机械化英语翻译法[钟平老师2013版]

ENGLISH ON CAMPUS2023年10期总第658期增译法在机械英语翻译中的应用摘　要：随着“中国制造2025”的推进，机械制造业的发展越来越重要，而机械英语翻译的重要性同样不言而喻。

由于英汉两种语言之间的差异，译者必然面临翻译挑战。

本文通过研究机械英语汉译的具体实例，着力分析增译这一种翻译方法在机械英语翻译中的应用，力求为机械英语文本的翻译提供借鉴。

关键词：科技英语；增译；机械英语作者简介：文虹，熊叶，胡永珊，罗志良，江西工业工程职业技术学院；官小飞，汕头大学文学院。

一、引言在科技日新月异的时代 ，全球的科技信息交流也日趋频繁，因此科技英语的翻译越来越重要。

由于科技英语文本本身的特殊性“表达客观、逻辑严密、行文规范、用词正式、句式严谨”，科技英语（EST）的翻译与通用英语（GE）的翻译有所不同，须根据其特定的文本特征提供专业准确的译文。

因此，在翻译时，为了使译文更加流畅自然地道，译者应基于英汉两种语言的语言结构和表达方式之间的差异，使用适当的翻译方法。

虽然简洁是语言的一大“美德”，但是在汉语中，有时候适当增补却是非常有必要的。

译者在做英汉翻译的过程中，为实现译文表达完整、语义清晰明确、符合汉语表达习惯，往往会在译文中适当增补不影响信息的词汇或表达。

这种翻译方法就是增译法。

二、机械英语文本的特点及翻译标准（一）机械英语文本的词汇特点机械英语用词正式，主要词汇特点表现为：缩略语使用频率高，如EV（electric vehicle）—电动汽车、NC（numerical control）—数控、CAD（computer-aided design）—计算机辅助设计；专业术语多，如gear（齿轮）、cam（凸轮）， crank （曲轴）；复合词多，如pig iron（生铁）、machine tool（机床）、headstock（主轴箱）；普通名词含义术语化，如die（模具，通用英语作动词一般表示“死亡”）、finish（光洁度，通用英语作动词一般表示“完成”）、feed（进给，通用英语作动词一般表示“喂养”）。

英汉翻译教案Unit 1 翻译概述1.1 翻译的定义与分类翻译是把一种语言文字所表达的思维内容用另一种语言表达出来的双语转换过程或结果。

翻译是一种语言活动过程，又是该活动的结果。

翻译是创造性实践活动，它形成于社会、文化和语言现实之中，同时又为促进社会、文化和语言发展服务。

语言是文化的载体，翻译过程涉及两种语言、两种社会文化；是通过语言机制的转换连接或沟通自身文化和异国文化的桥梁；是具有不同语言文化背景的人互相交际、交流思想，达到相互了解的媒介。

翻译属于交叉学科，它与语言学、符号学、修辞学、心理学、人类学等有着密切联系。

它正在发展成为一个自成体系的独立学科——翻译学。

翻译又是一门艺术。

翻译美学是翻译学的不可分割的组成部分。

翻译是一种融理论、技能、艺术于一体的语言实践活动。

翻译一般分为三类：（1）按翻译手段可分为：口译（interpretation）、笔译（translation）和机器翻译（machine translation）。

（2）按源出语（sourced language）和目的语（target language）的关系，可分为：a）语际翻译（interlingual translation：指发生在不同语言之间的翻译活动，诸如英汉互译、法英互译等。

）b）语内翻译（intralingual translation：指同一语言内部进行的翻译，如方言与民族共同语，古语与现代语等。

）c）符际翻译（intersemiotic translation：指不同符号之间进行的翻译，此类翻译往往只限于通讯及保密等工作。

）（3）按翻译题材，可分为政论翻译、应用文翻译、科技翻译、文学翻译等。

不同类型的翻译有着不同的要求，学习时应注意它们的共性和个性。

1.2 翻译的过程1.3 翻译的标准Unit 2 翻译标准练习练习1： It may be safely assumed that, two thousand years ago, before Caesar set foot in southern Britain, the whole countryside visible from the windows of the room, in which I write, was in what is called ‘the state of nature’.(1)赫胥黎独处一室之中，在英伦之南，背山而面野，槛外诸境，历历如在目下。

Basic Concept in MechanicsThe branch of scientific analysis which deals with motions , time , and forces is called mechanics and is made up of two parts , statics and dynamics , Statics deals with the analysis of stationary systems , i.e. , those in which time is not a factor , and dynamics deals with systems which change with time .对运动、时间和作用力做出科学分析的分支称为力学。

它由静力学和动力学两部分组成。

静力学对静止系统进行分析，即在其中不考虑时间这个因素，动力学对随时间而变化的系统进行分析。

When a number of bodies are connected together to form a group or system , the forces of action and reaction between any two of the connecting bodies are called constraint forces . These forces constrain the bodies to behave in a specific manner . Forces external to this system of bodies are called applied forces .当一些物体连接在一起形成一个组合体或者系统时，任何两个相连接的物体之间的作用力和反作用力被称为约束力。

这些力约束着各个物体，使其处于特定的状态。

从外部施加到这个物体的系统的力被称为外力。

机械化英语翻译法-———钟平老师基础版听课笔记简介：本方法主要是运用数学的逻辑思维，将长难句进行划分层次,然后运用所总结的公式进行翻译。

如果真正掌握后可以让语法近乎白痴的人在以后不会碰到翻译不了的句子,但切记:词汇是一切的根本。

一、英语之基本规则主干先行（主、谓、宾)，废话后置（定、状）二、主干的确定构成一句话的主要条件是：主语+谓语1〉谓语：a.划出所有动词;b.排除具有下列条件的动词:从句中的、句首状语、前面无助动词的分词、to do形式（谓语+to do除外，因为它整体作谓语）、活用的动词（如动词当名词用）* 单词的活用能通过运用简单词,让写出来的句子收到意想不到的效果。

例:Chinese economy is bettering!（中国的经济越来越好）You were，are and will be in my heart。

(你永远在我心中）2> 主语：a。

句首的第一个名词性结构；b.第一个谓语前的第一个名词性结构.名词性结构：名词、代词、动名词、动词不定式、从句、It+……+从句/to do;非名词性结构：介词短语中的名词性结构、从句中的名词性结构。

3〉宾语：每个谓语后面的名词性结构。

三、复杂英文模式之计算公式：［状语]+主语+(定语)+谓语+[小状语］+宾语+｛定语或状语}例：[Although not so world widely accepted],people (who are emotionally weak in daily business) are ［often］ losers ｛who are not able to fulfil any fruitful achievements in their lifetime that they endure}。

子公式（无宾语模式)：［状语］+主语+（定语)+谓语+[小状语］＊宾语后一般都是定语，除非一开始就有表示状语的概念(如程度、方式、目的、结果、原因等)四、定状的汉化（核心）1> 前提：分别划出各定状层次，包括:a.分词结构b。

北京领航--钟平--英汉机械化翻译公式机械化英语翻译法————领航钟平老师基础版听课笔记（钟平上周末来南昌高校讲座）简介：本方法主要是运用数学的逻辑思维，将长难句进行划分层次，然后运用所总结的公式进行翻译。

如果真正掌握后可以让语法近乎白痴的人在以后不会碰到翻译不了的句子，但切记：词汇是一切的根本。

一、英语之基本规则主干先行(主、谓、宾)，废话后置(定、状)二、主干的确定构成一句话的主要条件是：主语+谓语1> 谓语：a.划出所有动词；b.排除具有下列条件的动词：从句中的、句首状语、前面无助动词的分词、to do形式（谓语+to do除外，因为它整体作谓语）、活用的动词（如动词当名词用）* 单词的活用能通过运用简单词，让写出来的句子收到意想不到的效果。

例：Chinese economy is bettering!(中国的经济越来越好）You were,are and will be in my heart.(你永远在我心中）2> 主语：a.句首的第一个名词性结构；b.第一个谓语前的第一个名词性结构。

名词性结构：名词、代词、动名词、动词不定式、从句、It+……+从句/to do;非名词性结构：介词短语中的名词性结构、从句中的名词性结构。

3> 宾语：每个谓语后面的名词性结构。

三、复杂英文模式之计算公式：[状语]+主语+(定语)+谓语+[小状语]+宾语+{定语或状语}例：[Although not so world widely accepted],people (who are emotionally weak in daily business) are [often] losers {who are not able to fulfil any fruitful achievements in their lifetime that they endure}.子公式(无宾语模式)：[状语]+主语+(定语)+谓语+[小状语]* 宾语后一般都是定语，除非一开始就有表示状语的概念（如程度、方式、目的、结果、原因等）四、定状的汉化（核心）1> 前提：分别划出各定状层次，包括：a.分词结构b.从句c.介词短语。

Although not so world widely accepted, people who are emotionally weak in daily business are often losers who are not able to fulfill any fruitful achievements in their lifetime that they endure.Science developed as an autonomous method of intellectual inquiry that successfully disengaged itself from the social constrains of organized religion and from the political constrains of the centralized modern authority.Thus, in the American economic system it is the demand of individual consumers, coupled with the desire of businessmen to maximize profits and the desire of individuals to maximize their incomes, that together determine what shall be produced and how resources are used to produce it.Such large, impersonal manipulation of capital and industry greatly increased the numbers and importance of shareholders as a class, an element in national life representing irresponsible wealth detached from the land and the duties of the landowners: and almost equally detached from the responsible management of business.Private businessmen. striving to make profits, produce these goods andservices in competition with other businessmen; and the profit motive, operating under competitive pressures, largely determines how these goods and services are produced.Under a system deployed on the white house website for the first time at last time, those who want to send a message to President Bush must now navigate as many as nine web pages and fill out a detailed form that starts by asking whether the sender of the message supports the white house policy or differs with it.These comments, whether accepted, clarified the norms and requirements of the covenant which was already in power in practice and enabled the committee to make a significant contribution to the justice promotion in a particular right or issue, while other article has failed to function as has been expected in those meetings which was held with great hope.The American economic system is organized around a basicallyprivate-enterprise, market-oriented economy in which consumers largely determine what shall be produced by spending their money in the marketplace for those goods and services that they want most.Until these issues are resolved, a technology of behavior will continue to be rejected, and with it possibly the only way to solve our problems.The method of scientific investigation is nothing but the expression of the necessary mode of working of the human mind and it is simply the mode by which all phenomena are reasoned about and given precise and exact explanation.Science moves forward，they say，not so much through the insights of great men of genius as because of more ordinary things like improved techniques and tools.In short，a leader of the new school contends，the scientific revolution，as we call it，was largely the improvement and invention and use of a series of instruments that expanded the reach of science in innumerable directions.Over the years，tools and technology themselves as a source of fundamental innovation have largely been ignored by historians and philosophers of science.Whether the Government should increase the financing of pure science at the expense of technology or vice versa（反之）often depends on the issue of which is seen as the driving force.How well the predictions will be validated by later performance depends upon the amount，reliability，and appropriateness of the information used and on the skill and wisdom with which it is interpreted.Interest in historical methods has arisen less through external challenge to the validity of history as an intellectual discipline and more from internal quarrels among historians themselves.During this transfer，traditional historical methods were augmented by additional methodologies designed to interpret the new forms of evidence in the historical study.Under modern conditions，this requires varying measures of centralized control and hence the help of specialized scientists such as economists and operational research experts.In the early industrialized countries of Europe the process of industrialization—with all the farreaching changes in social patterns that followed—was spread over nearly a century，whereas nowadays a developing nation may undergo the same process in a decade or so.The role of natural selection in evolution was formulated only a little more than a hundred years ago, and the selective role of the environment in shaping and maintaining the behavior of the individual is only beginning to be recognized and studied.Social science is that branch of intellectual enquiry which seeks to study humans and their endeavors in the same reasoned, orderly, systematic, and dispassioned manner that natural scientists use for the study of natural phenomena.The emphasis on data gathered first-hand, combined with across-cultural perspective brought to the analysis of cultures past and present, makes this study a unique and distinctly important social science. Tylor defined culture as “… that complex whole which includes belief, art, morals, law, custom, and any other capabilities and habits acquired by man as a member of society.”Being interested in the relationship of the language and thought，Whorf developed the idea that the structure of the language determines the structure of habitual thought in a societyWhorf came to believe in a sort of linguistic determinism which，in its strongest from，states that language imprisons the mind，and that the grammatical patterns in a language can produce farreaching consequences for the culture of a societyI shall define him as an individual who has elected as his primary duty and pleasure in life the activity of thinking in Socratic(苏格拉底) way about moral problems .Traditionally, legal learning has been viewed in such institutions as the special preserve of lawyers rather than a necessary part of the intellectual equipment of an educated person.In fact, it is difficult to see how journalists who do not have a clear grasp of the basic features of the Canadian Constitution can do a competent job on political stories.he believes that this very difficulty may have had the compensating advantage of forcing him to think long and intently about every sentence, and thus enabling him to detect errors in reasoning and in his own observations.It may be said that the measure of the worth of any social institution is its effect in enlarging and improving experience ; but this effect is not a part of its original motive。

机械工程专业英语English inMechanicalEngineering宋宜梅songym@桂林电子科技大学——机电工程学院2008.02翻译的基本方法–转换词性Skills of Translation–transform part of speech and way 转换词性是根据翻译的需要将英语某一词性的词译为汉语另一词性的方法的词译为汉语另一词性的方法。

在以下情况下可考虑转换词性在以下情况下可考虑转换词性：：当英语某一词性的词相当于汉语另一词性时当英语某一词性的词相当于汉语另一词性时；； 当某词按同一词性翻译不能确切表达该词的意义时; 当某词按同一词性翻译而使得汉语句子不通顺时当某词按同一词性翻译而使得汉语句子不通顺时。

1、转译为汉语动词1）名词转译成动词名词转译成动词：：英语中往往习惯于利用动名词英语中往往习惯于利用动名词、、具有动作意义的抽象名词和由动词派生的名词来表达动作概念的抽象名词和由动词派生的名词来表达动作概念，，而在翻译中往往需要将其转译成汉语动词而在翻译中往往需要将其转译成汉语动词，，以便译句符合汉语的语言习惯句符合汉语的语言习惯。

The flow of electrons is from the negative plate to the positive.One of the principal rules of thelathe maintenance is timely lubrication of all friction surfaces.Let me have a look at the machine.2）形容词转译成动词由于英汉两种语言对某些要领的表达方式不。

英语句子中的形容词有时需要转译成汉语动词。

同，英语句子中的形容词有时需要转译成汉语动词 The force is perpendicular to the surface. We are grateful to you for your help.3）副词转译成动词Engineers took the machine apart yesterday.The reaction force to this action force pushes rocket ship along.课堂小练习 I am certain be saw me.2. 转译成汉语名词 1）动词转译成名词为了符合汉语习惯为了符合汉语习惯，，英语句子中某些动词不宜照译为汉语动词译为汉语动词，，而应该转译在汉语名词而应该转译在汉语名词。

Spur GearsGears , defined as toothed members transmitting rotary motion from one shaft to another , are among the oldest devices and inventions of man . In about 2600 B.C. , the Chinese are known to have used a chariot incorporating a complex series of gears . Aristotle , in the fourth century B.C. , wrote of gears as if they were commonplace . In the fifteenth century A.D. , Leonardo da Vinci designed a multitude of devices incorporating many kinds of gears .齿轮，在最古老的设备和发明人中，被定义为通过轮齿将旋转运动从一根轴传递到另一根轴，大约在公元前2600年，中国人就知道用战车组成一系列复杂的齿轮系。

西元前四世纪，亚里士多德记述了齿轮就好像是他们司空见惯的一样。

在十五世纪，达芬奇设计了大量的包含各种各样齿轮的设备。

Among the various means of mechanical power transmission (including primarily gears , belts , and chains ) , gears are generally the most rugged and durable . Their power transmission efficiency is as high as 98 percent . On the other hand , gears are usually more costly than chains and belts . As would be expected , gear manufacturing costs increase sharply with increased precision -- as required for the combination of high speeds and heavy loads , and for low noise levels . ( Standard tolerances for various degrees of manufacturing precision have been established by the AGMA , American Gear Manufacturers Association. )在众多的机械传动方式中（包括齿轮传动，带传动，链传动），一般来说，齿轮是最经久耐用的，它的能量传递效率高达98%。

Application and evaluation of VR-based CAPP systemQ.Peng *,F.R.Hall,P.M.ListerSchool of Engineering and the Built Environment,University of Wolverhampton,Wolverhampton WV11SB,UKAbstractThis paper proposes an approach to an integrated CAPP/VR system.A desktop VR environment is used to explore the machining process element of CAPP.An architecture of a virtual CAPP system is proposed based on an incorporated VR design interface,which can respond to the dynamic manufacturing process.The key problems under discussion are to ®nd an effective method to quickly capture the 3D information from the manufacturing environment,and to de®ne a uniform and well-organised structure of the program layout for achieving improved sharing of VR resources.Examples of the simulation for cutting process are supplied to demonstrate and verify the proposed CAPP/VR integration system.#2000Published by Elsevier Science B.V .Keywords:CAPP;Virtual reality;CAD/CAM;Engineering simulation1.IntroductionManufacturing competition has acted as a driving force for the application of new technologies in industries.Suc-cessful industrial companies must be able to adapt quickly to fast-changing conditions by the market and competitors within a shorter lead time at a low cost.Although great emphasis has been placed on concurrent engineering,it is still a challenge for engineers to bridge the gap created by the con¯ict between design demands and manufacturing requirements.As a bridge between computer-aided design (CAD)and computer-aided manufacturing (CAM),compu-ter-aided process planning (CAPP)plays an important role in an integrated CAD/CAM system.The aim of process planning is to de®ne in detail the process required for producing a product according to its speci®cations and available manufacturing resources.This can be a very complex process.The selection of a machine tool,cutter,or a material removal process is based on a wide variety of factors,therefore CAPP relies on a good interface between the engineer and the computer system being used.So far,research projects have led to the experimental systems that are strictly limited in their applications.These limitations can be summarised as follows:Failure to process dynamically .Since the manufacturing process is a dynamic system,classical programs are notable to satisfy the demands of current manufacture.Some-times,the new knowledge is required to ensure correct manufacturing,and often time does not allow for this knowledge base to be added to the CAPP system.Separate design and manufacturing process .A process planner receives a design and may complete the process plan separately and remotely from the design engineer.The plan is then sent to the shop floor for manufacturing.Direct communication and interaction between the design and manufacturing process is therefore not encouraged. Poor data collection .As process planning can be highly complex and involves the expertise and intricate relations of knowledge coming from various sources,it is a difficult and time consuming task to represent and formalise the manufacturing knowledge used by a CAPP system.Arti-ficially intelligent (AI)systems,fuzzy logic and neural network technologies have been employed to overcome this difficulty in the following areas [1]:the recognition and processing of machining features; part families,machining cells and group technologies; operation selection and planning;and operation sequence planning.These applications,however,currently work with rather restricted models.They cannot be used without a well formed model.The correct execution of these systems depends on the pre-de®ned knowledge and data provided by human experts.The AI systems readily fail with non-heuristic problems.To overcome these dif®culties,a potential method to assist in the generation of process plans is to supporttheJournal of Materials Processing Technology 107(2000)153±159*Corresponding author.Tel.: 44-1902-322276.E-mail address :pengQ@cc.Umanitoba.CA (Q.Peng).0924-0136/00/$±see front matter #2000Published by Elsevier Science B.V .PII:S 0924-0136(00)00677-4process planner by giving him direct access to the infor-mation about the products,manufacturing resources,and manufacturing methods.A virtual environment is a computer simulator in which the user feels that he or she is immersed within a realistic surroundings and is able to interact with the objects and operations.The virtual environment generated by computer is more affordable and interactive than a traditional simu-lator.Therefore,virtual reality(VR)offers the opportunity to visualise,explore,manipulate,and interact with objects within a computer generated environment,and is a useful tool to enhance CAPP involved in design,development, evaluation,and validation.It is expected that the application of this new technology will bridge the some of the gaps that currently exist.The following parts of this paper evaluate the applications of VR-based CAPP systems,and propose a cost-effective integrated CAPP/VR system aiming towards meeting the current requirement for competitive manufac-turing processes.2.Applications of CAPP and VRCAPP has been a very popular research area for the recent years.Many researches have been working towards the improvement of CAPP systems because of the shortage of experienced process planners and the need for integrated CAD/CAM systems.There are two major traditional approaches to CAPP system:variant and generative methods [2].The variant CAPP system uses an information retrieval procedure based on group technology(GT).All the parts involved in this system are grouped into component families according to their similarity of design and manufacture.This method may be useful for relatively well-established com-panies,since they have relatively stable products.The generative CAPP system uses manufacturing knowledge to generate process plans.This is advantageous for new product development,but it relies on the development of AI, fuzzy logic and neural network technologies as mentioned previously.A conventional CAPP procedure is shown in Fig.1.This process is completed generally by a`serial'approach from the input of part information to the output of the process plan.This procedure cannot meet the needs of concurrent engineering,and will not serve to develop new products within shortened lead times.VR technology has shown its advantages over conven-tional simulation processes where it can aid the understand-ing of sophisticated engineering problems.AVR system can provide not only basic computerised functions,but also an ef®cient way to utilise human sense and interaction to engineering applications in a virtual environment.A number of researchers have employed VR techniques to deal with various aspects and issues in design and manu-facturing.Mine[3]developed a meta-CAD system for virtual environments to take advantage of the natural and intuitive forms of interaction available in a virtual world. Dani and Gadh[4]provided an approach to concept shape designs via a virtual reality interface,whilst Schulz et al.[5] presented their research in developing a virtual environment for car-body engineering applications by creating VRML scenes using the Internet as a communication platform for analysing engineering simulation.The use of VR to support industrial applications is rapidly increasing[6,7].BMW uses VR to explore the visualisation of new car layouts to enhance communication andtheFig.1.An example of a conventional CAPP procedure.154Q.Peng et al./Journal of Materials Processing Technology107(2000)153±159simulation of processes,while Rolls Royce Aeroengines and Associates use VR technology in their early veri®cation of maintenance procedures,training maintenance engineers in these procedures,enhanced visualisation of complex envir-onments and rapid prototyping of plant control and instru-mentation.Several commercial software toolkits,such as dVise [8],Superscape [9],and the Deneb Robotics'package [10]are available to support the creation of virtual environment.These tools provide a VR environment to support existing CAD technology,such as modelling and database construc-tion.A user can generate a synthetic virtual environment which can make the user have the feeling of immersion through a wide variety of VR hardware.Deneb Robotics has developed several VR tools to support machining and robot environments [10].These tools have been used to support this research.Fig.2shows a virtual manufacturing workshop produced by the Deneb Robotics toolkit.Navigation around the VR environment can be performed by using the com-puter mouse and keyboard.A designer can design plan,test and redesign the object and the manufacturing process using VRs specialist input devices.When the design is satisfactory,the information may then be transferred into the CNC machines to generate a real prototype.The applications of VR in process planning can be justi®ed as follows:Process simulation can employ the virtual environment as a real-time,interactive graphical visualisation or inter-face.By using VR,it is hoped that process planners will be able to respond immediately to production demands. Easier user interface.Support via user groups or networks,a very powerful and cost-effective means of process planning will be obtained by combining VR technology and Internet technology.Desktop VR is seen as a tool which can provide ¯exible visualisation and simulation,and provide not only improved design and process planning but also training of engineers and the workforce.3.A virtual CAPP systemA virtual CAPP system can be de®ned as a computer system that can generate the same information about machining process planning as we can observe in a real workshop.A virtual CAPP system has been constructed by the authors based on the Deneb Robotics VR toolkit (see Fig.3).An example of 3D machining simulation of a component is shown in Fig.4.The ®rst step to run the system is to select the machine tool and workpiece blank from the database,and load the blank into the worktable of the machine tool.An interactive process allows the user to either select machine tools from a menu with the mouse button,or to type in or to select an input from data ®les.The position of the machine and blank can be moved or rotated so that the user's viewpoint could be positioned close to the workpiece.The next step is to load the machining process in the form of NC code that is used to machine the workpiece.The machining operations can then be run.The dimensions of the part can be inspected using the system control menu duringoperations.Fig.2.A virtual manufacturing environment produced by Deneb Robotics toolkit [9].Q.Peng et al./Journal of Materials Processing Technology 107(2000)153±159155This system allows the user to create a 3D model of components from an original design,simulate the machining process based on existing NC code,and pass the code to NC machines in the real world to create the real parts.The machining process of a part can be viewed from different directions in a 3D simulation process,such that the user can easily ®nd failures or weaknesses in the process planning.It is therefore a useful tool for either training or for trial run purposes in order to detect any errors that might exist in the process planning.This virtual CAPP system,however,is still a `series'process from top to bottom,as shown in Fig.3,with a VR environment providing a 3D simulator of the existing pro-cess planning.The models of machine tools and workpieces must exist in the database or library,and it cannot support a real-time respond for process planning.A virtual CAPP system ideally would integrate various activities of the manufacturing process,resources,and the virtual environment as shown in Fig.5.It should have the following capabilities:improve the response of real-time process for the CAPP system;enhance the application interface with existing software packages;ease the interaction of user with machines and equipment on the shop floor;flexible control of the shop floor;consider easily uncertainly factors during machining process from multiple viewpoints;bridge the gap between process planning and machining process;andovercome the difficulties of automatic generation of process plan from the component geometric model.Clearly,there are some dif®culties in developing user-based application using existing VR toolkits due to the following reasons:there are obvious differences in the performance of these VR toolkits between their demonstration and the practical applicability,because of the poor capability of integration with other CAD/CAM systems;it takes a time to construct a user-based application because of a relatively inefficient interface for data input and limited modelling capabilities;and it is difficult to support a real-time process.Most existing toolkits,for example,can only simulate pre-de®ned processes,and does not allow the user to interact with the virtual environment in real-time.Issues such as the immediate feedback for the modi®cation of a machining process,and real-time decision making cannot be addressed.Understandably,therefore,research efforts have been made to improve the current CAPP/VRsystem.Fig.3.The process of a virtual CAPP system based on Deneb Robotics VRtoolkit.Fig.4.An example of 3D machining simulation of acomponent.Fig.5.The resources of a virtual CAPP system.156Q.Peng et al./Journal of Materials Processing Technology 107(2000)153±1594.Capturing of user-based environments and modelling of objectsModelling is the most time consuming task in the con-struction of a VR system,and the creation of a virtual environment from separate objects can be daunting.To develop a cost-effective method in building a virtual envi-ronment will save considerable time and allow existing objects to be captured very quickly.Most current VR systems are designed to use CAD modelling tools outside the virtual environment.Feature-based methods are used by most of the current CAD systems.Starting with a simple shape,features are added or modi®ed to re®ne the model.This approach speeds up the model creation process because existing designs can be used as the basis for new models.However,modelling from other CAD tools requires translator programs to convert data from one CAD system to another,because there is not a universal database format available.It therefore takes a signi®cant amount of time to build a new VR environment if an existing CAD database is not available.The3D laser scanner is a popular and accurate tool to recover3D data from an object.However,its capturing process is slow,because it scans the surface line by line, and the high energy light source also has to be treated with care.An alternative tactile approach to3D shape capture measures the surface of an object by the touch of a mechani-cal arm.The relative coordinate positions are determined by the sensors in the joints of the arm,which can be supported by robotic devices.This method is accurate and reliable but the slow speed is a disadvantage.Furthermore,access to all surfaces may be dif®cult.In the electro-magnetic sensor system,a transmitter is driven by a pulsed DC signal.The sensor measures the transmitted magnetic-®eld pulse referenced to the magnetic transmitter.An electronics card controls the transmitting and receiving elements and converts the received signals into3D position and orientation measurements.This method sup-ports real-time measurement with high accuracy,but its disadvantages include the touch tracking process with the wire and sensor,limited captured points from sensors,and the limitation of the magnetic-®eld applied.An image is generally represented in a computer as a 2D array of pixels.Each pixel has a value which represents the image intensity sampled at a point,or a small rectangular picture cell.In a greyscale image,each pixel takes a number of different values,which allows256different intensity levels.Image-based methods are characterised by their non-contact measurement,low energy,and instant capturing of the overall surface data.Therefore,a new method has been used by the authors[11]which integrates the shape from shading and binocular stereo techniques to overcome the weaknesses of the above-mentioned methods.The emphasis of the methodology is to extract the geometric information from a3D object in the mini-mum time and transfer this information into the VR system.It can support the development of the manufacturing environments.5.Manufacturing knowledge representation and acquisitionManufacturing knowledge in process planning is mainly concerned with the machining process of a part,such as the part feature,set-up,tooling,®xture,process de®nition, machining parameter and NC program.It deals with the geometric representation of the parts,form-generating cap-ability of process,and constrained machining knowledge. The feature-based approach can be used to perform the manufacturing knowledge representation.The geometry and topology features of the part are linked by the different machining methods.The system consists of a parametric library of machining features.These features,for example, include:planar,cylinder,hole,slot,pocket,step,notch and ®llet.The hierarchy of the feature-based knowledge model is shown in Fig.6.Cutting parameters can be stored in a database,while the machining process knowledge can be stored in a knowledge base with either the form of the frame, or the rules.A user interface based on the VR environment enables the system to easily acquire,modify or update this knowledge base.The planner can easily construct the shape of the object,position the selected features,generate the operations and arrange the operation sequence.6.De®nition of a uniform and well-organised structure for the virtual environmentA uniform and well-organised structure for the virtual environment can create improved sharing of VR resources. Visualisation of both the product geometry and the physical arrangement of the process planning can help to generate acceptable,accurate and ef®cient process plans.It canalsoFig.6.Hierarchy of the feature-based knowledge model.Q.Peng et al./Journal of Materials Processing Technology107(2000)153±159157increase the degree of customer acceptance and improve the ®nished product.The architecture of an integrated CAPP/VR system is proposed by the authors in Fig.7.It can access directly various resources from a database,a knowledge base,and Internet data during the process planning.The design process of CAPP can be simulated visually and can interact with the designer in real-time.7.Example and discussionFig.8shows an example to simulate a machining process of a part in the system's user interactive ers can operate this window to complete the process plan,for data retrieval,machining simulation and feedback in real-time.The system has the capability to update process data,andtoFig.7.Proposed architecture for an integrated CAPP/VRsystem.Fig.8.An example for simulating a machining process of a part with the system's user interactive window.158Q.Peng et al./Journal of Materials Processing Technology 107(2000)153±159communicate information regarding emergency situations through the user interactive window.This system can overcome many conventional problems that affect the¯exibility and reactivity of the CAPP system. It has the following advantages:it provides the design for manufacturing practice at the early stages of process planning,with immediate feed-back from the integrated CAPP/VR system;dynamic on-line activity reduces the variety of shop floor manufacturing constraints,thereby improving the validity of the process plans;when re-planning,the VR-based tool makes quick deci-sion making possible;andsharing manufacturing resources through Intranet becomes feasible.However,there is clearly still much work required:An evaluation of the method,comparing the output with generalised models derived from industry.Compound features need to be defined in a feature library, including pattern holes,cross-slot,and multi-step.More compound features can be defined by combining primi-tive features through the user interface.Integration of the3D information capturing system and VR environment.Integration of process planning and supply chain issues, which can support order/purchase activities through the Internet.8.ConclusionsVR is becoming an important method to solve engineer-ing problems because of its special simulation features,such as immersion,real-time interaction,and3D graphics.Its further application will not only depend on the development of VR technology,but more on its capability to provide cost-effective solutions to real industrial problems.CAPP normally deals with the complex processes and multi-factors arising from a wide variety of manufacturing environments,and therefore,it relies on a good interface between the engineers and the computer system.The devel-opment and application of VR technology enhances the capability of the engineering simulation process.VR pro-vides a3D virtual environment and can be used in the design and validation of a CAPP system.The VR application of a particular CAPP system will have real potential in the manufacturing environment,however, currently it is dif®cult for user to build using existing VR toolkits,which identi®es the area for future improvements to be made.An integrated CAPP/VR model has been proposed by the authors to improve current CAPP applications. The development of an effective CAPP system will rely upon the application of VR technology and the integration of a wide variety of existing CAD,knowledge base,arti®cial intelligence,optimisation,CAM and internet/network technologies.References[1]L.Monostori,H.Van Brussel,E.Westkampfer,Machine learningapproaches to manufacturing,Ann.CIRP45(2)(1996)675±708.[2]C.McMahon,J.Browne,CAD/CAM Principle,Practice andManufacturing Management,2nd Edition,Addison-Wesley,Reading, MA,1998.[3]M.R.Mine,ISAAC:a meta-CAD system for virtual environments,Computer-Aided Des.29(8)(1997)547±553.[4]T.H.Dani,R.Gadh,Creation of concept shape designs via a virtualreality interface,Computer-Aided Des.29(8)(1997)555±563.[5]M.Schulz,T.Reuding,T.Ertl,Analysing engineering simulations ina virtual environment,IEEE Comput.Graphics Appl.18(6)(November/December1998)46±51.[6]J.R Wilson,S.Cobb,M.D'Cruz,R.Eastgate,Virtual Reality forIndustrial Application:Opportunities and Limitations,Nottingham University Press,1996.ISBN1-897676-573.[7]L.J.Rosenblum,M.R.Macedonia,Projects in VR,IEEE Comput.Graphics Appl.18(6)(November/December1998)6±9.[8]dVise User Manual,Version4.1,Division Ltd.,UK,1997.[9]Superscape web site:///.[10]Deneb Robotics,Inc.,Simulation Software Product,VNC,Quest,Reference Manuals,1998.[11]Q.Peng,M.Loftus,A fast3D modelling approach for virtual realityenvironments,advances in manufacturing technology,in:Proceed-ings of the XII National Conference on Manufacturing Research, Derby,UK,Professional Engineering Publishing Limited,1998, pp.309±314.ISBN1-86058-172-2.Q.Peng et al./Journal of Materials Processing Technology107(2000)153±159159。