Shanghai Daoqin Plastics Co., Ltd.

         high light, high product for/regarding injection molding enterprise 说确实 is relatively difficult product, is it 隐藏不 external defect, is workshop powder 尘也会造 formed product different degree defect defect, 如, 沙眼, 麻点, and other, therefore ring is effect/influence this category of product key/critical factors 之一.

         一, phenomenon

         product surface 白雾, from 视觉角 degree 讲, it is white 状, therefore in white product 时亦不 obvious, black high light most is obvious, PP材 material product, surface 呈现出 large large small small white 斑纹, 像云雾般 症状, this type is 白雾.

        二, 理论

         according to upper 述 出 理论 based on is: in lower material stage/phase plastics and plastics between in 一定 空隙, screw rear by belt/tape material 筒, in screw process in, material internal 会发生 material 理变化, from 玻璃态转变 is high elastic 态, from high elastic again to viscous 流态, 此变化 process can can has 几秒-几十秒 between, (according to machine or product large small) in this short time inner need 转变一 complex process, injection molding defect 也随即 generate, plastics between by pressure shrink material internal generate gas 体, in 塑化时未 can will gas 体排出至 material external, in gas 体则裹入熔 material by injection to mold type 腔, mold is can 够顺利排出就取决于 mold gas is good, generate 发雾困 gas or phenomenon.

         very 显然, 白雾也 is gas types phenomenon, very more from injection molding technology 人员误认 is has 烧焦才 is gas, or 者出现困 gas 就 开排 gas 槽, this is 不科学, is is gas heavy, gas in high pressure, high speed lower by pressure shrink to generate local 燃烧, temperature degree can to 达600-800℃, this belongs to gas most high 境界.

        三, solutions

         how can let gas most good 排出而不 generate phenomenon?

        1. mold

        排 gas non full mold solution, for/regarding PP材 material features 讲, temperature degree scope/range non 常广, its flow property can excellent 越, mold gas 槽开 太 large or 位置不 for, can positive gas, but also also easy generate flash defect, therefore positive 确 排 gas is has use.

        2. process

        掌握 positive 确 调 machine tips/techniques in 实际工 as in is non has 效.

        1)如 reduce screw speed degree, can make material temperature degree uniform, belt/tape gas machine need small, screw speed degree fast, belt/tape gas machine need more;熔 material screw function force large, scratch hot 导致熔 material temperature degree non-uniform, material separation understanding generate gas 体.

        2) improve/increase mold temperature degree, can high pressure, slow speed 充填赢 time, if mold temperature degree low, product surface easy 于 早冻结, slow speed 充填无 method achieve, can can short shot.

        3) reduce injection speed degree, speed degree fast, gas pressure shrink fast, temperature degree high. speed degree slow, gas pressure shrink slow, has gas 体 排出.

        4) clamping force, clamping force large, type surface gas 效果越差, clamping force small, type surface gas 效果越 good.