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【正文】 ity 對 MFR的誤解 , 它與加工能力無關(guān) ? Whatdoes it affect?它的影響 8 2. Plastic Flow Rate Typical Plastic Flow 典型的塑膠流動率 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 e 黏度曲線 ,決定最佳注入時間1 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 9 2. Plastic Flow Rate Typical Plastic Flow 典型的塑膠流動 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 e 黏度曲線 ,決定最佳注入時間1 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 T im e)R elat iv e V is c o s ityStiff Easy Slow Fast Non Newtonian Mixed Newtonian 10 2. Plastic Flow Rate Newtonian fluids can be defined as those for which viscosity is a constant regardless of shear stress or rate of shear. 牛頓流體 可被定義為黏度是一個常數(shù) ,不隨著剪切應(yīng)力或剪切率變化的流體。 行政費用S a l e s amp。 Use machine graph 使用機器圖表 18 4. Cooling Rate amp。雷諾號碼 Cooling Line Location冷卻管路的位置 Clean Channels 干凈的管道 Time 時間 Temperature difference 溫度區(qū)別 ? Reynolds Equation (Nr): Reynolds公式 (雷諾號碼 ) Nr =3160 x Q Q = GPM of coolant冷卻劑的 GPM D x n D = Channel Diameter (in)管道直 (吋 ) n = Kinematic Viscosity動態(tài)黏度 (cs) 21 4. Cooling Rate amp。 Time Cooling Issues有關(guān)冷卻的議題 ? Uniform for each cavity每穴位需均勻 ? Same GPM for each line各管路同樣的 GPM ? Delta T should be maximum 4 F最大 DeltaT應(yīng)該是 4F ? Larger Hoses than mold channels水喉要比模子管路更大 ? Use parallel / series bo使用并聯(lián)與串聯(lián)組合方式 Cooling Time is affected by:冷卻時間受影響于 : ? How thick is the thickest section最厚部分的厚度 ? Delta T between plastic and mold steel在塑料和模金屬之間的 Delta T ? Stiffness amp。更高的溫度 26 5. Plastic Temperature Temperature profile溫度特征 ? Target mid range of mfg. remendations目標(biāo)為使用原料商推薦范圍之中間值 ? Use 800 – 1200 psi to turn screw用 800– 1200 psi轉(zhuǎn)動螺桿 ? Most energy to melt plastic es from screw rotation (shearing effect)多數(shù)熔化塑料的能量來自螺桿的轉(zhuǎn)動 (剪切熱作用 ) ? Front zone should not attempt to change melt temperature前面區(qū)域不應(yīng)該試圖用來改變?nèi)廴跍囟? Watch Temperature controller during molding:成型時要時常觀察溫度控制器 ? If zone overrides set points如果區(qū)域超過設(shè)定點 ? raise rear or center zone–提高后方或中心區(qū)域 slow scr
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