axescarry the tool and the two rotary axes carry the workpiece.5. Workspace of a five-axis machine Before defining the workspace of the five-axis machine tool, it is appropriate to define the workspace of the tool and the workspace of the workpiece. The workspace of the tool is the space obtained by sweeping the tool reference point (e.g. tool tip) along the path of the tool carrying axes. The workspace of the workpiece carrying axes is defined in the same way (the center of the machine table can be chosen as reference point).These workspaces can be determined by computing the swept volume 6.Based on the above-definitions some quantitative parameters can be defined which are useful for comparison, selection and design of different types of machines.6.Selection criteria of a five-axis machine It is not the objective to make a complete study on how to select or design a five-axis machine for a certain application. Only the main criteria which can be used to justify the selection of a five-axis machine are discussed.6.1. Applications of five-axis machine toolsThe applications can be classified in positioning and contouring. Figs. 12 and 13 explain the difference between five-axis positioning and five-axis contouring.6.1.1. Five-axis positioningFig. 12 shows a part with a lot of holes and flat planes under different angles, to make this part with a three axis milling machine it is not possible to process the part in one set up. If a five-axis machine is used the tool can process. More details on countouring can be found in Ref. 13. Applications of five-axis contouring are: (i) production of blades, such as compressor and turbine blades; (ii) injectors of fuel pumps; (iii) profiles of tires; (iv) medical prosthesis such as artificial heart valves; (v) molds made of complex surfaces.6.1.2. Five-axis contouringFig. 13 shows an example of five-axis contouring, tomachine the complex shape of the surface we need to control the orientation of the tool relative to the part during cutting. The tool workpiece orientation changes in each step. The CNC controller needs to control all the five-axes simultaneously during the material removal process. More details on countouring can be found in Ref. 13. Applications of five-axis contouring are: (i) production of blades, such as compressor and turbine blades; (ii) injectors of fuel pumps; (iii) profiles of tires; (iv) medical prosthesis such as artificial heart valves; (v)molds made of complex surfaces.6.2. Axes configuration selectionThe size and weight of the part is very important as a first criterion to design or select a configuration. Very heavy workpieces require short workpiece kinematic chains. Also there is a preference for horizontal machine tables which makes it more convenient to fix and handle the workpiece. Putting a heavy workpiece on a single rotary axis kinematic chain will increase the orientation flexibility very much. It can be observed from Fig. 4that providing a single horizontal rotary axis to carry the workpiece will make the machine more flexible. In most cases the tool carrying kinematic chains will be kept as short as possible because the toolspindle drive must also be carried.6.3.five-axes machining of jewelryA typical workpiece could be a flower shaped part as in Fig. 14. This application is clearly contouring. The part will be relatively small compared to the tool assembly. Also small diameter tools will require a high speed spindle. A horizontal rotary table would be a very good option as the operator will have a good view of the part (with range 360). All axes as workpiece carrying axes would be a good choice because the toolspindlecould be fixed and made very rigid. There are 20 ways in which the axes can be combined in the workpiece kinematic chain (Section 4.2.1). Here only two kinematic chains will be considered. Case one will be a TTTRR kinematic chain shown in Fig. 15. Case two will be a RRTTT kinematic chain shown in Fig. 16.For model I a machine with a range of X=300mmY=250 mm, Z=200 mm, C=n 360 and A=360, and a machine tool table of 100 mm diameter will be considered. For this kinematic chain the tool workspace is a single point. The set of tool reference points which can be selected is also small. With the above machine travel ranges the workpiece workspace will be the space swept by the center of the machine table. If the centerline of the two rotary axes intersect in the reference point, a prismatic workpiece workspace will be obtained with as size XYZ or 300250200 mm3. If the centerlines of the two rotary axes do not intersect in the workpiece reference point then the workpiece workspace will be larger.It will be a prismatic shape with rounded edges. The radius of this rounded edge is the excentricity of the bworkpiece reference point relative to each centerline. Model II in Fig. 15 has the rotary axes at the beginning of the kinematic chain (RRTTT). Here also two different values of the rotary axes excentricity will be considered. The same range of the axes as in model I is considered. The parameters defined in Section 5 are computed for each model and excentricity and summarized in Table 1. It can be seen that with the rotary axes at the end of the kinematic chain (model I), a much smaller machine tool workspace is obtained. There are two main reasons for this. The swept volume of the tool and workpiece WSTOOLWSWORK is much smaller for model I. The second reason is due to the fact that a large part of the machine tool workspace cannot be used in the case of model I, because of interference with the linear axes. The workspace utilization factor however is larger for the model I with no excentricity because the union of the tool workspace and workpiece workspace is relatively smaller compared with model I with excentricity e=50 mm. The orientation space index is the same for both cases if the table diameter is kept the same. Model II can handle much larger workpieces for the same range of linear axes as in model I. The rotary axes are here in the beginning of the kinematic chain, resulting in a much larger machine tool workspace then for model I. Also there is much less interference of the machine tool workspace with the slides. The other 18 possible kinematicchain selections will give index values somewhat in between the above cases.6.4. rotary table selectionTwo machines with the same kinematic diagram (TTRRT) and the same range of travel in the linear axes will be compared (Fig. 17). There are two options for the rotary axes: two-axis table with vertical table (model I), two-axis table with horizontal table (model II). Tables 2 and 3 give the comparison of the important features. It can be observed that reducing the range of the rotary axes increases the machine tool workspace. So model I will be more suited for smaller workpieces with operations which require a large orientation range, typically contouring applications. Model II will be suited for larger workpieces with less variation in tool orientation or will require two setups. This extra setup requirement could be of less importance then the larger size. The horizontal table can use pallets which transform the internal setup to external setup. The larger angle range in the B-axes 105 to +105, Fig. 17. Model I and model II TTRRT machines. compared to 45 to +20, makes model I more suited for complex sculptured surfaces, also because the much higher angular speed range of the vertical angular table. The option with the highest spindle speed should be selected and it will permit the use of smaller cutter diameters resulting in less undercut and smaller cutting forces. The high spindle speed will make the cutting of copper electrodes for die sinking EDM machines easier. The vertical table is also better for the chip removal. The large range of angular orientation, however, reduces the maximum size of the workpiece to about 300 mm and 100 kg. Model II with the same linear axes range as model I, but much smaller range in the rotation, can easily handle a workpiece of double size and weight. Model II will be good for positioning applications. Model I cannot be provided with automatic workpiece exchange, making it less suitable for mass production. Model II has automatic workpiece exchange and is suitable for mass production of position applications. Model I could, however, be selected for positioning applications for parts such as hydraulic valve housings which are small and would require a large angular range.7.New machine concepts based on the Stewart platform Conventional machine tool structures are based on Carthesian coordinates. Many surface contouring applications can be machined in optimal conditions only with five-axis machines. This five-axis machine structure requires two additional rotary axes. To make accurate machines, with the required stiffness, able to carry large workpieces, very heavy and large machines are required. As can be seen from the kinematic chain diagram of the classical five-axis machine design the first axis in the chain carries all the subsequent axes. So the dynamic responce will be limited by the combined inertia. A mechanism which can move the workpiece without having to carry the other axes would be the ideal. A new design concept is the use of a HEXAPOD. Stewart 16 described the hexapod principle in 1965. It was first constructed by Gough and Whitehall 20 in 1954 and served as tire tester. Many possible uses were proposed but it was only applied to flight simulator platforms. The reason was the complexity of the control of the six actuators. Recently with the amazing increase of speed and reduction in cost of computing, the Stewart platform is used by two American Companies in the design of new machine tools. The first machine is the VARIAX machine from the company Giddings and Lewis, USA. The second machine is the HEXAPOD from the Ingersoll company, USA. The systematic design of Hexapods and other similar systems is discussed in Ref. 17. The problem of defining and determining the workspace of virtual axis machine tools is discussed in Ref. 18. It can be observed from the design of the machine that once the position of the tool carrying plane is determined uniquely by the CL date (point + vector), it is still possible to rotate the tool carrying platform around the tool axis. This results in a large number of possible length combinations of the telescopic actuators for the same CL data.8.ConclusionTheoretically there are large number of ways in which a five-axis machine can be built. Nearly all classical Cartesian five-axis machines belong to the group with three linear and two rotational axes or three rotational axes and two linear axes. This group can be subdivided in six subgroups each with 720 instances.If only the instances with three linear axes are considered there are still 360 instances in each group. The instances are differentiated based on the order of the axes in both tool and workpiece carrying kinematic chain.If only the location of the rotary axes in the tool and workpiece kinematic chain is considered for grouping five-axis machines with three linear axes and two rotational axes, three groups can be distinguished. In the first group the two rotary axes are implemented in the workpiece kinematic chain. In the second group the two rotary axes are implemented in the tool kinematic chain. In the third group there is one rotary axis in each kinematic chain. Each group still has twenty possible instances. To determine the best instance for a specific application area is a complex issue. To facilitate this some indexes for comparison have been defined such as the machine tool workspace, workspace utilization factor, orientation space index, orientation angle index and machine tool space efficiency. An algorithm to compute the machine tool workspace and the diameter of the largest spherical dome which can be machined on the machine was outlined. The use of these indexes for two examples was discussed in detail. The first example considers the design of a five-axis machine for jewelry machining. The second example illustrates the selection of the rotary axes options in the case of a machine with the same range in linear axes.翻译题名：Five-axis milling machine tool kinematic chain design and analysis期刊与作者：E.L.J. Bohez 出版社： International Journal of Machine Tools & Manufacture 42 (2002) 505520 英文译文 摘要： 现如今五轴数控加工中心已经非常普及。大部分机床的运动学分析都 基于笛卡尔直角坐标系。本文罗列了现有的概念设计与实际应用，这些从理论上都基于自由度的综合。一些有用的参数都有所规定，比如工件使用系数，机床空间效率，方向空间搜索以及方向角等。每一种概念，它的优缺点都有所分析。选择的标准及机器参数设置的标准都给出来了。据于Stewart平台的新概念最近行业内已有介绍并作简短讨论。1.绪论设计一台数控机床主要要遵循以下规则：1，刀具和工件在空间方向上要有足够的灵活性。2，方向和位置的改变要尽可能的快。3，方向和位置的改变要尽可能的准确。4，刀具和工件快速变、换。5，环保6，切削材料速度快 一台数控机床的轴的数目通常取决于其自由度数目或者独立控制运动的导轨数目。国际标准委员会推荐通过右手笛卡儿坐标系来命名坐标轴，刀具相应的为Z轴。一个三轴铣床有三条导轨，X,Y,Z向，它们可用来在长度范围内可以在任意位置移动。加工过程中刀具轴的位置始终不变。这就限制了刀具相对于工件在方向上变化的灵活性，并且导致许多偏差的出现。为了尽可能的提高刀具相对于工件的灵活性，无需重启，必须要加入多个自由度。对于传统三轴机床来说这可以通过提供旋转滑台来实现。图1给出了一个五轴铣床的例子。图1 五轴数控机床1.运动链图表 通过制作机器的运动链图表对于机器的分析来说十分有用。通过运动简图可知两组轴可以迅速的区分开：工件装夹轴和刀具轴。图2给出了图1.五轴机床的运动链简图。由图上可以看出工件由四根轴承载，刀具仅在一根轴上。这个五轴机床与两工位操作机器人很相似，一个机器人夹住工件，另一个夹住刀具。为了获得刀具工件方向上的最大自由，五个自由度已是最低要求，这就意味着工件和刀具可以在任意角度位置相对定位。最低需求的轴数也可以通过刚体运动学的方法来分析。两个刚体在空间确定相对位置，每个刚体需要6个到12个自由度。然而由于任意的移动或转动并不改变相对位置就允许将自由度减少到6.两个刚体之间的距离通过刀具轨迹来描述，并且允许去掉一个额外的自由度，结果也就是5个自由度。图2 运动链图2.参考文献 最早（1970年）到目前并且仍就有参考价值的对五轴数控铣床的介绍之一是由 Baughman提出的并清楚的阐述了它的应用（附录1有他的介绍）。APT语言随后成为唯一的五轴轮廓加工的编程语言之一。后处理阶段的问题也在数控发展的早期由Sim清楚的表述出来（附录2有对他的介绍），并且大部分问题到现在仍然有效。Boyd（详见附录3）也是最早引进数控机床的先驱之一。Beziers的书（见附录4）也是非常有用的介绍。Held（见附录5）在他的小型铣削加工的书里对多轴机床也有非常简短但启发性的定义。目前一篇适用于解决五轴数控机床工作空间计算的文章，通过使用Denawit-Hartenberg发表并由 Abdel-Malek and Othman（见附录6）改进的算法 应用于多弧段切削。许多对机床的类型和概念设计，这些可以被应用于五轴机床，Ref都有讨论（见附录8）.关于对刀具路径生成的技巧和新需求由B.K. Choi et al给出（见附录9）。工件与刀具的图像模拟也是研究的热点并且可以在Ref（见附录10）的书是一个好的入门读物。3.五轴机床运动结构的分类 从R轴（旋转轴）和T轴（移动轴）划分大致可以分为四大部分：（i）3个移动轴和2个转动轴；（ii）2个T轴和3个R轴；（iii）1个移动轴和4个转动轴以及（iv）5个转动轴；几乎所有五轴机床都是第一组。也有一些焊接机器人，弯折机器以及激光机器也属于这一类。只有限距五轴机床属于第二组，用以制造船舶螺旋桨用。第三组和第四组用于制造机器人，常常另加三个自由度。在不同的制品中，五根轴可以在工件或刀具之间分配。第一分类可以由工件和刀具所承载的轴数以及每根轴在运动链中的功能来划分。另一种分法是据于旋转轴的位置，在工件一边还是在刀具一边。五自由度基于笛卡尔坐标系的机床是：3个移动轴X,Y,Z(通常表述为TTT)和2个旋转运动AB,AC,BC（通常称作RR）。拥有3个旋转轴和2个移动轴的制品并不多见。如果一个轴装夹工件，习惯上不另加东西在这根轴上。由图1五轴机床可记为 X Y A B Z. XYAB轴装夹工件，Z轴装刀具。图3展示的是XYZAB型机床，3个移动轴装夹刀具，2个旋转轴装工件。图3 XYZA B 型机床5.五轴机床工作空间 在定义五轴机床工作空间之前，有必要说明一下刀具工作空间和工件工作空间。刀具工作空间就是通过刀具参考点沿着刀具轨迹生成轴（详见刀具帮助说明）来获得。工件空间也是同样定义的（工作台中心可以被选择为工件参考原点）。这些工作空间可以通过计算切削量来定义。 基于上述定义一些参数量可以定下来，这些参数对比较，选择以及设计不同类型机床都是十分有用的。 图11 G2/G3组中的 R R机床6.选择五轴机床的标准 完全学习好如何为专用机床选择或设计一个五轴机床是不现实的。只有主要标准，这些标准可以用来核实五轴机床的我们加以讨论。6.1 五轴机床的应用应用可以分为位置和轮廓。图12和图13展示了五轴位置机床和用于轮廓机床。6.1.1图12展示了一个多孔以及不同角度有平台的工件。要用一个三轴磨床加工这个工件，一步也无法完成。如果用五轴机床则可以加工。轮廓更多的参数等信息可以在参考文献13中去查看。五轴机床用于加工轮廓的有：（i）叶片类产品，例如空气压缩机的叶片和涡轮机的叶片；（ii）燃料泵的喷嘴；（iii）轮胎的轮廓；（iv）医学假肢，例如人工心脏瓣膜；（v）复杂表面的模具。图12 五轴加工多孔复杂方位角零件 图13 五轴加工复杂轮廓零件6.1.2五轴轮廓图13显示了一个轮