LSR自动化成型科学与材料特性

LSR自动化成型科学与材料特性液态硅胶射出成型介绍(一)➢SiliconeRubber─Applications&Advantage•Easyfabricating•Goodappearanceandsafe•Excellentelectricalinsulation•Thermalstability➢早期大多是以热压缩或挤压方法做成型•热压缩成型─大量的毛边及余料─人事成本高─半自动生产─不良率高…•挤压成型─单一断面液态硅胶射出成型介绍(二)液态硅胶射出成型介绍(三)➢液态硅橡胶成型(LSR)─生产周期短─余料少─全自动生产(搭配机械手)─尺寸精确─几何形状复杂之产品…液态硅胶射出成型介绍(四)➢生产流程合模鎖模射出保壓開模頂出待機加熱硫化混料計量LSR的注塑成型加工(InjectionMoldingofLSR)液态硅胶流动分析的重点射出机控制•计量位置•射出速度•射出压力•VP切换点•保压压力•保压时间•硫化时间硅胶成型条件•温度•流动•热固化成型性质•尺寸•物理特性•化学性质•光学特性液态硅胶加工条件LSRInjectionMoldingMachine➢ARBURGLSRmoldingmachineisusedinthisexperimentalongwith2KMdosingunit.MachineTypeARBURG370S700-290ClampingUnitClampingforceMax.700kNClosingforceMax.38kNOpeningforceMax.24kNOpeningstrokeMax.400mmDistancebetweentiebars370X370mmPlatensize(hor.xvert.)510X510mmEjectorforceMax.30kNEjectorstrokeMax.125mmInjectionUnitScrewdiameter30mmScrewstrokeMax.150mmCalculatedInjectionVolume106cm3InjectionpressureMax.2500barInjectionflowMax.102ccm3/sBackpressurepositive/negativeMax.200barCircumferentialscrewspeedMax.46m/minScrewtorqueMax.320NmNozzlecontactforceMax.60kNARBURG370S700-2902KMliquiddosingunit液态硅胶成形：冷料遇上热模冷料的来源热模的来源•高流动性可以充填微细及肉薄的产品设计区域液态硅胶的低黏度特性•低射压的优点：射座简易、锁模力低•低射压的缺点：逆止阀止逆效果(计量精准度)、排气困难液态硅胶的低黏度特性排气-射压抵抗气体阻力逃气不良之产品20%40%70%90%ActualShortShotSimulationMetering波前的比对包封区域与排气沟的设定•Meltfrontisflowingfasterinthethickestcenterregion,whichcouldcreate,creatingapotentialvoidatthelastfilledarea•Flowpatternmaybeimprovedtobeuniformbychangingthethicknessaroundtheregionnearthegatesoastoslowdownthemeltenterthethickestcenterregion几何设计与流动平衡性40%70%2.5mmThinnestregion:1mm1.6mmThickestregion:4.0mm•Generallytheshearratemaintainsquitelow(below50s-1)duringfilling.Highestshearrateisobservedatthegateregionwithmagnitudereaching3.8e5s-1.•Excesshighshearratecouldresultinshearheatingandprematurecuringandhighinjectionpressure.•Gatedesignshouldbere-considered.Max_ShearRate迟滞、流痕与折射率分布液态硅胶温度分析的重点Source:明志科技大学郭启全教授•加热装置的设计•模具与管嘴的绝热•模具瞬时温度分析•LSR流动时的温度变化•固化阶段的温度均匀度液态硅胶温度分析的重点加热装置的功率热电耦的位置PID参数优化1/5dt:P=3,I=1,D=01/5dt:P=3,I=0.5,D=1.5模具组件非匹配网格技术恒温水套的CFD流动分析射口绝热对材料升温的影响未绝热绝热FillingnearthegateFillingapproachcompletion30ºC175ºC材料因流动而升温的影响材料因流动而升温的影响液态硅胶固化分析的重点Source:明志科技大学郭启全教授•固化均匀度•固化时间与成形周期预测•脱模损伤液态硅胶固化分析的重点固化均匀度Bluecolour:curingreactionnotyetstartedRedcolour:curingreactionstartedPartcuringtime:about30secondsNotcuredyetCuredCuringTime30S60S80SConversion：75%Conversion：91%Conversion：90%固化时间与成形周期预测液态硅胶的材料性质与量测•硅烷橡胶/硅橡胶的种类•固态高温加硫型有机硅烷橡胶─HTV•俗称HTV(HightemperatureVulcanizate),或HCR(Highconsistencyrubber)•液态高温加硫型有机硅烷橡胶─LSR•俗称LSR(LiquidSiliconeRubber),或LIMS(LiquidSiliconeRubberInjectionMoldingSystem)•室温硬化型有机硅烷橡胶─RTV•俗称RTV(RoomTemperatureVulcanizate)SiliconeRubber有三种主要型态•Themethylgroupsalongthechaincanbesubstitutedbymanyothergroups(e.g.,phenyl,vinylortrifluoropropyl).SiliconeRubber─硅烷橡胶,硅橡胶wheren=0,1,...Dimenthylpolysiloxanesiliconatomisconnectedwithtwooxygenatoms•Thesynthesisofsiloxaneshasbeendescribedelsewhere[1,2,3].Insummary,PDMSisobtainedfromthehydrolysisofdimethyldichlorosilaneMe2SiCl2,whichleadstoamixtureoflinearandcyclicoligomers:3•HighermolecularweightPDMSisobtainedafterpolymerisation,SiliconeRubber─硅烷橡胶,硅橡胶反应机理•优点•成型时间非常短,可以快速反应固化•不需后加工,如裁剪毛边等•因自动包装完全密封,故较不易受污染•可全自动化生产,加工人力使用少•远较固态硅胶(HCR)在制程上减少很多费料/废料•可制做非常精密的产品(因流动性极佳)•缺点•LSR为热固性材料无法回收再使用•LSR的硬化反应性相对敏感,成型上控制条件较重要•LSR流动性佳,模具配合精度要求较高•LSR价格高液态硅烷橡胶(LSR)的优缺点•LSR的优点:•极佳的耐热性•goodheatresistance(200°cupto225°c)•在低温环境中可保有非常好的柔软性•verygoodflexibilityatcoldtemperature•具有非常好的弹性及压缩回弹性•verygoodelasticityandDRCCompressionResidualDistortion(elasticmemory)•具优良的耐老化性,耐臭氧,抗UV等-ozone,UVstability,goodageingproperties•优良的高电压下介电性质•gooddielectricproperties(highvoltageapplication)•生物组织兼容性,无毒性•physiologicalcharacteristic(FDA,BGAagreements)•饮用水接触认证•KTWagreementfordrinkablewater(20and26series)液态硅烷橡胶的优点•Lowintermolecularforceandstrongcoil-forming•Dimenthylpolysiloxane(二甲基聚硅氧烷),atypicalpolymericconstituentofsiliconerubbers,hasahelicalorcoiledmolecularconfigurationwithasmallintermolecularforcesothatithashighresilience(回弹性),largecompressibility(可压缩性)andexcellentcoldresistance.Furthermore,theoutwardlydirectedmethylgroupsareabletorotatefreelyresultingintheuniquesurfacepropertiesofsiliconessuchaswaterrepellenceandsurface-releasability.液态硅烷橡胶的优点•Siliconegelsarecompliant,selfhealingandoutstandingforprotectingthinwire-bondingfromthermalshocks,vibrationandcorrosion.•TheresponseoftheirelasticandstoragemodulusislinearoverawiderangeoftemperatureandfrequencySiliconeRubber─的黏弹特性ThermosetMaterialPropertyShrinkageThermalPropertyMechanicalPropertyCuringKineticsRheologicalPropertyThermosetMaterialProperty•CuringKinetics•StudyofCuringKinetics•CuringKineticsModel•RheologicalProperty•RheologicalCharacterization•ViscosityModelLSRrheologicalproperty•Therateoftheconversionofthepolymerizationreactioniscontrolledbythekinetics.•Manytechniquescanbeusedtomonitorthecuringkinetics:•DSC,FTIR…•Severalempiricalkineticmodelshavebeenofferedtofittheexperimentaldata.•Combinedmodel,nth-order,…CuringKineticsofLSRCuringKineticMeasurementandModelingCharacterizedbyDSC–ReactionRate(Combinedmodel)nmkkdt