Shanghai Daoqin Plastics Co., Ltd.

一, more injection shot plastics flow principle: 1, 第一射胶 low speed 进胶, will nozzle to cold material 头移开 again improve/increase 二段射 speed 充满模穴以 shrink short gate plastics to time, make in plastics viscosity most small solid 化, high speed injection shot need control positive holding pressure 切换点 very difficult, therefore must utilizing more decrease speed can has control holding pressure 切换点. 2, separation injection shot as principle: utilizing electrical light control 指挥油 pressure system in amount ratio/proportion 阀瞬间 obtain in 一点位置 射胶 speed degree, to separation speed. 二, separation injection shot speed and pressure 关系: 1, separation injection shot molding process in, process tube/pipe has 几段变化 its pressure has pressure one-time pressure, holding pressure stage/phase tube/pipe holding pressure its speed degree maintain 一 即 can. 2, separation injection shot 实例: ⑴同一 formed product can use relatively small clamping force molding, from can long machine, injection molding parts mold lifespan; ⑵ separation decrease speed positive holding pressure 切换点 can has ensure quality stability; ⑶ molding plastics flow good 时, anti flash/burrs generate low speed 射胶, make raw materials cooling solid is 原则, melt resin through thick again improve/increase speed fast speed 充满模穴, flow marks （ is melt 脂逐渐以 gate is in 心而呈现 strip/profile 纹状模样） is most 初流入模穴 inner resin cooling fast and its 次流入 resin between formed 交界 致. ⑷进胶口（即 gate ）部位 molding relatively thick 情况, speed fast formed 乱流, cold material easy 残留通道而形 formed flow marks, slow speed low pressure 进胶推开 cold material 头, make rear plastics 顺利进入. ⑸ injection shot molding engineering in nozzle and injection molding parts mold 接触因 injection molding parts mold cooling water cooling injection molding parts mold temperature degree relatively low, separation hot by injection molding parts mold belt/tape 走, nozzle easy generate cold material 头, this cold material 头射入 injection molding parts mold in, in gate retardant 塞而引起流纹 or strip/profile 状痕迹, separation injection shot can improvement defect. ⑹ precision fine small parts, gate dimensions fine, more 数模穴之 gate balanced made as upper difficult easy, will gate 开同一 dimensions large small again utilizing more injection shot technology can 克服. ⑺第一段 low speed injection shot and 第二段 high speed injection shot 之交界切换位置 改变, can will weld lines local 位移修 positive, in appearance upper obvious 部位移至 relatively obvious 位置（如贴签处）. ⑻凹陷 and combined defect phenomenon in molding in is versus for 立, use methods can meanwhile improvement; product 凹陷部位射 speed drop, table/sheet cold solid rear fast speed improve/increase speed 充填模穴, generate weld lines 部位应采取 fast speed 射胶以 anti combined defect （ generally molding product surface lower in thick 处发生, it is melt resin cooling solid 化时 体积 shrinkage 致）. ⑼ in holding pressure process in separation reduce can make molding product 残留应 force decrease small. ⑽ molding product thin flow long molding conditions high pressure can 顺利完 formed, high speed high pressure 射胶容 easy formed gate 部残留应 force, from effect/influence quality therefore high speed 进胶, in speed 充填, low speed holding pressure remove 残留应 force, from anti formed product deformation. ⑾ injection molding parts mold cooling improvement: mold temperature degree low mold temperature degree high molding product 不会发生 inner toward warpage, mold temperature degree relatively high molding product can can outer toward warpage phenomenon. ⑿烧焦（ is due to inner gas pressure shrink 燃烧引起 phenomenon ） most easy in separation or 熔接处, resin surface black carbon 化之痕迹, make gas can 顺利排出模穴, must reduce speed. poly plastics in 线