外文翻译--机械设计与制造业.doc

MachineDesignandmanufacturingMachinedesignistheapplicationofscienceandtechnologytodeviseneworimprovedproductsforthepurposeofsatisfyinghumanneeds．Itisavastfieldofengineeringtechnologywhichnotonlyconcernsitselfwiththeoriginalconceptionoftheproductintermofitssize,shapeandconstrictiondetails，butalsoconsidersthevariousfactorsinvolvedinthemanufacture，marketinganduseoftheproduct.Peoplewhoperformthevariousfunctionsofmachinedesignaretypicallycalleddesigners，ordesignengineers.Machinedesignisbasicallyacreativeactivity．However，inadditiontobeinginnovative，adesignengineermustalsohaveasolidbackgroundintheareasofmechanicaldrawing，kinematics,dynamics，materialsengineering，strengthofmaterialsandmanufacturingprocesses.Asstatedpreviously，thepurposeofmachinedesignistoproduceaproductwhichwillserveaneedforman．Inventions，discoveriesandscientificknowledgebythemselvesdonotnecessarilybenefitpeopleonlyiftheyareincorporatedintoadesignedproductwillabenefitbederived．Itshouldberecognized，therefore，thatahumanneedmustbeidentifiedbeforeaparticularproductisdesigned．Machinedesignshouldbeconsideredtobeanopportunitytouseinnovativetalentstoenvisionadesignofaproduct，toanalyzethesystemandthenmakesoundjudgmentsonhowtheproductistobemanufactured．Itisimportanttounderstandthefundamentalsofengineeringratherthanmemorizemerefactsandequations．Therearenofactsorequationswhichalonecanbeusedtoprovideallthecorrectdecisionsrequiredtoproduceagooddesign．Ontheotherhand，anycalculationsmademustbedonewiththeutmostcareandprecision.Forexample，ifadecimalpointismisplaced，anotherwiseacceptabledesignmaynotfunction．Gooddesignsrequiretryingnewideasandbeingwillingtotakeacertainamountofrisk，knowingthatifthenewideadoesnotworktheexistingmethodcanbereinstated．Thusadesignermusthavepatience，sincethereisnoassuranceofsuccessforthetimeandeffortexpended．Creatingacompletelynewdesigngenerallyrequiresthatmanyoldandwellestablishedmethodsbethnistaside．Thisisnoteasysincemanypeopleclingtofamiliarideas，techniquesandattitudes．Adesignengineershouldconstantlysearchforwaystoimproveanexistingproductandmustdecidewhatold，provenconceptsshouldbeusedandwhatnew,untriedideasshouldbeincorporated．Newdesignsgenerallyhavebugsorunforeseenproblemswhichmustbeworkedoutbeforethesuperiorcharacteristicsofthenewdesignscanbeenjoyed．Thusthereisachanceforasuperiorproduct，butonlyathigherrisk．Itshouldbeemphasizedthat，ifadesigndoesnotwarrantradicalnewmethods，suchmethodsshouldnotbeappliedmerelyforthesakeofchange．Duringthebeginningstagesofdesign，creativityshouldbeallowedtoflourishwithoutagreatnumberofconstraints．Eventhoughmanyimpracticalideasmayarise，itisusuallyeasytoeliminatethemintheearlystagesofdesignbeforefirmdetailsrequiredbymanufacturing．Inthisway，innovativeideasarenotinhibited．Quiteoften，morethanonedesignisdeveloped，uptothepointwheretheycanbecomparedagainsteachother．Itisentirelypossiblethatthedesignwhichisultimatelyacceptedwilluseideasadstinginoneoftherejecteddesignsthatdidnotshowasmuchoverallpromise.Psychologistsfrequentlytalkabouttryingtofitpeopletothemachinesoperate．It,isessentiallytheresponsibilitythedesignengineertostrivetofitmachinestopeople．Thisisnotaneasytask，sincethereisreallynoaveragepersonforwhichcertainoperatingdimensionsandproceduresareoptimum．Anotherimportantpointwhichshouldberecognizedisthatadesignengineermustbeabletocommunicateideastootherpeopleifthey，tobeincorporated．Initially，thedesignermustcommunicateapreliminarydesigntogetmanagementapproval．Thisisusuallydonebyverbaldiscussionsinconjunctionwithdrawinglayoutsandwrittenmaterial．Tocommunicateeffectively，thefollowingquestionsmustbeanswered（1）Doesthedesignreallyserveahumanneed（2）Willitbecompetitivewithexistingproductsofrivalcompanies（3）Isiteconomicaltoproduce（4）Canitbereadilymaintained（5）WillitsellandmakeaprofitOnlytimewillprovidethetrueanswerstotheprecedingquestions，buttheproductshouldbedesigned，manufacturedandmarketedonlywithinitialaffirmativeanswers．Thedesignengineeralsomustcommunicatethefinalizeddesigntomanufacturingthroughtheuseofdetailandassemblydrawings．Quiteoften，aproblemwilloccurduringthemanufacturingcycle．Itmaybethatachangeisrequiredinthedimensioningortolerancingofapartsothatitcanbemorereadilyproduced．Thisfallsinthecategoryofengineeringchangeswhichmustbeapprovedbythedesignengineersothattheproductfunctionwillnotbeadverselyaffected．Inothercases，adeficiencyinthedesignmayappearduringassemblyortestingjustpriortoshipping．Theserealitiessimplybearoutthefactthatdesignisalivingprocess．Thereisalwaysabetterwaytodoitandthedesignershouldconstantlystrivetowardsfundingthatbetterway．Inthedevelopmentofmanufacturingplans,computeraidedprocessplanningcanbethepreparationofthousandsofprocessesandprocessingProcesstoselectthebestprocessingprogramIntheworkshop,thedistributedintelligenceofthisformtothemicroprocessortocontrolmachinetools,automaticcontrolforloadingandunloadingmaterialsPreparationandworkshoponthecurrentstateofthecollectionofinformations.However,theseseparatereformsarestillfarfromenough.WhatweneedisacommonsoftwareEndedbeforetheterminalfromalltheautomationcontrolsystem.Ingeneral,thecomputercanprovideawiderangeofintegrated,timelyandaccurateinformationcanbeministriestoimproveDoorsbetweentheexchangeandcommunication,theintroductionofmorestringentcontrol,andoftentoenhancetheoverallqualityofthewholesystemAndefficiency.Forexample,toimproveexchangeandcommunicationwillmeanthatthedesignofbettermanufacturability.NCprogrammersandprocessequipmentdesignershavetheopportunitytoputforwardtheviewsofproductdesigners,andviceversa.Thuscanreducethetechnicalaspectsofthechange,andthenecessarychangesforthosewhocanmoreeffectivelytodealwith.Thecomputercannotonlychangemorequicklyonthedetailsofthemake,butalsocanchangethenthedatatotellusers.TheuseofuptodatedataontheproductioncontrolprocesscanbeapointofordertodevelopbetterandmoreefficientproductionProgress.Thus,expensiveequipmentcanbebetterutilizedtoimprovethepartsintheproductionprocessofthedeliveryofEfficiencyandreducethecostoftheproductsProductqualitycanbeimproved.Forexample,notonlycanimprovethedesignaccuracy,butalsoenablesqualityassurancePermittheuseofdesigndatadepartments,toavoiderrorsduetoamisunderstanding.Canmakepeoplebetteraccomplishtheirwork.ByavoidingthelengthycalculationandwritetheworkThisinformationisnottofindthetimethecomputernotonlymakespeopleworkmoreeffectively,butalsoLiberatethemtodoonlytheworkofmancandotothinkcreatively.ComputerIntegratedManufacturingwillalsoattractnewtalentintothemanufacturingsector.Wastoattracttalentedpeoplefromthereasonforthisisthattheyhopethatamodern,technologicallyadvancedenvironment.Inmanufacturingengineering,CAD/CAMequipmenttoreducetheprocessdesign,NCprogrammingandthepreparationoftheProcessRequired.Moreover,speeduptheresponsespeed,whichwilleventuallybeoutsidethecurrentprocessingoftheworkcommissionedfrominternalstafftocomplete.机械设计与制造业机械设计是一门通过设计新产品或者改进老产品来满足人类需求的应用技术科学。它是一个广阔的工程技术领域，不仅要研究产品在尺寸、形状和详细结构等方面的基本构思，还要考虑产品在制造、销售和使用等方面的有关问题。进行各种机械设计工作的人员通常被称为设计人员或者设计工程师。机械设计是一项创造性的工作。设计工程师不仅在工作上要有创新性，还必须在机械制图、运动学、动力学、工程材料、材料力学和机械制造工艺等方面具有深厚的基础知识。如前面所述，机械设计的目的是生产能够满足人类需求的产品。发明、发现和科学知识本身并不一定能给人类带来益处，只有当它们被用在产品上才能产生效益。因而，应该认识到在一个特定产品进行设计之前，必须先确定人们是否需要这种产品。应当把机械设计看成是设计人员运用创造性的才能进行产品设计、系统分析和制订产品的制造工艺的一个良机。掌握工程基础知识要比熟记一些数据和公式更为重要。仅仅使用数据和公式是不足以在一个好的设计中做出所需的全部决定。另一方面，应该认真精确地进行所有运算。例如，即使将一个小数点的位置放错，也会使正确的设计变成错误的。一个好的设计人员应该勇于提出新的想法，而且愿意承担一定的风险，当新的方法不适用时，就恢复采用原来的方法。因此，设计人员必须要有耐心，因为所花费的时间和努力并不能保证带来成功。一个全新的设计，要求摒弃许多陈旧的，为人们所熟知的方法。由于许多人易于墨守成规，这样做并不是一件容易的事情。一位设计工程师应该不断地探索改进现有产品的办法，在此过程中应该认真选择原有的、经过验证的设计原理，将其与未经过验证的新观念结合起来。新设计本身会有许多缺陷和未能预料的问题发生，只有当这些缺陷和问题被解决之后，才能体现出新产品的优越性。因此，一个性能优越的产品诞生的同时，也伴随着较高的风险。应该强调的是，如果设计本身不要求采用全新的方法，就没有必要仅仅为了变革的目的而采用新办法。在设计的初始阶段，应该允许设计人员不受各种约束，充分发挥创造性。即使产生了许多不切合实际的想法，也会在设计的早期，即绘制生产图纸之前被改正掉。只有这样，才不至于堵塞创新的思路。通常要提出几套设计方案，然后加以比较。很有可能在最后选定的方案中，采用了某些未被接受的方案中的一些想法。