知识辅助注射模具三维CAD设计系统(7)

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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

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