排气系统设计

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1、為何排氣仍然還是一個問題？Whyventingisstillaproblem?因為降低射速，讓積風有較多的時間逃氣，是一件太容易的事。但是…Becauseitistooeasytoslowdowntheinjectionspeedandgivethetrappedairmoretimetoescape.But...排氣Vent射速一降，熔膠溫度很快降低，射壓必須提高，殘餘應力隨之提高，翹曲的可能性增加。如果想藉提高料溫，以降低射壓，料溫必須升得很高，這樣又會引起塑料裂解。Wheninjectionspeedislower,melttemperaturegoesdo

2、wnveryfast,injectionpressurehastobeincreased,residualstressisincreasedandthepossibilitygettingwarppagebecomeshigher.Ifonewouldliketoincreasebarreltemperaturetoreducetherequiredinjectionpressure,thebarreltemperaturehastobeincreasedtoaquitehighlevelandpolymerdegradationwouldbeinduced.排氣

3、Vent高料溫和高射壓都說明充填系統有了流動的問題Bothhighbarreltemperatureandhighinjectionpressureareindicationsofflowprobleminthefillingsystem.排氣Vent我們常發現:射速提高時，塑料表現得更為出色。Itisquitecommonthatmaterialperformsbetterwhenitisinjectedfaster.最適化螺桿速度充分運用摩擦熱，將塑流保持在最佳狀態。許多充填和翹曲的問題也就迎刃而解。Anoptimizedramspeedprofilefull

4、yusesthefrictionheattokeepthebestflowcharacteristics,whichcorrectsmanyofthefillandwarpageproblems.排氣Vent有了適當的排氣，射速可以提高，充填和保壓可達良好狀態，不須過度增加料管和噴嘴的溫度。Withproperventing,theinjectionspeedcouldbeincreasedtoachievegoodfillandpackconditions,withouthavingtoraisethebarrelandnozzleheats,improperl

5、y.排氣Vent深度(depth):1.0.075mm易流塑料(easy-flowmat.)2.0.125mm難流塑料(stiffer-flowmat.)3.深度深到流道末端見毛邊為準(deepenoughtofeelflashatrunnerend)寬度(width):和流道同寬(aswideasrunnerdia.)排氣唇部(ventlip):1.5mmA1拋光(finish)排氣通道通大氣(ventchanneltoatmosphere):1mm深(deep)流道排氣RunnerVents深度(depth):參照廠商建議(refertomanufacture

6、r’srecommendation)寬度(width):全圓周長(wholeperimeter)or5mm長度(length):1.5mmA1拋光(finish)排氣通道通大氣(ventchanneltoatmosphere):1mm深(deep)分模面排氣PartingLineVents分模面排氣PartingLineVents深度(depth):參照廠商建議(refertomanufacturer’srecommendation)寬度(width):全圓周長(wholeperimeter)長度(length):1.5mm排氣溝(ventgroove):1mm深

7、(deep)頂出銷或心型銷排氣EjectorandCorePinVents