Shanghai Daoqin Plastics Co., Ltd.

         plastics material in active in ratio/proportion 越 越 high, for/regarding its quality requirements 也越 越 high, injection molding as is important production 手段, for technology improve/increase 也越 越迫切, injection molding products effect/influence factors relatively more, injection molding processing process conditions is important effect/influence factors 之一, lower will introduction process parameters for/regarding products property can effect/influence.

        传统 mold design and process parameters main/primary 依赖于 design experience and tips/techniques, mold design combined property has 靠反复 mold trial and 修模, process parameters 设置也 can 靠反复 mold trial 进行修改,缺乏科学 based on, production cycle long, cost high, quality difficult ensure.

        而 for molding process 进行模拟, in mold manufacturing front can design in issues, make mold design and process parameters 设置建立 in analysis 基础之 upper, can shrink short production cycle, improve/increase products quality. for products quality requirements improve/increase, for molding process forecast formed is design can less step/link. therefore,建立 injection molding process melt in mold cavity in flow and hot 数学模 type,并 using/adopting value true methods achieve molding process tool has important 意义.

         due to molding process process parameters 直接决定 melt in mold cavity in flow 状态, for products quality has most most deep effect/influence, therefore to products molding most excellent process conditions, for molding process process control, is improve/increase plastics products quality has 效途径.

         this is is, molding process in, precision molding machine 械, combined mold design and excellent 良 材 material property can has in combined molding process lower can 体现出 另一方面, molding machine 械, mold design and material property can defect has can through combined molding process 设置 弥补. can 见, injection molding process for products quality has important function

         injection molding process conditions and its effect/influence

        1, injection molding pressure

         injection pressure is in injection process in screw or for/regarding plastics melt add pressure. it function is for/regarding make material mixed combined and 塑化, screw (or 柱塞)必 must provide solid pellets and material in material and nozzle in flow retardant force. make plastics melt 以一定 speed degree type 腔, in type 腔充满 melt rear injection pressure to pressure function.

         from make parts 致密, for material cooling generate shrinkage 进行补 material, from make parts maintain 精确 形状, obtain need property can. injection pressure main/primary plastics types type, injection molding machine type type, mold temperature degree, mold structure, parts thick 决定, its in system dimensions and structure for/regarding injection pressure effect/influence very large.

        2, holding pressure pressure

        当 melt type rear, injection pressure function is for/regarding inner melt pressure 实, 此时我们 injection pressure 也叫做 holding pressure pressure, in production in, holding pressure pressure and other or small injection use pressure. holding pressure pressure and injection pressure versus and other 时, 往往会 make parts shrinkage rate reduce, but also can ensure parts stability property and parts force property can.

        但常常也会伴随 demolding residual stress increase, formed parts demolding difficult, make parts easy generate deformation, surface and other, easy make parts generate flash, effect/influence table/sheet quality. therefore, selection holding pressure pressure need more 方面考虑, heavy selection.

         generally 讲, holding pressure pressure for products quality effect/influence and injection pressure effect/influence versus 似. large more plastics holding pressure pressure in injection pressure between, specific holding pressure pressure 确定, main/primary 考虑塑 parts material features and made parts structure, 并克服 melt from machine to mold cavity flow retardant force, will material type will pressure 实.

        3, pressure

        塑化 pressure is screw 顶部熔 material in screw rear 退时 受 to pressure. it for injection molding effect/influence main/primary in injection machine for material material 塑化效果 and its can force 方面. generally 讲, increase large pressure, screw rear speed degree decrease small, machine inner melt to pressure increase. is 塑化时剪切 function add strong/high,塑化效果 improve/increase.

        但 must is, increase large back pressure meanwhile, high pressure 一方面因 melt in 螺槽边缘 反流 and 漏流而 decrease/reduce amount, can can 引起计 amount 不足, 另一方面会 make hot high 剪切应 force large, has can can make material material degradation, generate bubbles or 烧伤, effect/influence parts quality.

        4, mold temperature degree

         mold temperature degree is in molding process in mold cavity surface temperature degree, mold temperature degree effect/influence melt flow is, products cooling speed degree and molding rear products property can and other. mold temperature setting main/primary 取决于熔 material viscosity. material viscosity relatively low can low mold temperature injection shrink short cooling time, improve/increase production efficiency. material viscosity relatively high using/adopting high mold temperature injection molding.

         generally improve/increase mold temperature can make made parts cooling speed rate uniform 一致, anti 止凹痕 and cracks and other molding defect generate. crystallization type plastics mold temperature control 直接决定 cooling speed rate, from 而进一步决定 crystallization speed rate. mold temperature high cooling speed rate small, crystallization speed rate large, has separation 子 松弛 process, separation orientation small. mold temperature high, long molding cycle and make product 发脆.

         mold temperature low, cooling speed rate large, material flow and crystallization 同步进行, due to material in crystallization temperature degree +区间停留 time shrink short, 不利于晶体 生 long, formed product separation crystallization degree relatively low, effect/influence its use property can. in addition, mold temperature low, plastics melt flow retardant force very large, speed 变缓, in in solid rear material, make made parts short 射, strong/high orientation large, formed parts material, 凹陷, 熔接缝 and other defect.

        5, material temperature degree

         is ensure plastics melt positive flow meanwhile also make its 发生变质 separation understanding, need combined selection material temperature degree, separation quality large, separation quality distribution also relatively in plastics and reinforcement plastics selection temperature degree relatively high material temperature degree. material temperature degree generally is front high rear low 原则进行排布, plastics in has more water 费时也 can improve/increase rear temperature degree.

        6, nozzle temperature degree

         is melt in nozzle generate phenomenon, usually need make nozzle temperature degree low material most high temperature degree, in production in generally will low speed for injection lower, solvent belt/tape 泡, light slip is temperature degree combined standards.

        7, melt temperature degree

         melt temperature degree main/primary 取决于 machine and nozzle separation temperature degree, effect/influence material material and melt injection 充模. injection temperature degree improve/increase main/primary has improvement melt flow property, it and products very more features has 关. rise high melt temperature degree, can make parts internal stress, direction impact strong/high degree and degree, tensile strength and other machine force property can reduce,而 make 垂直于流线 direction impact strong/high degree, flow long degree, surface coarse degree and other property can has improvement, can reduce products rear shrinkage.

         from upper 看, improve/increase melt temperature degree has improvement 充模状况以 and in mold cavity inner 传递, reduce orientation property and other, has products comprehensive property can improve/increase high temperature degree can 取. melt temperature degree injection molding temperature degree scope/range upper value 时, 一方面容 easy generate relatively more gas 体, make parts generate bubbles, 空洞, color, and other,也因 more improvement flow property generate flash, effect/influence products table/sheet quality 另一方面, high temperature degree make plastics degradation function, make parts strong/high degree reduce, elastic property and other, effect/influence use property can.

        8, injection time

         injection time is control injection speed rate parameters 之一.

         injection time short, injection speed rate high, injection speed rate large small for parts property can has very large effect/influence. improve/increase injection speed rate can make pressure improve/increase, has 利于充模 process,并 make in hot amount dispersion decrease/reduce, mold cavity temperature degree comparison uniform, products uniform 而密实. meanwhile can reduce products shrinkage rate, decrease/reduce parts orientation, increase 熔接缝 strong/high degree.

         injection speed rate improve/increase has products comprehensive property can, high injection speed rate increase pressure loss 失, reduce solid thick degree, improve/increase parts table/sheet orientation property, make melt elastic property 湍流, make parts easy formed flash, surface cracks and other.

        经实验证明: high low injection speed rate 都会导致 impact strong/high degree decline. 另一方面, low injection speed rate make parts 熔接缝 strong/high degree decline, orientation function increase large, internal stress increase high and other, effect/influence products force property can.

        9, holding pressure time

         holding pressure time and cooling time long short for parts quality generate effect/influence. shrink short holding pressure time, make mold cavity pressure reduce add fast, has can can generate 倒流, make parts generate shrink 孔, and other defect, effect/influence parts dimensions stability property.

         add long holding pressure time, can improve/increase parts dimensions stability property upper defect 发生, to product. meanwhile make mold cavity pressure improve/increase, due to temperature degree 不均而 generate internal stress. increase demolding difficult degree, has easy generate surface ejection or will parts phenomenon.

        材 material time long short can effect/influence quality, effect/influence product property can. time short can make uniform, temperature degree 一致, easy generate hard block, silver streaks and other long also make material screw function 而发生 separation understanding, and other,也 to product quality belt/tape defect effect/influence.

        10, process effect/influence

        振动 injection molding, in high pressure lower, 随 振动 frequency rate improve/increase, products tensile property can and notched impact strength obvious to improve/increase. remove outer ultra- 声 process add can to good 效果.

        结 论

         injection molding processing process conditions for plastics products table/sheet and force property can formed effect/influence, process conditions parameters versus effect/influence is 独立, has products defect is versus effect/influence 结果.