Shanghai Daoqin Plastics Co., Ltd.

using/adopting ASTM D 955－89 standards ABS plastics in different process conditions lower injection molding shrinkage, ABS plastics molding shrinkage process conditions 变化规律, is made combined process conditions, positive process control and injection molding parts mold design, from production combined dimensions product provide important based on. key/critical 词: ABS; injection molding parts molding; shrinkage rate plastics shrinkage rate 直接关系 to products and dimensions degree. plastics products features, injection molding parts mold design, process conditions control and other effect/influence molding shrinkage and rear shrinkage factors, for injection molding parts products and its stability property effect/influence large ［门. currently injection molding parts mold dimensions design usually use belt/tape or shrinkage rate methods 计算, injection molding parts mold in mold trial rear, according to made products dimensions positive injection molding parts mold, however high hardness. low coarse degree injection molding parts mold surface dimensions positive versus difficult, 且费工费时, has 时甚至无 method positive, formed large loss 失. therefore, need to dimensions precision injection molding parts parts, meanwhile also can amount decrease/reduce for injection molding parts mold positive, need separation understanding molding shrinkage process conditions 变化规律, 预先精确测定 molding shrinkage. （ propylene 膨丁二惭 styrene ） terpolymer （ABS） plastics comprehensive propylene chemical resistant product property, oil resistant property, rigid degree and hardness, butadiene tough property and resistant property and styrene electrical property can, by widely used in automotive, electrical appliances table/sheet and machine industrial in, is currently general purpose engineering plastics in application most product types 之一［z］. outer for plastics molding shrinkage research relatively 早, comparison research formed 果「3－7］, inner from plastics molding shrinkage research more ［8－11］. therefore, using/adopting xsrn n oss－so standards 测定 ＾ss plastics in different process conditions lower injection molding shrinkage, ABS plastics molding shrinkage process conditions 变化规律, is made combined process conditions positive process control and injection molding parts mold design from production combined dimensions products provide important based on. 一, 实验部 separation （一） main/primary Raw Materials ABS: IH－100, Shanghai high 桥石化 company. （二） main/primary equipment drying material 斗: FNH－A type, Japan day chemical industry 株式会社; mold temperature adjustment machine: NT－55 type, Japan day chemical industry 株式会社; injection molding parts machine: PS40SESASE type, Japan day resin l业株式会社; injection molding parts mold: 按ASTM D 955－89 manufacturing, long strip/profile 模, sheet/slice 模, made. （三） testing methods Sample separation is long strip/profile 门27．045 mm x 10•000 mm X3．200 mm） and sheet/slice （o101．975 mm）. testing use belt/tape separation table/sheet 靠模, degree is 0．of mm, testing long strip/profile Sample in 平行于 flow direction and sheet/slice Sample in and 垂直于 flow direction upper dimensions 变化. amount time separation is Sample rear 2, 24, 48 h. 按公式（1）计算 Sample molding shrinkage （S）. in s—— Sample molding shrinkage, ％; L0—— injection molding parts mold type 腔任意 mono toward upper dimensions, mm; L1—— Sample in different testing time versus mono toward upper dimensions, mm. （四） basic process conditions will ABS raw materials drying 4 h, injection molding parts molding is standards Sample, rear in time inner testing. specific injection process conditions table/sheet 1. 二, and plastics molding shrinkage main/primary hot shrinkage, versus shrinkage, orientation shrinkage and pressure shrink shrinkage and elastic property 回复四部 separation formed. for 无定形 ABS plastics, in versus shrinkage. lower separation 别讨论 testing standards, molding process parameters for ABS molding shrinkage effect/influence. （一）且 testing standards 确定 测定 plastics Sample shrinkage rate standards has very multiple, 如国际 standards ISO25557/1－1989（E） Germany standards DIN, front standards TOCT [CT C3B 890－78] and USA standards ASTM D955－89 and other [l2－15]. its in, standards is “ most large shrinkage rate ” and “部 separation shrinkage rate ”, but also testing scope/range 汉限于无定形 thermoplastic property plastics, can glass fiber reinforced and crystallization property plastics; Germany standards 同佯山 is 测定“ most large shrinkage rate ” methods, 仅限于无定形 thermoplastic property plastics; front standards although can various plastics “ shrinkage rate ”, ‘’ rear shrinkage rate ” and “各 toward property shrinkage （横 toward shrinkage and toward shrinkage ratio value 广, 但测定 “ shrinkage rate ” suitable for pressure made molding. USA standards suitable for various different type type plastics, can 测定“l~2 h”, “24 h”. “48 h” molding shrinkage, therefore its testing scope/range 广, can plastics product types more, can 测定反映纵, toward shrinkage rate 差异 “各 toward property shrinkage ”, but also can plastics parts shrinkage rate time 变化规律, this is upper standards can to. therefore, selection USA ASTM D 955—89 standards as is ABS Sample molding shrinkage standards. （二） injection molding parts process for ABS molding shrinkage effect/influence 1. injection molding parts pressure injection molding parts pressure for ABS molding shrinkage effect/influence 如图l 示. 由图1看出, molding shrinkage injection molding parts pressure improve/increase decrease small. this is is increase injection molding parts pressure make ABS products 密实程 degree increase, 线胀系数 decrease small, hot shrinkage decrease small, elastic property add large, from make molding shrinkage decrease small. and meanwhile, injection molding parts pressure increase large, ABS separation orientation has increase, this make shrinkage rate large, comparison types 效应, front 者占主导 位. 图12. holding pressure pressure holding pressure pressure for ABS molding shrinkage effect/influence most large, 如图2 示. this is is in injection molding parts process in type 腔尚未充满 melt, injection molding parts pressure for melt pressure obvious, holding pressure pressure function injection molding parts mold type by 充满, therefore holding pressure pressure for products shrink. pressure function obvious, from 而导致 products molding shrinkage large large reduce. 由图2 also can 看出, holding pressure pressure increase to 80＊抡 rear, pressure for molding shrinkage effect/influence already obvious. 图23. screw speed 图3 is ABS molding shrinkage screw speed 变化 关系曲线. 由图3 can 看出, screw speed increase large, molding shrinkage decrease small. this is is screw speed increase, material inner function increase, make material temperature upper rise, melt viscosity decrease small, flow retardant force decrease small, pressure 传递, make molding shrinkage reduce. 但另一方面, products hot shrinkage rate large, 图3 is comprehensive above types to 结果. screw speed relatively small 时, speed improve/increase, decrease small shrinkage rate factors 占主导 位, speed improve/increase to 120r／mi. above, decrease small and increase large shrinkage rate factors balanced, for products molding shrinkage effect/influence 趋缓. 图34. injection speed rate injection speed rate increase large can promote ABS separation orientation, fast speed 充模时, make products in relatively high temperature degree lower cooling, separation in high temperature lower time long, obvious for understanding orientation has 利, make orientation degree reduce, molding shrinkage decrease small, 结果如图4 示. 反之, if low speed injection, melt temperature degree versus for low, orientation structure more, meanwhile polymer/macromolecule 链布朗运动 can force decrease low, understanding orientation function small, make molding shrinkage increase large. 图45. holding pressure time long holding pressure time, can decrease/reduce melt toward gate 倒流, reinforcement shrink function, make products 密实, from make products molding shrinkage decrease small, 如图5 示. is; in gate rear again long holding pressure time, 就起不 to shrink function. 由图5 can 见, holding pressure time increase, molding shrinkage 出现一平台, 由此看出, injection Sample gate time is 15 S. 6. injection molding parts mold temperature degree injection molding parts mold temperature degree rise high, although melt 充模时 cooling slow, has make products add large elastic property function, but also injection molding parts mold temperature degree high, understanding orientation function significantly, make separation toward decrease/reduce, molding shrinkage decrease small. injection molding parts mold temperature degree high make products hot shrinkage add large, molding shrinkage increase large. 图6 is injection molding parts mold temperature degree and ABS molding shrinkage 关系曲线. 由图6 can 知, in injection molding parts mold temperature degree relatively low 时, hot shrinkage 居于次 need 位, 因而随 injection molding parts mold temperature degree rise high; products molding shrink rate decrease small; in relatively high injection molding parts mold temperature degree lower, hot shrinkage formed is main/primary effect/influence factors, 此时, injection molding parts mold temperature degree improve/increase, products molding shrinkage increase large. therefore, in control injection molding parts mold temperature degree 时, high injection molding parts mold temperature degree is combined 适. 7. material temperature degree 图7 is material temperature degree and ABS molding shrinkage 关系曲线. 由图7 can 看出, material temperature degree rise high, ABS products molding shrinkage decrease small, rear again increase large. this is is material temperature rise high make melt viscosity reduce, pressure loss decrease small, this and improve/increase pressure has same function, meanwhile, material temperature high separation understanding orientation function reinforcement, make molding shrinkage decrease small; material temperature rise high, hot shrinkage function more add significantly, make products molding shrinkage increase large. therefore, in 图7 in low temperature separation toward main/primary function, in high temperature hot shrinkage is main/primary effect/influence factors. 三, through molding shrinkage different standards comparison, most selection USA ASTMD 955－89 standards ABS Sample molding shrinkage. in experiment/testing conditions lower, ABS molding shrinkage scope/range is 0．29％－0．76％. ABS molding shrinkage injection molding parts pressure, holding pressure pressure, screw speed, injection speed rate, holding pressure time, injection molding parts mold temperature degree and material temperature degree and other more factors effect/influence, its in holding pressure pressure, holding pressure time effect/influence most significantly. (end)