Shanghai Daoqin Plastics Co., Ltd.

一, screw speed

1, plastics melt, large is screw generate hot amount, therefore screw speed fast, has lower effect/influence:

plastics hot separation understanding;

glass fiber (GF) （ add plastics ） decrease short;

screw or add hot abrasion loss add fast.

2, speed setting, can its speed （circumferen-tial screw speed） large small amount: speed n（转 speed ）*d（直径）*π（圆周 rate ）

usually, low viscosity hot property good plastics, its screw 杆旋转 圆周 speed can setting to 1m/s upper lower, hot property plastics, low to 0.1 left right.

3, in application in, can amount low screw speed, make 旋转进 material in mold opening front formed can.

二, back pressure

1, screw 旋转进 material 时, to screw front 端 熔胶 蓄积 pressure is back pressure, in injection shot molding can adjustment injection shot pressure 缸 退油 pressure adjustment, back pressure can has below/following 效果:

熔胶 more uniform understanding.

color agent and filling material more add uniform dispersion.

make gas 体由落 material 口退出.

进 material amount 准确.

2, back pressure high low, is plastics viscosity and its hot property 决定, high back pressure make material time long, 也因旋转剪切 force improve/increase, easy make plastics generate hot. generally 以5~15kg/cm2 is 宜.

三, 松退

1, 杆旋转进 material rear, make screw 适当抽退, can screw front 端熔胶 pressure reduce, is 松退, its can anti nozzle 部 滴 material.

2, 松退不足, easy make runner （SPRUE） mold sticking; more 松退, can 吸进空 gas, make molding product gas 痕.

四, parameters positive

1, back pressure is need adjustment;

2, adjustment screw speed, make amount time short cooling time;

3, 确认计 amount time is stability, can adjustment add hot temperature degree degree;

4, 确认 nozzle is has material, runner is 否发生猪尾巴 or mold sticking, formed product has gas and other phenomenon, adjustment nozzle temperature degree or 松退距离.

五, more holding pressure and more speed active 动

1, generally 而言, in effect/influence appearance lower, injection high speed is 原则, in through gate and holding pressure front relatively low speed 进行;

2, holding pressure using/adopting decline, 以避免 molding product internal stress 残留太 high, make molding product easy deformation.