大学专业英语系列教程 机电工程专业英语 ENGLISH FOR ELECTROMECHANICAL ENGINEERING 王永鼎姜少杰主编 同济大学出版社
内容提要 阿跳流a心业 图书在版编目（☑P)数据 1SBN7-5608-3361- 中国版本图书馆CP数据核字(2006)第087423号 机电工程专业英语 王水鼎姜少杰主编 责仟第排朱报华 责任校对谢惠云物前设计潘向装 安行储大学版业 任前全港书电 开木787mm×960mm1/16 版次2006年9月第1版 2006年9月第1次印到 书号1SBN75608-3361-6/H·403 定价 38.00元 本书若有印装质量题，请向本社发行部调换
前言 随着21世纪信息技术的发展，机电行业的国际学术交流和技术合作越来越 繁。英语作为国际交流的工其，其作用不可忽视。然而因专业英语的特性，仅仅通 过一般英语语言知识的学习无法解决生产实际问题。专业英语的应用能力已成为 高等院校学生和科技工作者应有的基本素质。 本书的宗指是提高机电工程、机械设计制造及其自动化、机械工程及自动化、 工业工程等专业学生的专业英语实际应用能力，适应从大学英语教学基础阶段（一 至年级)到应用提高阶段（三至四年级）的过波，为路入工作岗位做好准备。 全书包括七个部分。第一部分为科普短文，第二部分为机械零件、机构和机 器，第三部分为设计，第四部分为机床和加工，第五部分为制造系统，第六部分为测 试，第七部分为教育。所有文章均选自相关具有权威性和代表性的专业书籍，注重 实用性。每篇课文配有参考译文，具有一定的参考价值。 教材由浅入深，增加了具有趣味性的机械专业科普短文，以提高学生的学习兴 趣。在编量上，每惯都有两篇雅度系数不同但内容密切相关的文章，每篇文章都附 有生词表及疑难句注释，方便读者阅读和理解，也便于学生自学。各校教师可以根 据自己学校学生的具体情况选择其中的一篇进行教学，另一篇作为阅读材料。每 高课文都呢有相关习题，以巩国文章的知识要点，进一步熟专业词汇。 本书油王水鼎(ParI,PartVI、姜少杰(PartⅡ，PartⅢ，PartN,PartV及译 文)主编，参加第写的还有李俊(PartV及译文)、周华(Appendix)。由于作者水平 有限，对书中的不足之处，悬请广大读者指正。 编者 2D06年8月
Part I Short Articles about Science and Technology
Unit 1 ■ What is a PLC?□ The PLC.or Prog y machine o PLC.where i n the xast hundreds of ti and relays would have boon ro cd to do the task.The machine or svste rarely,if ever.interacts directly with the PLC's program.When it is ne to either edit or create the PLC program.a personal computer is usually (but not always)conpected to it. In the 1960s.the American automotive industry was searchine for a way to do business better.The proccsscs of scqucncing,control and intcrlock logic needed for automobile manufacturing was a time consuming and arduous task. which required manual updating of relays,timers and dedicated cloed-loop controllers.When a new year's model was coming off the drawing board skilled electricians were called on to reset the production line.GM Hydramatic specifically requcsted proposals for a replaccment for the old system that would speed up the sand keep c came the first F mable based units that.in put.and process impediment.Theyaso control attached motor starters.pilot 3
Uni证I lights,valves and many other devics.Both function repond to a custom,us pro ()rrts. and are typically Reduced Instruction Set (RISC) based.They are designed for real-time use.and often must withstand harsh environments on the shop floor.The programmable logic controller circuitry monitors the status of multiple snsor inputs.which control output actuators. which may be things like motor starters,solenoids,lights and displays.or valves. Most PLCs are programmed in a special language called Ladder Logi Ladder Logic ally a Bo olean logic-solving prograr m with a graphica to look ke an clementar ing diag A m rn prog to Basic or C.Typically on in a and then controller directly through a cable connection.The program is stored in the programmable logic controller in non-volatile memory. Words and Expressions ，计时器，定时器 hydnanmEtc[dhaitonrtik 油压[麦压]白动式的 互 gnate ['pet 以指花指出，任 GM 美通用汽车公 port [poa]
Unit 2 ■ CNC Machining you to control the motion of tools and computer programs that use numeric data.CNC machining can be used with nearly any traditional machine. CNC machining starts with a piece of metal,sometimes called a"billet". (Billet:pretentious word for"lump of metal".used by machinests and e oe naimorng only copu and motors on the control knobs installed.This is bsically iust a robot machinist.Youuse a rotating cutting tool to cut away all the metal that isn't your crank.3D metal etch-a-sketch.with the computer interpolating so the circles comeout looking pretty smooth. The down-side of CNC machinins There are a coupl of issucs.First,it wastes a lot of metal.The stuff removed is juist metal shvings,and can only be sold for scrp.By comparion. almost all of the metal. xoept for a little bit of "flash"that sccps int the k between the tooand the di.Thep can be tme melting things This is cially important for ing tool. severely weakened if you get it too hot,never mind near to melting).prt
Uni证2 that is“'sprawling”likc ed to th nd m technolooy that can measure to0 005 mm (o000 1")while covered in ail. CNC machine has a minimum of 6 motors (including some to change tools.and one or more to pump oil and coolant various places).This translates to running costs that may be well over $l/minute.(The computer is not a significant part of the cost any more.) it docsn't have the tightly comers that hav that crack Advantages of CNC machining omer it would cut rather than uush the metal into nlac CNC machinine doesn't impose sch restrictions,though to get nicely radiused corners.you might have to change tools.to make the last rass.(vou use a flat tool to get rid of the bulk of the mctal over the flat arcas,and se a round nosed tool to form the inside radius where needed.Soeliminating stress risers means more expensive machining time. Words and Expressions tik[saa.通用的，万能的|mmer在[nmmk]d.数字的 5
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Unit3 Unit 3 What is PID Control？ PID can be describd as a sct rules with which precise regulation of -loop control system is obta d.Closed loop control means a method i e me ement of the proc re tha red as the SETPOINT.The hbest way of a In its basic form.PID involyes three mathematical control functions working toeether.Pronortional-Inteeral-Derivative.The most important of these,Proportional Control,determines the magnitude of the difference between the SETPOINT and the PROCESS VARIABLE (known as ERROR). and then applies appropriate proportionl changes to the CONTROL VARIABLE to eliminate ERROR.Many control systems will.in fact,work quite well with ony Proportionl Control.Integral Control examines the offset of SETPOINT and the PROCESS VARIABLE over time and corrects it whe PROCES quently makes changes to the OUTPU A lal changes the ions is govemed by a uer- and. pre PID Tuning.although considered"black magic"by many.really is,of
