Injection

molding徐海清Haiqing.xu@第1頁InjectionMoldingMachinePhotocourtesyofCincinnatiMilacron第2頁MoldingSequence-Start

注塑順序-開始

Toolclosing關(guān)模第3頁MoldingSequence-FillingPhase

注塑順序-填充階段

ToolclosingFilling關(guān)模充填第4頁MoldingSequence-FillingPhase

注塑順序-填充階段

ToolclosingFillingPacking關(guān)模充填壓縮第5頁MoldingSequence-FillingPhase

注塑順序-填充階段

ToolclosingFillingPackingHolding關(guān)模充填壓縮保壓第6頁MoldingSequence-CoolingPhase

注塑順序-冷卻階段

ToolclosingFillingPackingHoldingFeeding關(guān)模充填壓縮保壓進(jìn)料塑化第7頁MoldingSequence-CoolingPhase

注塑順序-冷卻階段

ToolclosingFillingPackingHoldingFeeding關(guān)模充填壓縮保壓進(jìn)料塑化Cooling冷卻Toolpressure

release模具御壓第8頁MoldingSequence-CoolingPhase

注塑順序-冷卻階段

ToolclosingFillingPackingHoldingFeeding關(guān)模充填壓縮保壓下料Toolopening開模Cooling冷卻Toolpressure

release模具御壓第9頁MoldingSequence-EjectionPhase

注塑順序-頂出階段

ToolclosingFillingPackingHoldingFeeding關(guān)模充填壓縮保壓下料Ejection頂出Toolopening開模Cooling冷卻Toolpressure

release模具御壓第10頁MoldingSequence-Start

注塑順序-開始

ToolclosingFillingPackingHoldingFeeding關(guān)模充填壓縮保壓下料Ejectorretract Ejection頂桿退回 頂出Toolopening開模Cooling冷卻Toolpressure

release模具御壓第11頁InjectionmouldingcycleCycletimeClosingofthemouldInjectionunitforwards

InjectionHoldingpressureInjectionunitbackwardsPlastificationMachinesetcoolingtimeRealcoolingtimeOpening/ejection第12頁HotAirDryerExhaustAmbient PumpAirHeaterHopper第13頁DehumidifyingDryer第14頁DewPointTOFINDDEWPOINT-SummerDegreesFDegreesCDegreesKEnterTemperature80.026.7299.7CalculatedDewPoint69.520.8293.8EnterRelativeHumidity%70.0TOFINDDEWPOINT-WinterDegreesFDegreesCDegreesKEnterTemperature70.021.1294.1CalculatedDewPoint32.80.5273.5EnterRelativeHumidity%25.0第15頁SpecificationofMoldingMachine1Injectionpressure;PiDsL? Fi (ton ) =2p * Di4-3* P *10injectionforce?Pi=Screwcrosssectionalarea2Di=p*Di*P Di24 = *P2 2p*Ds Ds4P,Q1Injectioncapacity,gr;21Plastificizingcapacity;

?P.C.=extrudedamountof

material/rotation*RPM*60(min)

=catalogvalue*efficiencyp*Ds? C(cm3/shot)=4?G=C×δ×ε*Lwhere,Gisshotweight

δisdensity1Injectionrate;Ds? Injectionrate(cm^3/sec)=Di22*Qεisefficiencyofnon-returnvalue第16頁SpecificationofMoldingMachine1ClampingforceF(clampingforce)≥P(cavitypressure)×A(projectedarea)

where,P:independentinresinA:Includingthepart,runnerandgate Movableplate1ClampstrokeClampstroke≥(daylightopening-moldthickness)

Clampstroke≥2×(partdepth)Max.daylightopeningStationaryplateMoldclampingstrokeMin.moldthickness1MaximumdaylightopeningMax.daylightopening>2×(partdepth)+moldthickness第17頁SpecificationofMoldingMachine1Stationary,MovableplatenofmoldVV’HH’Movableplaten Stationaryplaten?Dieplate=H’×V’?Clearancebetweentiebars=H×V?Thepositionandsizeofejectorrodarechangedaccordingto

themold.?Thesizeofboltholeischangedaccordingtotheweightof

mold.1Max.moldmountingareaTiebar?Max.moldmountingarea=

?Therecanbewarpageontheplatewhenthemoldistoosmall

inthetoggletypeinjectionmachine.第18頁ScrewDesign?Compressionratio=2~3?AccordingtothepositionofRingvalve,thequantity

ofinjectionandchargeisdetermined?Incasethecushionisnotconstant,thebackflowmay

occuraccordingtothedamageofringvalve第19頁DeliverySystem主流道

?Sprue澆口

?Runner Gate?Gate?Coldslugwell冷料井

ColdSlugWellSprue產(chǎn)品

Part分流道

MainRunner次分流道

BranchRunner第20頁EffectsofNozzleTemperatureR=r[1+(0~0.5)]D=d+(0.5~1.0)?lengthofSprueend:approx.5~10mmisadequate.?IncaseStringshappen,increasesuckbackand?decreasethetemperatureofnozzle第21頁P(yáng)urging(Cleaning)CheckringMainBody?TemperatureCrystallineresin=Tm+10~20°CNon-crystallineresin=Tf+10~20°C(Tf=Tg+50~60°C)?PressureMax.pressure.GenerallynoBackpressure.ResinTfTgTmOccasionallyincreasebackpressure,andthenHDPE134checkaforeignsubstance.PP165~170PC240?SpeedGPPS150100PurginginMax.speedABS150~160100~110PMMA160100第22頁InjectionSpeedFlowmark

ShortshotASlowGoodBMeltGatemarkFracture

(Cloudy)C DJetting,Burning

Silver,FlashEFastInjectionSpeed第23頁InjectionPressure?inFillingprocess:minimumvaluetoestablishinjectionspeed?inPackprocess:actualpressurevaluebecauseoflowinjectionspeedSettingPressurePLoadpressureP1 P2,3Settingspeed=actualspeedVPrimaryPressureInjectiontime第24頁InjectionPressureProfilePeakInjectionPressureHy

d

ra

u

licP

re

s

s

u

reFillTime

TimePressureAppliedbyInjectionBackPressure RamtoForcethePlasticFromtheBarreltotheMold.ScrewRunTime第25頁Switch-OveriPurpose:toperformasmoothtransitionfromthefillingphasetotheholding

phase1TooLatePTime1TooEarlyPTime1CorrectPTime?OccurringPressurePeak?Pressuredecreasedsuddenly?smoothtransitioninadequate?Occurringflashby?Defectoccurrence:switch-overpositionover-packingsinkmark,surfacemarketc第26頁HoldingPressureiPurpose:tocompensatethermalcontraction(shrinkage)ofthematerial

duringsolidification1InfluenceWeight,dimensionalaccuracyandinternalstructureofthemoldingAirbubble,sinkmarks,shrinkageandwarpageSafetyregionGmax.GatefrozenTime?Positionwherethere’sno

moreweightchangebyback

flowneargatearea;Gate

frozentime第27頁BackPressure?NotusingtheBackpressure,theshotsizecanbechangedineveryshot.?Generallyused5~15kg/cm2ingaugepressure?Incasetoohigh:degradationbyfrictionalheating;Gas,materialdrooling?IncaseofaddingGlass-fibers,toohighbackpressurecausedamageofscrewandcylinder.AdvantageDisadvantage?Bettermixing?Morefrictionalheatresidencetimeprolonged?Makeshotsizeconsistency?Meteringtimeprolonged?Air,gasandvolatile?Morematerialdroolingsubstanceeliminate?Bettercoloring第28頁SuckBack(Decompression,PullBack)iPurpose:topreventdroolingoutofnozzle

front1Incasethere’snoSuckbackAftercharging,materialdroolingoccurinthenozzlefront1Incasethere’stoomuchSuckbackSuctionofairinthenozzlefrontinducesomedefectslikesilverline,

bubbleorburning第29頁OptimizetheMoldingConditionsShotsize?Makeashortshotfirst,secondlyincreaseshotsizeandfinallysetoptimumcondition?Changefillingspeed,fillingpressure,compensationpressureandshotsizeaccording

cushionquantityasastandard.?Cushionisadequateto5~7mmingeneralinjectionmachine.Product

ConditionCushion Counterplan0~2mmIncreaseshotsize(meteringstroke)Shortshot3~10mmCorrectMorethanIncreasefillingvelocity/pressureor10mmDecreasemeteringstroke第30頁OptimizetheMoldingConditionsInjectionspeedInjectionPressure?Setpressuremaximumvalueandthen?Minimumvaluetoestablishthevelocitychangeinjectionspeedobtainedbyinjectionprocess?Usingmiddlevalueinnodefectarea?Wecanjudgetheoptimizedminimumpressurewhenprimarypressuretimedon’tchangeanymore.ShortshotMoldflashShortshotflowmarkSpeedPressure第31頁OptimizetheMoldingConditionsChangeoverposition?Afterdecisionofspeedandpressure,

changingtheswitchoverpositionandusingmiddlevalueintherealmofnodefect.

?Generallylocatedin3%~5%Moldflash ShortshotHoldingPressure?Usingmiddlevalueintherealmofno

defectWeightupperlimitShort MoldflashPositionshotsinkmarkHoldingpressure第32頁Opt