




全文预览已结束
下载本文档
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
InternationalJournalofAutomotiveTechnology,Vol.13,No.2,pp.273277(2012)DOI10.1007/s1223901200245Copyright2012KSAE/06311pISSN12299138/eISSN1976-3832273DESIGNOPTIMIZATIONOFANINJECTIONMOLDFORMINIMIZINGTEMPERATUREDEVIATIONJ.-H.CHOI1),S.-H.CHOI1),D.PARK2),C.-H.PARK2),B.-O.RHEE1)*andD.-H.CHOI2)1)GraduateSchoolofMechanicalEngineering,AjouUniversity,Gyeonggi443-740,Korea2)GraduateSchoolofMechanicalEngineering,HanynagUniversity,Seoul133-791,Korea(Received24January2011;Revised15June2011;Accepted17June2011)ABSTRACTThequalityofaninjectionmoldedpartislargelyaffectedbythemoldcooling.Consequently,thismakesitnecessarytooptimizethemoldcoolingcircuitwhendesigningthepartbutpriortodesigningthemold.Variousapproachesofoptimizingthemoldcoolingcircuithavebeenproposedpreviously.Inthiswork,optimizationofthemoldcoolingcircuitwasautomatedbyacommercialprocessintegrationanddesignoptimizationtoolcalledProcessIntegration,AutomationandOptimization(PIAnO),whichisoftenusedforlargeautomotivepartssuchasbumpersandinstrumentpanels.Thecoolingchannelsandbaffletubeswerelocatedontheoffsetprofileequidistantfromthepartsurface.Thelocationsofthecoolingchannelsandthebaffletubeswereautomaticallygeneratedandinputintothemoldcoolingcomputer-aidedengineeringprogram,AutodeskMoldflowInsight2010.Theobjectivefunctionwasthedeviationofthemoldsurfacetemperaturefromagivendesigntemperature.Designvariablesintheoptimizationwerethedepths,distancesanddiametersofthecoolingchannelsandthebaffletubes.Foramorepracticalanalysis,thepressuredropandtemperaturedropwereconsideredthelimitedvalues.Optimizationwasperformedusingtheprogressivequadraticresponsesurfacemethod.Theoptimizationresultedinamoreuniformtemperaturedistributionwhencomparedtotheinitialdesign,andutilizingtheproposedoptimizationmethod,asatisfactorysolutioncouldbemadeatalowercost.KEYWORDS:Injectionmolding,Coolingchannel,Coolinganalysis,PQRSM,Designoptimization1.INTRODUCTIONThecoolingstageisthelongeststageduringthecycletimeoftheinjectionmoldingprocess.Therefore,themosteffectivemethodtoreducethecycletimeistoreducethecoolingtime.Thecoolingtimeisfundamentallydeterminedbythepartthicknessandmoldtemperature,whichcreatesacoolingtimelimitation.Ifthemoldtemperatureandpartthicknessareuniformoverawholepart,thecoolingtimeisnotaconcern;however,non-uniformpartthicknessandmoldtemperaturedistributionlengthentheoverallcoolingtime.Alongercoolingtimemeanspoortemperatureuniformity,whichcancausetheparttowarp.Thisisespeciallytrueforlargeproducts,suchasautomotivebumpersandinstrumentpanels.Itisforthesetypesofpartsthattemperatureuniformitybecomesthemostimportantfactorinmolddesign.Wedevelopedanautomatedoptimizationofthecoolingcircuitforanearlypartdesigninordertocheckthedesignvalidity.Usuallytheearlypartdesignischeckedbythefiling/packingandwarpageanalyseswithoutacoolinganalysis.Thisisbecausetheassumptionisthatthemoldtemperatureisuniform,whichisnotactuallytrue.Providingarapidlyoptimizedcoolingcircuitforthedesignedpartwouldhelppartdesignerscorrecttheirdesign(KoresawaandSuzuki,1999).Theoptimizationwasdesignedtominimizetheparttemperaturedeviationusingdesignvariablessuchasthediametersanddistancesofthecoolingchannelsandbaffletubesandthedepthsofthepartfromthemoldsurfaceofthecoolingchannelsandbaffletubes.Acommercialcomputer-aidedengineering(CAE)tool,AutodeskMoldflowInsight,wasusedforthecoolinganalysis.Wesuccessfullyobtainedanoptimizedcoolingcircuitinatimemuchshorterthancanbeachievedinamanualdesign.Inordertodeveloptheautomatedoptimizationofthecoolingcircuitforthepracticalmolddesign,practicaldesignparameterssuchasthepressuredroplimitandthecoolanttemperaturerisewereconsideredintheoptimization.Theperformanceoftheoptimizationtechniquecanbeaffectedbynumericalnoiseintheresponses.Tofindanoptimumsolutioneffectivelywhennumericalnoiseexists,weperformedanoptimizationbyapplyingaregression-basedsequentialapproximateoptimizerknownastheProgressiveQuadraticResponseSurfaceMethod(PQRSM)(Hongetal.,2000),whichwaspartofacommercialprocessintegrationanddesignoptimization(PIDO)toolknownastheProcessIntegration,AutomationandOptimization(PIAnO)(FRAMAX,2009).*Correspondingauthor.e-mail:rhexajou.ac.kr274J.-H.CHOIetal.2.MODELANDCHANNELCONFIGURATION2.1.ModelConfigurationThemodelusedfortheoptimizationandCAEanalysiswasanautomotivefrontbumper(FB).Thesizeofthepartwas1,800600mm,theelementtypewastriangularandthenumberofelementsinthemodelwasapproximately26,000,withanaverageaspectratioof1.5.ThemodelisshowninFigure1.2.2.CoolingChannelConfigurationThecoolingcircuitfortheautomotivebumpermoldistypicallydesignedtohaveahorizontalplaneoflinecoolingchannelsandtoinstallbaffletubesfromthelinecoolingchannels.However,inthisdesign,unnecessarilylongbaffletubesattachedatalinecoolingchannelmaycauseahighpressuredropinthecoolingchannel.Thelinecoolingchannelsmaynotcontributetomoldcoolingduetotheirlargedistancefromthepartsurface.Inordertoimprovethedesign,thelinecoolingchannelswerelocatedalongtheoffsetprofileofthepartsurfaceasshowninFigure2.Theendpointsofthebaffletubeswerealsolocatedontheoffsetprofilealongalinecoolingchannel.Eitherthelinecoolingchannelsorbaffletubeswerelocatedontheoffsetprofileswithequalarcdistancesbetweenthem.3.FORMULATION3.1.DesignConstraintsThelimitationofthepressuredropandthetemperaturerisebetweentheinletandoutletofcoolingchannelshouldalsobeconsideredinthedesignofthemoldcoolingcircuit.Ahighpressuredropusuallyoccursinaneedlesslylongcoolingcircuit.Inalongcoolingcircuit,theflowrateofcoolantislow,whichresultsinahighmoldtemperatureandahightemperatureriseattheoutlet.Thedesigndefectcouldeventuallybefoundinthecoolinganalysis;however,theoptimizationisalreadytimeconsuming,soitisbettertoinsteadapplythelimitsasconstraintsintheoptimization.Inthisworkweassumedthat4linecoolingchannelswereconnectedinseriesasacluster,asshowninFigure3.Clustersareconnectedinparallelbyamanifold.Usually,themaximumpressuredropinaclusterislimitedto200kPa,andthemaximumtemperatureriseattheoutletis5oC(Mengesetal.,2001).Inthecoolinganalysis,eachlinecoolingchannelisregardedasaseparateindependentcircuitforconvenience.Becausetherewere4linecoolingchannelsinacircuit,thelimitsonthepressuredropandthetemperatureriseineachlinecoolingchannelwere50kPaand1.25oC,respectively.Wealsohaveanadditionalconstraintduetothefactthatthediameterofthebaffletubemustbegreaterthanorequaltothediameterofthecoolingchannelbecausethebaffletubehaslowerheatremovalefficiencythanthecoolingchannel.ThesethreedesignconstraintscanbeexpressedasEquations(1),(2)and(3),(13)whereG1istheconstraintonpressuredrop,G2istheconstraintontemperaturerise,andG3representsthesubtractionofthediameterofthebaffletubefromthediameterofthecoolingchannel.3.2.DesignVariablesInthiswork,thediameters,distancesanddepthsofthelinecoolingchannelsandbaffletubeswerechosenasdesignvariablesforoptimization.Thetotalnumberofdesignvariableswas6asshowninTable1.Typically,thediametersofthecoolingchannelsandbaffletubesaredeterminedbythemolddesigneraccordingtotheirruleof0PaG150000pa0CoG21.2CoG30mmFigure1.Finiteelementmodeloftheproductusedfortheoptimization.Figure2.Configurationofcoolingchannelslocatedalongtheoffsetprofiles.Figure3.Clustersconsistingof4coolingchannelswithbaffletubes.DESIGNOPTIMIZATIONOFANINJECTIONMOLDFORMINIMIZINGTEMPERATUREDEVIATION275thumb(Rheeetal.,2010).However,ithasbeenexaminedingreatdetailamongthemolddesigners.Table1showsthedesignvariableswiththeirrangesandinitialvalues.Theminimumvaluesforthecoolingchanneldistance,baffledistanceandbaffledepthweredeterminedbytheconstraintsofthemachiningrequirement.Themaximumvaluesofcoolingchanneldistanceandbaffledistanceweredeterminedbytheempiricalmaximumobtainedfromthemolddesigners.ThebaffledistancewasadiscretevariableduetoarestrictionintheautomateduseoftheCAEsoftware.Inthiswork,thebaffledistancesforoptimizationwere60,90and120mm.3.3.ObjectiveFunctionAprincipalpurposeofthemoldcoolingcircuitoptimizationistoachieveuniformtemperaturedistributionoverthepart.Theuniformtemperaturedistributionmeansthatthetemperaturedeviationcausedbythecoolingchannelsisminimized,asshowninFigure4.TheobjectivefunctionintheoptimizationwasthestandarddeviationofparttemperatureasshowninEquation(4).Theparttemperaturewasanarithmeticaverageoftheupperandthelowersurfacesofthemoldhalves.Themoldsurfacetemperaturewascalculatedfromthefiniteelementofthepart.min,(4)whereisthestandarddeviationoftheparttemperature,Eiisthetemperatureofi-thelement,Ewistheaveragetemperatureoftheentiretriangularelements,andNisthenumberofelements.4.OPTIMIZATION4.1.ParametricStudyInordertoexaminetheeffectsofthedesignvariablesontheobjectivefunction,pressuredropandtemperaturerise,parametricstudieswerecarriedout.Aparametricstudywasperformedbychangingavariableinacertainrangewhilekeepingallothervariablesfixed.Figures5-7showtheresultsofparametricstudiesfortheobjectivefunction,pressuredroptemperaturerise,respectively.Ineachfigure,thex-axisindicatesthelevelsofdesignvariables.Everydesignvariablewasdividedinto11levelsfromitslowerboundtoitsupperbound.-5and5meanthelowerandupperbounds,respectively.Whenexaminingthetemperaturedeviation,thediameterofthecoolingchannelsshowslittleinfluencetotheobjectivefunction(seeFigure5.).Thisresultwaspredictablebecausethecoolingchannelaffectstheparttemperaturetoalesserdegreethanthebaffletubesintheautomotivebumpermold.Theautomotivebumpermoldhasadeepcoresothatthemoldcoolingdependsuponthebaffletubesratherthanthecoolingchannels.Anotherreasonofthelackofinfluencecanbethattheflowstateinthecoolingchannelremainsturbulentintherangeoftheparametricstudy.Thecoolingchannelusuallyhasasmallerdiameterthanthebaffletube.Whentheflowinthebaffletubeiskeptintheturbulentstate,theflowinthecoolingchannelwillbeintheturbulentstate.Thediametersofthebaffletubesshowatangibleinfluencewhenitincreasesaboveacertainvalue.Increasingofthediameterchangestheflowinthetubetoalaminarflowstate.Thisisthecauseforthelowerheattransfercoefficientwhencomparedtotheturbulentflowstate.Thisiswhythetemperaturedeviationbecomeslargerwhenthebaffletubediameterincreases.EiEw()2N-i1=N=Figure4.Schemeofthetemperaturefieldbythecoolingchannels.Table1.Lowerandtheupperboundsfordesignvariablesandtheinitialvaluesfortheoptimization(unit:mm).DescriptionLowerInitialUpperX1Channeldiameter103040X2Bafflediameter103040X3Channeldistance6090120X4Baffledistance6060120X5Channeldepth306090X6Bafledepth306090Figure5.Parametricstudyresultoftemperaturedeviation(objectivefunction).276J.-H.CHOIetal.Amongallparameters,thebaffledepthshowsthelargestinfluenceontheobjectivefunction,asshowninFigure5.Asthebaffledepthincreases,theobjectivefunctionincreases.Thismeansthatthedeeperlocationofthebaffletubescausesthetemperaturedeviationtoincrease.Also,itconfirmsthatthecoolingoftheautomotivebumpermolddependsuponthebaffletubes.Thediametersofthecoolingchannelsandthebaffletubeshavethehighestinfluenceonthepressuredropinthecoolingcircuit,whiletheothervariablesshowlittleinfluence(seeFigure6.).Asthediametersincrease,thepressuredropdecreasesafteracertainvalue.Thisisalsoapredictableresultasalargerdiameterdecreasesthepressuredrop.TheinfluencesofthetemperatureriseattheoutletareshowninFigure7.Themostinfluentialparametersarethebafflediameterandthechanneldistance.Theinfluenceofthebafflediametershowsthehighestvaluesintherangefrom-1to3.Inthecaseofthesmallerbafflediameter,thereducedsurfaceareafortheheattransfermaycauseasmallertemperaturerise,whilethelargerbafflediametermaycausethelowerheattransfercoefficientduetothelowerflowrate.Theincreasedchanneldistancemeansthateachcoolingchanneltakesupalargerareaofthepartsurfacewithalargeramountofh
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 影像本科头颈部影像诊断学复习题
- 优化项目的计划方案
- 财务审计人员保密协议及离职竞业禁止合同
- 创新离婚协议书范本注重离婚后子女教育问题
- 社区小院花园改造方案
- 精密仪器使用厂房租赁安全协议范本
- 主题婚礼策划与执行合同
- 电子产品回收处理与售后服务协议
- 劳务分包实施方案
- 标杆管理控制方案模板
- 2025江苏省惠隆资产管理限公司招聘30人易考易错模拟试题(共500题)试卷后附参考答案
- 《农村基层干部廉洁履行职责规定》解读与培训
- 2023年上海高考生物真题试卷(答案解析版)
- 安全评价 课件
- 临床各科急救流程规范规范图
- 交安工程劳务分包参考价格(范本)
- 2022年专业技术人员继续教育公需课题库(含答案)
- GB∕T 13554-2020 高效空气过滤器
- (新版)孤残儿童试题库(含答案)
- 普通生物学说课(张艳丽)
- 欧亨利介绍及其作品
评论
0/150
提交评论