GE公司注塑技术

GEPlasticsINJECTIONMOLDINGe注射模塑技术InjectionMoldingIntroduction注塑之优点高生产率可大批量生产低人工成本易自动化最少的二次加工可生产很小制件最少报废率可生产紧公差制件可注塑带嵌件制品可加玻纤,碳纤等填充物可生产复杂制件可有好的装饰InjectionMoldingIntroductionGOODPARTMaterial材料Tooling模具Processing工艺Design设计好产品Equipment设备InjectionMoldingEquipmentMACHINESHOTSIZE机器注射容量PartWeight=40-80%ofMachineShotSize制件重量=40-80%机器注射容量OptimalPartWeight=40~60%ofMachineShotSize制件重量=40-60%机器注射容量InjectionMoldingEquipmentInjectionMoldingEquipmentScrewTypeMachinesAreRecommended推荐采用的螺杆类型UniformPlasticizing

均匀塑化LessPressureLoss

低压力损耗FasterCycles更快成型周期UniformStockTemperature

均匀储料温度StreamlinedMeltFlow

线性熔融流动InjectionMoldingEquipmentMetering计量Feed进料ScrewandCylinderDesign螺杆和料筒设计hfhmL/D长径比=20:1(18:1~24:1)CompressionRatio压缩比

=2.5:1(2:1~2.5:1)Cylinderbi-metallicforAbrasionResistance双金属料筒hmhfTransition过渡LDInjectionMoldingEquipment往复式螺杆头结构检查环类型:止回环熔融树脂流过开放检查环检查环关闭,防止在注塑过程中料的回流建议采用止逆阀InjectionMoldingEquipmentStandardCylinderNozzles标准料筒喷嘴HeatingBand加热环CylinderBore料筒主体ToMoldProvidesMechanicalandThermalConnectionFromHotCylindertoColderMold提供从热的料筒到相对冷的模具的机械和热连接到模具InjectionMoldingSprueBushing主流道衬套Nozzle喷嘴Radius半径Orifice主流道孔口段道长度最大5mm射嘴开口:4.76~9.53mm主流道衬套孔口要比喷嘴口径大0.8~1mm尽可能地短Tooling模具InjectionMoldingtoolingRunnerUseAdequateRunners(FullRound)6to10mm熔体由内层向前流动外层接触模具冷却固化RunnerFlow流道:平衡的配置是最好的重要点-全圆形或梯形的流道10mm>250mm8mm75-250mm6mm<75mmRunner流道半径微小的增加就可以很大程度地增加流量,并相应地减小压力降Q=流量

P=压力降R=浇口半径N=粘度L=流动距离Q=

8n

LQProportionaltoR4

nR

P4RunnerRunners

Design效率最好较好避免使用PLToolingRunnersSpruePullerREVERSETAPERBESTZPULLERGOODGROOVETROUBLE-SOMESUCKERPINNOTRECOMMENDEDToolingRunnersRESTRICTIVEPREFERREDToolingRunners流动方向冷料井ToolingRunners冷料井流道直径:D1.5XDUnbalancedSystemAAAABBBBToolingRunnersBalancedSystemAAAAAAAAToolingRunners浇口定位要考虑的基本因素有：制件设计、流动和产品最终使用要求。应牢记下面的几点，以此作为一般指南。•需要多浇口的大制件，应该有位置足够紧密的浇口，以减少压力损失。这样做可使树脂流动前缘交汇点的冷却最小化，从而提供较好的熔合线强度。应选择合适的浇口尺寸，以使树脂的充填有一个合理的压力和速度。•浇口过渡段长度应保持尽可能的短。•撞流浇口将有助于保证流入的流体直接对着模腔壁或型芯，从而可以避免漩纹。•为避免夹气，来自浇口树脂流，应将空气导向排气槽。•浇口位置应确定好，以便让树脂从厚壁部位流向薄壁部位；让熔合线最小化；并且远离冲击和应力区。•要使漩蚊、放射斑和浇口白晕减至最少，浇口应与流道有一个合适的角度(下图).•直接浇注到装饰性表面，会引起表面缺陷。GatedesignGating侧浇口的高度应为80~100%的壁厚,宽度应为浇口深度的2倍侧浇口0.5mmLandLength1.27~2.53mm900点浇口GatingMoldedPartSpruePartingLine加设倒圆改善流动KnockOutPinTunnelGateToolingGating3004501mm(min.)R10~25RGateCashewGateToolingGating252.5DVENTINGToolingVentingPartingLineDepth0.035~0.075mmGate2.5mmNoteStep 6mm(min.)0.4~0.75mmToolingVenting25~50mmClearanceAroundKnockout.0025EjectorPinToolingVentingMoldingProcess

成型工艺InjectionMolding使用合适的设备,正确的条件对材料进行预干燥DryEnvironment-30CdewpointAirFlowRate1cfm/hourlylbofresinusedTemperature120CTime4hrs+InjectionMoldingPredryProcessing工艺Start-up:开机:

PurgewiththeCorrectMaterial

用正确料清洗

UseCorrectProcessingConditions

采用正确加工参数InjectionMoldingProcessRecommendedPurgeMaterials推荐清洗料Polymer PurgeMaterial聚合物 清洗料Cycolac®/Cycoloy® PMMA,PS,SANNoryl® PS,PMMALexan® PMMA,HDPEValox® PS,HDPEUltem® LEXAN,HDPE(ExtrusionGrade)Supec® HDPEInjectionMoldingProcessInjectionMoldingProcessImportantProcessVariables重要加工参数MeltTemperature熔融温度MoldTemperature模具温度TemperatureProfiles温度曲线ResidenceTime停留时间InjectionSpeed注射速度InjectionPressure注射压力PackPressure保压ClampTonnage锁模力Cushion缓冲料垫InjectionMoldingProcessModelofAmorphousPolymersAddingHeatIncreasesSpace外热提供空间BetweenMolecularChains在分子链之间RaiseTemperatureofPolymer

TGLocked固态EntanglementsStiffFlow难于流动EasierFlow较易流动InjectionMoldingVariablesMeltTemperature熔融温度35302520151050.030 .060 .090 .120 .150 .180 .210 .240WallThicknessinInches壁厚(In)MeltFlow(in.)LEXAN?101550degF.101@600deg.FIncreasedMeltTemperatureyieldsincreasedFlow.提高熔融温度导致增加流动However,TooHighaMeltTemperatureMayCauseDegradation.但,过高熔融温度造成降解InjectionMoldingMaterialThermoplasticsandDegradation热塑性塑料和降解Degradation降解TemperatureTime时间Howisheataddedtothepolymer?外热如何作用于高分子材料ElectricalHeat:电加热HeaterBands加热带MechanicalHeat机械热ScrewSpeed螺杆速度BackPressure背压InjectionPressure/Speed注射速度/压力Product MeltTemperature(0C)CYCOLAC® 220-260LEXAN® 270-320NORYL® 240-320VALOX® 235-275ULTEM® 340-440CYCOLOY® 240-280XENOY® 240-280SUPEC® 305-330GELOY® 195-220InjectionMoldingProcess产品类别熔体温度InjectionMoldingBarrelUnitTheReciprocatingScrewScrewRotationFeedsandShearsMaterialIntoaMelt.MeltCollectsIntoFrontofBarrel,ForcingScrewBackShotRotationandBackPressure出量通过螺杆回转，熔体聚集于料筒前部，反作用力使螺杆后退。回转力矩和背压15010050255075125150100ScrewDiainmmRPMSCREWSPEEDSuggestions推荐螺杆转速螺杆直径转速InjectionMolding建议的螺杆转速是根据直径而确定的。螺杆的最佳O.D.（外径）线速度为：每秒8英寸(202.4mm).RPM=[每秒8英寸（202.4mm）的最佳线速度×60]/[螺杆直径×3.14].例如：螺杆直径为3英寸（75.9mm）。那么，3(螺杆直径)×3.1416=9.248,再被每秒8英寸（202.4mm）(最佳线速度)×60来除=51RPM,即为螺杆转速。InjectionMoldingInjectionMoldingEquipmentBarrelUnitTheReciprocatingScrewMeltRequiredtoFillMoldReadyforInjectionShotInjectionPressure注射压力将要注入模具内的熔体InjectionMoldingEquipmentBarrelUnitTheReciprocatingScrewScrewPushesForward:InjectCushionPackingPressure缓冲垫保压注射InjectionMoldingVariablesInjectionSpeed100010010100 1000 10000LEXAN?141@644degFLEXAN?141@608degFLEXAN?141@572degFApparentViscosity(Pa/s)ShearRate(1/s)InjectionSpeedaffectstheviscosityofthemoltenmaterial.注射速度表观粘度剪切速率注射速度影响熔体粘度InjectionMoldingVariablesInjectionPressureProfileHydraulicPressureTimeFillTimeScrewRunTimeBackPressurePeakInjectionPressurePressureAppliedbyInjectionRamtoForcethePlasticFromtheBarreltotheMold.注射压力曲线注射压力峰值液压压力填充时间MachineDowntime停机2小时以下时,建议将料管温度降低56degC.停机2~8小时时,建议将料管温度降低至170degC.停机超过8小时的,建议将料管清洗干净,且停止加热.对于玻纤增强树脂,如果停机时间超过30分钟,应将料管清洗干净.对于含PC的树脂,不要将料管温度降至160degC以下Downtime:停机模温MoldTempeatureInjectionMoldingProcessInjectionMoldingProcessPartCoolingandSolidificationHotMeltCooledMoldSolidPart制件冷却和固化热熔体温度较低的模具固化的制件MoldTemperature模温对制件的外观很重要模温一致对尺寸控制很重要均匀的模温可以减少翘曲合理的模温可以降低产品内应力合理的模温可以改善材料流动性InjectionMoldingCooling模温CoolingsystemMoldCoolingSeriesBubblerINOUTPOORPinBladeINOUT30

CoolingSystemGoodCoolingSystemREGRINDSUGGESTIONSUseOnlyCleanNon-degradedUncontaminatedResinforRegrindKeepItAsNewMaterialNormally20%ofRegrindcanbeUsedScreenSizesshouldbe7to9mmInjectionMoldingRegrind对材料回收使用的建议只使用未降解材料回收料不能有污染要象保存新料一样通常允许添加20%的回收料过滤网应该在7至9MMInjectio