*There is a need to integrate the design and manufacturing phases in order to cut short the lead time, thus winning a competitive situation in the international market.（有必要把设计和制造的阶段集成在一起可以减少订货至交货的时间，这样可以在国际化市场上具有竞争力） Benefits of Group Technology
(1)Benefits in product design.（在产品设计的优势）Concerning design of products, the principal benefit of group technology is that it enables product designers to avoid \the wheel\or duplicating engineering efforts. （关于产品的设计，成组技术最主要的好处在于可以防止重复发明和复制工程成果）In other words, it eliminates the possibility of designing a product that was previously designed because it facilitates storage and easy retrieval of engineering designs.（换句话说，由于它存储方便，并且相关的工程设计很容易被取出，所以消除了发明以前就存在的产品）When an order of a part is released, the part is first coded, and then existing designs that match that code are retrieved from the company's library of designs stored in the memory of a computer, thus saving a large amount of time in design work. （一旦要求设计某一个零件，这个零件首先被编码，然后检索存储于计算机存储器中的该公司的设计库，找出与这个编码相匹配的已有设计，这样便可节省大量的重复设计时间）If the exact part design is not included in the company's computerized files, a design close enough to the required one can be retrieved and modified in order to satisfy the requirements,（如果在公司计算机存储器中没有完全吻合的设计，那就找出与之最相似的设计，修正后可以满足要求）A further advantage of group technology is that it promotes standardization of production tools and work-holding devices.（此外，成组技术可以促进生产工具和工件夹持装置的标准化）
(2)Standardization of tooling and setup. （加工和装配的标准化）Since parts are grouped into families, a flexible design for a work-holding device(jig or fixture)can be made for each family in such a manner that it can accommodate every member of that family, thus reducing the cost of fixturing by reducing the number of fixtures required.（因为工件被分成
了类别，对工件夹持装置的灵活设计可以应用于每个类的所有零件，这样可以减少所需要的夹持件的数量，从而减少了夹持装置的费用）Also, it is obvious that a machine setup can bemade once for the whole family(because of the similarities between the parts of a family)instead of a machine setup for each of the individual parts.（并且，很显然一次的机器装配可以用于此类的所有零件，而不是只对单个零件适用） (3)More efficient material handling. （更高效的物料输送）When the plant layout is based on the group technology principles, i. e, dividing the plant into cells, each consisting of a group of different machine tools and wholly devoted to the production of a family of parts, material handling is more efficient because of the minimal routing paths of parts between machine tools achieved in this case. （基于成组技术原理规划工厂布局，即把工厂分为单元，每个单元由一组用于生产同一族零件的各种机床组成，这时原材料的传送是很有效的，因为这种情形下的零件在机床间的移动路径最短。）This is in contrast with the \lines in the case of the conventional departmentalization-by-process layout. That comparison is clearly illustrated in Fig.6.1,which indicates both cases.（这与传统的按工序分部门的很乱的布局形成了对比！） (4)Improving economies of batch-type production.(提高分批式生产的经济效益)Usually, batch-type production involves a wide variety of nonstandard parts, seemingly with nothing in common. （通常，分批式生产包括各种各样的不标准零件，貌似它们没有共性）Therefore, grouping parts(and processes)in families enable to achieve economies that are obtainable only in mass production.（但是，分组技术只有在大量生产时才可以取得经济效益）
(5)Easier scheduling.（更容易安排）Grouping the parts into families facilitates the task of scheduling, since this work will be done for each family instead of for each part.（将工件分族可以降低安排任务的难度） (6)Reduced work-in-process and lead time.（减少在制品和订货至交货的时间）Reduced work-in-process(WIP)and lead time result directly from reduced setup and material-handling time. （WIP源于减少了安装和原材料处理的时间）In other words, parts are not redundantly
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transferred between machining departments, since material handling is carried out efficiently within each of the individual cells. （换句话说，由于在每个单元之间高效的物料输送，零件在加工部门传送地一点都不冗余）This is in contrast to the production in a typical plant with a process-type layout, where a piece that requires only a few minutes of machining may spend days on the shop floor. （这与本来一个工件可以几分钟加工完的却用了几天的基于过程布局的车间的生产形成了对比，）This latter situation involves increased WIP, which adversely affects the inventory turuover and the cash-flow cycle. （后一种情形下需要较多的在制品，这对库存换新率及现金的周转率产生不利的影响）Also, lead time for a product manufactured in a plant designed according to group technology principles is far shorter than that of a product manufactured in a plant with a process-type layout.（而且，基于成组技术的车间产品的订货至交货的时间比基于过程的车间快得多）
(7)Faster and more rational process planning. （更快更理智的过程设计）Group technology paves the way for automated process planning. （成组技术为自动过程设计做好了准备）This can be achieved through proper parts classification and coding system, where a detailed process plan for each part is stored under its code and thus can be easily retrieved.（这可以通过合理的零件分类和编码系统来实现，详细的加工计划储存在编码里面并且很容易被取出） 以下无。。。。。。。
Unit7 CAD/CAM /CAPP
CAD/CAM is a term which means computer-aided design and compuer-aided manufacturing. It is
CAD/CAM这个词条的意思是计算机辅助设计和计算机辅助制造。它是在设计和制造中运用
the technology concerned which the use of digital computers to perform certain functions in
数字化计算机执行某些职能的技术。这项技术正在向设计制造更高的一体化发展。
design and production. This technology is moving in the direction of
greater integration of design
这两个在生产企业中被看作是截然不同的，相互分离的。最终，cad/cam将会提供给未来的计算机集成化工厂技术基础。
and manufacturing, two activities which have traditionally been treated as distinct and separate functions in a production firm. Ultimately, CAD/CAM will provide the technology base for the computer-intgrated factory of the future.
Computer-aided design(CAD) can be defined as the use of computer systems to assist in the
计算机辅助设计可以定义为使用计算机系统来协助一个设计方案的形成，修改，分析及优化
creation, modification, analysis, or optimization of a design. The computer systems consist of the
计算机系统由硬件和软件组成来进行公司特定用户需要的专门设计功能。
hardware and software to perform the specialized design functions required by the particular user firm.The CAD hardware typically includes the computer, one or more graphics display terminals,
cad硬件通常包括计算机，一个或多个图形显示终端，键盘，和一些其他的外围设备。
keybosrds, and other peripheral equipment.The CAD software consists of the computer programs
cad软件是由计算机指令组成，他在系统中加上一些应用程序实施计算机绘图从而给用户电脑的工程功能提供便利。
to implement computer graphics on the system plus application programs to facilitate the engineering functions of the user computer. Example of these application programs include
例如，这些应用程序包括应力应变分析组件，动态反应机制，热传递计算，和数控编程的一部分。该应用程序的内容将会随着企业用户的不同而变化，这是因为他们的生产线，生产工艺和消费者市场不同。这些因素导致对cad系统要求的不同。
stress-strain analysis of components, dynamic response of mechanisms,
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heat-transfer calculations,and numerical control part programming. The collection of application programs will vary from one user firm to the next because their product lines, manufacturing processes, and customer markets are different. These factors give rise to differences in CAD system requirements.
Compuer-aided manufacturing (CAM) can be defined as the utilization of computer systems to
计算机辅助制造（CAM）可以被定义为利用计算机系统进行规划，管理和控制一个制造工厂通过计算机将接口直接或间接的计算机将接口和工厂生产资源，正如所指出的定义，计算机辅助制造的应用被归结为两大类；
plan, manage, and control the operations of a manufacturing plant through either direct or indirect computer interface with the plant’s production resources. As indicated by the definition, the applications of computer-aided manufacturing fall into two broad categories:
(1) Computer monitoring and control. These are the direct applications in which the computer is connected directly to the manufacturing process for the purpose of monitoring or controlling the process.电脑监测和控制（这两段基本上不会考）
(2) Manufacturing support applications. These are the indirect applications in which the computer is used in support of the production operations in the plant, but there is no direct interface between the computer and the manufacturing process制造业应用支持. Increasing Drafting Productivity
CAD/CAM systems can entail a whole new set of drafting philosophies, all of which enhance productivity. Cad、cam可以推导出一整组全新的绘图原理，他们都能够提高生产率。
For instance, most systems now on the market have a number of built-in functions that make new and useful drafting techniques automatically. Layering, for example, enables drafters to create drawing in logical segments that can be stored separately for easy identification; but the segments can still be output together , in one single piece , which
illustrates the entire drawing at once. The method is analogous to the anatomical drawing we are used to seeing in biology texts. The skeleton ,nerves ,internal organs ,blood vessels,an musles are all
例如，现在市场上大部分系统都有一些能自动生成新的有用的绘图技术的内置功能。例如，分层法能够使起草者在可以被分开储存易于识别的逻辑段内作图，但这些段仍然可以一起输出，在一个单独的片内就可以立刻显示整个绘图。这种方法类似于我们经常在生物练习上看到的解剖图，
骨骼，神经，内部器官，血管和肌肉
represented on individual overlays of clear plastic . They can be viewed individually , or ,by laying them on top of one another, all together , to show how the pieces fit in relation to one another . Layering with a graphics system uses the same principle except the overlays are logical rather than physical . The uses for this are myriad . Layer can be used to separate English and metric dimensioning information , inventory data , textual information , electrical requirement , plumbing ,machine tool paths, and a host of other things . The result is cleaner , less cluttered drawings .
分别由具有不同颜色的塑料所替代。他们被看做个体，或者把他们叠加在一起，来显示各个部件之间是如何相匹配的。通过图象系统来分层设色，采用相同的原则，除非覆盖物是逻辑的而不是非物理的 。诸如此类的应用有很多。分层也可用于区分英文和数字维度信息，数据信息。文本信息，电子需要锯锤测探、机械部件路径等。结果是清晰、明了的图样
Another example of a productivity enhancement for drafting involve automating auxiliary views of
a design . By pressing the right button or by entering the right command , a drawing could be turned 90 degrees in one direction or anther . Three-dimensional designs could be rotated on any axis or displayed in any of several projections.
在绘图方面提高生产效率的另一个例子是自动生成设计图的辅助试图，通过按适当的键或输入正确的指令，设计图可以朝一个方
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向或另一个方向旋转90度，三维设计图可以绕任意坐标轴旋转，或显示其任意一个投影图。
The potential is really endless. Productivity increases are limited only when system management
这个潜力死无穷无尽的。只有当系统的管理理念是有限的才会限制生产率的增长。举另一个例子，想想一个专门从事设计仓库的建筑公司的起草中心，设计工作较多的是重复的，可以从一个工作转到另一个。在这种情况下，每张图的标准部件可由生成宏指令自动生成，这些宏指令只不过是一组串起来的绘图系统的指令，他们可以作为独立的单元来使用。例如，一个标准的平面图和标准的楼梯，或者一个标准的门和门框。这个系统可以在几秒钟之内做这个工作，起草者就不用再每次需要插图一个图的时候重新做那个部分的设计了。
philosophies are limited. As an additional example, consider a drafting center for an architectural firm that specializes in designing warehouse. In such a situation, standard components of each drawing can be automated by creating macros.These macros are nothing more than a series of graphics system commands strung together and executed as a single unit to build, for example, a standard floor plan or a standard staircase, or a standard door and door frame.The system can do the work in seconds and the drafter is relieved from recreating that part of the design each time it must be inserted into a drawing.
Other macro programs could be useful.A set of commands might be put together that change the
其他的宏程序可能是有用的。一组指令可能被组合在一起自动的把一个图纸的尺寸从英尺改成公尺或者是延展一整个图纸，把它旋转到预定的方向，或者生成一个复杂的工程图纸的材料清单。
dimensioning of a drawing automatically from English to meteric units---or that automatically scale an entire drawing and rotate it to a deired orientation---or that generate a bill of materials list for complicated engineering drawings.
To take it one step further, remember that enotire designs can be stored
on the system.When the drafter receives a job that has specifications similar to a stored drawing, he merely retrives it, brings it into working storage, and edits those portions of the design that are not consistent with the specifications of the new job. Productivity increases are thus compounded. The original job is speeded up, and that job, in turn, is used to speed up the next job even further. This illustrates the need to maintain a complete and up-to-date data base that can be accessed easily by all users.
进一步说，整套设计方案可以保存在系统中，当起草者接到一份和他储存的设计极其类似的工作时，他只要把它检索出来，把它放到工作方案中，修改一下和这份新工作中不太相关的部分。从而加速了生产率的提高。原来的工作加快了，那个工作，反过来说又进一步加快了下一个工作，这说明有必要保持一个可以让用户轻松访问的完整的和最新的资料库。 Other analytical benefits 其它分析的好处：
Cad/cam can infiuence a company's engineering systems in many other ways as well.
CAD/CAM也可以通过其它方式影响一个公司的工程系统，它能把所有的物理过程流线化，并且允许对现代化的工程技术方法和工艺过程进行重新评估。CAD/CAM提高了确保质量的技术，自然而然的适合于保持精度完善文件材料，并且保存了零件的数量与材料清单的精确记录。
The proper installation of a fully integrated cad/cam syetem forces a company to evaluate all design and production methods and to begin appropriate standardization of those methods.
一个完全集成CAD/CAM系统的正确安装，促进了一个公司对设计及生产方法的评估，并且开创了那些方法所适合的标准。通常这个评估证明是有效的，但也能给那些没做好准备的人带来意外伤害。对这两方面的问题都考虑到的管理者是很聪明的，CAD/CAM的应用始终都是一件复杂的事。
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What are the drawbacks ? 缺点是什么呢？
The drawbacks of cad/cam may not be so obvious,but they can be devastating even to the best plans. CAD/CAM的缺点或许并不明显，但即使对于最好的设计也是?具有破坏性的。其中最大 的缺点是来自于从手工草图和保存的记录到
CAD/CAM系统径直移动所必须的跳跃。这就好像是把喷气式飞机的引擎安装在大众汽车上，汽车开始可能在很短的时间内行驶的很快，但是，如果底盘不够坚固来处理作用力，那么所有的设计将震动分离。
In other words ,cad/cam will highlight the inadequacies of the weakest areas of work.
换句话说，CAD/CAM将突出工作最脆弱的区域的不完全性，这对于人和不能保持的规则来说是残忍的，就像一个对它的描述：―如果一个公司内部对绘图材料清单和部分数字系统不能很好的使用，CAD/CAM系统将使问题恶化。‖
When such unsatisfactory results occur,the finger is often pointed at the cad/cam system-hardly a fair accusation,but it is usually more comfortable than pointing at people or organization.
当这种令人不满的结果发生时，通常会把矛头指向CAD/CAM系统---虽几乎是不能谴责的是，但通常比将矛头指向人或组织更好。任何一台计算机将只能在输入数据时工作，这是最基本的数据处理规则：废物进，废物出。如果一个公司正在使用一个不完全的目录控制系统，仅仅是因为它是自动的。这个系统将得不到改善。事实上，自动化将会使这个不完全更加明显。并且可能更混乱。因此当实施CAD/CAM系统是不仅评估技术的需要很重要，而且对于期望提高的现存的规则也是很重要的。
If management is unwilling to evaluate the existing operating conditions,standards,and procedures ,the implementation of cad/cam is very likely to fail-for a number of compounding reasons.
如果管理者不愿对现存的操作条件，标准，工艺过程进行评估，那对CAD/CAM的使用将很可能会失败----因为一系列的原因。原因之一，管理政策将因为CAD/CAM系统与标准操作过程的分离而不能被很好的组织。在低水平的管理者中将产生一种这个系统永远不会被人们有效使用的感觉。另一个原因，不同的部门之间的信息通道还没有建立起来，这也导致产生CAD/CAM系统不能被长期使用的感觉。还有一个原因，就是操作员对系统实施的方面没有输入，这就导致了绘图标准的缺点，系统管理的贫乏，系统使用者的无知，这种循环是不可原谅的。特别是对于标准操作条件的评价将直接给提高这些工艺过程提供意见，即使是CAD/CAM系统从来没被使用过。 CAD/CAM的应用
Cad/cam technology has come a long way since SKETCHPAD . CAD/CAM技术从画图板发展到如今已经经过了一个很长的历程，它已经广泛的应用在各种工业生产，涉及范围从航天飞机控制到武器研究。从绘图到动态诊断，从电路分析到结构钢分析。CAD/CAM广泛应用于绘图和制造的各个环节，从绘制影视音像设备草图到控制大量的机器人组装线，它的用途在不断的发展。
The first applications of cad/cam were mostly in electronics.
CAD/CAM首先应用于电子制作业。这是因为CAD/CAM并不是一项公认的超越计算机产业的技术。人们才觉察到CAD/CAM在航空民用工业等领域的市场需求。新的复杂的设计已经无法由借助查图手册的手工绘图所满足。CAD/CAM成了必然的解决方法。如今这项技术已经具备了强大的技术和资金基础。因此，潜在的CAD/CAM的用户能够满足最终所采用的挑剔要求，他们再也不用购买低劣的或不会使用的设备了。
The cad/cam marketplace today 当今的CAD/CAM市场：
Today there are 4 different kinds of cad/cam vendors in the marketplace.
现在，市场上有4种CAD/CAM的提供商。第一种是大型公司的附属机构或部门。IBM的CAD/CAM分部就是一个例子。这些分公司和他的总公司哟着大宗的商业买卖，他们不仅销售钥匙系统，还称作售后
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