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注塑工艺设计注塑工艺设计徐昌煜CharlesHsuCharlesHsu先进成型技术学会创会理事2010年11月18日于深圳禧莲酒店注射成型周期InjectionMoldingCycle117(1).充填阶段Fillingstage(2).后充填阶段Post-fillingstage2(1)(3)Post-fillingstage(3).开模阶段Mold-openingstage361.成型周期开始Cyclebegins2.充填/保压切换点F/Pswitchesover3.型腔完全充满5Cavityisallfilled4.保压释放Packingpres.isreleased5.冷却/开模切换点P/Oswitchesover6开模5(2)6.开模Moldopens7.关模及下个周期开始Moldclosesandnextcyclebegins4模温MoldTemperatureMoldtemperaturesareimportantindeterminingfinalpartfinishandmolded-instresslevelsColdmoldsaremoredifficulttofillandmoldedinstresslevels.Coldmoldsaremoredifficulttofill,necessitatinghighinjectionpressureandmelttemperature.Heatedmoldsgenerallyproduceapartwithabetterfinishandgylowermoldedinstress.Becauseofthehighheatdistortiontemperaturesofengineeringthermoplasticresins,partsarejtdilthihttejectedeasilyathighertemperatures.ThemidpointofthesuggestedrangewillgenerallygivegoodThemidpointofthesuggestedrangewillgenerallygivegoodresultswithrespecttopartappearanceandcycletime.Highermoldtemperaturescanresultinbetterflow,strongerknitlinesandlowermolded-instresses.Usinglowerthanthesuggestedmoldtemperatureswillgenerallyresultinhighermolded-instressesandi(危及)tititcompromise(危及)partintegrity.熔胶温度MeltTemperatureAsageneralrule,residencetimeshouldbeasshortaspossiblewhenmoldingnearthemaximumsuggestedmelttemperature.Whenprocessingnear,orat,theupperlimitofthemeltrange,thehtihthldh80t90%fthliditfshotweightshouldapproach80to90%ofthecylindercapacityofthemachine.(当料温接近上限时，射料量应当接近注射机射胶量的80到90%)Ifthecylindertemperatureexceedstheupperlimit的80到90%)Ifthecylindertemperatureexceedstheupperlimitofthesuggestedmeltrange,thermaldegradationoftheresinandlossofphysicalpropertiesmayresult.熔胶温度MeltTemperatureArelativelysmallincreaseinscrewspeed(RPM)orbackpressurecanresltinadramaticincreaseinmelttemperatreithnocanresultinadramaticincreaseinmelttemperaturewithnochangeincontrollersetpoint.(即使设定料温不变，稍微增加螺杆转速或背压就会明显增加融胶温度。)Itissuggestedthatmelt转速或背压就会明显增加融胶温度)Itissuggestedthatmelttemperaturesbemeasuredusinghand-heldpyrometers.Thesemeasuresshouldbetakenonthethermoplasticmeltsafterthemachineisoncycle.IncreasedmelttemperatureswillreduceviscosityandincreaseIncreasedmelttemperatureswillreduceviscosityandincreaseresinflow,thusprovidingforlongerflowforthinwallsectionsandhelpproducelowerresidualstress.Whenhighermelthelpproducelowerresidualstress.Whenhighermelttemperaturesareused,reducedbarrel/residencetimesareneededtominimizeanydegradationoftheresin.螺杆转速ScrewSpeedScrewspeeds(RPM)shouldbeadjustedtopermitscrewrotationScrewspeeds(RPM)shouldbeadjustedtopermitscrewrotationduringtheentirecoolingcyclewithoutdelayingtheoverallcycle.Lowscrewspeedswillhelpreduceglassfiberdamageduringplasticationwhenmoldingreinforcedgrades.(塑化加補強物塑料時，低的螺桿轉速可以減少玻纖的損毀。)SuggestedscrewspeedisdependentonscrewdiameterOptimumlinearvelocityspeedisdependentonscrewdiameter.OptimumlinearvelocityofscrewO.D.istypically8inches(202.4mm)persecond.RPM=(60x8inches/secondor202.4mm/second)/(πxscrewRPM(60x8inches/secondor202.4mm/second)/(πxscrewdiameter).Forexample,fora3inch(75.9mm)diameterscrew:3(screwDia.)x3.1416=9.4248dividedinto8inches(202.4mm)persecond(optimumlinearvelocity)x60=51RPM.背压BackPressureBackPressureAbackpressureof50to100psi(0.35to0.7MPa)issuggestedtohelpensureahomogeneousmeltandmaintainconsistentshotsize.(推荐采用0.35到0.7MPa的背压，以确保均匀的融胶及维持一致的射料量)Higherbkdtiltiiltibackpressuresusedtoimprovemeltmixingresultinhighermelttemperaturesandpossiblydegradationduetoexcessiveshearingoftheresintoexcessiveshearingoftheresin.射速InjectionSpeedThefastestfillspeedpossibleprovideslongerflowfillsThefastestfillspeedpossibleprovideslongerflow,fillsthinnerwallsections,andhelpstocreateabettersurfacefinish.Slowerfillissuggestedforsprue-gatedandedge-gatedpartstohelppreventgateblush,splayandjetting.Inthickwallparts[0.2inches(5.06mm)andup]slowfillhelpsreducesinksandvoidshelpsreducesinksandvoids.射压InjectionPressureInjectionPressurejTheactualinjectionpressurewilldependonvariablessuchasltttldttttllmelttemperature,moldtemperature,partgeometry,wallthickness,flowlength,andothermoldandequipmentconsiderationsGenerallythelowestpressureswhichconsiderations.Generally,thelowestpressureswhichprovidethedesiredproperties,appearance,andmoldingcyclearepreferred.(一般說來，最低射壓可以提供需求的性質、外觀和成型週期。)Ideally,injectionpressureshouldvarytomaintaintheintendedramspeed.Thisiscalledvelocitytlldijtididthldhcontrolledinjectionandprovidesthemolderamuchmorerobustandrespectableprocessthancontrollinginjectionpressureduringfillpressureduringfill.射压对充填时间变化曲线InjectionPressurevsFillTimeDVD盒的翘曲及锁模力需求WarpageandRequiredWarpageandRequiredClampForceofaDVDBoxDVD盒,PP,广东省珠海市,2002.8.6.DVD盒PP2型腔模注射时间18秒DVD盒,PP,2型腔模,注射时间:1.8秒公称厚度1.3mm,铰链厚度0.18mm产品简介产品：DVDBox材料：PP产品尺寸(展开)﹕产品尺寸(展开)﹕284x191x9.4mm产品尺寸(合上)﹕136x191x14mm369模具为一出二。产品壁厚分布如上图所示，公称壁厚为1.3mm，侧壁壁厚为1.8mm、1.6mm和0.8mm，中间铰链处最小厚度为0.18mm。方案比较表保压切换位置为99%保压压力为切换时注射压力的80%保压切换位置为99%,保压压力为切换时注射压力的80%.模温设定﹕8°C；料温设定﹕260°C1234567891011注射时间(s)1.50.20.50.81.01.21.51.82.02.53.0射压(MPA)49.956.146.844.644.143.844.145.546.14951锁模力(Ton)252191153158163168181194203221