模具冷卻設計的目的.ppt

模具冷卻設計的目的PurposesofMoldCoolingDesign,1.均衡冷卻(改良產品品質)EvenCooling(ImprovePartQuality)2.有效冷卻(提高生產力)EfficientCooling(IncreaseProductivity),薄殼產品不像傳統壁厚者一般可以承受較大的因熱傳不均而產生的殘餘應力。為了將收縮彎翹控制在可以接受的程度，均衡的冷卻設計變得非常重要。Thin-wallpartcannotaffordasmuchthermalinducedresidualstressastheconventionalonedoes.Anevencoolingdesignbecomesveryimportanttocontroltheshrinkageandwarpageatanacceptablelevel.,冷卻設計CoolingDesign,射出成型週期時間InjectionMoldingCycleTime,充填時間FillTime,對冰箱蔬果盤之類的大零件而言，材料往往佔成本50%以上。對小而薄的零件而言，成形機費用可佔成本的90%，材料6%，而模具只佔4%。小而薄的產品較之厚者更能從冷卻的改善而獲得效益。Forlargermoldedparts,materialtypicallyrepresentsmorethan50%ofthepartcostforarefrigeratorcrispertray.Inthecaseofathin-wallsmallpart,thepresscostcouldbe90%ofthecostofthepart;materialconstitutes6%andthemoldonly4%ofthecostofeachpart.Smallthin-wallpartstypicallybenefitfromimprovedcoolingmorethanthickparts.,冷卻設計CoolingDesign,典型的冷卻系統TypicalCoolingSystem,模具冷卻管路MoldSchematic,冷卻孔道CoolingChannels,噴泉管Bubbler,障板管Baffle,熱管HeatPipe,熱管的應用TheApplicationOfHeatPipe,理論上最短冷卻時間Min.PossibleCoolingTime,冷卻時間和厚度分佈CoolingTimeandThicknessProfile,冷卻孔道直徑、深度和節距建議值RecommendedDiameter,Depth&Pitch,D:直徑為10至14mmDiameterofCoolingChannel,10to14mmd:深度為D至3DDepth,D,to3DP:節距為3D至5DPitch,3Dto5D,原始設計OriginalDesign,修正設計RevisedDesign,原始設計OriginalDesign,修正設計RevisedDesign,原始設計OriginalDesign,修正設計(1)RevisedDesign(1),修正設計(2)RevisedDesign(2),不平衡的設計UnbalancedDesign,平衡的設計BalancedDesign,不用限流孔梢的內歧管設計InternalManifoldDesignwithoutFrops,使用限流孔梢的內歧管設計InternalManifoldDesignUtilizingFrops,限流孔梢FlowResistanceOrificePin,紊流和層流TurbulentandLaminarFlows,紊流TurbulentFlow,層流LaminarFlow,雷諾數ReynoldsNumber,Nu對雷諾數(Re)NusseltNumberVs.ReynoldsNumber,差的設計PoorDesign,好的設計BetterDesign,差的設計PoorDesign,好的設計BetterDesign,差的設計PoorDesign,好的設計BetterDesign,冷卻設計原則CoolingDesignPrinciples,選擇熱擴散係數大的塑料。SelectPlasticMaterialwithlargethermaldiffusivity.採用薄而均一的製件厚度。Useathinanduniformpartthickness.在型腔周圍均衡的配置冷卻孔道。Layoutcoolingchannelsaroundcavitiesevenly.在熱傳的道路上移除空氣間隙和空氣囊。Removeairgapsandpocketsfromheattransferpath.平衡冷卻液流動。Balan