科學化射出成型_-免費閱讀
【正文】 進料到測量部分 Range: :1 to 8:1范圍 : :1 到 8:1 High ratios tend to work the plastic more。 P 最大變數(shù) :時間 amp。 Time Conduction Cooling傳導冷卻 : ? Depends on:依靠 Turbulent flow。 NonNewtonian fluids are those for which viscosity is not a constant, but varies based upon the rate of shear or the shear 頓流體 是那些黏度不是一個常數(shù) , 而是隨著剪切應力或剪切率變化的流體 11 2. Plastic Flow Rate Momentum Effect 慣性作用 V is c o s ity C u r v e , D e te r m in e s O p tim u m F ill Tim e1 0 . 6 95 . 2 72 . 2 01 . 2 70 . 6 60 . 4 70 . 3 20 . 2 20 . 1 00 . 1 30 . 1 605,00010,00015,00020,00025,00030,00035,00040,00045,000 S h ear R ate 1/ s ec (1/ F ill Tim e)R elativ e V is c o s ityStiff Easy Slow Fast Electric電力 Hydraulic水力 12 2. Plastic Flow Rate MFR Effect MFR 效應 V is c o s ity C u r v e , D e te r m in e s O p tim u m F ill Tim e1 0 . 6 95 . 2 72 . 2 01 . 2 70 . 6 60 . 4 70 . 3 20 . 2 20 . 1 00 . 1 30 . 1 605,00010,00015,00020,00025,00030,00035,00040,00045,000 S h ear R ate 1/ s ec (1/ F ill Tim e)R elativ e V is c o s ityStiff Easy Slow Fast MFR 6 MFR MFR 10 gm/10 minutes. Shear Rate 1/10/60 = .007 Machine flow rate 30 gm in .5 sec =3/.05=60 13 2. Plastic Flow Rate Melt Temp Effect 融熔溫度效應 V is c o s ity C u r v e , D e te r m in e s O p tim u m F ill Tim e1 0 . 6 95 . 2 72 . 2 01 . 2 70 . 6 60 . 4 70 . 3 20 . 2 20 . 1 00 . 1 30 . 1 605,00010,00015,00020,00025,00030,00035,00040,00045,000 S h ear R ate 1/ s ec (1/ F ill Tim e)R elativ e V is c o s ityStiff Easy Slow Fast 525 deg F 425 deg F 14 2. Plastic Flow Rate Plastic Viscosity Varies塑料黏度的變化與以下有關 ? With injection speed與射出速度 ? Lot changes, temperature生產(chǎn)批號變化 , 溫度 ? % regrind, colorants再生料 %,抽料制程 ? Screw rotate time螺桿旋轉(zhuǎn)速度 But these can be minimized by velocity control但這些可經(jīng)速度控制減到最小 What else changes the viscosity?其他改變黏度的因素 : In order to have cruise control on velocity, we need to have constant fill time (same fill time on any press).為了在速度上的穩(wěn)定性 , 我們需要有穩(wěn)定的注料時間 (在任何射出循環(huán)有穩(wěn)定的注料時間 ) In order to have control on constant fill time, we need to use abundant pressure difference between pressure at transfer and available machine pressure Delta 間進行控制 , 我們需要在 移轉(zhuǎn)的壓力和可利用的機器壓力之間使用大量的壓力差 Delta P 15 2. Plastic Flow Rate Two Stage Molding成型二階段 ? Fill to 9599% on 1st stage第一步注料 95%99% ? Pack and hold on 2nd Stage第二步 射飽和保壓 ? Velocity control, delta P速度控制 ,delta P ? Switch over by positio
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