393
ejectorpinisSteptypeTasksinthedetailedinjectionmoulddesignmayRule2:IF
ANDejectorpin¼0:4mmbeinterrelatedwithmanyoftheinjectionmould
objects’designelements.Therefore,the nalde-THENejectorpin¼2:0mm;
tailedmoulddesigncanberegardedasadesignejectorpin¼4:0mm;composedoftheinjectionmouldobjects.Repre-ejectorpin¼0:5mm;
sentationofaninjectionmouldobjectandtheejectorpin¼20:0mmknowledgeusedfordetailedmoulddesignisex-plainedinalatersection.Basedonthatrepre-ejectorpinisRectangulartypesentation,anassemblytreecanbeautomaticallyRule3:IF
generatedandmodi edduringthedetailmoulddesign.(2)Thedesignformanufacture.ThismoduleisdevelopedmainlyfortheCAPP/CNCofthe naldesignedmould.Inprocessplanning,thesequenceofmachiningprocessestomanufacturethede-signedmouldisacomplicatedtaskandrequires
manufacturingknowledge.Manufacturingfeaturesneededtobeabstractedfromthe naldesignedmouldandarelativesequencedprocesshastobegeneratedbasedonknowledgestoredintheknowledgebase.Inaddition,atoollibraryforthespeci cNCmachineisusedtoautomatically
generatetheNCcodeforthemanufacturingpro-cess.Detaileddesignofthemanufacturemodulein
theIKB-MOULDisnotpresentedinthispaper.
(3)Thedesignforthe2Ddrawing.Withthehelpofanapplication-programming-interface(API)providedbythecommercialsolidmodellingsoftware,most2Ddrawingsofpartscanbeobtainedfromthesolidmodel.Someintelligenttoolsneedtobedevelopedforgeneratingdetaileddimensions.
(4)Thedesignforthebillofmaterial(BOM).Similartothedesignfortheassemblyinthedetailedmoulddesign,allpropertiesofthedesignedinjectionmouldobjectscanbetraced.Atoolcanbedevel-opedtoautomaticallygeneratetheBOM.3.3Knowledgebaseandlibraries3.3.1Knowledgerepresentation
Knowledgeforaninjectionmoulddesignisgainedmainlythroughexperienceandhandbooks.Eachmoduleofthemoulddesignprocessneedstobesupportedbytheknowledgebase.Knowledgeinvolvedinthemoulddevelopmentcanberepresentedintermsofdesignrules:IF(conditions)THEN(designsolution).
SomedesignrulesintheIKB-MOULDusedtodeterminetheejectorpinsizefromboththecata-loguelibraryanddesignexperiencearerepresentedasfollows:Rule1:IF
ejectorpinisStraightcirculartypeANDejectorpin¼1:0mm
THEN
ejectorpin¼3:0mm;ejector
pin
¼4:0mm
ANDejectorpin¼1:8Â3:0mmTHENejectorpin¼15:0mm;ejectorpin¼4:0mm;
Ejectorstepdia¼10:0mm;ejectorpin¼20:0mmRule4:IFMouldbase¼TRUEANDCore¼TRUETHENEjectorpin¼ðzcoÀordinateofproductejectionpointatcoreÞÀðzco-ordinateofejectorbackplatebaseÞ
IntheIKB-MOULD,knowledgerulesarestoredingroupsthatareassociatedwiththedesigntasks.Many
designtasksinthemoulddesignmoduleareshowninFig.1.Toimplementeachtask,someinjectionmouldobjectsneedtobedeterminedusingtheknowledgebase.Consider,forexample,thefeedingsystemdesigntaskin
thedetailedmoulddesign.Someinjectionmouldobjectssuchasrunnersandgatesaretobede ned.Thedetailed
runnerdesignhasasetofdesignsolutionsthatcanbeapplied;forexample,runnertypescanbecircularortrapezoid.3.3.2Thelibrary
TheIKB-MOULDalsohasusefullibrariesthatsupporttheinjectionmoulddesignmodule.Threetypesofli-brariesarethemateriallibrary,themouldbase/compo-nentslibraryandthetoollibrary.Themateriallibrarystoresthedetailedmaterialpropertiesandtheshrinkageratesof38di erentmaterials.Themouldbase/compo-nentslibrarystoresallstandardmouldbasesandothercomponentsusedinthedetailedmoulddesign.ThetoollibraryisreservedmainlyforautomaticNCcodegen-erationandtostoretoolinginformationsuchasfeedrateandspeed.Alllibrariescanbeexpandedtomeettheuser’srequirements.
4Acasestudy
Sofar,thedetailedmoulddesignmoduleshavebeenpresentedintheprevioussection.IntheIKB-MOULD,theimplementationofthosemodulesisrealisedina