CAD与CAPP集成技术.docx
- 文档编号:23025372
- 上传时间:2023-04-30
- 格式:DOCX
- 页数:13
- 大小:23.85KB
CAD与CAPP集成技术.docx
《CAD与CAPP集成技术.docx》由会员分享,可在线阅读,更多相关《CAD与CAPP集成技术.docx(13页珍藏版)》请在冰豆网上搜索。
CAD与CAPP集成技术
DesignofaSTEPcompliantsystemforturningoperations
Thechangingeconomicclimatehasmadeglobalmanufacturingagrowingnecessityoverthelastdecade,forcingcompaniesfromEastandWesttocollaboratebeyondgeographicboundariesinthedesign,manufactureandassemblyofproducts.TheISO10303andISO14649Standards(STEPandSTEP-NC)havebeendevelopedtointroduceinteroperabilityintomanufacturingenterprisessoastomeetthechallengesofrespondingtoproductionondemand.ThispaperdescribesandillustratesaSTEPcompliantCAD/CAPP/CAMSystemforthemanufactureofrotationalpartsonCNCturningcenters.TheinformationmodelstosupporttheproposedsystemtogetherwiththedatamodelsdefinedintheISO14649standardusedtocreatetheNCprogramsarealsodescribed.AstructuredviewofaSTEPcompliantCAD/CAPP/CAMsystemframeworksupportingthenextgenerationofintelligentCNCcontrollersforturn/millcomponentmanufactureisprovided.FinallyaproposedcomputationalenvironmentforaSTEP-NCcompliantsystemforturningoperations(SCSTO)isdescribed.SCSTOistheexperimentalaspectoftheresearchandissupportedbyinformationmodelsthatandhavebeenconstructedusingastructuredmethodologyandobject-orientedmethods.SCSTOwasdevelopedtogenerateaPart21filebasedonmachiningfeaturestosupporttheinteractivegenerationofprocessplansutilizingfeatureextraction.AcasestudycomponenthasbeendevelopedtoprovetheconceptofusingthemillingandturningpartsofISO14649toprovideaturn-millCAD/CAPP/CAMenvironment.
Design-to-fabricationautomationforthecognitivemachineshop
Tomeettherisingdemandsforpurecustomizationofproducts,newapproachesforautomatedfabricationofcustomizedpartgeometryareneeded,onboththesoftwareandhardwareside,thatbalanceflexibility,robustnessandefficiency.Thisisagreatchallengesincetodayitrequiressignificanthumanexpertisesupported,onlypartially,bycomputer-aidedapproaches.Thispaperintroducesanewapproachandframeworkforanautonomousdesign-to-fabricationsystemthatintegratescognitivecapabilities,suchasreasoningfromknowledgemodelsandautonomousplanning,andembedstheseinthemachinesthemselvestoautomaticallyfabricatecustomizedparts.Theframeworkintegratesintoacommonprocessautomaticworkpieceselectionusinganontology,generativeCNCmachiningplanningusingshapegrammarsandautomatedfixturedesign,basedonanovelflexiblefixturedevicehardware.Initialresultsaregivenforthemachiningplanningapproachappliedto2.5Dpartswithadefinedapproachdirectionandtheprototypedfixturedeviceispresented.Theadvantagesandpotentialoftheframeworkstemmainlyfromapplyingtheprinciplesofcognitivetechnicalsystemstoafabricationsystemtodevelopanintegratedandon-lineapproach.Themethodsaredevelopedspecificallyforuseonthemachineshopfloortotakeadvantageofthepossibilitytoupdateandextendknowledgemodelstoreflectcurrentfabricationcapabilitiesandtoadapttochangesintheenvironmentandre-planduringoperation.Finally,futuredirections,includingintegratingon-lineperceptionandlearning,arediscussed,whicharerequiredtocreateatrulyflexibleandcognitivefabricationsystem.
Areviewofautomatedfeaturerecognitionwithrule-basedpatternrecognition
Automatedfeaturerecognition(AFR)hasprovidedthegreatestcontributiontofullyautomatedCAPPsystemdevelopment.TheobjectiveofthispaperistoreviewvariousapproachesforsolvingthreemajorAFRproblems:
(i)extractionofgeometricprimitivesfromaCADmodel;(ii)definingasuitablepartrepresentationforformfeatureidentification;and(iii)featurepatternmatching/recognition.Anovel,detailedclassificationofdevelopedAFRsystemshasbeenintroduced.Thispaperalsoprovidesathoroughinvestigationofmethodsforgeometricfeatureextraction,emphasizingSTEPstandardapplicationand,finally,areviewofrecentresearchreportsinthefieldofAFRwithrule-basedfeaturepatternrecognition.Wediscusspotentialsandlimitationsoftheseapproachesandemphasizedirectionsforfurtherresearchwork.
Computeraidedmanufacturabilityanalysis:
Closingtheknowledgegapbetweenthedesignerandthemanufacturer
Manufacturingtodayismarkedbyincreasedcompetitionanddispersedglobalorganization,thusnecessitatingenhancedcollaborationamongdesignersandmanufacturers.Nevertheless,whileDesignforManufacturability(DFM)hasbeenthesubjectofin-depthresearchoverthepastdecades,thesupportingsoftwaresolutionshavenotasyetmatured.Inthispaperwepresentaholisticapproachandsupportingsoftwaretool,termedtheComputerAidedManufacturabilityAnalysis(CAMA)tool,forcapitalizingonavailablemanufacturabilityknowledge.Thisisachievedbyclosingtheknowledgeloopbetweenthedesignandmanufacturingenvironments.CAMAcapturestheknowledgeinastructuredmannerandincorporatesthisknowledgewithintheproductdesigntools(CADsystems),thusenablingimprovedproducttimelinessandprofitability.CAMArepresentsproofofconceptandconstitutesademonstrativeprototypeofanadaptiveandopenDFXtool.ItisbasedonindustrialsurveysoftheKnowledge,InformationandData(KID)flowsinCAD,CAPPandCAMprocesseswithinthemanufacturingoutsourcingenvironment.CAMAdiffersfromotherapproachesinthatitisanopensystemthatenablescontinuousandintuitivecapture,modificationandimplementationofupdatedmanufacturabilityKID.
ISO14649-basednonlinearprocessplanningimplementationforcomplexmachining
Increasingattentionisbeingpaidtocompletemachining,i.e.,machiningofthewholepartinasinglemachinetool,inthemetalworkingindustry.Forthispurpose,complexmachinetoolsequippedwithmachiningcomponents,suchasmultiplespindlesandturretshavebeendevelopedbyleadingmachinetoolbuilders.Theefficiencyofcomplexmachinetoolsislargelydependentonhowthemachiningcomponentsareutilized.Themainthrustofthispaperistwofold:
(1)PropositionofanonlinearprocessplanningbasedontheSTEP-NC(STEP-compliantdatainterfacefornumericalcontrols)paradigmwhosedatamodelisformalizedasISO14649,and
(2)Developmentofanoptimalsolutionalgorithmforprocessplanningforcomplexmachining.Thedevelopedalgorithmisbasedonthebranch-and-boundapproachandheuristicsderivedfromengineeringinsights.ThedevelopedprocessplanningmethodandoptimizationalgorithmwereimplementedandtestedviatheTurnSTEPsystemdevelopedbyourresearchteam.Throughtheexperiments,weareconvincedthatthenewprocessplanningandalgorithmcanbeusedasafundamentalmeansforimplementingthethirdtypeofSTEP-NC[SuhS.TurnSTEP:
ToolstocreateCNCturningprograms.In:
WhitepaperpresentedonSTEPImplementers’ForumISOTC184/SC4Meeting.2004],i.e.,anIntelligentandAutonomousSTEP-NCsystemfortheCAD-CAM-CNCchainsupportinge-Manufacturing.
Motionnavigationforarcweldingrobotsbasedonfeaturemappinginasimulationenvironment
Theefficiencyoftheoff-lineprogrammingforthearcweldingrobotsdependsonthecomplexityoftheworkpiecesandtheweldingexperienceofthetechnician.Whentheworkpiecesorfixturesareredesignedortherobotworkstationlayoutischanged,theresultofprioroff-lineprogrammingcannotbereused.WiththethoughtofCAD/CAPP/CAMintegration,thispaperpresentsafeaturemappingalgorithm,whichconvertsthedesignfeaturesoftheworkpiecestothemachiningfeaturesoftheseams.Thenamotionnavigationmethodbasedonfeaturemappinginasimulationenvironmentisproposed.Thismethodcomprisesinitialpositionguidingandseamtracking.Forinitialpositionguiding,amotionpathwiththeleastenergyconsumptionisgeneratedbasedontheweightedoptimalcontrol;thenthepathisrevisedforavoidingobstaclesbysettingthepathtagsdynamically.Forseamtracking,theseamisdispersedintodiscreteweldingpoints;thentheweldinggunmovesthrougheachpointaccordingtotheweldingsequence.Themethodisimplementedinthedevelopmentofanoff-lineprogrammingsimulationsystem.Industrialcasesoftheweldingrobotworkcelllayoutforautomobiledoorframesshowthemethodcanmaketheoff-lineprogrammingmuchmoreeffective.
Anartificialintelligenceplanningapproachtomanufacturingfeaturerecognition
Withinmanufacturing,featureshavebeenwidelyacceptedasusefulconcepts,andinparticulartheyareusedasaninterfacebetweenCADandCAPPsystems.Previousresearchonfeaturerecognitionfocusontheissuesofintersectingfeaturesandmultipleinterpretations,butdonotaddresstheproblemofcustomfeaturesrepresentation.Representationoffeaturesisanimportantaspectformakingfeaturerecognitionmoreapplicableinpractice.Inthispaperahybridproceduralandknowledge-basedapproachbasedonartificialintelligenceplanningispresented,whichaddressesbothclassicfeatureinterpretationandalsofeaturerepresentationproblems.STEPdesignsarepresentedascasestudiesinordertodemonstratetheeffectivenessofthemodel.
Applicationofgeneticalgorithmtocomputer-aidedprocessplanninginpreliminaryanddetailedplanning
Computer-aidedprocessplanning(CAPP)isanimportantinterfacebetweencomputer-aideddesign(CAD)andcomputer-aidedmanufacturing(CAM)inthecomputerintegratedmanufacturing(CIM)environment.Agoodprocessplanofapartisbuiltupbasedontwoelements:
(1)optimizedsequenceoftheoperationsofthepart;and
(2)optimizedselectionofthemachine,cuttingtoolandtoolaccessdirection(TAD)foreachoperation.Ontheotherhand,twolevelsofplanningin
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- CAD CAPP 集成 技术
![提示](https://static.bdocx.com/images/bang_tan.gif)