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conductedtoautomaticallydeterminethepartingdirection,todeterminethepartingline,togeneratethepartingsurface,torecogniseundercutfeaturesandtogeneratethecore/cavity.RaviandSrinivasan[14]pre-sentedninerulesthatcanbeusedbythemoulddesignengineertodevelopasuitablepartinglineintheprod-uct.Theserulesareprojectedarea, atness,draw,draft,undercuts,dimensionalstability, ash,machinedsur-facesanddirectionalsolidi cation.HuiandTan[15]proposedthesweepmethodtoformthecavityandcore.Thecavityandcorearegeneratedinanumberofsteps.Sweepingthemouldpartinthedrawdirectiongeneratesasolid.Oneendofthesweptsolidissubtractedfromthe rstmouldblock.Theotherendofthemouldblockissubtractedfromthemouldpart.Theresultsoftheabovestepsaresubtractedwiththepartattheclosedpositiontoobtainthecavityandcore.ShinandLee[16]pro-posedamethodofcoreandcavitydevelopmentsothatthesidecoresandcorrespondingcoreandcavityplatescanbegenerated.Thismethodiscomposedof3steps.Thedesignerdeterminesthepartinglinethatseparatestheproductinto2groupsoffaces.Eachgroupfacehasthepartingsurfaceattachedtoit.Thenexternalfacesareaddedtoeachgroupface.Shinaddedthatamouldcouldbemadeupofmanypiecesinadditiontothecavity,coreandsidecores.Hui[17]studiedthemoul-dabilityofaninjectionmouldbasedonanexternalandinternalundercutanalysisonlyforpolyhedralsolids.Ablockageconceptispresentedtodeterminethemainpartingdirectionandasubdivisiontechniqueisdevel-opedtoevaluatethegeometryofanundercut.Chenetal.[18]introducedtheconceptofvisibilitymaps(V-maps)ofthepocketstodeterminethepartingdirection.Themethoddidnottakeintoaccountinternalundercuts.Fuetal.[19]andNeeetal.[20]gaveanewclassi cationofundercutsaccordingtotheexternalloopsandtheinternalloopsofamouldedpart.Thepartingdirectionisthendeterminedbasedontheproposedpartingdirectioncriteriaconsideringthedirections,location,numberandvolumesofundercutfeatures.Fuetal.[21]proposedanapproachtogeneratethepartingsurfacebyextrudingthepartinglineedgesandcreatethecore/cavityblockusingtheBooleanregulariseddi erenceoperation(BRDO).Amethodologythatgeneratesnon-planarpartinglinesandsurfacesispresentedbyNeeetal.[22].Wongetal.[23]proposedamethodtodeterminethecuttingplaneofacomplexshapedproduct.Theirmethodusesanalgorithmthatslicestheproduct.Thepartinglineandsurfacesformedbythismethodareplanar.
Currentresearchonautomaticmoulddesignisongoing.However,somemethodscanbequitetheo-reticalandthemoulddesigncanhaveacomplicatedproductgeometry.Mostmoulddevelopmentactivitiesinvolveahighlevelofskill,awidevarietyofdesignexpertiseandknowledge.Duetothefactthatautomaticmoulddevelopmentisstillfarbeyondthecurrenttech-nology,itismorereasonabletoprovideintelligentrulesorguidelinesthatpreventthedesignfromcon- ictingwithdesignconstraints.Theserulesalsoprovide
interactivetoolsinthedetailedmoulddesignenviron-ment.Thispaperpresentsaninteractiveknowledge-basedinjectionmoulddesignsystem(IKB-MOULD).Thissystemintegratestheinitialmoulddesignandde-tailedmoulddesignwithbothknowledgebaseandinteractivecommercialCAD/CAMsoftware.
Thenextsectionofthispaperoutlinesananalysisoftheinjectionmoulddesignprocessbasedonthemoulddesigner’spointofview.AlatersectionintroducesthebasicstructureofourIKB-MOULDforinjectionmoulddesign.AcasestudyoftheinjectionmoulddesignforaplasticproductinIKB-MOULDisthenpresented.Theconclusionandfutureworkislocatedinthelastsection.
2Theinjectionmoulddesignprocessrequirementanalysis
Aninjectionmoulddesigniscomposedoftwosteps:theinitialdesignandthedetaileddesign.Theinitialdesigniscomposedofdecisionsmadeattheearlystageofthemoulddesign,suchasthetypeofmouldcon guration,thenumberofcavities,thetypeofrunner,thetypeofgateandthetypeofmouldbase.Thedetaileddesigniscomposedoftheinsert(core/cavity)design,theejectionsystemdesign,thecoolingandventingcomponentde-sign,theassemblyanalysisandthe naldrafting.
TodevelopagoodCAIMDS,ananalysisof‘whattheyhave’and‘whattheywant’needstobeperformed.Whattheyhave:
–Thecustomer’srequirementsfortheproduct.This
includesthedetailedgeometryanddimensionre-–quirementsoftheproduct.
Anexistingmoulddesignlibrary.Thislibrarycoversthestandardorpreviouslydesignedcomponentsandassembliesofthemoulddesign,forexample,themouldbase(the xedhalfandthemovinghalf)and–thepocket(the xedhalfandthemovinghalf).
Anexpertknowledgeininjectionmoulddesign.Ex-pertknowledgeofbothinitialanddetaileddesignsfortheinjectionmouldisobtainedmainlyfromexperi-encedmoulddesigners.Suchknowledgeincludesmaterialselection,shrinkagesuggestion,cavitylayoutsuggestionandothers.Whattheywant:
–Anintelligentandinteractivemoulddesignenviron-ment.Moulddesignisoftencomposedofaseriesofdesignprocedures.Theseproceduresusuallyrequirecertainmouldpartstobecreatedandexistingmouldpartstobeassembled.Suchamoulddesignenvi-ronmentneednotbefullyautomatic,especiallyforcomplicatedproductswithmanyundercuts.Anintelligentandinteractiveenvironmentwillbeagoodchoicetointegratesomeusefulautomationalgo-rithms,heuristicknowledgeandon-lineinteractionbytheexperiencedmoulddesigner.