塑胶射出成型问题诊断与产品模具设计

模具設計的優先順序PrioritiesofMoldDesign澆注系統設計(FillingSystemDesign)排氣系統設計(VentingSystemDesign)冷卻系統設計(CoolingSystemDesign)脫模系統設計(EjectingSystemDesign)澆注系統設計的優先順序PrioritiesofFillingSystemDesign產品設計(PartDesign)型腔設計(CavityDesign)澆口設計(GateDesign)流道設計(RunnerDesign)噴嘴設計(NozzleDesign)豎澆道Sprue主流道MainRunner成品Part澆口Gate冷料井ColdSlugWell支流道BranchRunner典型的澆注系統TypicalFillingSystem壁厚不均是注塑成型中最大的麻煩製造者。這對薄壁產品尤然。這些麻煩包括了遲滯現象、短射、凹陷、發赤、噴流、翹曲及長冷卻時間等；目前都可用CAE以直接或間接的方式預測。Non-uniformwallthicknessisthebiggesttroublemakerinplasticinjectionmolding.Thisisespeciallytruetothin-wallpart.Thetroubles,includinghesitation,shortshot,sinkmark,blush,jetting,warpageandlongcoolingtimeetc.,canbepredicted,directlyorindirectly,byusingCAE.壁厚不均Non-uniformWallThickness壁厚設計WallThicknessDesign差[Poor]較好[Better]最好[Best]掏空設計(1)CoringOutDesign(1)改進設計[Improved]原設計[Original]差[Poor]改進[Improved]掏空設計(2)CoringOutDesign(2)氣泡或/和凹陷的形成Voidor/andSinkMarkForming氣泡(Void)凹陷(SinkMark)肋厚和內圓角半徑的影響TheEffectofRibThickness&FilletRadius肋的底部厚度BottomThicknessofRibW0.5W2.5WW1.2WD1.5WD(A)(B)肋的設計(1)RibDesign(1)t=wallthichnessB=0.5tC=3tAAD=2BE=0.13mm(radius)F=1.5-2deg假如需要更大的強度,可增加肋的數目Ifmorestrengthisrequired,addadditionalribs.FBDECt肋的設計(2)RibDesign(2)肋的設計(3)RibDesign(3)與側壁相連之凸轂(熱塑性塑膠)BossatWall(Thermoplastics)A=凸轂附著處壁厚wallthicknessB=凸轂外環直徑dia.ofbossoverradiiC=0.5AD=2BE=1~2degF=0.13mm(radius)G=DH=0.8AI=A/4J=2BK=0.3~1JL=0.5ALHA'A'KEIGJDAFCBSectionA'-A'遠離側壁之凸轂(熱塑性塑膠)BossAwayFromWall(Thermoplastics)A=凸轂附著處壁厚wallthicknessB=凸轂外環直徑(含底部修整圓弧半徑)dia.ofbossoverradiiC=0.5AD=2BE=1-2degF=0.13mm(radius)G=0.95DH=0.3Gmin.toGmax.I=0.5AHEFDFGCBAI外側凸轂OutsideBossA'A'A(DIA)BB=AB=2A(max.)SectionA'-A'EIMr1Where1/r:樑的曲率curvatureofthebeamM:彎曲力矩bendingmomentE:彈性模數modulusofelasticityI:斷面積對中立軸的慣性矩momentofinertiaofthecross-sectionalareawithrespecttotheneutralaxisEI:撓曲剛性flexuralrigidity撓曲剛性FlexuralRigidityAvarietyofmolded-ininterlockscanaddstiffnesstothin-wallhousingdesigns.各種一體成型的內鎖件能增加薄殼的剛性。結構設計是薄殼成型零件的基礎。Structuraldesignisthebaseofthin-wallmoldingparts.薄殼成型產品不僅僅是一趨勢，而且也是降低成本和提高競爭力的有效途徑。Thin-wallmoldingpartisnotonlyatrendbutalsoaneffectivewaytoachievecostreductionandcompetitivenessincrease.結構設計和薄殼成型產品StructuralDesign&Thin-wallMoldingParts熔膠波前推進Melt-FrontAdvancement充填模式,積風和熔接線FillingPatterns,Air-TrapsandWeldLinesLocation熔接線WeldLines材料[Material]:PC-GF50原設計[Original]更改設計[Revised]更改澆口位置以重新定位熔接線WeldLinesCanBeRelocatedByChangingGateLocation典型對頭熔接線伸張強度保留值TypicalButtWeldTensileStrengthRetentionValuesMaterialTypeReinforcementTypeTensileStrengthRetention(%)PP0%GF86%PP20%GF47%PP30%GF34%SAN0%GF80%SAN30%GF40%PC0%GF99%PC10%GF86%PC30%GF64%PSF0%GF100%PSF30%GF62%PPS0%GF83%PPS10%GF38%PPS40%GF20%PA660%GF83-100%PA6610%GF87-93%PA6630%GF56-64%熔接線冷料井WeldSlugWell對頭熔接線[Buttweld]熔接線冷料井[Weldslugwell]積風AirTraps排氣Vent大部份熱塑性塑膠MostThermoplasticsA0.08mmB3.18mmC12.7mmD0.25mm耐隆和聚縮醛(POM)NylonandAcetal(POM)A0.04mmB3.18mmC12.7mmD0.25mm進料流道FeedRunner塑膠成品PlasticPartAD排氣孔VentBSEC.A'-A'CA'A'每增加一個澆口，至少增加一條熔接線，同時增加一個澆口痕跡、增加流道的體積以及增加較多的積風。Everytimeonegateisadded,oneweldline,atleast,onegatemark,morerunnervolumeandmoreairtrapswillbeadded.在型腔能夠完滿充填的前提下，澆口數目是愈少愈好。Aslongasthecavityisabletobefilledappropriately,gatesarethelessthebetter.為了減少澆口數目，每一澆口應就塑流力所能及的流長/壁厚比之內，找出可以涵蓋最大產品面積的進澆位置。Inordertoreducethenumberofgates,eachgateshallbelocatedatwherethemeltisabletocovermaximumpartareabasedonthelargestmeltflowlength/thicknessratio.澆口數目TheNumberofGates充填均衡FlowBalance熔膠波前於同一時間抵達型腔各末端。Meltfrontreachestheendsofcavityatthesametime.洗衣機圈板洗衣機圈板冷氣通風飾罩-原始設計Air-conditionerGrille-Original18gatespressure:76MPa冷氣通風飾罩-修正設計Air-conditionerGrille-Revised8gatespressure:75MPa分析結果比較表ComparisonofAnalysisResults十二澆口設計12GateDesign原始設計OriginalDesign電子零件置物箱材料Material：ABS四澆口設計4GateDesign修正設計RevisedDesign電子零件置物箱材料Material：ABS電子零件置物箱四澆口和十二澆口設計比較表原始設計修正設計澆口數目124充填時間(s)22最大射壓(MPa)58.461.8鎖模力需求(Ton)950820產品重量(g)41364136流道系統重量(g)29498如何快速平衡眾多模穴之流道HowtoBalanceFlowInAMulti-cavityMold•首先調整一排支流道內之次支流道尺寸，使此支流道內之各模穴可平衡充填。First,adjustrunnersizeinonebranchtomakeflowbalancedinthisbranch.•再調整各支流道前段之尺寸，使各支流道可平衡充填。Then,adjustthefirstsection’srunnersizeineachbranchtomakeflowbalancedinallbranches.一排支流道之不平衡充填UnbalancedFlowInABranch一排支流道平衡後之充填BalancedFlowInABranch全模具(128模穴)之不平衡充填UnbalancedFlowInAMold全模具(128模穴)平衡後之充填BalancedFlowInAMoldThemeltfillstheinsidecavitiesbeforefillingtheoutsidecavities.Therunnersystemshowsthatwarmer,low-viscositymaterial(yellowandred)followstheinsidewallwhenthemeltsplitsatanintersection.Melt”Flipper”導致平直產品的澆口設計GateDesignforFlatPart中心澆口CenterGate扇形澆口FanGate最壞的Worst壞的Worse較好的Better最好的Best側澆口EdgeGate薄模澆口FilmGate澆口設計(減少滯流效應)GateDesigntoAvoidHesitation澆口gate薄thin厚thick差的設計Poor好的設計Good薄thin厚thick澆口gate0.94秒時，遲滯現象在1.2mm厚凸片處發生公稱厚度3.2mm幫浦零件(Part,Pump)塑料(Polymer):POM沒有遲滯現象幫浦零件(Part,Pump)塑料(Polymer):POM澆口設計(避免凹陷和氣泡)GateDesigntoAvoidSinkMark&Void澆口gate澆口gate差的Poor好的Good使用重疊澆口以避免噴流AvoidJettingbyUsingOverlapGate差的Poor好的Good正確的澆口位置以避免噴流AvoidJettingbyLocatingGateCorrectly差的Poor好的Good使用凸片澆口以避免噴流AvoidJettingbyUsingTabGate使用適當的澆口形狀以避免噴流AvoidJettingbyProfilingGateProperly差的Poor好的Good幫浦零件(Part,Pump)塑料(Polymer):POM進澆處(Polymere