机电专业英语第2版课件

ComputerNumericalControlledMachinesUnit8数控机床

ComputerNumericalUnit8数控机床CNCmachines华中数控面板数控机床CNCmachines华中数控面板数控机床2CNCMachinesTranslationReadingMoreTranslatingSkillsTextCNCMachinesTranslationReadi3

Unit8CNCmachines

Earlymachinestoolswereoperatedbycraftsmenwhodecidedmanyvariablessuchasspeeds,feeds,anddepthofcut,etc1.Withthedevelopmentofscienceandtechnology,anewterm,numericalcontrol(NC)appeared.Controllingamachinetoolusingapunchedtapeorstoredprogramisknownasnumericalcontrol(NC).NChasbeendefinedbytheElectronicIndustriesAssociation(EIA)as“Asysteminwhichactionsarecontrolledbythedirectinsertionofnumericaldataatsomepoint.Thesystemmustautomaticallyinterpretatleastsomeportionofthisdatadj.”..Unit84

Inthepast,machinetoolswerekeptassimpleaspossibleinordertokeeptheircostsdown.Becauseoftheever-risingcostoflabor,bettermachinetools,completewithelectroniccontrols,weredevelopedsothatindustrycouldproducemoreandbettergoodsatpricesthatwerecompetitivewiththoseoffshoreindustries.NCisbeingusedonalltypesofmachinetools,fromthesimplesttothemostcomplex.Themostcommonmachinetoolsarethesingle-spindledrillingmachine,lathe,millingmachine,turningcenter,andmachiningcenter.Inthepast,machinetoo51.Single-SpindleDrillingMachineOneofthesimplestnumericallycontrolledmachinetoolsisthesingle-spindledrillingmachine.Mostdrillingmachinesareprogrammedonthreeaxes:a.TheX-axiscontrolsthetablemovementtotherightandleft.b.TheY-axiscontrolsthetablemovementtowardorawayfromthecolumn.c.TheZ-axiscontrolstheupordownmovementofthespindletodrillholestodepth.

1.Single-SpindleDrillingM6

2.LatheTheenginelathe,oneofthemostproductivemachinetools,hasalwaysbeenaveryefficientmeansofproducingroundparts(Fig.7-1).Mostlathesareprogrammedontwoaxes:a.TheX-axiscontrolsthecrossmotion(inorout)ofthecuttingtool.b.TheZ-axiscontrolsthecarriagetraveltowardorawayfromtheheadstock.

73.MillingMachineFig.7-2theverticalkneeandcolumnmillingmachineThemillingmachinehasalwaysbeenoneofthemostversatilemachinetoolsusedinindustry(Fig.7-2).Operationssuchasmilling,contouring,gearcutting,drilling,boring,andreamingareonlyafewofthemanyoperationsthatcanbeperformedonamillingmachine4.Themillingmachinecanbeprogrammedonthreeaxes:a.TheX-axiscontrolsthetablemovementleftorright.b.TheY-axiscontrolsthetablemovementtowardorawayfromthecolumn.c.TheZ-axiscontrolsthevertical(upanddown)movementofthekneeorspindle.3.MillingMachine84.TurningCenterTurningCentersweredevelopedinthemid-1960safterstudiesshowedthatabout40percentofallmetalcuttingoperationswereperformedonlathes.Thesenumericallycontrolledmachinesarecapableofgreateraccuracyandhigherproductionratesthanwerepossibleontheenginelathe.Thebasicturningcenteroperatesononlytwoaxes:a.TheX-axiscontrolsthecrossmotionoftheturrethead.b.TheZ-axiscontrolsthelengthwisetravel(towardorawayfromtheheadstock)oftheturrethead.4.TurningCenter95.MachiningCenterMachiningcentersweredevelopedinthe1960ssothatapartdidnothavetobemovedfrommachinetomachineinordertoperformvariousoperations.Thesemachinesgreatlyincreasedproductionratesbecausemoreoperationscouldbeperformedonawork-pieceinonesetup.Therearetwomaintypesofmachiningcenters,thehorizontalandtheverticalspindletypes.a.Thehorizontalspindle-machiningcenteroperatesonthreeaxes:(a)TheX-axiscontrolsthetablemovementleftorright.(b)TheY-axiscontrolstheverticalmovement(upanddown)ofthespindle.(c)TheZ-axiscontrolsthehorizontalmovement(inorout)ofthespindle.b.Theverticalspindle-machiningcenteroperatesonthreeaxes:(a)TheX-axiscontrolsthetablemovementleftorright.(b)TheY-axiscontrolsthetablemovementtowardorawayfromthecolumn.(c)TheZ-axiscontrolstheverticalmovement(upanddown)ofthespindle.5.MachiningCenter10

punch[pʌntʃ]n.冲压机；钻孔机vt.开洞；以拳重击vi.用拳猛击interpret[in'tə:prit]vt.说明；口译vi.解释；翻译electronic[,ilek'trɔnik]adj.电子的drill[dril]n.训练；钻孔机vi.钻孔；训练carriage['kæridʒ]n.（机床的）滑板；刀架headstock['hedstɔk]n.主轴箱milling['miliŋ]n.铣削contouring[kən'tuəriŋ]n.成形加工boring['bɔ:riŋ]n.镗孔；镗削加工reaming['ri:miŋ]n.铰孔knee[ni:]n.升降台turning['tə:niŋ]n.车削punch[pʌntʃ]n.冲压机；钻孔机vt.开11knee[ni:]n.升降台turning['tə:niŋ]n.车削headstock['hedstɔk]n.主轴承accuracy['ækjurəsi]n.精确性，准确度，精度work-piece[wə:kpi:s]n.工件horizontal['hɔri'zɔntəl]adj.水平的vertical['və:tikəl]adj.垂直的，直立的productionrate生产率numericalcontrol(NC)数字控制apunchedtape穿孔纸带knee[ni:]n.升降台12theElectronicIndustriesAssociation(EIA)（美国）电子工业协会drillingmachine钻床enginelathe卧式车床gearcutting齿轮加工turningcenter切削中心machiningcenter加工中心turrethead转塔头metalcutting金属切削crossmotion横向运动lengthwisetravel纵向运动theElectronicIndustriesAsso131.Earlymachineswereoperatedbycraftsmenwhodecidedmanyvariablessuchasspeeds,feeds,depthofcut,etc.

翻译：老式机床通常是由工人操作并由他们决定机床速度、进给量、切削深度等。句中Whodecidedmanyvariables…是定语从句修饰craftsmen。例如：Theengineerswhowemetyesterdayhavedesignedanewautomaticdevice.

我们昨天碰到的那些工程师设计出了一种新的自动化装置。1.Earlymachineswereoperate14

2.NChasbeendefined…as“Asysteminwhichactionsarecontrolledbythedirectinsertionofnumericaldataatsomepoint.Thesystemmustautomaticallyinterpretatleastsomeportionofthisdatadj.”

数控被定义为“采用在某些点直接插入数字数据来控制操作的系统，此系统必须能够自动解释翻译这些信息中的一部分。”句中as的宾语是Asystem，which引导的定语从句修饰system。2.NChasbeendefined…as15

3.Becauseoftheever-risingcostoflabor,bettermachinetools,completewithelectroniccontrols,weredevelopedsothatindustrycouldproducemoreandbettergoodsatpricesthatwerecompetitivewiththoseofoffshoreindustries.由于劳动成本日益上涨，人们研制出性能更好的机床，并配有电控设备，这样企业可以生产更多更好价格较低的产品，以和国际上的产品相竞争。句中bettermachinetools是句子的主语，weredeveloped是句子的谓语，sothat引导结果状语从句，that引导的定语从句修饰goods。3.Becauseoftheever-ris164.Operationssuchasmilling,contouring,gearcutting,drilling,boring,andreamingareonlyafewofthemanyoperationsthatcanbeperformedonamillingmachine.像铣削、成型加工、齿加工、钻、镗、铰等只是可在铣床上进行的一少部分加工。句中that引导定语从句修饰themanyoperations。4.Operationssuchasmill17I.Answerthefollowingquestionsaccordingtothetext.

1.WhatismeantbythetermNC?

Asysteminwhichactionsarecontrolledbythedirectinsertionofnumericaldataatsomepoint.Thesystemmustautomaticallyinterpretatleastsomeportionofthisdatadj.

.

Themostcommonmachinetoolsarethesingle-spindledrillingmachine,lathe,millingmachine,turningcenter,andmachiningcenter.2.Whatarethemostcommonmachinetools?keykeyI.Answerthefollowingquest18II.TranslatethefollowingtermsintoEnglish.

1.数字控制

2.加工中心3.齿轮加工4.穿孔纸带5.数控车床6.生产率7.垂直运动8.电子工业协会numericalcontrol

machiningcentre

gearcuttingpunchedtape

turningcenterproductionrateverticalmotionElectronicsIndustryAssociationkeykeykeykeykeykeykeykeyII.Translatethefollowingte19Ⅲ．TranslatethefollowingintoEnglish．1.从最简单到最复杂的机床都会用到数控技术。

NCisbeingusedonalltypesofmachinetools,fromthesimplesttothemostcomplex.

2.卧式车床是生产效率最高的机床之一。

Theenginelathe,oneofthemostproductivemachinetools.keykeyⅢ．Translatethefollowinginto203.研究表明，整个金属材料的切削操作大约40%是在车床上进行的。

Studiesshowedthatabout40percentofallmetalcuttingoperationswereperformedonlathes.

4.卧式加工中心可在三个坐标轴上工作。

Thehorizontalspindle-machiningcenteroperatesonthreeaxes.

keykey3.研究表明，整个金属材料的切削操作大约421

科技英语(EnglishforScienceandTechnology，简称EST)可以泛指一切论及或谈及科学和技术的书面语和口语。其中包括：一、科技著述、科技论文和报告、实验报告和方案；二、各类科技情报和文字资料；三、科技实用手册的结构描述和操作规程；四、有关科技问题的会谈、会议、交谈的用语；五、有关科技的影片、录像等有声资料的解说词等等。本章首先介绍科技英语的特征。科技英语词汇概括起来主要有5个特点：（1）科技英语词汇多源于希腊语和拉丁语；（2）词义专一；（3）前后缀出现频率高；（4）专业词汇出现的频率低；（5）广泛使用缩略词。科技英语词汇可以分为三种类：科技词汇、半科技词汇和非科技词汇。科技英语词汇的结构和特征Ⅰ科技英语(EnglishforScien221．科技词汇（technicalterms）

科技英语有许多专门的术语，只在某一特定的科技领域来用。许多情况下，虽然同为科学家，这个领域的科学家并不明白另一领域的词汇，比如物理学家就可能不明白生物学领域的专业术语。且由于科学技术发展，科技术语(词汇)也日益增多。这些科技词汇只有该领域的专家或工作人员了解。例如：化学领域中的isotope（同位素）；物理领域的photon(光子)；以及生物领域的chromosome(染色体)等等，都是科技词汇。1．科技词汇（technicalterms）232.半科技词汇（semi-technicalterms）

半科技词汇指的是那些不同于生活中的语言词汇，而且在不同领域又有不同的含义的词汇，也称通用科技术语。例如orbit,在医学上指的是“眼眶”，而在物理学上则是“轨道”；operation,在医学上指的是“手术”，在计算机领域是“操作”，而在商务上却是“公司”；ahugemultinationalelectronicsoperation在数学上指的是“运算”。很普通的词web(网)、net(网)、site(站点)在计算机科学中都成了与原词仍然关联的专业词汇，如website(网址、网站)、internet(互联网)；Mouse(老鼠)、memory(记忆)、read(阅读)分别成了计算机科学中的术语“鼠标”、“内存”和“读取”。2.半科技词汇（semi-technicalterms）243非科技词汇（non-technicalterms）非科技词汇经常用于科学技术领域的词汇，在日常生活当中则不常用的词汇，在修辞学上指的是那些正式用语（learnedandformalwords）。因为科技英语是一种描述各种自然现象、客观事实的发生过程和特性的语言，所以科技英语的文章不用那些日常生活中的常用词汇（commonwords）。例如，日常生活中我们用give、have，而科技英语中我们用posses；日常生活中用referto，科技英语中用alludeto，日常生活中用mad，科技英语中用insane等等。3非科技词汇（non-technicalterms）25AdvantagesofNC华中数控面板数控机床AdvantagesofNC华中数控面板数控机床26

AdvantagesofNC

Recentstudiesshowthatoftheamountoftimeanaveragepartspentinashop,onlyafractionofthattimewasactuallyspentinthemachiningprocess.Letusassumethatapartspent50hoursfromthetimeitarrivedataplantasaroughcastingorbarstocktothetimeitwasafinishedproduct.Duringthistime,itwouldbeonthemachineforonly2.5hoursandbecutforonly0.75hour.Therestofthetimewouldbespentonwaiting,moving,settingup,loading,unloading,inspectingthepart,settingspeedsandfeeds,andchangingcuttingtools.

近期研究表明，在加工零件时，只有一少部分时间真正用于加工工件。假定把毛坯或棒料加工为成品零件需要50h,那么,工件在机床上的时间只有2.5h,用于切削的时间仅有0.75h,其余时间都用在等待加工、运输、安装、装夹、拆卸、检验、设置转速与进给、换刀上。Advantag27

NCreducestheamountofnon-chip-producingtimebyselectingspeedsandfeeds,makingrapidmovesbetweensurfacestobecut,usingautomaticfixtures,automatictoolchanging,controllingthecoolant,in-processgauging,andloadingandunloadingthepart.Thesefactors,plusthefactthatitisnolongernecessarytotrainmachineoperators,haveresultedinconsiderablesavingsthroughouttheentiremanufacturingprocessandcausedtremendousgrowthintheuseofNC.SomeofthemajoradvantagesofNCareasfollows:

通过转速与进给量的设定、刀具在待切削表面间的快速移动、自动夹具的运用、刀具的自动切换、切削液的控制、在线检测及零件的自动装卸，NC缩短了非切削加工的时间。上述因素,加之无需培训机床操作工,使整个加工过程耗时大量减少，促进了数控的推广应用。NC的主要优点如下:

NCreducestheamountofnon28

Helicalgearshavecertainadvantages,forexample,whenconnectingparallelshafts,theyhaveahigherloadcarryingcapacitythanspurgearswiththesametoothnumbersandcutwiththesamecutter.Becauseoftheoverlappingactionoftheteeth,theyaresmootherinactionandcanoperateathigherpitch-linevelocitiesthanspurgears.Thepitch-linevelocityisthevelocityinthepitchcircle.Sincetheteethareinclinedtoaxisofrotation,helicalgearscreateanaxialthrust.Ifusedsingle,thisthrustmustbeabsorbedintheshaftbearings.Thethrustproblemcanbeovercomebycuttingtwosetsofopposedhelicalteethonthesameblank.Dependingonthemethodofmanufacture,thegearmaybeofthecontinuous-toothherringbonevarietyoradouble-helicalgearwithaspacebetweenthetwohalvestopermitthecuttingtooltorunout.Double-helicalgearsarewellsuitedfortheefficienttransmissionofpowerathighspeeds.

斜齿轮具有某些优点。例如当连接平行轴时，其承载能力高于有相同齿数并用相同刀具切削的正齿轮。由于轮齿的重合作用，其传动更为平稳，允许的节线速度比正齿轮高。节线速度是节圆上的线速度。因为轮齿倾斜于旋转轴线，所以斜齿轮会产生轴向推力。如果单独使用这种齿轮，轴向推力由轴向轴承来承担。轴向推力问题可通过在一个齿坯上加工两对斜齿来解决。根据加工方法，这种齿轮可以是连续齿人字型齿轮或有退刀槽的双斜齿轮。双斜齿轮非常适于在高速下高效传输动力。Helicalgearshavecertain29

(1)

Thereisautomaticorsemiautomaticoperationofmachinetools.Thedegreeofautomationcanbeselectedasrequired.(2)Flexiblemanufacturingofpartsismucheasier.Onlythetapeneedschangingtoproduceanotherpart.(3)Storagespaceisreduced.Simplework-holdingfixturesaregenerallyused,reducingthenumberofjigsorfixturesthatmustbestored(4)Smallpartlotscanberuneconomically.OftenasinglepartcanbeproducedmorequicklyandbetterbyNC.(5)Nonproductivetimeisreduced.Moretimeisspentonmachiningthepart,andlesstimeisspentonmovingandwaiting.1)机床可以自动运行，亦可半自动运行，使用时按需要选取2)零件的柔性制造更为简便。更换纸带即可加工不同零件。3)减小存储空间，通常采用简单的工装夹具，因而减少了存储夹具的数量。4)加工小批量零件非常经济。用NC机床加工出的单件质量好且加工快。5)缩短非加工时间。花在加工零件上的时间多了，用于运输和等待的时间短了。(1)Thereisautomaticorsem30(6)Toolingcostsarereduced.Inmostcasescomplexjigsandfixturesarenotrequired.(7)Inspectionandassemblycostsarelower.Thequalityoftheproductisimproved,reducingtheneedforinspectionandensuringthatpartsfitasrequired.(8)Machineutilizationtimeisincreased.Thereislesstimethatamachinetoolisidlebecauseworkpieceandtoolchangesarerapidandautomatic.(9)Complexformscaneasilybemachined.Thenewcontrolunitfeaturesandprogrammingcapabilitiesmakethemachiningofcontoursandcomplexformsveryeasy.(10)Partsinventoryisreduced.Partscanbemadeasrequiredfromtheinformationonthepunchedtape.6)降低加工成本。数控机床在多数情况下无需复杂夹具。7)降低检验与装配成本。产品质量提高了，因而减少了检验的必要，保证零件能按需装配。8)增加机床使用时间。由于能迅速自动地更换工件与刀具，机床闲置时间缩短了。9)便于加工复杂形状的工件。新型控制器功能多、编程能力强，因而轮廓加工与复杂形状的加工非常方便。10)减少零件存货。人们能根据穿孔带上的信息加工所要求的零件

(6)Toolingcostsarere31Sincethefirstindustrialrevolution,about200yearsago,NChashadasignificanteffectontheindustrialworld.ThedevelopmentsinthecomputerandNChaveextendedaperson’smindandmuscle.TheNCunittakessymbolicinputandchangesittousefuloutput,expandingaperson’sconceptsintocreativeandproductiveresults.NCtechnologyhasmadesuchrapidadvancesthatitisbeingusedinalmosteveryareaofmanufacturing,suchasmachining,welding,press-working,andassembly.Ifindustry’splanningandlogicaregood,thesecondindustrialrevolutionwillhaveasmuchormoreeffectonsocietyasthefirstindustrialrevolutionhad.AsweprogressthroughthevariousstagesofNC,itistheentiremanufacturingprocessthatmustbekeptinmind.如果工业规划合理、逻辑正确，与第一次工业革命一样，第二次工业革命将对人类社会产生同样甚至更大的影响。在我们从事NC不同阶段的工作时，必须牢记NC技术贯穿于整个加工过程的始终。回顾数控技术的发展历史，我们相信计算机辅助制造（CAM）与计算机集成制造（CIM）是制造业的发展趋势，自动化工厂在不远的未来将成为现实Sincethefirstind32Computer-assistedmanufacturing(CAM)andcomputer-integratedmachining(CIM)arecertainlywherethefutureofmanufacturinglies,andconsideringthedevelopmentsofthepast,itwillnotbetoofarinthefuturebeforetheautomatedfactoryisareality.Developedoriginallyforuseinaerospaceindustries,NCisenjoyingwidespreadacceptanceinmanufacturing.TheuseofCNCmachinescontinuestoincrease,becomingvisibleinmostmetalworkingandmanufacturingindustries.Aerospace,defensecontract,automotive,electronic,appliance,andtoolingindustriesallemploynumericalcontrolmachinery.AdvancesinmicroelectronicshaveloweredthecostofacquiringCNCequipment.ItisnotunusualtofindCNCmachineryincontracttool,die,andmold-makingshops.

NC虽然起源于航空工业，但它在当今制造业中得到了广泛应用。很明显，再大多数金属加工与制造业中，CNC机床的应用持续增长，航空、国防、汽车、电子、仪器、机床行业都采用数控机床。微电子技术的发展降低了CNC装置的成本，在工具、模具与制模车间使用CNC机床已是一件常事。

Computer-assisted33WiththeadventoflowcostOEM(originalequipmentmanufacturer)andretrofitCNCverticalmillingmachines,evenshopsspecializinginone-of-a-kindprototypeworkareusingCNCs.Althoughnumericalcontrolmachinestraditionallyhavebeenmachinetools,bending,forming,stamping,andinspectionmachineshavealsobeenproducedasnumericalcontrolsystems.自从有了OEM（设备制造商）与立式CNC铣床的改进，甚至那些专门生产某种标准工件的车间也会使用CNC机床。虽然数控机床传统上是指金属切削机床，但折弯机、成形机、冲压机和测量机也使用数字控制系统。Withtheadvent34load[ləud]n.负载，工作量vi.加载；装载vt.使担负；装填feed[fi:d]n.进给vt.喂养；供给；chip[tʃip]n.芯片；碎片vt.削；切成碎片vi.剥落；碎裂fixture['fikstʃə]n.夹具；设备；固定装置coolant['ku:lənt]n.冷却剂；切削液gauge[ɡeidʒ]n.计量器；容量规格vt.测量；检验；校准=gagesemiautomatic['semi,ɔ:tə'mætik]adj.[电]半自动的automation[,ɔ:tə'meiʃən]n.自动化；自动操作work-holdingn.工件夹紧jig[dʒiɡ]n.夹具；治具；钻模assembly[ə'sembli]n.装配；组装件；集会，集合contour['kɔntuə]n.轮廓；等高线；电路；概要vt.画轮廓；画等高线integrate['intiɡreit,'intiɡrit,-ɡreit]v.使一体化，集成的

load[ləud]n.负载，工作量vi.加载；装载35metalworking[‘metəl,wə:kiŋ]n.金属加工；金属制造adj.金属制造的die[dai]]n.模具，冲模retrofit['retrəufit]n.改型（装，进）；（式样）翻新stamping['spæmpiŋ]n.冲压v.冲压advent['ædvənt]n.(事件、时期等的)出现roughcasting铸造毛坯barstock棒料finishedproduct成品toolchanging(toolchange)换刀in-processinggauging在程检测computer-assistedmanufacturing(CAM)计算机辅助制造computer-integratedmachining(CIM)计算机集成制造toolingindustry刀具工业prototypework标准工件moldmaking模具制作metalworking[‘metəl,wə:kiŋ]n36Decidewhetherthefollowingstatementsaretrueorfalse.Alotoftimewasactuallyspentinthemachiningprocess.2.Thereisonlyautomaticoperationofmachinetools.3.SmallpartlotscanberuneconomicallywithNCmachining.4.LesstimeisspentonmachiningthepartwithNCmachining,andmoretimeisspentonmovingandwaiting.5.NCmachiningcanmakeInspectionandassemblycostslower.6.CAD/CAMwillnotbetoofarinthefuturebeforetheautomatedfactoryisareality.keykeykeykeyFFFTTTkeykeyDecidewhetherthefollowings37近期研究表明，在加工零件时，只有一少部分时间真正用于加工工件。假定把毛坯或棒料加工为成品零件需要50h,那么,工件在机床上的时间只有2.5h,用于切削的时间仅有0.75h,其余时间都用在等待加工、运输、安装、装夹、拆卸、检验、设置转速与进给、换刀上。通过转速与进给量的设定、刀具在待切削表面间的快速移动、自动夹具的运用、刀具的自动切换、切削液的控制、在线检测及零件的自动装卸，NC缩短了非切削加工的时间。上述因素,加之无需培训机床操作工,使整个加工过程耗时大量减少，促进了数控的推广应用。NC的主要优点如下:。近期研究表明，在加工零件时，只有一少部分时间真正用381)机床可以