CADCAM 原理与应用（英文版）课件 intro to course project、Part 1 An overview of CAD CAM、Part 2 Solid modeling

CAD/CAM:PrinciplesandApplicationsCAD/CAM原理与应用Preface:IntroductiontoCourseProject主讲人：康兰Lecturer:KangLanCollegeofMechanicalandElectricalEngineering,HohaiUniversity（河海大学机电工程学院）

Whytakeacourseproject?RequirementsIntroductiontoCourseProjectWheredodesignideascomefrom?Whytakeacourseproject?Engineeringstudentsareproblem-solvers,sostudentsareexpectedtolearnknowledgeintheclass,andapplywhattheyknowtosolveauthenticproblemsafterclass.Inotherwords,learningbydoingisalwaysthebestmethod.SoIencouragestudentstotakeadvantageofdigitaltoolstodesigndigitalproductswithhighquality.Therefore,courseprojectswillbeassignedforstudents,studentscanworkinateamorindividually.Whytakeacourseproject?Projectsmaycomefromenterprises,orbegivenbyyoursupervisors,orbeconceivedbyyourselves.Forteamwork,usually2or3studentsworktogetheronaproject.RequirementsBytheendofthecourse,studentsarerequiredtoprovide:2.students’in-classpresentationsontheirprojects.1.projectreportsaswellas3Ddigitalmodelsofproducts.*Ifthereisnoenoughtimetodosoforallstudents,theteacherwillpickupseveraltopdesignstobepresentedinclass.Wheredodesignideascomefrom?Creativeideascomefromourdailylife!!!

Mechanicalengineersareproblemsolvers!!!

Someideastohelpyougetstartedthinkingaboutpossibleprojects.

Becreative—don’tfeellimitedbytheseideas1.Observeproductsyouuseinyourdailylives,findtheirflawsindesign,thenimprovethemanddesignyourownproduct.Forexample,thinkaboutroundtablesinrestaurants,isitpossiblethatwecanchangethesizeofthetableaccordingtothenumberofdiners?Wheredodesignideascomefrom?P.S:Thisdesignwasdoneby康兰and王义斌PlaythevideoWheredodesignideascomefrom?2.Inourdailylives,eventherearealotofniceproductstoserveus,stillyoucancreateanotheronetoserveusbetter.Forexample:Wheredodesignideascomefrom?AKids’scooterWheredodesignideascomefrom?AKids’scooterWheredodesignideascomefrom?P.S:Thisdesignwasdoneby康兰PlaythevideoWheredodesignideascomefrom?3.Inmechanicalengineering,youcandevelopsomedesignideasfromobservationofdifferentmachines.Forexample:roboticarmsWheredodesignideascomefrom?Theideamatters!!!

ENDAsengineersifyoucansolvethose“smallsimpleproblems”throughyourdesign,somedayyouareabletosolvethose“bigcomplicatedengineeringproblems”,sodon’thesitate,gettingstartedwithyourcourseprojectfirst.主讲人：康兰CAD/CAM:PrinciplesandApplicationsCAD/CAM原理与应用CollegeofMechanicalandElectricalEngineering,HohaiUniversity（河海大学机电工程学院）

Part1:AnOverviewofCAD/CAMContents1.1ConceptofCAD/CAM1.3ProcessofComputerAidedManufacturing1.4IntegrationofCAD/CAM1.5CAD/CAMEnvironment1.7HistoryandTrendsofCAD/CAM1.6ApplicationsofCAD/CAM1.2ProcessofDesigningProducts1.8TipsforStudents1.1.1Introduction1.1.2ConceptofComputerAidedDesign

Wearenowlivinginainformationage.

CADistheuseof

computer

systemstoassistinthecreation,modification,analysis,oroptimizationofa

design.Communicationsamongengineershavebeeninthedigitalformat.

CAD/CAE/CAMhavealreadygainedwideacceptanceinindustry.

1.1ConceptofCAD/CAMFigure1.1TheInputandOutputofaCADSystem1.1ConceptofCAD/CAMCADinvolvesthecreationandpreparationofanengineeringdocumentation,suchas:

3Ddigitalmodelofareducer

CharacteristicsofaCADSystemCADSystemTeamworkandEffectiveCommunicationsIntegrationofEngineeringAnalysisIntegrationofCAMCreativity,InnovationandMulti-disciplines1.1ConceptofCAD/CAM1.1ConceptofCAD/CAMeDrawingsisatypicalexampleforteamworkandeffectivecommunications.

CollaborateWithoutConstraints:eDrawingsenables3Dcollaborationwithouthavingtoworryaboutsoftwarecompatibility.ItsupportsthecreationofeDrawingsfromSolidworks,AutoCAD,Inventor,Pro/ENGINEER,CATIA,SIEMENSNX,SolidEdge,PTCCREOsoftwareandSketchUp.AnexampleinSolidworks1.1ConceptofCAD/CAMeDrawingsensureseasytwowaydesigncommunicationwithinternalandexternalprojectstakeholder.

WitheDrawingsyouhavecompletecontrolofyourdesignIntellectualPropertysharingonlywhatyouneed

toshared,whileenablingeasyproductcommunicationtoensureontimetomarketdelivery.eDrawingsViewer

Mobile

deliversAR(foriOSandAndroid)and

VR(foriOS)modesthattakesmobiledesigncommunicationtothenextlevel.1.1ConceptofCAD/CAMAnotherexample:SolidworksWorkgroupPDMprovidesanotherkindofteamworkandeffectivecommunicationsfordesigners1.Introduction2.ConceptofCAM

TheoriginalideaofCAMcamefromeffortstofacilitatetheflowfromthedesignprocesstothemanufacturingprocessusingnumericalcontrol(NC)technologiesTheuseofcomputersandcomputertechnologytocontrol,manage,operate,andmonitormanufacturingprocesses.

1.1.3ConceptofCAM1.1ConceptofCAD/CAMFig.TheInputandOutputofaCAMSystem1.1ConceptofCAD/CAM1.2ProcessofDesigningProductsFig.Processofdesigningproducts1.Domarketresearch,findaneed.Anexample:designanewwristexercisedevice2.Conceptualdesign.1.2ProcessofDesigningProductsP.S:Thisdesignwasdoneby康兰3.Createa3Ddigitalmodel.1.2ProcessofDesigningProducts4.Produceaprototypetoverifythedesign.5.Improvethedesign.6.Putitintoproduction.1.3ProcessofComputer-AidedManufacturingWhyisfeaturerecognition(FR)neededinCAMsystem?1.3ProcessofComputer-AidedManufacturingFeaturesdefinedduringdesignprocess(CADmodels)aredifferentfrommanufacturingfeatures.

AutomaticFeatureRecognition(AFR)isregardedasanidealsolutiontoautomate/integratedesignandmanufacturingprocesses.FeaturerecognitionisneededtoextractthesemanufacturingfeaturesfromexistingCADmodels.

FRandAFRhavebeenanactiveresearcharea,andreceivedsignificantattentionforthedevelopmentofComputerIntegratedManufacturing(CIM).1.3ProcessofComputerAidedManufacturingThefinalmissionofCAMsystemistogenerateG-codewhichcanbeusedtodriveaCNCmachinetoproducetheproduct."G-code":alinkorabridgebetweenCAD/CAM/CNCsystems."STEP-NC":apossiblereplacementof"G-code",itisanewmodelofdatatransferbetweenCAD/CAMsystemandCNCmachines.Theresearchworkon“STEP-NC”isundergoing.Theresearchworkwasinitiatedbyseveralresearchinstitutesanduniversitiesaroundworld.1.4IntegrationofCADandCAMWhyisintegrationneeded?Inthebeginning,therewereonlyCADsystems.EngineersusedCADsystemstodraftdrawingsofparts.ThefirstCAMsystemshelpedanNCprogrammer(machinist/manufacturingengineer)programfromthesedrawings.Thismakingofdrawings,andprogrammingpartsfromdrawings,was(andstillis)timeconsumingandsubjecttoalotofhumanerror.Someonegotthebrightideatoeliminatethisto-and-fromdrawingstep,andintegratedCAD/CAMwasborn.IntegrationofCAD/CAMhasbeenanactiveresearcharea.However,Today’stechnologyprovidesflexiblealternativestotheoldsameapplicationapproach.HistoricallyallCAD/CAMsolutionsofferinghighlevelsofintegrationhaveachieveditbyputtingallfunctionsinthesamecomputerprogram.

Somedevelopersaretryingtoprovideexcellentintegrationbetweendifferentapplicationsbydevelopingthe3thpartysoftwarebasedonFRandAFRtechnologies.Fewcommercialfeaturerecognitionsystemsarealsoavailable.1.4IntegrationofCADandCAMFeaturerecognitiontechnologycanbeappliedforvariousapplications.Forexamplecommercialsoftwarehaveeffectivelyadoptedfeaturerecognitiontechnologyforrecreatingthefeaturetreefromimportedmodelssothateventheimportedmodelscanbeeditedasifitwereanativesolidmodel,orconvertimported3Dmodelsintonativefeatureaccordingtomodels.SomeCAMsoftwarearealsobuiltusingfeaturerecognitiontechnology.1.4IntegrationofCADandCAMFewCAD/CAMsoftwarehaveusedcommerciallyavailablethird-partyfeaturerecognitionlibrary,whichrecognizesvariousfeaturesfrom3-DB-Repmodels.SomeseparatelibrariesareavailableforDesign,ManufacturingandSheetmetalapplications.Theserecognitionlibrariescanrecognizedifferentfeaturesusedfordifferentpurposes.

FurthermoreresearchworkinFRandAFRareas:Identifyfeaturetypesthatarenotidentifiedbycurrentcommercialsystems.1.4IntegrationofCADandCAMManufacturingfeaturessuchas3-axisand5-axisfeaturerecognitionaregenerallynotavailableinsuchcommercialsystems.

Whatarefeatures?*ThiswillbeintroducedinPart3indetails.1.4IntegrationofCADandCAM1.5CAD/CAMEnvironment1.5.1HardwareEnvironmentThemainhardwarecomponentsofCAD/CAMsystem:workstationsorPCs.plottersandotheroutputdevices,suchas3Dprintersetc.storagedevices.CAD/CAMHardwarecomponentsareavailableinavarietyofsizes,configurationsandcapabilities.1.5CAD/CAMEnvironmentAutoCADCATIANXUnigraphics(UG）Pro/Engineering(PTCCreoorCreoParametric)1.5.2SoftwareEnvironmentSolidworks/SolidCAMCimatronE:mainlyusedformolddesignSolidEdgeAutodeskInventor3DSMAX,Maya,RhinoParametricfeature-basedtechnologyBasicapplications:1.6ApplicationsofCAD/CAMBuild3DModelsofParts

UnfoldFoldandunfoldsheetmetalautomatically.1.6ApplicationsofCAD/CAMBuild3DModelsofAssemblies

FigureA3Ddesignmodelofanassembly1.6ApplicationsofCAD/CAM3DCADmodelsofplasticinjectionmoldsConstructing2Dengineeringdrawingsfrom3Dmodels

AdetailedworkingdrawingAnassemblydrawing1.6ApplicationsofCAD/CAM(a)Toolpathsimulation(b)manufacturingprocesssimulationManufacturingProcessSimulation

(a)Postprocess(b)G-code1.6ApplicationsofCAD/CAMSimulationAnalysis

1.6ApplicationsofCAD/CAMTheaboveapplicationsarethebasicfunctionsformostcommercialCAD/CAMsystem.ThefunctionofCAD/CAMsystemcanbeexpendedwiththehelpofplug-insandtheotherthirdpartysoftware.Watchvideos“whatSolidworkscandoforyou?”.Similarly,allworksthatcanbedonewithSolidworkscanalsobefinishedinother3Dsoftware.Ifyouareusingother3Dsystem,testalltheabovefunctionswithit,andseewhethertherearesuchfunctionsinother3Dsystem.1.6ApplicationsofCAD/CAM

2Dtimelower-end2Dsystems：AutoCAD2Dparametricsystems:CAXA，GH-CAD(高华CAD)

1)3Dwireframemodels2)3DsurfacemodelsHistory

3Dtime3)solidmodels1.7HistoryandTrendsofCAD/CAM5)Directmodeling4)3DparametricsolidmodelsPresent

CAD/CAE/CAMsystemsarenowwidelyacceptedandusedthroughouttheindustry.Future

Anticipatingafullyimmersive3Denvironmentwheremodelingtoolsincludespecialglovesandgoggleswillbeused.—Virtualreality—Augmentedreality1.7HistoryandTrendsofCAD/CAMAgloveAgoggleWatchvideosinVirtual/AugmentedRealitysectiontoknowmoreaboutit.1.7HistoryandTrendsofCAD/CAMTrends

StandardizationIntegrationofCAD/CAM/CAEEmphasisontheproductlifecyclemanagement(PLM）DesigndataanalysisKnowledge-basedmachining(KBM）Automaticfeaturerecognition(AFR)CAMwithfeedrateoptimization1.7HistoryandTrendsofCAD/CAMIncorporatedatafromanyCADsystemMoreefficientanduserfriendlyAutomationMachinetoolsimulation1.7HistoryandTrendsofCAD/CAMSimulationofthemanufacturingprocessMachinetoolsimulationduringmanufacturingprocess

3Dfeature-basedCADmodelswiththeembeddedparametricandassociatecapability,iswidelyusedinmechanicaldesign.1.8TipsforStudentsFeature-basedCADmodelshavebecomeaveryeffectiveandimportantwaytoexpressyourdesignideasinmechanicalengineering.Nowadays,forouryounggenerationyoucannotimaginehowtodesignaproductwithoutthehelpofCADsystem,justlikeyoucannotimaginehowtolivewithoutcellphones.Toliveinthisdigitalworld,youhavetocooperatewiththesenewdigitaltechnologies.Otherwiseyouwillbeout!!1.8TipsforStudentsThejourneyofathousandmilesbeginswithasinglestep.TheendDevelopedbyAssociateProfessor:LanKang(康兰)CAD/CAM:PrinciplesandApplicationsCAD/CAM原理与应用CollegeofMechanicalandElectricalEngineering,HohaiUniversity（河海大学机电工程学院）

Part2:SolidModeling2.1IntroductiontoSolidModelingContents2.2Wireframemodel2.3

SolidModelCreationScheme2.4CSGScheme2.5B-RepScheme2.6SweepingScheme2.7ParametricFeatured-basedSolidmodeling2.8TrendsofSolidModeling2.9IntroductiontoSolidworks

2.1IntroductiontoSolidModelingSolidModelRepresentations:WireframeModelSolidModelSurfaceModel*SurfacemodelingwillbeintroducedinPart4.Solidmodelsareused:inengineeringinentertainmentindustryinmedicalindustry2.2WireframeModelThemainproblemofwireframemodelistheambiguity.Isthisobjecta),b)orc)?Soit’snotusedincurrentcommercialsoftware.2.3SolidModelCreationScheme

Solidmodelscanbegeneratedbythefollowingschemes.(1)ConstructiveSolidGeometry(CSG)(2)BoundaryRepresentation(B-Rep)(3)Sweeping(4)ParametricFeature-basedModels(5)ReverseEngineering(RE)*REwillbeintroducedinPart3.

Basicidea:

solidprimitives+Booleanoperationssolidprimitives:2.4CSGSchemeunion(∪),subtraction(-),intersection(∩)Booleanoperations:2.4CSGSchemeCSGtree2.4CSGSchemeBasicideabehindtreedatabasestructure2.4CSGScheme

Basicidea:AB-Repsolid:asetoffaces+topologicalinformationAnexampleofB-Repsolidscheme2.5B-RepScheme2.5B-RepScheme•Vertex(V):Apointinspace.InB-Rep,amodelismadeupofthefollowing

primitives:•Body(B):Entitythathasfaces,edgesandvertices.•Edge(E):Afinite,no-intersectingspacecurveboundedbytwovertices.•Face(F):Afiniteconnected,non-self-intersecting,regionofaclosedorientedsurface,boundedbyoneormoreloops.•Loop(L):Annon-self-intersectingclosedspacecurve,whichmaybeaboundaryofaface.Awinged-edgerepresentationofarectangularpyramid2.5B-RepSchemeAnexampleofdescribingtopologicalinformationamongfaces.2.5B-RepSchemeInthiscase,tablesareusedforstoringB-Rep.EdgeVerticesFacesLeftTraverseRightTraverseVerticesCoordinatesNameStartEndLeftRightPredSuccPredSuccV1E1V1V2F5F1E5E1E6E5V2E2V2V3F5F2E1E3E7E6V3E3V3V4F3F2E4E2E7E8V4E4V4V1F5F4E3E1E5E8V5E5V1V5F1F4E1E6E8E4

E6V2V5F2F1E2E7E5E1eE7V3V5F3F2E3E8E4E2E8V4V5F4F3E5E4E7E82.5B-RepSchemeBecauseanedgemaybesharedbyfaces,soleftandrighttraverseareaddedinordertodecidethefaces.EntriesofedgeE1ApolyhedronForexample:2.5B-RepSchemeInthiscase,itshowstheinformationfortheentriesofedge

E1.Thefouredges

E2,

E4,

E3andE5

arethe

wingsofedge

E1

andhenceedge

E1

is"winged."Soit’scalledawinged-edgerepresentation.EdgeVerticesFacesLeftTraverseRightTraverseNameStartEndLeftRightPredSuccPredSuccE1V1V2F1F2E4E2E3E52.6SweepingSchemeSweptsolidsaredefinedbyextrusionorrevolutionofaprofile.AsimplesweepingAcomplexsweeping2.7ParametricFeatured-basedSolidmodelingAnIntroductionParametricfeatured-basedsolidmodelingisregardedasakeyfactortowardsCAD/CAPP/CAMintegration.WhatareFeatures?Broadlyspeaking,featuresareasetofhigh-levelentitiesthatcouldbeusedtointerpret,andreasonaboutthegeometryspecifiedbyanengineeringdesignerwithengineeringmeanings.2.7ParametricFeatured-basedSolidmodelingSofeaturesmaybeinterpretedindifferentwaysaccordingtotheirusages.InCADsystem,featuresmainlyrefertoformfeatures.Formfeaturescontainparametricshapeinformationandotherattributes.2.7ParametricFeatured-basedSolidmodelingThedesignprocessactuallyisaprocessofcreatingfeatures.Allfeaturesareorganizedandarrangedinacertainway,sothatdesignerscaneditandtraceallthesefeatures.Forexample:FeatureTree(Solidworks)2.7ParametricFeatured-basedSolidmodelingModelingbasedonfeaturesMainfeaturesofparametricmodeling2.7ParametricFeatured-basedSolidmodelingModelingbasedonhistoryModelingbasedonvariableparametersdimensionandconstraintdrivendesign.Forexample：2.7ParametricFeatured-basedSolidmodelingTheshapeofacylindricalcamdrivenbyacurveandanequation.2.7ParametricFeatured-basedSolidmodelingCommonlyusedconstraintsModelingbasedonconstraintsCoincidentConcentricCoradialCollinearEqualEqualCurvatureFixHorizontalMidpointParallelSymmetricTangentVerticalPierce2.7ParametricFeatured-basedSolidmodelingModelingbasedondesignintentDesignintentDesignintentindicateshowthemodelbehaveswhendimensionsandconstraintsaremodified.Forexample,holesonthehingewithaspecificdesignintentembedded.Changetheoverallsizeofthehinge,relationshipbetweenholesaremaintainedaccordingtodesignintent.2.7ParametricFeatured-basedSolidmodelingKeepitinmind:Planningdesignintentbeforemodeling.Capturingdesignintentwhiledesign.Editingdesignintentwhiledesign.Adesignwithoutdesignintentisa“3Dpicture”,notaengineeringdesign.2.7ParametricFeatured-basedSolidmodelingModelingbasedonassociativity

AssociativityensuresthatanydesignchangeswillupdateallrelatedgeometryinallassociativeCAD

data.

Forexample:Thischangeisabi-directionalchange.2.7ParametricFeatured-basedSolidmodelingAnexampleofassociativity2.8TrendsofSolidModelingDirectModeling(DM)ItisanewtechnologyreleasedbyPTCCreo.Thebasicideabehinditistodesignaproductinanatureway.Forexample:2.8TrendsofSolidModelingHistory-basedmodeling:Parametricfeature-basedmodelingHistory-freemodeling:DirectmodelingAcomparisonbetweentwomodelingapproaches2.8TrendsofSolidModelingAnexample:DirectmodelinginPTCCreoSelecting,dragginganddropping2.8TrendsofSolidModelingSynchronousTechnology(ST)

Somesoftwarescombinedirectmodelingwithdimensiondrivendesignunderthename“SynchronousTechnology”.2.8TrendsofSolidModeling

AnexamplereleasedbySolidEdgewithSynchronousTechnology,it’scalledsteeringarevolution.2.8TrendsofSolidModeli