Lesson 19 Introduction to machine design 机械专业专业英语教学用书教学教案PPT课件下载推荐.pptx
《Lesson 19 Introduction to machine design 机械专业专业英语教学用书教学教案PPT课件下载推荐.pptx》由会员分享,可在线阅读,更多相关《Lesson 19 Introduction to machine design 机械专业专业英语教学用书教学教案PPT课件下载推荐.pptx(14页珍藏版)》请在冰豆网上搜索。
Lesson19Introductiontomachinedesign,Machinedesignistheapplicationofscienceandtechnologytodeviseneworimprovedproductsforthepurposeofsatisfyinghumanneeds.Itisavastfieldofengineeringtechnologywhichnotonlyconcernsitselfwiththeoriginalconception(最初的概念)oftheproductintermsofitssize,shapeandconstructiondetails,butalsoconsidersthevariousfactorsinvolvedinthemanufacture,marketinganduseoftheproduct.,Lesson19Introductiontomachinedesign,Peoplewhoperformthevariousfunctionsofmachinedesignaretypicallycalleddesigners,ordesignengineers.Machinedesignisbasicallyacreativeactivity.However,inadditiontobeinginnovative(革新的),adesignengineermustalsohaveasolidbackgroundintheareasofmechanicaldrawing,kinematics,dynamics,materialsengineering,strengthofmaterialsandmanufacturingprocesses.,Lesson19Introductiontomachinedesign,Asstatedpreviously,thepurposeofmachinedesignistoproduceaproductwhichwillserveaneedforman.Inventions,discoveriesandscientificknowledgebythemselvesdonotnecessarilybenefitpeople;@#@onlyiftheyareincorporatedintoadesignedproductwillabenefitbederived.Itshouldberecognized,therefore,thatahumanneedmustbeidentifiedbeforeaparticularproductisdesigned.,Lesson19IntroductiontomachinedesignMachinedesignshouldbeconsideredtobeanopportunitytouseinnovativetalentstoenvisionadesignofaproduct,toanalyzethesystemandthenmakesoundjudgments(合理的判断)onhowtheproductistobemanufactured.Itisimportanttounderstandthefundamentalsofengineeringratherthanmemorizemerefactsandequations.Therearenofactsorequationswhichalonecanbeusedtoprovideallthecorrectdecisionsrequiredtoproduceagooddesign.Ontheotherhand,anycalculationsmademustbedonewiththeutmost(极度的)careandprecision.Forexample,ifadecimalpointismisplaced,anotherwiseacceptabledesignmaynotfunction.,Lesson19Introductiontomachinedesign,Gooddesignrequiretryingnewideasandbeingwillingtotakeacertainamountofrisk,knowingthatifthenewideadoesnotworktheexistingmethodcanbereinstated(使复职).Thusadesignermusthavepatience,sincethereisnoassuranceofsuccessforthetimeandeffortexpended.Creatingacompletelynewdesigngenerallyrequiresthatmanyoldandwell-establishedmethodsbethrustaside(推开).,Lesson19Introductiontomachinedesign,Duringthebeginningstagesofdesign,creativityshouldbeallowedtoflourishwithoutagreatnumberofconstraints.Eventhoughmanyimpracticalideasmayarise,itisusuallyeasytoeliminatethemintheearlystagesofdesignbeforefirmdetailsarerequiredbymanufacturing.Inthisway,innovativeideasarenotinhibited(抑制).Quiteoften,morethanonedesignisdeveloped,uptothepointwheretheycanbecomparedagainsteachother.Itisentirelypossiblethatthedesignwhichisultimatelyacceptedwilluseideasexistinginoneoftherejecteddesignsthatdidnotshowasmuchoverallpromise.,Lesson19Introductiontomachinedesign,Psychologistsfrequentlytalkabouttryingtofitpeopletothemachinestheyoperate.Itisessentiallytheresponsibilityofthedesignengineertostrivetofitmachinestopeople.Thisisnotaneasytask,sincethereisreallynoaveragepersonforwhichcertainoperatingdimensionsandproceduresareoptimum(这不是一件容易的工作,因为实际上并不存在着一个对所有人来说都是最优的操作范围和操作过程).,Lesson19Introductiontomachinedesign,Anotherimportantpointwhichshouldberecognizedisthatadesignengineermustbeabletocommunicateideastootherpeopleiftheyaretobeincorporated(一起工作的的).Initially,thedesignermustcommunicateapreliminary(预备的)designtogetmanagementapproval.Thisisusuallydonebyverbaldiscussionsinconjunctionwithdrawinglayouts(草图)andwrittenmaterial.Tocommunicateeffectively,thefollowingquestionsmustbeanswered:
@#@,Lesson19Introductiontomachinedesign,Doesthedesignreallyserveahumanneed?
@#@Willitbecompetitivewithexistingproductsofrivalcompanies?
@#@Isiteconomicaltoproduce?
@#@(4)Canitbereadilymaintained?
@#@(5)Willitsellandmakeaprofit?
@#@,Lesson19Introductiontomachinedesign,Onlytimewillprovidethetrueanswerstotheprecedingquestions,buttheproductshouldbedesigned,manufacturedandmarketedonlywithinitialaffirmativeanswers.Thedesignengineeralsomustcommunicatethefinalizeddesigntomanufacturingthroughtheuseofdetailandassemblydrawings.,Lesson19Introductiontomachinedesign,Quiteoften,aproblemwilloccurduringthemanufacturingcycle.Itmaybethatachangeisrequiredinthedimensioningortolerancingofapartsothatitcanbemorereadilyproduced.Thisfallsinthecategoryofengineeringchangeswhichmustbeapprovedbythedesignengineersothattheproductfunctionwillnotbeadverselyaffected.,Lesson19Introductiontomachinedesign,Inothercases,adeficiencyinthedesignmayapp