塑料件注塑基本知识10478.pptx

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1、塑料的分类热固性酚醛树脂氨基塑料有机硅塑料硅酮塑料环氧树脂热塑性GeneralpurposeABS,PP,PE.EngineeringPC,PC+ABS,PBT,PET,Nylon.ReinforcedFiber,Mineral.热固性塑料的填料粉状填料滑石粉,云母粉,石英粉流动好,比容小,塑料性脆,成型压力小.木粉流动好,比容小,易吸湿.热固性塑料的填料纤维填料棉纤维,石纤维,碎布纤维.流动性差,比容大,易吸湿,成型压力大,强度好.填充性不良,易熔接不良.玻璃纤维流动性差,方向明显.比容大,装模不便,模具磨损大.加压时机:过早,填料与树脂分离,溢料多.过晚易发生填充不足.热塑性塑料成形收缩率

2、塑料粒子分子量大小,结晶/非结晶.塑件结构嵌件布局/数量,料流方向料流方向大，垂直小玻纤增强：料流方向小，垂直大浇口形式,尺寸,分布成型条件热塑性塑料流动性好分子量大小:分子量小,分子量分布寛.分子结构规整性差熔融指数高表现粘度小流动比大.热塑性塑料结晶性结晶型壁薄,冷却快,结晶低,收缩小,透明度高各向异性,内应力大.易变形,翘曲非结晶型热塑性塑料热敏性及水敏性热敏性:料温高,易变色,易降解,对模具的腐蚀大.水敏性:在有水的情况下,在高温,高压下会降解.热塑性塑料吸湿性吸湿,粘附水份不易吸湿,粘附水份水解使树脂起泡,流动性下降,外观及机电性能不良.塑件设计脱模斜度精度高,取小值较高,较大的尺寸

3、,取小值形状复杂不易脱模取大值收缩率大的取大值壁厚较厚者取大值型心面比型腔面小.增强塑料宜取大,自润材料可取小.塑件的壁厚壁厚均匀原则壁厚越厚,流程越长壁厚决定塑件的使用性能:强度,电气性能,尺寸稳定性装配壁厚一般为16mm,常用23mm避免翘曲变形的设计保持壁厚均匀检查相交部分逐渐改变壁厚加强筋加强筋的厚度必须小于相连接的壁厚网格式加强筋须低于四周的高度.有可能的情况下,螺丝柱需与本体连接.支承面小支承面的配合优于大支承面以螺丝柱部位可得到高强度的可靠装配圆角和孔连接处以圆角过渡：减小应力，改善流动，提高强度：0.51mm孔间距不宜太小：用长圆孔加凸台螺钉孔加倒角以容屑铰链铰链的截面不易过长

4、壁厚减薄过渡处以圆弧过渡壁厚一般为0.20.4mm材料：注：融体流向必须是通过铰链部分，使其线性分子延主链折弯塑件的尺寸精度影响因素成型材料成型条件塑件形状模具结构：Gate,Flow,Direction,Parting,Tooling存放条件塑料机的发展开炼机和压延机螺杆挤出机(十九世纪后期)柱塞式注射成型机(二十世纪初)线式螺杆注射机(1956年)塑机的分类混炼机械捏合，开炼，密炼机压铸机挤出机注射机压延机：人造革，塑料薄膜等吸塑机吹塑机注射机的结构组成注射装置塑化部件：螺杆，料筒和喷嘴料斗，计量装置，传动装置，注射和移动油缸合模装置前后固定模板，移动模板，连接前后固定板用拉杆，合模油缸，

5、移动油缸，连杆机构，调模装置，顶出装置注射成型过程FillFillInjectionInjectionPackPackInjectionInjectionHoldHoldScrewScrewReturnReturnDecompressionDecompressionCoolingCoolingTimeTimeMoldMoldOpenOpenEjector Ejector ForwardForwardEjectorEjectorBackBackMold Mold ClosesCloses注射机的基本参数公称注射量注射压力注射速率塑化能力锁模力合模装置的基本尺寸模板尺寸，拉杆空间，模板最大开距，动

6、模板的行程，模具最大小厚度注射模分类单分型面注射模具双分型面注射模具带有活动镶件的注射模具横向分型轴芯注射模具自动卸螺纹模具定模顶出模具无流道模具（热流道，绝热流道）单分型面注射模具双分型面注射模具注射模典型结构成型零部件浇注系统导向部分分型抽芯机构顶出装置冷却，加热系统排气系统Leader PinLeader PinClamping PlateClamping PlateStationary Stationary HalfHalfMoveable Moveable HalfHalfEjector Ejector PlatePlateCavityCavitySprue BushingSprue

7、 BushingThepathwayformaterialtofollowtogetfromtheinjectionnozzletothemoldcavity.Comprisedof:SprueRunnerGateRunnerSystemUseBalancedRunnerSystemsDiameter(min)vs.Length(max)3/16”=6”long5/16”=12”long3/8”=15”longRunnersUnbalancedUnbalancedBalancedBalancedColdwellTrapscoldslugsformedattipofinjectionnozzle

8、KeepsslugsfromenteringmoldColdwellColdwellRunnersFull RoundFull RoundModifiedModifiedTrapezoidalTrapezoidalTrapezoidalTrapezoidalHalfHalfRoundRoundA runner is only as efficient as the largest full round runner drawn in its cross sectionSprueBushingsSizingDraft(1.53.5PerSide)Pullers&ColdwellA sprue b

9、ushing is the entry portA sprue bushing is the entry portfor injecting resin into the moldfor injecting resin into the moldUndercut RingUndercut RingBall PullerBall PullerZ PullerZ PullerReverse TaperReverse TaperDesigned to pull the sprue from the sprue Designed to pull the sprue from the sprue bus

10、hing when the mold is openedbushing when the mold is openedSpruePuller浇口设计流动的分布需均匀开在最厚的部分，以便保持最大的保压浇口应设计到熔体最后冷却的地方注意玻纤排列方向的影响浇口的类型针点式浇口潜伏式浇口边缘浇口扇形浇口平缝式浇口（薄片浇口）圆环形浇口浇口的类型轮輻式浇口爪浇口护耳式浇口直浇口浇口的类型Tunnel/SubTunnel/SubEdgePinpointPinpointHotManifoldsHotManifoldsHotmanifoldssystems:Providesheatedpassagetomol

11、dcavityAllows15%to20%fastercyclesEliminatessprue&runnerscrapImprovespartqualityReducesmoldedinstressExternallyHeatedManifoldAIRGAPINSULATESMANIFOLDFROMPLATESUNIFORMTEMPERATUREALONGMELTCHANNELEXTERNALLYHEATEDUNRESTRICTEDFLOWLESSPRESSUREDROPEASIERMAINTENANCECourtesy ofHotManifoldsHeaterHeaterProbeProb

12、eMeltMeltChannelChannelCoolingCoolingPlugPlugLocatorLocatorRingRingHeaterHeaterHeaterManifoldManifoldManifoldPocketPocketPocketMelt Melt Melt ChannelChannelChannelHeaterHeaterHeaterCoolingCoolingCoolingINTERNALLYINTERNALLYHEATEDHEATEDEXTERNALLYEXTERNALLYHEATEDHEATEDHotManifoldsExternallyheatedhotrun

13、nersystemsarerecommended:ReducepressuredropReduceshearandthermalhistoryPreventburnandbrownstreaksEasechangesincolorormaterialFacilitatepurgingValveGatedHotManifoldsCYLINDERCYLINDERPISTONPISTONVALVE PINVALVE PINSPRUE BUSHINGSPRUE BUSHINGMANIFOLDMANIFOLDINSULATORINSULATORINSULATING AIR GAPINSULATING A

14、IR GAPNOZZLE HOUSINGNOZZLE HOUSINGNOZZLE TIPNOZZLE TIPNOZZLE HEATERNOZZLE HEATERMANIFOLD PLATEMANIFOLD PLATECAVITY PLATECAVITY PLATEHotManifoldsManifoldsizingStreamliningTipdesignStandoffs/insulationControlsHotManifoldsBALANCEDMANIFOLDUNBALANCEDMANIFOLD分型抽芯机构手动侧向分型抽芯机动侧向分型抽芯弹簧，斜导柱，弯销，斜导槽，锲块，斜滑块液压气动侧

15、向分型抽芯分型抽芯机构模具模拟动画八上一个返回分型抽芯机构Cooling/HeatingWateristypicallyusedtoheatorcoolmoldUniformmoldtemperatureiscriticalto:CycletimeWarpagecontrolShrinkageDimensionalcontrolSurfaceappearanceStresscontrolCrystallinitySinksandvoidsWeldlinesBlushGlass/mineralJettingColdflowPlan Water First Plan Water First Whe

16、n Designing MoldWhen Designing Mold Cooling/HeatingSomecriticaldetails:Depth/pitch/diameterTurbulentflowMTLsofconstructionDesignWater ChannelsWater ChannelsVenting Unfilled products .0005”-.001”Unfilled products .0005”-.001”Filled Products Filled Products .001”-.002”.001”-.002”(over 10%)(over 10%)D1

17、D1The route by which air is allowed to escape from the cavityThe route by which air is allowed to escape from the cavityParting Line VentParting Line VentD1D1OtherVentingTechniquesPin“flats”ContinuousventBladesPorousmetalVacuumOverflowMold SurfaceMold SurfaceEjectorEjectorPinPinPin VentingEjectionBl

18、adesPinsLiftersStripperringsSleevesDraftDraftallowseasierpartejectionfromtoolingConventional:1persideWithtexture:(1+1.5per.001”depth)No draftNo draftDraftDraftDraw DirectionToolingMetalSelectionMaterial TypeHomopolymersandUnfilledCopolymersReinforcedMaterialSteelTypeP20S7H13420Tool SteelCharacterist

19、icsMedium Alloy Mold SteelShock resisting tool steelHot work tool steel(Cr based)Stainless steelTypicalHardnessasFinished(Rockwell C)30-36 Rc54-56Rc50-52Rc50-52Rc模流分析(CAE)缺陷分析Troubleshooting缩痕变形毛邊熔合线银丝喷纹烧焦缺陷分析TroubleshootingBurnmarks:AddventsReduceinjectionspeedMovegatelocation缺陷分析TroubleshootingSin

20、kmarks:IncreasepackpressureortimeReduceinjectionspeedReduceribtowallthicknessratio缺陷分析TroubleshootingStringing:ReducenozzletemperatureUsedecompressionUsereversetapernozzle缺陷分析TroubleshootingWhiteSpots:DrymaterialReduceinjectionspeedAdjustmelttemperature缺陷分析TroubleshootingBurnStreaks:ReducemelttemperatureReduceinjectionspeedLookforcontaminationormaterialhangup谢谢观看/欢迎下载BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES.BY FAITH I BY FAITH