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

《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