机械工程英语-第二部分翻译(共70页).doc

精选优质文档-倾情为你奉上 Unit 3数控编程Unit 3 Programming for Numerical Control A program for numerical control consists of a sequence of directions that causes an NC machine to carry out a certain operation, machining being the most commonly used process. Programming for NC may be done by an internal programming department, on the shop floor, or purchased from an outside source. Also, programming may be done manually or with computer assistance.数控编程由一系列方向构成，这些方向导致数控车床执行某种操作，加工是最常用的进程。数控车床编程由内部编程部门来完成，在车间里，或者从外部源购买。编程还可以手动或者在计算机辅助下来完成。The program contains instructions and commands. Geometric instructions pertain to relative movements between the tool and the workpiece. Processing instructions pertain to spindle speeds, feeds, tools, and so on. Travel instructions pertain to the type of interpolation and slow or rapid movements of the tool or worktable. Switching commands pertain to on/off position for coolant supplies, spindle rotation, direction of spindle rotation, tool changes, workpiece feeding, clamping, and so on.程序包括指令和命令。几何指令涉及刀具和工件间的相对移动。进程指令涉及主轴速度，进给以及道具等。行动指令涉及插值的类型以及刀具或者工作台的缓慢和快速移动。切换命令涉及到开/关冷却液供给状况，主轴旋转，主轴方向，换刀，工件进给，夹具固定等等。(1) Manual programming. Manual part programming consists first of calculating the dimensional relationships of the tool, workpiece, and worktable, based on the engineering drawings of the part, and manufacturing operations to be performed and their sequence. A program sheet is then prepared, which consists of the necessary information to carry out the particular operation, such as cutting tools, spindle speeds, feeds, depth of cut, cutting fluids, power, and tool or workpiece relative positions and movements. Based on this information, the part program is prepared. Usually a paper tape is first prepared for trying out and debugging the program. Depending on how often it is to be used, the tape may be made of more durable mylar.（1）手工编程。手工编程包括根据部分工程图纸首先算出刀具，工件以及工作台的尺寸关系，继而决定执行的操作和工序。那么一个包括执行特定操作所需必要信息的程序表就准备好了，例如刀具切削，主轴转速，进给，切削深度，切削液，以及刀具或者工件间的相对位置或者移动。根据这些信息，部分程序就准备好了。通常一个纸带首先被准备好用于试用和调试程序。根据纸带被使用多久，纸袋通常用更耐用的聚酯薄膜制成。Manual programming can be done by someone who is knowledgeable about the particular manufacturing process and is able to understand, read, and change part programs. Because they are familiar with machine tools and process capabilities, skilled machinists can do manual programming with some training in programming. However, the work involved is tedious, time-consuming, and uneconomical consequently, manual programming is used mostly in simple point-to-point applications.手工编程可以由那些具有特定制造工艺知识和能够理解，阅读以及更改部分程序的人来完成。因为他们熟悉机床刀具和工艺流程，熟练的机械师可以做一些手工编程的编程培训。然而，所涉及的工作是乏味的，费时的，因此不合算。手工编程大多数用于简单的点对点应用上。 (2) Computer-aided programming. Computer-aided part programming involves special symbolic programming languages that determine the coordinate points of corners, edges, and surfaces of the part. Programming language is the means of communicating with the computer and involves the use of symbolic Characters. The programmer describes the component to be processed in this language, and the computer converts it to commands for the NC machine. Several languages having various features and applications are commercially available. The first language that used English-like statements was developed in the late 1950s and is called APT (for Automatically Programmed Tools). This language, in its various expanded forms, is still the most widely used for both point-to-point and continuous-path programming.（2）计算机辅助编程。计算机辅助编程是一种涉及到特殊符号的编程语言，这种语言可以决定角点的坐标，刀口以及工件的表面。编程语言是与计算机通信的方式并且涉及到符号字符。编程员用这种语言描述加工零件，而由计算机将零件程序转换为数控机床的执行指令。许多种商业应用上的语言有多种多样的特点和应用。第一种被使用的是类似于英语语句的语言，它在十九世纪五十年代末被开发出来并被称为APT语言。这种语言，由于它多种多样的扩展形式，一直是最广泛的用于点对点和连续路径编程的语言。 Complex parts are now machined using graphics-based, computer-aided machining programs. A tool path is created in a largely graphic environment that is similar to a CAD program. The machine code (G-Code) is created automatically by the program. 复杂的工件现在使用基本的绘图进行制造，计算机辅助制造程序。刀具的路径是在类似于一个CAD程序的大量的绘图环境下制造出来的。这种机器代码由程序自动生成。 Before production begins, the programs should be verified, either by viewing a simulation of the process on a monitor or by making the part from an inexpensive material (such as aluminum, wood, wax, or plastic), rather than from the actual material specified for the finished part. 在生产开始之前，程序应该被校验，还有就是通过一个显示器观看工艺流程的模仿或者使用廉价的材料（例如铝，木头，石蜡，或者是塑料）制作工件，而不是使用指定用于已加工零件的真实材料。Computer-aided part programming has the following significant advantages over manual methods: 计算机辅助编程有以下几个优于人工方式的重要优点。 Relatively easy use of symbolic language. Reduced programming time. Programming is capable of accommodating a large amount of data concerning machine characteristics and process variables, such as power, speeds, feed, tool shape, compensation for tool shape changes, tool wear, deflections, and coolant use. Reduced possibility of human error which can occur in manual programming. Capability of simple changeover of machining sequence or from machine to machine. Lower cost because less time is required for programming. 比较容易使用的符号语言 缩短了编程时间。编程是一种容纳了大量关于机械特点和工艺变量数据的一种能力，例如动力，速度，进给，刀具形状，刀具形状改变的补给量，刀具磨损，偏转，以及冷却液的使用。 减少了在人工编程中出现人为错误的可能性。 因为编程时所需更少的时间，降低了成本。The use of programming languages not only results in higher part quality but also allows for more rapid development of machining instructions. In addition, simulations can be run on remote computer terminals, to ensure that the program functions as intended. This method prevents unnecessary occupation of expensive machinery for debugging procedures. 编程语言的使用不仅导致更高的工件质量而且考虑到了机械指令的更加快速发展。另外，模拟可以在远程计算机的终端设备上运行，这就确保了程序按照既定来运行。这种方法可以防止昂贵的机器由于调试程序产生不必要的占用。Selection of a particular NC programming language mainly depends on the following factors:选择某一种数控机床编程语言主要取决于以下几个因素： Level expertise of the personnel in the manufacturing facility Complexity of the part Type of equipment and computers available Time and costs involved in programming 生产设施人员的专业水平级别 工件的复杂程度 设备的外形以及计算机的应用 涉及编程的时间及费用Because numerical control involves the insertion of data concerning workpiece materials and processing parameters, programming must be done by operators or programmers who are knowledgeable about the relevant aspects of the manufacturing processes being used. Before production begins, programs should be verified, either by viewing a simulation of the process on a CRT screen or by making the part from an inexpensive material, such as aluminum, wood, or plastic, rather than the material specified for the finished part. （无英语）因为数控涉及有关工件材料和加工参数的数据插入，编程必须由有制造业的相关方面知识的操作工和程序员来完成。在生产开始之前，程序应该被校验，还有通过一个CRT屏幕来观察工艺流程的模拟或者用廉价的材料制造工件，例如铝，木头或者塑料，而不是使用指定用于已加工零件的真实材料。NC part programming languages数控编程语言Probably over 100NC part programming languages have been developed since the initial MIT researchwhich are generally considered important.自从1956念麻省理工学院的初步研究数控编程系统以来大概有超过100种的数控编程语言已经被开发出来了。大多数语言开发用于特殊的需求和机械并且它们没有经受住时间的考验。然而，相当多的语言在今天一直被使用。在本小节，我们回顾一下那些被普遍认为是重要的语言。APTAPT(自动编程工具)，APT语言是麻省理工学院研发的关于数控机床控制编程系统的成果。它的研发开始于1956年六月，它第一次用于生产是在1959年左右。几天它是在美国应用最广泛的语言。虽然第一次打算作为一种轮廓语言。APT现在的版本可用于定位和持续路径的编程而且可用于多达五个基准轴的持续路径编程。 AUTOSPOT (用于定位工具的自动系统)。这个程序有IBM研发，在1962年第一次被引进用于PTP编程。AUTOSPOT现在的版本也可应被用于修证轮廓。COMPACT II。这种语言是来自于制造数据系统的封装。（MDSI公司），在安阿伯，密歇根州的一家公司。数控机床控制编程的许多特点于SPLIT相似。MDSI公司将COMPACT II系统租赁给以分时为依据的用户。这种程序通过使用远程终端把程序传送给MDSI公司的计算机，有计算机转向产生数控的纸带。ADAPT（APT的改编版本）。多种编程语言直接依据于APT程序。这些语言之一便是ADAPT，它是在空军合同下由IBM公司研发的。这种语言意图提供许多APT的特点但是用于小型计算机。ADAPT不如APT一样强大，但是能够被用于定位和修改轮廓工作的程序。EXAPT(APT的扩展子集)。这种语言是由德国研发的。，开始于1964年之间，以APT语言为依据。有三个版本：EXAPT I 被设计应用于定位（钻削和直切铣）。EXAPT II被设计用于车削，还有EXAPT III被设计用于限制轮廓的操作。EXAPT最重要的一个特点是尝试自动地计算最佳进给量和进给速度。APT不仅仅是一种数控语言；它也是一种以APT声明为依据执行计算来。生成切割位置的计算机程序。There are four types of statements in the APT languages:and so on在APT语言中声明有四种类型：几何声明。这些定义好的几何元素包括了工作组。它们有时也叫做定义声明。后处理程序声明。这些声明用于特殊的机械工具和控制系统。它们用于指定进给量和进给速度而且精确了机械的其他特点。辅助声明。这些不同种类的声明常用作定义工件，刀具，以及公差等等。CNC programming of mills and lathes is like any other machine programming process ;techniques are used for mill NC programming.铣床和车床的CNC编程于其他机械编程工艺是相似的；它需要对编程语言有一个透彻的理解。这种用作铣床和车床NC的语言通常被称为G代码。这些工序通常用于铣床机械和机加工中心，提供了一些G代码使用的经典例子，因为它包括大约了NC操作中的75%。下面编程和工艺的五类用于铣床NC编程。Manual Versus Automated Programming Programming of NC machines takes two forms: manual programming and code generation with the support of CAM software. Example 3-1 is an Example of manual programming. Starting with a drawing of the milled part, the programmer creates a G-code sequence that drives the machines cutting tool over the desired path. CAM generated NC code uses a postprocessor for the target machining tool to convert the drawing of the part directly to the G-code program that will run on the machine selected. The CAM software and postprocessors fell into two categories. One type, Master CAM and Smart-CAM, is stand-alone and works with drawing files from all the major CAM vendors. The second type, developed by the CAD vendor, is integrated with the CAD program and runs as part of the integrated CAD/CAM design software.自动化编程的人工指南NC机械编程采用两种形式：人工编程以及在CAM软件支持下的代码生成。例3-1是一个人工编程的例子。它以铣削零件图为开始，编程者设计一些能够驱动切削刀具沿着预期路径运行的G代码工序。CAM生成的NC代码为了使目标机械工具能够直接转换为零件图送给G代码程序运行在已选择的机械上，从而使用一个后处理程序。CAM软件和后处理程序分成两类。类型之一，专业CAM和简洁CAM，它是独立的，并且吸收了所有主要CAM供应商的绘图文件。第二种类型，是被CAD供应商研发的，它集成了CAD程序和运行，作为集成CAD / CAM设计件的一部分PART 2 Unit 4 机加工与切削加工中心This chapter describes major developments in the design and capabilities of computer-controlled machine tools.known as machining and turning centers,these machines have flexibility and versatility that other machine tools do not have,and they have,consequently,become the first choise in machine-tool selection.这篇文章介绍了计算机控制的机械刀具设计的能力和较大的发展，就想我们知道的机加工和切削加工中心，这些机器有其他机器工具没有的柔性和多功能性，应此他们作为加工工具第一选择。机加工与切削加工中心It was noted that each machine ,regardless of how highly it is automated ,is designed to perform basically one type of operation. It has alse shown that , in manufacturing, most parts require a number of different machining operations on their various surfaces.需要注意的是每台机器他的自动化程度有多高，都要设计一种基本的加工样式就像所展示的那样，在制造过程中不同的表面是用不同的加工方法加工的，Note,for example,that the parts shown inFig.4.1 have a variety of features and that all surfaces on these parts require different types of machining operations. such as milling,facing,boring drilling,reaming,and threading,to obtain certain specified dimendional tolerances and surface finish.例如，如图4.1所示，铣、端面车削、镗、钻、铰孔、切丝来获得额定的公差要求及最终表面精度。Traditionally ,machining operations are performed by moving the workpiece from one machine tool to another until all machining is completed.this is a viable manufacturing method that can be highlyautomated;it is the principle behind transfer lines.习惯性的加工过程的执行，始于工件的移动从一把加工刀具到另一把加工刀具直至所有的加工完成，这是一种切实可行的制造方法，并具有高度的自动化。Commonly used in high-volume or mass production.Transfer lines consist of several machine tools arranged in a sequence.这就是生产流水线的原理。最常见的是应用于高容量或大批量的生产，生产流水线是由几种加工刀具按一定的次序排列组成的，The workpiece, such as an automotive engine block, moves from station to station, with a specific machining operation perform at each station.The workpiece is then transferred to the next machine for another operation,and so on.诸如自动发动机模块这样的工件从一个加工地点到另一个加工地点，并且在每一个加工中心都运用特有的加工方式进行加工，工件会被输送到下一个机器进行下一个加工。There are products and situations, however, where transfer lines are not feasible or economical, particularly when the types of products to be machined are changed rapidly.An important concept,developed in the late 1950s,is that of machining centetrs.（5）有这样一些产品或加工方法，他们的生产路线是不可行或不经济的，特别是当这些种类的产品在加工时需要迅速转换加工方法。一个重要的概念，在20 世纪50 年代末期得到发展，那就是机加工中心。A machining center is a computer-controlled machine tool capable of performing a variety of cutting operations on different surfaces and different directions on a workpiece (Fig.4.2).In general,the workpiece is stationary and the cutting tool s totate,as they do in milling and drilling operations.一个机加工中心就是运用计算机控制的刀具在工件的不同表面和不同的方向上进行切削操作的能力，通常说工件是不动的，而切削工具进行旋转，比如铣和钻操作。The development of machining center is intimately related to advances in computer control of machine tools, in general, a numerically controlled lathe has two turrets carting several cutting tools for turning ,facing, boring, and threading.（6）机加工中心的发展暗示着计算机控制的机器刀具之间关系的进步。如数字控制的车床加工中心拥有两个转台带动几把切削刀具进行车削，端面车削，镗孔和切螺纹。The workpiece in a machining center is placed on a pallet or module that can be moved and swiveled in various directions(Fig.4.3).After a particular cutting operation has been completed,the workpiece does not have to be moved to another machine (as has been done traditionally )for additional operations,such as drilling,reaming,or tapping.In other words,the tools and the machine are brought to the workpiece.（7）工件在加工中心里是被安放在托盘上或模块上，那样可以被移动并且可以进行不同方向的旋转和定位，在进行特殊的切削过程完成后，工件不需要移动到另一台机器进行钻孔，铰孔，攻丝之类的附加加工。换句话说，工件和机器是被置于工件上的。After all the cutting operations have been completed, the pallet automatically moves away with the finished workpiece,and another pallet containing another workpiece to be machined is brought into position by automatic pallet changers(Fig.4.4).All movements are computer_controlled,and pallet_changing cycle times are on the order of 10 to 30 seconds. Pallet stationgs are available weth multiple pallets serving the machining cente. The machines can also be equipped with various automatic parts,such as loading and unloading devices.（8）当所有的加工工作完成后，托盘会自动离开已加工工件，并且另一个托盘运用自动托盘变速器将工件进行定位和加工。所有的传动机构都有计算机控制，并且托盘定位器有10-30 秒的循环时间，托盘台能够使得多级托盘更好的服务于加工中心，工具同样能够被装备到不同的自动化部件中，诸如上料与下料机构。The machining center is equipped with a programmable automatic tool changer. Depending on the design,up to 200 cutting tools can be stored in a magazine,drum,or chain(tool storage).Auxiliary tool storage is available on some special machining centers for many more cutting tools. （9）加工中心装备了可变程序的自动刀具变换器，依赖于这样的设计多达200 把切削刀具能够被贮存在刀库，刀鼓，刀链（工具库），辅助工具库能够更好的为一些特殊加工中心提供更好的切削道具，The cutting tools are automatically selected with random access for the shortest route to the machine spindle.The tool _exchange arm shown in Fig.4.5 is a common design .(SEE also Fig.4.2)It swings around to pick up a particular tool (each tool has its own toolholder)and places it in the spindle.这些刀具可以自动的任意选择到达机械主轴的最短路线，刀具交换臂是一个普通的设计机构，他可以旋转来拾取特殊的工具（每一个工具有他自己的刀杆）和他在主轴上的位置。Tools are identified by coded tags, bar codes,or memory chips attached directly to the tool holders.A tool changing time is typically between 5 and 10 seconds,they may be less than one second for small tools,or up to 30 seconds for tools weighing 110 kg (250lb). The trend in tool changers is to use simpler mechanisms,resulting in faster tool changing times.（10）刀具通过直接连接在刀具夹持口上的编码标签、条形码或记忆芯片来标识。一次换刀时间在5-10 秒钟，对于小的刀具可以少于1-2 秒，对于重达110 公斤的刀具可以达到30 秒，刀具变换器的设计趋势趋向于运用简单的原理提高换刀的时间。Machining centers may be equipped with a tool-and/or part-checking station that feeds information to the computer-numerical control to compensate for any variations in tool settings or tool wear（11