Shanghai Daoqin Plastics Co., Ltd.

        1, screw 直径（D）

        a, and requirements injection amount related: injection shot 容积=1/4*π*D2*S(injection shot 行程)*0.85;

        b, generally 而言, screw 直径D and most high injection pressure formed ratio, and can force formed positive ratio.

        2, 输送段

        a, negative plastics 输送, and preheating, ensure preheating to melting point;

        b, crystallization property plastics long (如: POM, PA) non property material 次之(如: PS, PU, ABS), hot property most short (如: PVC).

        3, pressure shrink 段

        a, negative plastics mixing/compounding, pressure shrink and add pressure gas, through this raw materials already 经几乎 full understanding, 但不一定会 uniform mixed combined;

        b, in 此区域, plastics 逐渐熔 melt, 螺槽体积必 must versus decline, for plastics 几何体积 decline, material pressure 不实, hot slow, gas defect;

        c, generally 占25% above screw as long degree, nylon (crystallization property material) screw pressure shrink 段约占15% screw as long degree, high viscosity, resistant property, low property, high add material and other plastics screw, 占40%''50% screw as long degree, PVC screw can 占100% screw as long degree, generate 激烈 剪切 hot.

        4, amount 段

        a, generally 占20''25% screw as long degree, ensure plastics full melt and temperature degree uniform, mixing/compounding uniform;

        b, amount long mixing/compounding 效果佳, long easy make melt 停留 久而 generate hot separation understanding, short easy make temperature degree non-uniform;

        c, PVC and other hot property plastics 不宜停留 time long, hot separation understanding, can use relatively short amount or need amount 段.

        5, material deep degree, amount deep degree

        a, material deep degree deep, 则输送 amount large, 但需考虑 screw strong/high degree, amount deep degree shallow, 则塑化发 hot, mixed combined property can 指数越 high, amount deep degree shallow 则剪切 hot increase, hot increase, temperature rise high,造 formed 塑 胶变 color or 烧焦, especially 不利于 hot property plastics;

        b, amount deep degree =KD=(0.03''0.07)*D, D increase large, 则K选 small value.

         effect/influence quality main/primary factors

         effect/influence quality main/primary factors is: long ratio, pressure shrink ratio, back pressure, screw speed, material add hot temperature degree and other.

        1, long ratio

         is screw has as long degree and screw ratio value.

        a, long ratio large material easy uniform;

        b, heat stabilized property relatively plastics can use relatively long screw improve/increase mixing/compounding property 而不烧焦, heat stabilized property relatively plastics can use relatively short screw or screw 尾端无螺纹. plastics features 考虑, generally long ratio lower: hot solid property is 14''16, hard 质PVC, high viscosity PU and other hot property is 17''18, generally plastics is 18''22, PC, POM and other high temperature stability property plastics is 22''24.

        2, pressure shrink ratio

         is material most rear 一 螺槽 deep degree and amount 段第一 螺槽 deep degree ratio value.

        a, material pressure shrink property, 装填程 degree, and other effect/influence, products need 密实, hot and gas;

        b, pressure shrink ratio can increase plastics density, make separation and separation between combined more add 紧密, has decrease/reduce gas 吸取, reduce pressure generate temperature rise, effect/influence amount 差异, 不适当 pressure shrink ratio will bad plastics material property;

        c, pressure shrink ratio value high, for plastics in material tube/pipe inner process in generate temperature rise high, for in plastics generate relatively mixed uniform degree, versus for material amount large is decrease/reduce.

        d, high pressure shrink ratio 适于不 easy plastics, especially tool low viscosity, heat stabilized property plastics; low pressure shrink ratio easy plastics, especially tool high viscosity, hot property plastics.

        3, back pressure

        a, increase back pressure can increase screw for melt resin 做 功, remove plastics pellets, increase material tube/pipe inner raw materials density and its uniform degree;

        b, back pressure by use improve/increase material temperature degree, its most is significantly;

        c, back pressure large, for hot property relatively high plastics easy separation understanding, for low viscosity plastics can can generate phenomenon, back pressure small, injection molding formed product can can has bubbles.

        4, screw speed

        a, screw speed degree effect/influence plastics in 螺旋槽 inner 切变;

        b, small type screw relatively shallow absorption hot fast speed, 足够促 make plastics in pressure shrink time soft 化, screw and material 筒壁间 摩 scratch hot can relatively low, high speed 旋转, increase can force;

        c, large type screw 则不宜 fast speed 旋转, 以免塑化不匀 and formed degree scratch hot;

        d, for hot property relatively high plastics, screw speed large 话, plastics very easy separation understanding;

        e, usually dimensions screw has 一定 转 speed scope/range, generally speed 100''150rpm;太 low method plastics, high will plastics 烧焦.

        5, electrical hot temperature degree setting

        a, make 滞留于 material and screw inner cold hard plastics melt 以利于 screw 转动, provide plastics obtain melt 需 一部 separation hot amount;

        b, setting ratio temperature degree low 5''10℃(部 separation scratch hot can provide);

        c, temperature degree adjustment can use control 流涎, cold material (塞咀), filament and other issues;

        d, crystallization property plastics generally temperature degree control.