机械设计制造及自动化毕业设计英文翻译资料.docx
《机械设计制造及自动化毕业设计英文翻译资料.docx》由会员分享,可在线阅读,更多相关《机械设计制造及自动化毕业设计英文翻译资料.docx(10页珍藏版)》请在冰豆网上搜索。
机械设计制造及自动化毕业设计英文翻译资料
ANOVELINTEGRATEDSYSTEMFORRAPIDPRODUCTDEVELOPMENT
Thispaperpresentsanovelintegratedsystemofrapidproductdevelopmentforreducingthetimeandcostofproductdevelopment.Thesystemiscomposedoffourbuildingblocks—digitalprototype,virtualprototype,physicalprototypeandrapidtoolingmanufacturingsystem.Itcanaideffectivelyinproductdesign,analysis,prototype,mould,andmanufacturingprocessdevelopmentbyintegratingcloselythevariousadvancedmanufacturingtechnologieswhichinvolvethe3DCAD,CAE,reverseengineering,rapidprototypingandrapidtooling.Furthermore,twoactualexamplesareprovidedtoillustratetheapplicationofthisintegratedsystem.Theresultsindicatethatthesystemhasahighpotentialtoreducefurtherthecycleandcostofproductdevelopment.
Keywords:
Rapidproductdevelopment;rapidprototyping;integratedsystem.
1.Introduction
Duetothepressureofinternationalcompetitionandmarketglobalizationinthe21stcentury,therecontinuestobestrongdrivingforcesinindustrytocompeteeffectivelybyreducingmanufacturingtimesandcostswhileassuringhighqualityproductsandservices.Currentindustriesarefacingthenewchallenges:
quickresponsetobusinessopportunityhasbeenconsideredasoneofthemostimportantfactorstoensurecompanycompetitiveness;manufacturingindustryisevolvingtowarddigitalization,networkandglobalization.Therefore,newproductsmustbemorequicklyandcheaplydeveloped,manufacturedandintroducedtothemarket.Inordertomeetthedemandofrapidproductdevelopment,thevariousnewtechnologiessuchasreverseengineering(RE),3DCAD,rapidprototyping(RP),andrapidtooling(RT)haveemergedandareregardedaskeyenablingtoolswiththeabilitytoshortentheproductdevelopmentandmanufacturingtime.Forexample,ithasbeenclaimedthatRPcancutnewproductdevelopmentcostsbyupto70%andthetimetomarketby90%.1Intheformofabetterdesign,moredesignpossibilities,a3DCADmodelcanbeshowntothecustomerforapprovalandpreventsmisunderstandings.Avirtualprototypingisemployedtoguideinoptimizationoftheproductdesignandmanufacturingprocessplanning,whichmayresultintheaccuratedeterminationoftheprocessparameters,andreducethenumberofcostlyphysicalprototypeiterations.Rapidtoolingtechniqueoffersafastandlowcostmethodtoproducemoulds,andshowsahighpotentialforfasterresponsetomarketdemands.Whenproperlyintegratedamong3DCAD,CAE,RE,RPandRT,thesetechnologieswillplayamuchmoreimportantroletoreducefurtherthedevelopmentcycleandcostoftheproductproduction.Onthebasisofabovetechnologies,anovelintegratedsystemofrapidproductdevelopmentistobefoundedsoastomeettherequirementofrapidproductdevelopment.
2.ArchitectureoftheIntegratedDevelopmentSystem
Thedevelopmentprocessfrominitialconceptualdesigntocommercialproductisaniterativeprocesswhichincludes:
productdesign;analysisofperformance,safetyandreliability;productprototypingforexperimentalevaluation;anddesignmodification.Therefore,anystepofthenewproductdevelopmentprocesshasadirectandstronginfluenceontime-to-marketinshortorder.Agoodproductdevelopmentsystemmustenabledesignersordesignteamstoconsiderallaspectsofproductdesign,manufacturing,sellingandrecyclingattheearlystageofthedesigncycle.Sothatdesigniterationandchangescanbemadeeasilyandeffectively.Themorefluentthefeedbackisthehigherpossibilityofsuccessthesystemhas.Designformanufacturing(DFM)andconcurrentengineering(CE)necessitatethatproductandprocessdesignbedevelopedsimultaneouslyratherthansequentially.
Theintegratedsystemofrapidproductdevelopmentiscomposedoffourmodules:
digitalprototype,virtualprototype,physicalprototypeandrapidtooling.Theproductdevelopmentstartsfromthecreationofa3DCADmodelusingaCADsoftwarepackage.Atthatstage,theproductgeometryisdefinedanditsaestheticanddimensionalcharacteristicsareverified.Themainfunctionofdigitalprototypeistoperform3DCADmodelling.TheCADmodelisregardedasacentralcomponentofthewholesystemorprojectinformationbasewhichmeansthatinalldesign,analysisandmanufacturingactivitiesthesamedataisutilized.Theproductanditscomponentsaredirectlydesignedona3DCADsystem(e.g.Pro/Engineer,Unigraphics,CATIA,IDEAS,etc.)duringthecreativedesign.Ifaphysicalpartisready,themodelcanbeconstructedbythereverseengineeringtechnique.REisamethodologyforconstructingCADmodelsofphysicalpartsbydigitizinganexistingpart,creatingadigitalmodelandthenusingittomanufacturecomponents.REcanreducethedevelopmentcyclewhenredesignsbecomenecessaryforimprovedproductquality.Preexistingpartswithfeaturesforimprovedperformancecanbereadilyincorporatedintothedesiredpartdesign.Therefore,itisveryusefulincreatingtheCADmodelofanexistingpartwhentheengineeringdesignislostorhasgonethroughmanydesignchanges.Whenadesignercreatesanewdesignusingmock-up,itisalsonecessarytoconstructtheCADmodelofthemock-upforfurtheruseofthedesigndatainanalysisandmanufacturing.ThethreeprimarystepsinREprocessarepartdigitization,featuresextraction,andCADmodelling.Partdigitizationisaccomplishedbyavarietyofcontactornon-contactdigitizers.Therearevariouscommercialsystemsavailableforpartdigitization.Thesesystemsrangefromcoordinatemeasuringmachine(CMM),laserscannerstoultrasonicdigitizers.Theycanbeclassifiedintotwobroadcategories:
contactandnon-contact.Lasertriangulationscanner(LTS),magneticresonanceimages(MRI),andcomputertomography(CT)arecommonlyusedasnon-contactdevices.ContactdigitizersmainlyhaveCMMandcross-sectionalimagingmeasurement(CIM).Featureextractionisnormallyachievedbysegmentingthedigitizeddataandcapturingsurfacefeaturessuchasedges.Partmodellingisfulfiledthroughfittingavarietyofsurfacestothesegmenteddatapoints.
Inordertoreducetheiterationsofdesign-prototype-testcycles,increasetheproductprocessandmanufacturingreliability,itisnecessarytoguideinoptimizingtheproductdesignandmanufacturingprocessthroughvirtualprototype(VP).VPisaprocessofusing3DCADmodel,inlieuofaphysicalprototype,fortestingandevaluationofspecificcharacteristicsofaproductoramanufacturingprocess.ItisoftencarriedoutbyCAEandvirtualmanufacturingsystem.Computeraidedengineering(CAE)analysisisanintegralpartoftime-compressiontechnologies.Varioussoftwaretoolsavailable(i.e.ANSYS,MARC,I-DEAS,AUTOFORM,DYNAFORM,etc.)canspeedupthedevelopmentofnewproductsbyinitiatingdesignoptimizationbeforephysicalprototypesarebuilt.TheCADmodelscanbetransferredtoaCAEenvironmentforananalysisoftheproductfunctionalperformanceandofthemanufacturingprocessesforproducingtheproduct’scomponents.Ithasalsoproventobeofgreatvalueinthedesignoptimizationofpartgeometry,todetermineitsdimensionsandtocontrolwarpageandshrinkagewhileminimizingprocess-inducedresidualstressesanddeformations.Virtualmanufacturingsystem(VM)isthenaturalextensionofCAE.Itsimulatestheproductfunctionalityandtheprocessesforproducingitpriortothedevelopmentofphysicalprototypes.VMenablesadesignertovisualizeandoptimizeaproductprocesswithasetofprocessparameters.Thevisualizationofavirtuallysimulatedpartpriortophysicalfabricationhelpstoreduceunwantedprototypeiterations.Therefore,aproductvirtualmanufacturingsystemmayresultinaccuratedeterminationoftheprocessparameters,andreducethenumberofcostlyphysicalprototypeiterations.3DCADmodelandVPallowmostproblemswithunfittingtobecomeobviousearlyintheproductdevelopmentprocess.AssembliescanbeverifiedforinterferenceasVPcanbeexercisedthrougharangeoftasks.StructureandthermalanalysiscanbeperformedonthesamemodelemployingCAEapplicationsaswellassimulatingdown-streammanufacturingprocesses.ItisclearthatVPincreasesprocessandproductreliability.AlthoughVPisintendedtoensurethatunsuitabledesignsarerejectedormodified,inmanycases,avisualandphysicalevaluationoftherealcomponentisneeded.Thisoftenrequiresphysicalprototypetobeproduced.Hence,oncetheVPisfinished,themodelmayoftenbesentdirectlytophysicalfabrication.
TheCADmodelcanbedirectlyconvertedtothephysicalprototypeusingaRPtechniqueorhigh-speedmachining(HSM)process.The3DCADmodelistobeexportednotonlyintheSTLformatwhichisconsideredthedefactostandardforinterfacingCADandRPsystems,butalsointheNCcodingwhichcanbeusedbyHSM.HSMhasapotentialforrapidproducingplasterorwoodenpatternforRT.RPisanewformingprocesswhichfabricatesphysicalpartslayerbylayerundercomputercontroldirectlyfrom3DCADmodelsinaveryshorttime.Incontrasttotraditionalmachiningmethods,themajorityofrapidprototypingsystemstendtofabricatepartsbasedonadditivemanufacturingprocess,ratherthansubtractionorremovalofmaterial.Therefore,thistypeoffabricationisunconstrainedbythelimitationsattributedtoconventionalmachiningapproaches.TheapplicationofRPtechniqueasausefultoolcanprovidebenefitsthroughouttheprocessofdevelopingnewproducts.Specifically,thereareseriousbenefitsthatRPcanbringintheareasofmarketresearch,salessupport,promotionalmaterial,andtheever-importantproductlaunch.PhysicalRPcanals