AbstractnoUniwandstreetsandprocessK1.lastprocessasneofwengineering”).turesomeUnihasplasticshundredshousehold-electric,URL:0924-0136/$doi:10.1016/j.jmatprotec.2005.04.006JournalofMaterialsProcessingTechnology175(2006)1519Anexampleofsimulationtoolsuseforlargeinjectionmouldsdesign:TheCONTENURTM2400lsolidwastecontainerJ.Aisaa,C.Javierrea,J.A.DelaSernabaT.I.I.P.,C.S.I.C.AssociatedUnit,DepartmentofMechanicalEngineering,UniversityofZaragoza,SpainbCONTENURESPANA,S.L.,PolgonoIndustrialLosAngeles,Getafe,Madrid,SpainLargecontainerswithvolumesabove1100lareusuallyproducedusingproceduressuchasrotomouldingprocess.Thesetechniqueshavepartweightordimensionallimits.T.I.I.P.,injectionmouldingplasticgroupoftheDepartmentofMechanicalEngineeringoftheZaragozaversity,developedwithCONTENURTManewproductunderEuropeannormsforsolidwastecontainersupto2000lvolume；theresultasanewmainbodyupto60kgweightinonepart.ThedesignprocesscombinedseveralCAEtools(aestheticaldesign,mechanicaldesignrheologicalsimulation)and,inlastJune,showedfinalresultandpasseddifferenttests.Nowadays,morethan5000samplesareonthewithoutbasicmodificationsinthemould(morethan100tonnesweight).Thepaperfocusesonthemethodologyusedtointegratetoolprocessdesignwithproductdefinition(i.e.injectionpressureandclampforceversusthicknessandpartshape).Someparametersaboutcontrolinthisparticularmould(injectionrate,temperature,viscosity,gatelocation,.)aredetailed.2005ElsevierB.V.Allrightsreserved.eywords:CAEdesign；Container；InjectionmouldingIntroductionCAEtoolshaveconstitutedanauthenticrevolutionintheyearswithininjectionofthermoplastics.Thesequentialuntilthefinalsolution(includingseveralsetupssuchdevelopment,testofprototypes,modificationoffigures,wtest,.)hasbeenreplacedbyafasteroneconsistingaprocedurewiththedesigner,transformerandfinalclientorkingtogetheronthesamecomputerfiles(“concurrentTherefore,thetimingformouldmanufac-andcompletionhasbeenreducedenormously；however,interestingadvicesaboutCAEusearedescribedin1.TheWorkshopofInjectionofthePlasticsIndustryoftheversityofZaragoza(T.I.I.P.),C.S.I.C.AssociatedUnit,beenworkingwithCAEtoolsoninjectionofthermo-formorethan15years,withenormousadvantageforofprojectsmadeindifferentsectors(automotive,packaging,toys,etc.).T.I.I.P.activitiesCorrespondingauthor.E-mailaddress:tiipunizar.es(J.Aisa)..includedtion,diftheufcollaboratedAssociationtryinjectiontechnologicalorishresearchcascadetechniques2.theseefrontmatter2005ElsevierB.V.Allrightsreserved.severalresearchprojects(rheologicalcharacteriza-semiautomaticmoulddesign,.)workingtogetherwithferentEuropeancompanies.Nevertheless,thisgrouphasalwaysbeenconsciousofnecessitytoarrangesimulationwithprocedureofman-acturenexttothemachine,ofsuchaformthathasbeenanddirectedbytheconstitutionoftheResearchoftheWorkshopofInjectionofthePlasticIndus-(a.i.T.I.I.P.)foundation,whichprovidesservicestothecompanieswithoutaprofitspirit(Fig.1).ThiscenterhasbeensupportedbyvariousnationalganizationssuchastheAragonsGovernmentandSpan-DepartmentofIndustrythroughdifferentprogramsandlines(newprocesseslikegas-assistedtechniquesorinjectionmoulding,newdesigns,process-measuringusingpressureandtemperaturedevices.).TheCONTENURProjectWhen,in1999,thefirstSpanishcompanyinvolvedinmanufactureofcontainersforthecollectionofurban16ProcessingsolidTpiecestestingofwithplasticofalltheplesbigmouldmakandtoandminimummaterial),J.Aisaetal./JournalofMaterialsFig.1.a.i.T.I.I.P.injectionmouldingarea,generalview.remainders(CONTENURSPAIN,S.L.)wenttothe.I.I.P.a.i.T.I.I.P.Grouptoworkjointlyonthedesignofofgreatsizeininjection,thenarrivedthemomentfortherealpossibilitiesoftheseprogramsinthisfield.Themainobjectiveoftheprojectwasthefastmanufacturecontainersofgreatcapacity(2400landmore)tocompetemarketproductswithweldedmetallicplatesolutionsoronesmadebyrotationalmouldingwiththeinclusionexpensivereinforcementstructures.Obviously,betweenthepiecesthatconstitutedtheset,themainchallengewasmanufactureofasinglepartbucket.Theliteratureshowsseveralpartandmoulddesignexam-andfailureadvices2,3,butitisnotpossibletofindplasticpartsupto40kgweightandamistakeinthissizewillhavenoeasysolution(tooltransporttomouldersmanufacturingplantwillbetooexpensive,andtrialerrormethodisnotavailable).Forthedesignofthiselement,thefollowingaspectshadbeconsidered:basicdimensionsagreedwiththeEuropeanNormEN125744；unloadingresistance(dischargesides)(Fig.2)；highimpactresistanceforfunctionalconditionsandloca-tion(parkingareas,forexample)；easilycleaningsurfaces；friendlyaspect,aestheticaldesign；minimumcost(notonlyforprocessingandassemblybutalsoforon-streetmaintenance)；restrictionoftheclampingforceimposedbytheinstalledpressmachine(bigspecialmachineswithlimitedclampingrangebetween5000and10,000tonnes)；preparedforlabelling,thatistosay,withvisiblefreeandflatspaces；materialrestrictions:samematerialsusedforotherCON-TENURdesigns.Specialmentionrequirestwolimitations:minimumcostmaximumclampingforceundermentionedlimits.Foracost,thicknessisfundamental(bythecostofrawinasmuchasthetimeofmanufacture；therefore,Fig.model,thethejectedstronglyaforcenottechniques(a)(b)TResultsMain(mm)/weightTechnology175(2006)15192.Boundaryconditionsforunloadingoperation,nonlinearmaterialfiniteelementmodel.costofthemachinederivedapproximatelydependsonsquareofthethickness5.Ontheotherhand,toreducetheclosingforce,thepro-areaofthepieceandthedistributionofpressuresarerelatedwithpartthickness(narrowsectionscausedhighinjectionpressure,whichcouldaswellsupposeahighofclosing).Themethodologyapplied,developedbyCastanyetal.,onlyforinjectionmouldingbutalsoforothersimilar68,isasgivenbelow:Determinationofthefeasibilityoftheproduct:clampingforceevaluationandthicknesspartonanagreedbasicgeometrytoadjustdimensionswiththeEuropeannorm.Onlygeneraldesignlines,andnotfunctionaldetails,wereincludedinthisstep.SomebasicresultsareshowninTable1.Theseanalysesweremadewithbasicparam-etersforgenericmaterialfamily,high-densitypolyethy-lene(Table2).Foradvancedsteps,calculationsweremadeusingseveraltemperatureconditions.Materialselection,combiningmeltflowindex(MFI)andmechanicalbehaviour,andinjectionpointlocationsweresimulated,withoutevenknowingthefinalgeometryofthecomponent.Bestresultswerefoundforseveralinjec-tionpointsarrangedaroundthebottomareainthemainable1forsimpleplasticmodel,firstanalysisusingsimulationtoolsbodythickness(kg)Maximuminjectionpressure(MPa)Requiredclampingforce(kN)6/5296166,0007/6071122,0008/685594,0009/764474,00010/843559,000ProcessingTComputingMeltInjectionMouldFig.ments.(c)(d)J.Aisaetal./JournalofMaterialsable2parametersforbasicsimulationstemperature(C)240timeatconstantramspeedInseconds20Inpercent50temperature(C)403.Basicline,Pro-Engineersoftware,beforefinalmouldingarrange-bodyofthecontainer.Thiscriteriawasalsoimposedbymouldstructureandpartshape.Analysisofthebodyformandthicknessofthepartcomparingconstructivealternatives:itssidewallshapes,metallicelementsofreinforcementand,ifnecessary,inclusionofthetubesinjectedwithgas-assistedtech-niquestoincreaseinertiaofthesections,etc.,werecon-sidered.Obviously,moulddimensionsandthepresenceofunder-cutssupposedaproblemaddedforthedesignofpieceandmould.Inthisway,semicircularshapeoftheborderTBasicHeightWLength(e)thegeometrysettlingsoriessetwCompan(othertrial1.2.3.Fig.4.SoftwareC-Mold:plastictemperatureTechnology175(2006)151917able3dimensionsfor2400lmainbody(mm)1600idth14801600oftheuppercontainerwasaharddesignproblem；itwasrequiredforfunctionalusebutsupposedanundercutareainvolvingslidesinthemould.Partvolumewasadaptedanddifferentaestheticformsappearedfeasibleconjunctionofthepossiblethick-nessbymanufacturewiththethicknessandformsbymechanicalresistance.Inthisstep,finiteanalysis,solid3Ddesignandfillingsimulationweremadesimultane-ously(Figs.3and4).ThefinalpartdimensionsareshowninTable3.Withthesebasicmagnitudescalculatedinthesefoursteps,designteamhadaninitialpointforthefinaldrawingofandtheinclusionoftheelementsofdetailslikedownofoutputangles,radios,positionofacces-oftheset(cork,skid,etc.).Industrialflowanalysiswasindefinitiveway,fixingoptimumpositionsformanifoldorkingtogetherwiththemouldmaker,KyowaIndustrialywithmouldplantsintheUSA,JapanandMexico.Themainaspectsoftheprocessandtheirsimulationsdetailscannotbepresentedinordertoprotectindus-know-how)are:Modelofthefigurewithgeometriestype2.5D.Locationoftheentrypointstothecavity.Theuseofracetracksforabettercontrolofthefillingwasconsidered,followingrheologicaldesignruleforsimultaneousendoffillingattheendofthecavity(avoidingover-packeffect),especiallyconsideringthebordershapewithsemicircularareas.Optimalconditionsofprocess:theselectionoftemper-atureanditsrelationwiththicknessandcyclestronglyconditionedthepermissiblevaluesforthedesign.Valuesbetween210and250Cwereevaluated.atejectionandcoolinglineslayout.18ProcessingFig.mould.4.tests(islatedbecausegradientscould5.J.Aisaetal./JournalofMaterials5.Realcontainermodelusedfortestingindustrialconditionsin2400lTheadjustmentofthefillingformbymeansofthecor-rectprogrammingofspeedsbecameessential.Atconstantspeedprofile,theincreaseofpressure-supposedvaluesofinadmissibleforceofclosingbythelimitationimposedtothedimensionsofthemachine.Inthefinalarrange-mentforcontainermould,severalramspeedstageswererecommended.ThisprocedurewasexperimentallyvalidatedwithrealusingalreadyexistingsmallerdimensioncontainerFig.5).TypicalramspeedprofilecalculatedwithCAEtechniquesshowninFig.6,butthis“function”cannotbetrans-totheinjectionmachinewithoutpracticalarrangements,hydraulicsystemsarenotabletofollowallthoseexactly.Anyway,around15%lessclampingforcebeachievedafterthisoptimisationprocedure.Afterthefillingpossibilitieswerefixed,thiswasverifiedwithane