Shanghai Daoqin Plastics Co., Ltd.

         in will plastics pellets is plastics products molding process in, plastics 往往受 to high temperature, high pressure function, in high speed rate lower flow molding, different molding conditions and process, for products quality belt/tape different effect/influence, injection molding has plastics raw materials, injection molding machine, mold and injection molding process 四 方面组 formed.

        如 plastics raw materials positive 确选定, injection molding machine technology parameters and mold structure combined injection molding conditions requirements, processing products quality excellent poor and injection molding process has 关.

         products quality has inner quality and appearance quality, inner quality main/primary is machine strong/high degree, internal stress large small effect/influence products machine strong/high degree high low, generate internal stress main/primary causes has products crystallization degree and plastics molding in separation orientation property and other 决定.

         products appearance quality is products surface quality, internal stress large formed products warpage deformation effect/influence appearance quality issues. products appearance quality has: products 不足, products 凹痕, 熔接痕, flash, bubbles, silver streaks, black spots, deformation, cracks, delamination and color and other, and molding temperature degree, pressure, amount, time and has 关.

        1.  molding temperature degree: has material temperature degree, temperature degree, nozzle temperature degree, mold temperature degree and plastics drying temperature degree and other

         material temperature degree: 就 is plastics melt temperature degree, material temperature degree setting high, plastics melt rear viscosity low, in and other injection molding pressure and amount lower, injection speed degree fast, molding products easy flash, silver streaks, color and 发脆.

         material temperature degree low, plastics defect, viscosity high, in and other injection pressure and amount lower injection speed degree slow, molding products easy 不足, 熔接痕 obvious, dimensions unstable and products in has cold block.

         nozzle temperature degree : nozzle temperature degree setting high, nozzle easy 流涎, formed products in has cold material filament. nozzle temperature degree low formed mold system 发生堵塞. injection pressure need increase large, can injection plastics, 但即时 can molding products in has cold material block.

         mold temperature degree : mold temperature degree high, injection pressure and amount can low 一点, in and other pressure amount lower, products easy flash, warpage deformation, products mold sticking ejection difficult and other. mold temperature degree low, in and other injection pressure and amount lower, products molding 不足, bubbles, 熔接痕 and other.

         plastics drying temperature degree : various plastics has different drying temperature degree. ABS plastics generally setting drying temperature degree 80～90℃, 否则就不 easy water separation and solvent agent drying 挥发掉, products easy has silver streaks and bubbles, products strong/high degree decline.

        2.  molding process pressure: has back pressure: injection molding pressure, pressure, holding pressure, and in pressure, pressure and other.

        预塑 back pressure : back pressure high material density high, in versus and other material inner material amount more. back pressure low material density low, material less. in setting material rear, again relatively large degree adjustment back pressure, must attention/notes heavy new setting material 位置, easy formed products flash or 不足.

         injection pressure : different product types plastics has different melt viscosity, non crystallization type plastics 随塑化 temperature degree 变化而 viscosity relatively large. injection pressure is according to plastics viscosity and plastics process/workflow ratio setting. injection pressure setting low, products 射不足, 凹痕, 熔接痕 and dimensions unstable. injection pressure high products flash, color and mold sticking ejection difficult.

        锁模 pressure : according to mold type 腔 投影面积 large small and injection pressure high low 而定. pressure products easy flash, weight increase. clamping force large, mold opening difficult. generally pressure setting ultra- 120par/cm2.

         holding pressure : injection 结束即继续 to screw pressure holding pressure, this mold type inner products has 冻结. holding pressure can to mold type 腔补塑, ensure products saturated 满. holding pressure, pressure setting high, for and 抽插芯 belt/tape retardant force large, products easy 顶白, warpage, another mold runner gate easy by plastics 胀紧, gate in runner inner. pressure low products has and dimensions unstable.

        托模 and in pressure , setting and in pressure is according to mold type 腔面积 large small and 抽插芯 芯子投影面积 large small, and molding products 几何形状 complex degree and other comprehensive setting pressure large small. generally this need will and in 子油缸 pressure setting in can products can.

        3. 流 amount: to injection molding machine speed degree, has screw speed, injection speed degree, and in speed degree and other.

         screw speed : remove adjustment 预塑流 amount outer, main/primary 受预塑 back pressure effect/influence. 如预塑流 amount large, back pressure also high, screw 旋转, plastics in material inner force large, plastics separation structure easy by 割断, products has black spots and strip/profile 纹, effect/influence products appearance quality and strong/high degree, and material add hot temperature degree easy control. 预塑流 amount setting low, 预塑储 material time long, effect/influence molding cycle.

         injection speed degree : for injection speed degree need setting combined property, effect/influence product quality, injection speed degree fast, products belt/tape has bubbles, 烧焦, color and other. injection speed degree slow products molding 不足, has 熔接痕 and other.

        托模 and in amount: 不宜 setting large, ejection and 抽芯动 as fast, formed ejection and 抽插芯不稳, products easy 顶白.

        3.  time setting: in injection molding process in has drying time, injection and holding pressure time, cooling time and other.

         drying time : is for plastics raw materials dry time, various type plastics has most drying temperature degree and time. ABS plastics drying temperature degree 80～90℃, time 2 small 时. ABS plastics generally 24 small 时, water amount 0.2～0.4%, can injection molding water amount 0.1～0.2%.

         injection and holding pressure time : electrical injection machine control methods has more grade injection can separation grade pressure, speed and injection plastics amount. make mold type plastics speed degree to speed, improve/increase molding products appearance and inner quality.

         therefore injection process commonly used control, use time control, holding pressure is use time control, holding pressure time relatively long, products density large, weight is heavy, internal stress large, demolding difficult, easy 顶白, molding cycle long. holding pressure time short, products easy generate 凹痕, dimensions unstable.

         cooling time: is ensure products type stability, is will injection mold type inner plastics molding formed products rear has cooling type time, mold opening products easy warpage deformation, ejection easy deformation and 顶白. cooling time long, long molding cycle, 而不经济.

        4. 位置 control: separation injection molding machine has 移模位置, 托模位置, material and injection molding control.

        移模位置 is from mold opening to 闭模锁紧整 移动距离叫移模位置. most 佳位置 this need can will products 顺利取出即 can. mold opening large, molding cycle need long.

        托模位置 need control from mold in ejection can 方便取 lower products and can.

        储 material 位置: need ensure molding products one-time injection plastics amount, its need control material inner material amount. material control ultra- one-time injection amount more, products easy flash, products molding 不足.

         material material amount more, plastics in material inner time long, products easy color, effect/influence molding products strong/high degree. effect/influence plastics quality, in holding pressure material to mold in, products molding has 凹痕.

         summary

         injection molding products quality,涉 and products design, plastics 材质, mold design and processing quality, injection molding machine selection and process adjustment and other.

         for positive production mold 而言, need ensure and improvement products quality, for injection process adjustment;即 for temperature degree, pressure amount speed degree, time and adjustment.

         process adjustment must comprehensive 统筹兼顾. 如 products dimensions large, can from plastics raw materials upper 考虑, is crystallization plastics also is non crystallization plastics, plastics molecular weight large small and other. is crystallization plastics and large separation plastics, need products crystallization degree and separation orientation, products for molding flow 变化, 而引起 products internal stress and large small, formed products shrinkage 变化.

         solution products dimensions small, from process upper can improve/increase material temperature, reduce mold temperature degree, control injection material amount, reduce injection pressure, improve/increase injection speed degree, to 瞬间充满 mold type 腔, decrease/reduce holding pressure time, long cooling time, in ensure products 射足 情况 decline low products density. to reduce products internal stress, decrease small products shrinkage 变化.

        总之讲 injection process adjustment can mono from certain upper 入手, must from injection process principle upper 入手. comprehensive 统筹兼顾考虑 issues, can from more 方面逐 adjustment or more issues one-time adjustment. adjustment methods and adjustment principle, need from production products quality and process 状况而定.