Shanghai Daoqin Plastics Co., Ltd.

        摘 need

        针 for (acrylonitrile / butadiene / styrene) copolymer (ABS) injection molding parts in use in 经常出现放射状 cracks, from formed made parts waste issues. in analysis causes 时往往 考虑 molding process effect/influence,而 overlook use ring effect/influence. through experiment/testing to ABS injection molding parts use in generate cracks is acid, paint dilute material and other formed outer force 释放 致,并提出 ABS injection molding parts design, manufacturing, assembly and use positive as methods, is ABS injection molding parts safety use provide based on.

        (acrylonitrile / butadiene / styrene) copolymer (ABS) resin blending modified rear,形 formed multiple different grade, its molding methods has injection, extrusion, thermoforming and other, its in injection molding is main/primary molding processing methods. injection molding main/primary has can molding complex, dimensions precision made parts, easy achieve 自动化,操 as simple and other advantages,但也存 in injection molding parts 会出现 various quality issues disadvantages. ABS injection molding parts quality separation is internal quality and external quality 两方面 inner 容. internal quality made parts internal material structure 形态, made parts density, strong/high degree, force and other; external quality is made parts surface quality, Common has 欠注(未注满), separation type obvious (跑 material), 凹陷(塌坑 or shrink 痕), color (separation understanding 纹), dark 纹(黑印), 熔接痕(combined material 纹), silver streaks (water 纹), 剥层(peeling), flow 痕(water 波纹), 喷射流(蛇行纹), deformation (warpage, 扭曲), light degree 差(划伤, 划痕), crazing (cracks), gloss (不亮), bubbles (空洞 or in 空), whitening (has 白印) and other. effect/influence ABS injection molding parts quality issues factors very more, its in force cracking is Common defect 之一,严 heavy retardant ABS injection molding parts application.

        1, ABS injection molding parts force cracking causes analysis

        1. 1　应 force classification and generate process polymer force rear, internal generate and outer force versus balanced inner force, mono 位面积 upper inner force is force. according to formed causes force can separation is internal stress and outer force. internal stress 包括主动应 force and 诱发应 force types type type. 主动应 force is and outer force (injection molding pressure, holding pressure pressure and other) versus balanced inner force,故也称 is molding force.

         molding force large small 取决于 polymer large separation structure, rigid property, melt 流变学 property and made parts complex degree and thick large small and other many factors. molding force value large, very easy make made parts 发生应 force cracking and melt and other molding defect. 诱发应 force formed causes very more,诸如 plastics melt or injection molding parts internal temperature or shrinkage non-uniform inner force; made parts demolding is mold cavity pressure and outer pressure value inner force;

         plastics melt is flow orientation inner force and other. 显然,诱发应 force generally method and outer force balanced, and very easy in cooling rear made parts internal, formed is residual stress, from for made parts quality generate effect/influence. outer force main/primary injection molding parts use in to outer force function generate force. for/regarding plastics structural parts, use in and metal solid parts 连接, is to solid, 牢靠, from make made parts to relatively large 剪切, pressure, made parts internal generate and outer force versus balanced inner force.

        应 force in injection process in for made parts quality effect/influence from upper 讲,当 polymer injection rear,如 can in holding pressure pressure function lower its slow cooling speed rate solid 化,则 polymer large separation in mold cavity inner has separation time deformation and heavy 排, from can make deformation amount and injection molding pressure and holding pressure pressure function to balanced, demolding rear made parts in residual stress, dimensions and stability. however, in production in,出于 for production rate requirements, upper methods is can can. make production in using/adopting cold measures, to cooling speed rate for/regarding large separation deformation and heavy 排 讲, still non 常剧烈.

        故充模 rear polymer in holding pressure pressure function lower cooling solid 化时, large separation can simple according to mold cavity 形状堆积 in 一起,而没 has time 进行趋 toward stability 状态 排列. therefore, deformation amount and injection molding pressure and holding pressure pressure function versus 适应, demolding rear made parts inner still will in relatively large residual stress. large separation also will time long 继续进行 deformation and heavy 排,以便 and molding 时 应 force function versus 适应(消 remove residual stress). belt/tape has relatively large residual stress made parts 经常会 in large outer force or solvent agent function lower cracking,即应 force cracking.

        应 force cracking is injection molding parts 常出现 quality issues 之一, especially is in gas temperature 差变化 relatively large 北方 区,应 force cracking phenomenon more is 突出. cracks more in made parts gate, 棱边, 熔接痕 and other force relatively in 部位. another, due to force function, made parts also 常出现 deformation, warpage, and other defect. internal stress from molding process upper versus measures, generally can make reduce to relatively low degree. outer force 往往容 easy by 人们忽略,以致于 injection molding parts cracking full 归结于 molding process in generate force, make quality issues method from upper to solution.

        2, effect/influence ABS injection molding parts force factors analysis

         effect/influence ABS injection molding parts force factors main/primary has resin quality, molding conditions, made parts and mold design combined property, made parts use ring and process and other. resin quality for made parts force effect/influence very large. material more, molecular weight distribution wide, made parts force large.

         molding conditions effect/influence factors main/primary has material in water separation, material temperature degree, injection molding pressure, holding pressure time, mold temperature degree and other. ABS resin molding front must drying, drying degree high, for reduce internal stress obvious. improve/increase material temperature degree, can reduce melt viscosity, has understanding remove separation orientation, reduce force,但 high material temperature degree easy make resin separation understanding,反而 increase large made parts force, therefore material temperature degree 应适宜. improve/increase injection molding pressure or long holding pressure time,会 increase separation orientation force,但 has drop low shrinkage force. mold temperature degree improve/increase reduce force,但会 make molding cycle long, increase resin separation understanding can can.

         made parts and mold structure main/primary made parts thick degree, 转角 渡, material methods and other. gate 位置, cooling pipeline 位置会 for made parts molding quality has relatively large effect/influence. increase made parts thick reduce separation orientation force,但 make shrinkage force increase. made parts 转角处 use 圆弧 渡, can 避免应 force in.

         made parts use ring main/primary 包括受 force 情况, is 否接触 solvent agent and other. made parts assembly in and metal combined,应 control assembly 扭矩, large easy make ABS injection molding parts in combined generate relatively large force. easy make ABS injection molding parts force cracking solvent agent or solvent agent gas ring 境应避免接触.