Shanghai Daoqin Plastics Co., Ltd.

1 injection molding parameters

1.1 injection amount

injection amount is injection molding machine screw (or 柱塞) in injection 时, toward mold inner injection material material melt amount (g). screw 推进容积 also 称理论 injection 容积, and injection screw 直径Ds and injection has 关.

in injection amount selection 时, 一方面必 must separation meet/satisfy products and its system use material amount, 另一方面必 must small injection molding machine injection 容积. therefore, injection molding machine can use processing small injection amount 10％ or ultra- injection amount 70％ products.

for already injection molding machine 说, injection amount is injection control.

1.2计 amount 行程(预塑行程)

每次 injection 程序终止 rear, screw is in material most front 位置, 当预塑程序 to 达时, screw 开始旋转, material material by to screw 头部, screw in material material pressure function lower rear 退, 直至碰 to 限位开关 is 止, process amount process or process, screw rear 退 距离称计 amount or 预塑行程. therefore, material material in screw 头部 占 has 容积就 is screw rear 退 形 formed amount 容积, injection 容积, its amount 行程就 is injection 行程. injection amount large small and amount 行程 精 degree has 关: if amount adjustment small formed injection amount 不足, 反之则会 make material 筒每次 injection rear material more, make melt temperature degree or hot separation understanding, amount heavy degree high low effect/influence injection amount 波动.

1.3余 material amount (缓冲垫)

screw injection molding 完 之 rear, 并不希望 screw 头部 熔 material full injection 出, also 希望存一, formed 一 余 material amount. this 样, 一方面 can anti screw and nozzle 接触发生 machine 械碰撞事故; 另一方面 can through material control injection amount heavy degree, to stability injection molding products quality (余 material small, 则达不 to 缓冲 目, large make material more).

1.4 anti amount (松退, shrink)

anti amount is screw amount (预塑) to rear, also 直线倒退一段距离, make amount in melt ratio increase, inner pressure decline, anti melt from amount toward outer 流出(through nozzle or 间隙). this rear as anti 流延, rear 退 距离称 anti amount or anti 流延行程. anti also has another 一 目 就 is in nozzle 不退回进行预塑时, reduce nozzle runner system pressure, decrease/reduce internal stress. in mold opening easy material 杆. anti amount need plastics viscosity and products 情况而定, large anti amount make amount in material bubbles, heavy effect/influence products quality, for viscosity large material material can anti amount.

1.5 screw speed

screw speed effect/influence injection molding material material in screw in and hot and 剪切效应, is effect/influence can force, quality and molding cycle and other factors important parameters. screw speed improve/increase, can force improve/increase, melt temperature degree and melt temperature degree uniform property improve/increase; function has decline.

for hot property plastics (如PVC, POM and other), using/adopting low screw speed, anti material material separation understanding; for melt viscosity relatively high plastics, using/adopting low screw speed.

1.6 back pressure (塑化 pressure)

screw 头部熔 material in screw rear 退时 受 to pressure back pressure or pressure, its large small can through liquid pressure system in 溢流阀 adjustment. 预塑时, has screw melt pressure, 克服／ screw rear system retardant force rear, screw can rear 退.

back pressure large small and quality, 驱动功 rate, and 漏流以 and can force and other has 关. back pressure for melt temperature degree effect/influence is non obvious: for different material material, in process parameters lower, melt temperature degree back pressure increase improve/increase. causes is back pressure increase melt inner pressure, add strong/high 剪切效果, formed hot. make large separation hot can increase, from improve/increase melt temperature degree.

back pressure improve/increase has 助于螺槽 in material material 密实, 驱赶走 material material in gas 体; back pressure increase make system retardant force add large, screw speed degree decrease slow, long material material in screw in hot process, quality to improvement. is large back pressure increase amount screw melt and 漏流, reduce melt can force, decrease/reduce amount, but also increase rate consumption; high back pressure make hot high or 剪切应 force large, make polymer/macromolecule material material degradation heavy effect/influence to products quality.

injection molding hot property plastics, 如PVC, POM and other, back pressure improve/increase, melt temperature degree rise high, products surface quality relatively good, has can can products color, property can poor 化, formed degradation; injection melt viscosity relatively high plastics, 如PC, PSF, PPO and other, back pressure high. easy 引起动 force 载; injection molding melt viscosity especially low plastics, 如PA and other, back pressure high, 一方面 easy 流延, 另一方面塑化 can force large large decline. above 情况, back pressure selection 都不宜太 high.

一 heat stabilized property comparison good, melt viscosity in plastics, 如PE, PP, PS and other, can improve/increase back pressure.

usually lower, back pressure ultra- 2MPa. back pressure high low and nozzle types type, add material methods has 关: selection 直通式(即敞开式) nozzle or rear add material methods, back pressure low, anti back pressure improve/increase formed 流延; 自锁式 nozzle or front add material, solid add material methods, back pressure can improve/increase.

1.7 injection pressure

injection pressure function is plastics melt from material toward mold type flow retardant force, to melt 一定 充模 speed degree and for melt pressure 实, shrink. this function not only and products quality, output/production volume has 密切联系, but also also plastics product types, injection molding machine type type, products and mold structure and its it process parameters and other effect/influence. lower injection pressure 几方面 function, introduction injection molding process in injection pressure setting.

(1) flow retardant force injection need flow retardant force, main/primary 自两方面: is runner. generally, runner long 且几何形状 complex 时, melt flow retardant force large, need using/adopting relatively high injection pressure can ensure melt 顺利充模. its is plastics friction coefficient and melt viscosity. is lubricated property material material, friction coefficient large, large separation in separation function force large melt viscosity high, 此时, flow retardant force relatively large, need relatively high injection pressure. if conditions same, 柱塞式 injection molding machine use injection pressure ratio screw large, causes is plastics in 柱塞式 injection molding machine material inner pressure loss large.

(2)充模 speed rate injection pressure in 一定程 degree upper plastics speed rate, effect/influence products quality. in stage/phase, injection pressure relatively low 时, plastics melt 呈铺展 flow, speed 平稳, slow, long injection time, products easy generate 熔接痕, density and other defect; injection pressure relatively high, gate also small 时, melt is 喷射式 flow, this easy will gas belt/tape products in, formed bubbles, and other defect, heavy also 会灼伤 products.

适当 improve/increase stage/phase injection pressure, can improve/increase speed rate, increase melt flow long degree and products 熔接痕 strong/high degree, products 密实, shrinkage rate decline, products easy orientation, internal stress increase.

总之, injection pressure selection and setting, plastics product types and its grade flow property, products and other different 而异, also need from injection molding machine can pressure. generally lower, injection pressure selection scope/range table/sheet 3.

1.8 holding pressure pressure

holding pressure is in mold cavity rear, for inner melt pressure 实, shrink process. 处于该 stage/phase injection pressure is holding pressure pressure.

实际 production in, holding pressure pressure setting, can and injection pressure versus and other, generally low injection pressure. holding pressure pressure relatively high 时, products shrinkage rate decrease small, surface light degree, density increase, 熔接痕 strong/high degree improve/increase, products dimensions stability. disadvantages is: demolding products in residual stress relatively large, easy generate 溢边.

1.9 injection speed rate
injection speed rate is mono time inner mold cavity in plastics melt 容积. high speed injection can decrease/reduce mold cavity inner melt temperature 差, improvement pressure 传递效果, can to density uniform, internal stress small precision products; high speed injection can using/adopting low temperature 模塑, shrink short molding cycle, especially in molding thin 壁, long process/workflow products and low foaming products can obtain relatively excellent products. is, injection speed rate high, melt nozzle gate and other 处时, easy generate a large amount of scratch hot, material material 烧焦以 and gas and gas defect and other phenomenon, effect/influence to products surface quality, generate 银纹, bubbles. meanwhile, high speed injection easy ensure injection and holding pressure pressure stability 撤换, filling make products 出现溢 material （ flash ）. therefore, injection speed rate according to use resin and processing products features, process requirements, gate design and mold cooling and other selection.

2 clamping parameters

2.1 clamping force

clamping force adjustment will effect/influence products surface quality and dimensions degree. if clamping force 不足, 会导致 mold 离缝, generate material; clamping force large make mold deformation, can amount consumption increase.

injection molding products 时 需 clamping force process clamping force. is ensure can 靠 锁模, process clamping force must small injection molding machine clamping force, generally 取0.8～0.9额定 clamping force. process clamping force can according to mold cavity pressure and products 投影面积 确定.

2.2 ejection force

当 products from mold upper demolding 时, need outer force products and mold force, outer force is ejection force. ejection force small, products can from mold upper lower; ejection force large, make products generate warpage deformation, 甚至会顶 bad products.

in addition, ejection speed degree and ejection 行程也同样 effect/influence ejection process. ejection speed degree fast, products easy warpage deformation and loss bad; ejection short. products easy lower.

2.3 temperature parameters
injection molding process in need control temperature degree has: material temperature degree, nozzle temperature degree, mold temperature degree and temperature 四方面 technology parameters.

3.1 material temperature degree

material temperature degree is material surface add hot wet degree. material separation add hot, from material to nozzle front 依次由 low to high, make plastics material 逐步熔 melt, 塑化. 第一段 is material solid 体输送段, temperature degree need low 一, material base/seat also use cooling water cooling, anti material material “架桥”并 ensure relatively high solid 体输送 efficiency; 第二段 is pressure shrink 段, is material material pressure shrink 状态并逐渐熔 melt, temperature degree setting generally ratio use plastics melting point or viscous temperature degree high 出20～25℃; 第三段 is amount 段, material material in 该段处于熔 melt 状态, in 预塑终止 rear formed amount 室, 储存塑化 good material material, temperature degree setting generally need ratio 第二段 high 出20～25℃. ensure material material 处于熔 melt 状态.
material temperature degree setting and processing plastics features has 关.

for/regarding type plastics, material 筒第三段 temperature degree high plastics viscous temperature degree Tf, for/regarding crystallization type plastics, high plastics melting point Tm, 但都必 must low plastics separation understanding temperature degree Td. usually, for/regarding Tf～Td scope/range relatively narrow plastics, material temperature degree low, ratio Tf稍 high can; for/regarding Tf～Td scope/range relatively wide plastics, material temperature degree can high, ratio Tf high more 一. 如PVC plastics, hot rear easy separation understanding, therefore material temperature degree setting low 一; 而PS Tf～Td scope/range relatively wide, material temperature degree can versus setting high.

for hot property plastics, 如PVC, POM and other, although material temperature degree control relatively low, if material material in high temperature lower time long, 同样会发生 degradation. therefore, processing type plastics 时, remove control material most high temperature degree outer, for plastics in material in time has made.

同一 types plastics, due to production different, grade 不一样, its flow temperature degree and degradation temperature degree has 差别. generally, versus for separation quality high, molecular weight distribution narrow plastics, melt viscosity high, flow property relatively 差, processing 时, material temperature degree 应适当 improve/increase; 反之则 reduce.

plastics additives （包括 filling agent, reinforcement agent ） 存 in, for molding temperature degree has effect/influence. additives is glass fiber or machine filler 时, melt flow property 会变差, therefore, need additives use amount increase, versus improve/increase material temperature degree; additives is increase agent or soft agent 时, material temperature degree can low.

同 types plastics selection different type type injection molding machine processing 时, material temperature degree setting different. selection 柱塞式 injection molding machine, due to plastics is material and separation surface hot, hot efficiency low 且不均勾. is improve/increase plastics melt flow property, must improve/increase material temperature degree; selection screw injection molding machine, due to 预塑时 screw generate relatively large 剪切摩 scratch hot, but also material inner material thin, hot easy, therefore, material temperature degree low, generally ratio 柱塞式 injection molding machine material temperature degree low 10～20℃.

due to thin products mold cavity relatively narrow. melt 注入时 retardant force large, cooling fast, therefore, is ensure can 顺利充模, material temperature degree high; injection molding thick products 时, can low 一. another, complex or belt/tape has metal parts products, due to process/workflow 曲折, time relatively long, 此时, material temperature degree setting high. material temperature degree selection for products property can has effect/influence: material temperature degree improve/increase rear, products surface light degree, impact strong/high degree and molding melt flow long degree improve/increase, injection molding pressure reduce, products shrinkage rate, orientation degree and internal stress decrease/reduce. can 见, improve/increase material temperature degree, has improvement products quality. therefore, in 允许 情况 lower, can improve/increase material temperature degree.

3.2 nozzle temperature degree

nozzle tool has accelerated melt flow, adjustment melt temperature degree and make material material function. in injection molding process in, nozzle and mold 直接接触, due to nozzle hot property very small, and relatively low temperature degree mold rear, make nozzle temperature degree very fast decline, 导致熔 material in nozzle cold 凝而堵塞 nozzle or mold system, but also cold material mold rear effect/influence products surface quality and property can, therefore, control nozzle temperature degree.

nozzle temperature degree usually need low material most high temperature degree. 一方面, this is is anti melt generate “流延” phenomenon; 另一方面, due to plastics melt in through nozzle 时, generate scratch hot make melt temperature degree high nozzle temperature degree, nozzle temperature degree control high, also make plastics separation understanding, effect/influence products quality. material temperature degree and nozzle temperature degree setting also and injection molding in its it process parameters has 关. 如: injection pressure relatively low 时, is ensure material material flow, 应适当 improve/increase material and nozzle temperature degree; 反之, reduce material and nozzle temperature degree. in injection molding front, generally need through “ for injection method ” and products “直观 analysis method ” adjustment molding process parameters. most material and nozzle temperature degree.

3.3 mold temperature degree

mold temperature degree is and products mold cavity surface temperature degree. it for products appearance quality and inner in property can effect/influence very large. mold temperature degree usually is 靠通入定 temperature cooling control, has 时也靠 melt mold cavity rear, rise temperature and dispersion hot to balanced maintain mold temperature, 特殊情况 lower, also can using/adopting electrical hot filament or electrical hot rod for mold add hot control mold temperature. tube/pipe using/adopting types methods make mold temperature 恒定. for thermoplastic property plastics melt is cooling process, is mold temperature degree value low plastics Tg or low heat deflection temperature (HDT) (HDT), has this 样, can make plastics type has demolding.

mold temperature degree high low main/primary 取决于 plastics features (is crystallization), products structure dimensions, products property can requirements and its it process parameters (如 melt temperature degree, injection pressure, injection speed rate, molding cycle and other).

无定 type plastics melt mold cavity rear, temperature degree reduce solid 化, in cooling process small 不发生 versus 转变. this 时, mold temperature main/primary effect/influence melt viscosity, 即充模 speed rate. usually, in ensure 充模顺利 情况 lower, amount using/adopting low mold temperature, is low mold temperature can shrink short cooling time, from improve/increase production efficiency. for/regarding melt viscosity relatively low plastics (如PS), due to its flow property good, easy 充模, therefore processing can using/adopting low mold temperature; for/regarding melt viscosity relatively high plastics (如PC, polyphenylene oxide (PPO), polysulfone (PSU) and other). mold temperature high. improve/increase mold temperature can adjustment products cooling speed degree, make products slow, uniform cooling, force to separation 松弛, anti products temperature large generate 凹痕, internal stress force and cracks and other defect. crystallization type plastics mold cavity rear, mold temperature degree effect/influence plastics crystallization degree and crystallization type. mold temperature high, cooling speed rate slow, crystallization speed rate fast, products hardness large, rigid property high, 但却延 long molding cycle make products shrinkage rate increase large; mold temperature low, cooling speed degree fast, crystallization speed rate slow, crystallization degree low, products tough property improve/increase. is, low mold temperature lower molding crystallization type plastics, its Tg relatively low 时, 会出现 rear crystallization, make products generate rear shrinkage and property can 变化. products is thick 壁, inner outer cooling speed rate can can 一致, anti inner outer temperature formed internal stress and its it defect (如凹痕, and other), 此时, mold temperature need versus high; in addition, large or flow retardant force large thin products, need relatively high mold temperature.

mold temperature degree selection and setting for products property can has very large effect/influence: improve/increase mold temperature degree, can increase melt flow long degree, improve/increase products surface light degree, crystallization degree and density, decrease small internal stress and pressure; due to cooling time long, production efficiency reduce, products shrinkage rate increase large.

3.4油 temperature

油 temperature is liquid pressure system pressure temperature degree. temperature effect/influence injection molding process parameters, 如: injection pressure, injection speed rate and other stability property.

当油 temperature rise high 时, liquid pressure viscosity reduce, 油泄漏 amount increase large, liquid pressure system pressure and amount 波动, make injection pressure and injection speed rate reduce, effect/influence products quality and production efficiency. therefore, in adjustment injection molding process parameters 时, attention/notes to temperature 变化. positive 常 油 temperature maintain in 30～50℃.

4 injection pressure and material temperature degree combined combined

in injection molding process in, injection pressure and material temperature degree upper is versus made 约. material temperature degree high 时, injection pressure can reduce.

for/regarding certain types plastics 说, material temperature degree and injection pressure separation is 坐标, made molding can positive 确 反映适宜 injection molding process parameters, 见图3. 如图3 示, in molding in, temperature degree and pressure combined can obtain molding products; in this 区域以 outer temperature degree and pressure combined, to molding belt/tape difficult or to products formed various defect. large type, positive raw materials production provide molding 面积图.

5 molding cycle
完 formed one-time injection process need time molding cycle. molding cycle below/following separation: due to molding cycle effect/influence to production rate and equipment utilizing rate. therefore, production in in ensure products quality front lower, amount shrink short molding cycle in has time.

in molding cycle in, injection time and inner cooling time setting most important, for products quality 起决定 function.

5.1充模 time

injection time in time short, injection speed rate fast, 此时, melt density high, temperature small, has improve/increase products degree, products upper easy generate 溢边, 银纹, bubbles and other defect. usually, time is 3～5s. for melt viscosity high, Tg high, cooling speed rate fast large type, thin 壁, precision products and glass fiber reinforcement products, low foaming products and other, using/adopting fast speed injection.

5.2 holding pressure time

holding pressure time is for type inner plastics pressure 实, shrink time, in injection time inner ratio/proportion relatively large, generally is 20～120 s, especially thick products can 达3～5min; 而形状 simple products, holding pressure time can very short, 如几秒钟. in gate melt 冻结之 front, holding pressure time long short, for products quality has relatively large effect/influence. holding pressure time short, products density low, dimensions small, easy shrink 孔; holding pressure time long, products internal stress large, strong/high degree low, demolding difficult. in addition, holding pressure time also and material temperature, mold temperature, runner and gate dimensions and other to has 关. if process parameters positive 常, system design combined 理, usually products shrinkage rate scope/range most small time is most holding pressure time. holding pressure time need factors has: plastics product types and property can; products and mold and other conditions; its it injection molding process conditions, temperature degree, back pressure, injection pressure, injection speed rate, screw speed and other process parameters.

5.3总 cooling time

setting main/primary 取决于 products thick degree, plastics thermal properties and crystallization property and mold temperature degree and other, ensure products demolding deformation is 原则. generally, Tg high and tool has crystallization property plastics, cooling time relatively short; 反之, long. if cooling time long, not only reduce production efficiency, but also make complex products demolding difficult, strong/high demolding will generate relatively large demolding force, heavy can can loss bad products.

gate rear cooling time and screw rear rear products in inner cooling time from upper 讲应该一致, 但实际 production is 不一致. generally 说, screw rear is in gate rear 才开始, in gate rear more long time screw 才开始 rear 退, is this time short good. if screw rear is in gate 冻结之 front, that will 发生倒流, this in production in is 不允许. gate rear cooling time and products property can very large; if time short, products easy generate internal stress, easy deformation; if time long, products 变脆. gate rear cooling time and products demolding difficult easy degree has 一定 关系: time short, residual stress relatively large, demolding difficult.

5.4 other time

molding cycle in its it time and production process is 否连续化 and 自动化, as 者 熟练程 degree and other has 关. ring time this is in add material lower, injection molding machine 空转一 cycle most less as time. this is injection molding machine process in 灵敏程 degree 一 标志.

6 more grade injection molding

products type relatively deep thick relatively thin, make mold type formed long narrow 流通, melt in 流经该部位时必 must fast speed through, 否则会 cooling solid, short shot, in setting high speed injection. high speed injection to melt belt/tape very large can, melt to 底时会 generate very large property impact, can amount loss and material phenomenon, this must make melt decrease speed, reduce pressure, holding pressure pressure, make melt in gate 凝封之 front toward mold cavity inner melt shrinkage. therefore, products injection molding process must using/adopting more grade injection molding.

more grade injection molding is in injection process in, screw toward mold cavity inner melt 时, different using/adopting different injection pressure and injection speed rate. use more grade injection molding has improve/increase products quality.

more grade injection molding combined thin products, long large type products, precision injection products and type 腔配置不均衡 or 锁模不太紧密 products production. in made more grade injection molding process 时, need according to products structure, weight, dimensions and 几何形状, mold type structure and products use plastics, selection good machine type, combined injection molding process parameters, made more grade injection pressure and more grade injection speed rate setting 图形, 并依图进行 adjustment, control.