外文翻译--工程师的CAx培训--不仅仅是CAD 英文版.pdf

EngineersCAxeducationitsnotonlyCADC.WernerDankwort,RolandWeidlich*,BirgitGuenther,JoergE.BlaurockUniversityofKaiserslautern,ResearchGroupforComputerApplicationandEngineeringDesign,P.O.Box3049,Kaiserlautern67663,GermanyReceived30January2004；accepted23February2004AbstractThegeneralproductdevelopmentcanbedividedintothreephases:creative,conceptualandengineeringphase.AllphasesofthecompletelifecycleofaproductaresupportedbyvariousIT-systemsoftencalledCAx1-systems.ThereforeCAD-educationshouldbeextendedtoCAx-educationandpayattentiontoallphasesofthelifecycle.WhenlookingattodaysprocesschainmanydifferentjobsrelatedtoCAxcanbeidentified.Allofthemrequiredifferentlevelsofknowledgeaboutsubjectslikeinformationtechnology,designproceduresorCAGD2-functionalities.Themethodstoteachthosesubjectsvaryfromsimpleautodidactic,viacomputersupportedtrainingmethodstointeractivepersontopersontraining.Inindustry,thetrainingmethodsareprimarilydependingonthecompanyssizeandbranch.Thebiggerthecompanyis,themorecomplexarethetrainingmethodsandthemorespecializedistheCAx-education.EnterprisesspecialisedonCAx-trainingbutalsoin-houseeducationdepartmentsareconcerned.OtherpossibilitiesforCAx-educationareinternships,technicalcollegesanduniversities.Allofthosesufferfromthecomplexityofthesubjectandresultofteninbroadbutsuperficialeducation.ApartfromknowledgeaboutCAx-systemsandtheirusage,thestudentshavetolearnalsoabouttheorganisationoftheCAx-processanditsstructuresincludingthecooperationofenterprises.FollowingtheseexperiencesthestudentsoremployeeswillatfirstbetrainedinfundamentalCAS/CAD/CAM.InasecondsteptheywillattendspecialcoursesforPDM,Dataexchange,FEM,orothers.OnhigherleveltherewillbecoursesdealingwithPLM3,process-andcompanynetworks,withfuturetrendsandtechniques.Duringthewholeeducationtheapplicationaspecthastobedominant.q2004ElsevierLtd.Allrightsreserved.Keywords:CAxjobprofiles；Humanfactors；Trainingmethods；CAxeducationinindustry；CAxeducationinuniversities1.MotivationInanewsletteroftheyear1999fromSolidWorksthefollowingquestionwasraised:“Whatisthemostimportantlearningobjective?”Theanswergivenwas“Toteachthatdesignisaprocess!”Lateroninthisnewsletteritwassaidthatengineeringeducationissupposedtoeducateengineersinhowtothinkinthemodernworldofproductdesignandmanufacturing1WhatdoesthismeanforCAD-educationinindustry,atschoolsanduniversities?ItcertainlydoesnotmeanthatCAD-educationisonlyrestrictedtoteachingsolidorsurfacemodelling.Thetaskisquitemorecomplex:thestudentortechnicalemployeehastolearnaboutthecompletedevelopmentprocessundertheaspectofCompu-terAidedProductCreation.2.AbriefhistoryofCAD-systemsModernCAx-systemshavevariousroots:TheAutomaticProgrammingTool(APT)developedbyRossatMITinthe1950stocontrolmachinesnumerically.ThiscanberegardedastheprecursorofmodernCAM-systems.Theearlycomputeraideddraftingsystems(likeCADAMfromLockheedMartin)weredevelopedto0010-4485/$-seefrontmatterq2004ElsevierLtd.Allrightsreserved.doi:10.1016/j.cad.2004.02.011Computer-AidedDesign36(2004)14391450/locate/cad*Correspondingauthor.Tel.:49-631-205-3686；fax:49-631-205-3872.E-mailaddress:weidlichmv.uni-kl.de(R.Weidlich).1CAx:SummarisedCAD,CAM,CAS,CAQ,2CAGD:ComputerAidedGeometricDesign3PDM:ProductDataManagement,PLM:ProductLifecycleManagementreducetimeandmoneybyreplacingtheconventionaldrawingboardinthe1970s.Theearlysystemsforthecreationofsculpturedsurfacesoriginallyweredevelopedfortheautomobileandthehelicopterindustry.Themotivationforthisdevelopmentwasnotthereductionintimebutadistinct3D-representationofsculpturedsurfaceswhichthencouldbeusedforNC-milling.This3D-surfacerepresentationcouldnotbecreatedwithconventional2D-drawingsandcutsections.ComputerAidedEngineeringbyFinite-Element-Methodsbeganinthe1960swithNastran,followedbyMarcandAnsysinthe1970s.FromtheserootsmoreandmoretasksinthedesignprocessweresupportedbyCAx-toolsduringthelast30years.Startingwithdraftingandsurfacingalsoclassicalmechan-icaldesignwasreplacedby3Dwireframe,solidmodellingandparametricandfeaturebaseddesign.Todaythecompleteproductcreationprocess,includingproductionpreparation,iscompletelyrunningwithCAx-techniques.AccordingtothevariousapplicationfieldsdifferentCAx-systemsweredeveloped,namedbydifferentCAx-methods:ComputerAidedStyling(CAS),ComputerAidedAestheticDesign(CAAD),ComputerAidedConceptualDesign(CACD).AllthesetechnologiesarecoveredbytheexpressionComputerAidedDesign(CAD).TwoveryimportantCA-fieldswerehistoricallydevelopedalmostindependently:ComputerAidedManufacturing(CAM)andComputerAidedEngin-eering(CAE).ThelastismainlyusedinalimitedsenseforsimulationandFiniteElementAnalysis.Althoughstartingindependentlythesetechnologiessoonaskedforinput-datafromCAD,I-DEAS,developedinthemid1970shasitsrootinthelinkofCADandFEA.WiththegrowingintegrationoftheseCAx-toolsthedataandinformationmanagementbecamemoreandmoreimportant.NowadaysthecomplexnetworkofCAx-systemsandtheirvariousdatacannotbehandledwithoutProductDataManagementSystems(PDMS).Theyareregardedasthebackboneofmodernproductdevelopmentandnowextendedtosupportthewholeproductlifecycle.Thisover-allinformationmanagementleadstotheconceptofProductLifecycleManagement(PLM).EducationconcerningComputerAidedProductCre-ationstilldoesreflectthishistory:Studentsorengineersusuallystarttheireducationwith2D-systems.Subsequentlytheyareintroducedto3D-modelling.Furtherontheyarefamiliarizedwithparametricandvariationaldesign.ParalleltheyhavetobetrainedinPDM-orPLM-systemstohandlealltheCAx-data.3.TodaysprocesschainInanexemplarysimplifiedprocesschain(seeFig.1)itisshownthatCADisonlyapartoftheproductdevelopmentprocess.Thisprocessbeginswithanidea,requirementsandspecificationsfortheproductandendswiththeserialproduction,customeraftersalesservice,recycling,scrap-pinganddisposal.CADisembeddedinthedevelopmentprocesstogetherwithmanyotherCAxtechnologies.InorderFig.1.Generalprocesschainofproductdevelopment2.C.W.Dankwortetal./Computer-AidedDesign36(2004)143914501440toavoidunnecessaryloopstheengineerhastohaveknowledgeofthesurroundingprocessstepsaswellasthekindandqualityofdata,respectivelyinformation,theyproduceorrequire.Theknowledgeaboutthepreviousprocessstepsistomaintainthedesignintend,theknowl-edgeaboutthefollowingprocessstepsistoguaranteetheirfeasibility.Inadditiontothiseconomicalaspectthequalityoftheproductdescribinginformationhastobetakenintoaccount.Themodernproductcreationprocessproceedsmoreandmoreasavirtualproductgenerationprocess.KeepinginmindthattheprocessesarecharacterizedbySimultaneousEngineering(performingdifferentprocessstepsatthesametime)andConcurrentEngineering(developingneighbouringcomponentsinparallel),itisobvious,thatanenormousamountofdataproducedhastobehandledbyanefficientproductdatamanagementsystem(PDM).Twofactsincreasethecomplexityofthesituation:FordifferenttaskswithinoneorvariousprocessstepssometimesquitedifferentCAx-systemshavetobeusedwithquitedifferentdatamodels.Inmodernindustryanetworkofsuppliersisinvolved,oftenworkingwithdifferentsystemsordifferentversionsofthesamesystem.ThereforenotonlyCAx-dataexchangewithdataconversionisakeytaskforsuccessfuldevelopmentandproductionprocessesbutalsothecompletesupplierintegration.4.CAxpeople:variousjobprofilesWhenlookingatthehistoryofCAD,thefirstusersofCA-toolsinthe1970swereCAD-draftsmenandCAD-surfacedesignerforcarbodiesorhelicoptershells(todayoftencalledsurfacer).Alreadyinthe1970sthesurfaceswereuseddirectlyforNC-millingofsurfaces,whiletheFEA-engineerusedtheCAD-geometryasinput.Draftsmanandsurfacersweretrainedprimarilybysystemsuppliersand/orbyanin-houseCAD-technician.TheseCAD-techniciansoftenhavebeenpilotusers,trainers,andin-housesystemsupportersatthesametime.Thesepioneersmadethenewtechniquepresentableandreducedprejudices,whichhadbeenraisedbytheconven-tionaldevelopment.WiththegrowingcapabilitiesoftheCAD-systemsinthefirsthalfofthe1980sthenumberofdifferentCADpeoplegrew.Inthe1990sthescopeofCAx-toolsincreasedandtodayCAx-technologyismoreorlessstandard.NowadaystheintensiveusageofCAx-technologiescanberegardedasapreconditionforanycompetitivecompany.Asaconsequencethevarioustaskscausevariousjobs.Followingtheprocesschainthereare(seeFig.1):Stylists,whoworkmanually,sketchingandmodellingwithclay,butalsomoreandmorewithCAS-systemslikeALIASSurfacers,whotransfertheshapes,designedbythestylists,toCA-Class-A-surfaces.Theyusespecialsurface-systemslikeICEM-SurforinformertimesSTRIM100.CNC-Modelmakers,whouseCAM-techniquestogeneratephysicalmodelsfromCAS-orCAD-data.Thisisdonetotransfertheshapesfromthevirtualworldtothephysicalworld.TofillthegapbetweenamanuallyoptimizedphysicalmodelandtherequiredCAD-surfacedescriptionaspecialtaskisnecessary:Thesurfacereconstructionorreverseengineering(ofshapes)InthefieldofstandardengineeringdesigntherearetheCAD-designersorCAD-engineers,whoareworkingwith3D-systems.Accordingtotheirtasks,workingfieldsandthelevelofCAD-applicationtheyareusingwireframetechniques,surface-systemsand/orsolidmodelling.Now,withintroductionofmoresophisticateddesigntechniquesandwiththeincreasinginformation,whichisstoredinaCAD-model,manyfieldsofCAD-applicationsandrelatedspecialjobprofilescanbedistinguished:Componentdesigners.Theyareinchargeofthedesignofspecialcomponentsoftheproduct.EngineersforParametric-AssociativeDesignCAD-designersfortoolsandqualityaids.ProcessplanersManufacturingsimulatorsCA-plantlay-outersParalleltotheCAD-designthesimulationofproductpropertiesisanotherimportanttaskintheproductdevelopment,whichgivesanotherjobprofile:Engineersforsimulation,analysisandcalculation.Togeneratereliableresultstheyusuallyarehighlyspecial-izedoncertaintasks.Consequentlythisjobprofilecouldbefurtherstructured.Informertimestheseengineersforsimulationoftenworkedinisolateddepartments,startingtheanalysiswhenthedesignhadbeenpreliminarilyfinished.Nowadaysthesetasksarecompletelyintegratedinthedesigndepartmentandgoalongwiththedesign.AtthemomentthereisatendencythattheengineersperformapreliminaryanalysiswithintheirCAx-systemtoevaluatetheirdesign.ThislistofpeopleandtasksinvolvedinCAxcanbecontinued,allofthemneedatleastsomeCAx-knowledge:SpecialistsforCAx-graphicsgenerationClerkswithinthepurchasingdepartmentsforarrangingcontractsbetweenOEMandthesubcontractorsC.W.Dankwortetal./Computer-AidedDesign36(2004)143914501441andsuppliers.SW-designandSW-implementationApplicationSWdefinitionCAx-systemsinoperationCAx-systemtestingandSW-qualitycontrolComputercentreandnetworkoperationInformationmanagementCAx-dataexchange:developmentandoperationofSW-toolsTheseexamplesshowthatthereisavarietyofdifferentjobs,eachneedingdifferentknow-howinthedifferentfields.SomeexamplesaregiveninFig.2.Industrialexpertsestimated,thatforoneCAD-work-stationabout10otherworkstationsareusedinsubsequentactivitieslikeviewingetc.3.5.TheHumanFactorandtheenvironmentThedifferentknowledge,whichisneededfororwhichisgainedinthedifferentjobs,isoneaspect.AnotherveryimportantaspectintrainingpeoplefortheirCAx-jobisthehumanfactor.Therearethreepointswhichhavetobeconsidered:Thepast,theeducationandtheexperienceofapersonThehumanpotential,theabilitytofulfilthetasksofmodernproductdevelopmentwithCAx-andInformationManagementtools.Theenvironmentinwhichapersonhasworkedbeforeandinwhichitisgoingtoworknext.Eachofthepointsabovewillbebrieflydescribedinthefollowing,alreadyshowingthecomplexityofmodernCAx-educationandthatthereisnothinglikeastandardizedCAD-education.5.1.Thepast,theeducationandtheexperienceofapersonEachpersonhasadifferentbackgroundand,ashis/hermindisstronglyinfluencedbyit,thewayofthinkingandlearningwillbedifferentfrompersontoperson.Anexample:Informertimesitwasastrenuoustasktomakedesigners,whohadworkedmanyyearsatdraftingtables,useaCAD-systemefficiently.Forthemthismeanttoapproachproblemsinacompletelynewway.Buttheexperience,whichwasgainedbysolvingproblemstheclassicalway,oftengotlost.Itcouldnotbetransferredtoyoungengineers,whostartedtheircareeronCAD-systems.ThisexampleshowsoneofthedutiesofCAx-education:Toteachalsosomedesignmethodsusedinformer(pre-CAD-)timetomakeusersawareofdifferentwaysofthinkingandofapproachingproblemsinordertoavoidriskslike:TherestrictionofthethinkingtothelimitsgivenbythecapabilityoftheIT-toolinuse.5.2.Th