模具基础知识讲解(二)---浇注系统设计

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1、模具设计的优先順序PrioritiesofMoldDesign浇注系統设计(FillingSystemDesign)排氣系统设计(VentingSystemDesign)冷卻系統设计(CoolingSystemDesign)脫模系統设计(EjectingSystemDesign)万学超2007.8.1浇注系统的优先順序PrioritiesofFillingSystemDesign产品设计(PartDesign)型腔设计(CavityDesign)浇口设计(GateDesign)流道设计(RunnerDesign)噴

2、嘴设计(NozzleDesign)直浇道Sprue主流道MainRunner成品Part浇口Gate冷料井ColdSlugWell支流道BranchRunner典型的浇注系統TypicalFillingSystem壁厚不均是注塑成型中最大的麻烦制造者。这对薄壁产品尤然。这些麻烦包括了迟滯現象、短射、凹陷、发赤、噴流、翘曲及长冷卻时间等；目前都可用CAE以直接或间接的方式預測。Non-uniformwallthicknessisthebiggesttroublemakerinplasticinjectionmoldi

3、ng.Thisisespeciallytruetothin-wallpart.Thetroubles,includinghesitation,shortshot,sinkmark,blush,jetting,warpageandlongcoolingtimeetc.,canbepredicted,directlyorindirectly,byusingCAE.壁厚不均Non-uniformWallThickness壁厚设变WallThicknessDesign差[Poor]较好[Better]最好[Best]掏空掏

4、空(1)CoringOutDesign(1)改进设计[Improved]原设计[Original]差[Poor]改进[Improved]掏空设计(2)CoringOutDesign(2)氣泡或和凹陷的形成Voidor/andSinkMarkForming氣泡(Void)凹陷(SinkMark)肋厚和內圆角半径的影响TheEffectofRibThickness&FilletRadius肋的底部厚度BottomThicknessofRibW0.5W2.5WW1.2WD1.5WD(A)(B)肋的设计(1)RibDesi

5、gn(1)t=wallthichnessB=0.5tC=3tAAD=2BE=0.13mm(radius)F=1.5-2deg假如需要更大的強度,可增加肋的数目Ifmorestrengthisrequired,addadditionalribs.FBDECt肋的设计(2)RibDesign(2)肋的设计(3)RibDesign(3)与側壁相连之凸辕(热塑性塑料)BossatWall(Thermoplastics)A=凸辕附著处壁厚wallthicknessB=凸辕外环直径dia.ofbossoverradiiC=0.

6、5AD=2BE=1~2degF=0.13mm(radius)G=DH=0.8AI=A/4J=2BK=0.3~1JL=0.5ALHA'A'KEIGJDAFCBSectionA'-A'远离側壁之凸辕(热塑性塑料)BossAwayFromWall(Thermoplastics)A=凸辕附著处壁厚wallthicknessB=凸辕外环直径(含底部修整圆弧半径)dia.ofbossoverradiiC=0.5AD=2BE=1-2degF=0.13mm(radius)G=0.95DH=0.3Gmin.toGmax.I=0.5A

7、HEFDFGCBAI外側凸辕OutsideBossA'A'A(DIA)BB=AB=2A(max.)SectionA'-A'Where1/r:梁的曲率curvatureofthebeamM:弯曲力矩bendingmomentE:弹性模数modulusofelasticityI:断面积对中立轴的惯性矩momentofinertiaofthecross-sectionalareawithrespecttotheneutralaxisEI:挠曲刚性flexuralrigidity挠曲刚性FlexuralRigidityAv

8、arietyofmolded-ininterlockscanaddstiffnesstothin-wallhousingdesigns.各种一体成型的內锁件能增加薄辕的刚性。结构设计是薄辕成型零件的基础。Structuraldesignisthebaseofthin-wallmoldingparts.薄辕成型产品不仅仅是一趋势，而且也是降低成本和提高竞争力的