塑料注射成型工艺基础

塑料注射成型工艺基础内容提要注射工艺过程注射压力填充模式浇注系统与流道平衡冷却系统应力、收缩与翘曲常见的注塑缺陷CAE软件应用指南Co-injectionmoldingFusiblecoreinjectionmoldingGas-assistedinjectionmoldingInjection-compressionmoldingLamellar(microlayer)injectionmoldingLive-feedinjectionmoldingLow-pressureinjectionmoldingPush-pullinjectionmoldingStructuralfoaminjectionmoldingProcesscycleImportanceofprocessconditionsResindatatableGenericNameMeltTemperature(C/F)

MoldTemperature(C/F)

Min.

Rec.

Max.

Min.

Rec.

Max.

ABS

200/392

230/446

280/536

25/77

50/122

80/176

PA6

230/446

255/491

300/572

70/158

85/185

110/230

PC

260/500

305/581

340/644

70/158

95/203

120/248

PET

265/509

270/518

290/554

80/176

100/212

120/248

PMMA

240/464

250/482

280/536

35/90

60/140

80/176

POM

180/356

225/437

235/455

50/122

70/158

105/221

PP

200/392

230/446

280/536

20/68

50/122

80/176

PS

180/356

230/446

280/536

20/68

50/122

70/158

PVC

160/320

190/374

220/428

20/68

40/104

70/158

SAN

200/392

230/446

270/518

40/104

60/140

80/176

Temperature-timecurveatvariouslocationsinthemoldScrewpositionsatvariousstagesCycletimeanditscomponentsRequiredmoldopeningDeterminationofthegate/partfreezingtimePressuredecreasesalongthedeliverysystemandthecavityFactorsinfluencinginjectionpressurerequirements(I)

Variable

Higherinjectionpressurerequired

Lowerinjectionpressure

required

PARTDESIGNPartthickness

PartsurfaceareaFactorsinfluencinginjectionpressurerequirements(II)

Variable

Higherinjectionpressurerequired

Lowerinjectionpressure

required

GATEDESIGN

Gatesize

Flowlength

Factorsinfluencinginjectionpressurerequirements(III)

Variable

Higherinjectionpressurerequired

Lowerinjectionpressure

required

PROCESSINGCONDITIONS

Melttemperature

PartsurfaceareaRamspeed

Factorsinfluencinginjectionpressurerequirements(IV)

Variable

Higherinjectionpressurerequired

Lowerinjectionpressure

required

MATERIALSELECTIONMeltflowindex

InjectionpressureasafunctionMeltfrontadvancementsMelt-frontvelocityandmelt-frontareaFiberorientationsVariationofMFABasicrunnersystemlayoutsCommonlyusedrunnercrosssectionsEquivalenthydraulicdiametersRunnerdiameterchartEffectofrunnerlengthHotrunnersystemtypesFillingpatternsresultingfromvariousinjectionratesColdslugAfamily-moldpartwithartificiallybalancedrunners

Gatesizeterminology

FIGURE1.Gatesizeterminology

Gatetypes（I）Direct(sprue)gate

Tabgate

Edge(standard)gate

Overlapgate

Fangate

Disk(diaphragm)gate

Gatetypes（II）Ringgate

Spoke(spider)gate

Film(flash)gate

Moldcoolingaccountsformorethantwo