Shanghai Daoqin Plastics Co., Ltd.

近代 injection molding products, in field/area to application, products 形状十 separation complex, use polymer property can 差别也 very large. is types material products, due to system and 各部位几何形状 different, different for/regarding melt flow （ speed degree, pressure ）提出 requirements, 否则就 need effect/influence melt in this 一部位 流变 property can or polymer/macromolecule crystallization toward function, and products table/sheet quality. in injection process in, screw toward mold melt 时, requirements achieve in different upper has different injection speed degree and different injection pressure and other process parameters control, this type of injection process is more grade injection molding.

数字拨码式 injection molding machine comparison rear, has or 二段射胶, holding pressure, 一段熔胶 control 程序, for/regarding structure complex, appearance quality requirements high product, very difficult setting and control injection speed degree and its it process conditions, 导致 injection molding parts 出现 一 appearance defect method through injection molding parameters methods improvement. is meet/satisfy improve/increase injection molding parts appearance quality need, upper issues, injection molding machine manufacturing development production tool has more grade 射胶, more grade holding pressure, more grade function injection molding machine, this is injection molding processing industry one-time breakthrough property technology 进步.

currently, large more is injection speed degree more grade control injection molding machine, usually can injection full 冲程像图a that separation 3 or 4 区域, 并 各区域设置 formed different injection speed degree.

如图b, using/adopting in injection use low speed, mold cavity 充填时 use high speed, 充填接近终 时 again use low speed injection methods. through injection speed degree control and adjustment, can anti and improvement products appearance flash/burrs, 喷射痕, strip/profile or and other various defect phenomenon.

more grade injection control can according to runner structure, gate and injection molding parts structure different, combined setting more injection pressure, injection speed degree, holding pressure pressure and methods, has improve/increase 塑化效果, improve/increase product quality, reduce defect rate and long mold / machine lifespan.

through more grade control injection molding machine pressure, screw 位置, screw speed, can improvement molding parts appearance defect, improvement sink marks, warpage and flash/burrs for measures, decrease/reduce 各模每次 injection molding parts dimensions 不均一.

more grade control 效果

formed type strip/profile parts
 效 果
 
注 塑 speed degree
  anti gate gas marks /流纹, anti 止锐角 flow 痕迹, anti 止模芯 倒塌, anti flash/burrs.
 
二 次 pressure force
  decrease light internal stress 变, anti sink marks.
 
螺 杆 转 数
 计 amount stability property
 
背 pressure
 计 amount stability property
 

however, very more injection molding technology still 然习惯 use 一段射胶 methods, how to more 段射胶位置 and methods, make tool has more 段射胶 function machine 发挥不 its advantages.

一, setting more grade injection methods:

generally parts injection molding less need setting or 四段射胶才 is comparison 科学. water runner is 第一段, gate is 第二段, product to 90% left right is 第三段, 剩余 部 separation is 第四段(亦称末段).

for/regarding structure simple appearance quality requirements high parts injection molding 时, can using/adopting 三段射胶 程序. for structure comparison complex, appearance defect more, quality requirements high parts injection molding 时, using/adopting above control 程序.

setting 几段射胶程序, need according to runner structure, gate 形式/位置/数 amount / large small, injection molding parts structure, product quality and mold gas and other factors 进行科学 analysis, combined setting.

二, more grade injection selection methods:

1, weight method

总 weight = has parts separation weight + runner separation weight

injection 时 射胶 amount is weight, 一段射胶位置即 is runner separation amount; 二段射胶位置即 is product 走胶90%时 射胶 amount; is 末段 射胶 amount.

according to 自己 初步估计, will injection 时 找位置点 pressure / speed degree is 零, 观察实际走胶 位置, again according to 实际情况进行 micro 调, 直至找 to need selection 位置.

lower 面以图例说明 products and more grade control between 关系

图一 is according to process conditions different speed degree, for injection screw more grade speed degree 转换（切换）.

图二 is for products 几何形状 analysis upper selection more grade injection molding process : due to products type relatively deep also relatively thin, make mold type formed long narrow runner, melt this 部位时必 must very fast through, easy cooling solid, 会导致充不满 mold cavity 危险, in setting high speed injection. is high speed injection to melt belt/tape very large can, melt to 底时会 generate very large property impact, can amount loss and phenomenon, this must make melt decrease speed, reduce pressure need usually holding pressure pressure （二次 pressure, rear pressure ） make melt in gate solid front toward mold cavity inner melt shrinkage, this for injection molding process more grade injection speed degree and pressure requirements.

in in screw amount is according to products use material amount and amount setting. injection screw from 位置“97” to “20” is products thin separation, in stage/phase setting high speed value is 10, its is high speed can anti melt dispersion hot time long flow 终止; screw from 位置“20”→“15”→“2”时, also setting versus low speed 5, its is decrease/reduce melt speed and its impact mold can.
当 screw in “97”, “20”, “5” 位置时, setting relatively high one-time injection pressure 以克服充模 retardant force, from “5” to “2”时 also setting relatively low injection pressure, decrease small can impact.
more grade injection setting 原则

（1）    for/regarding gate product, can using/adopting mono grade injection 形式, can using/adopting more grade injection 形式. for/regarding structure simple degree requirements high small type plastics made parts, can using/adopting low grade injection control methods.

（2）    for/regarding complex and degree requirements relatively high, large type plastics products, need selection grade above more grade injection process.

（3）    more grade injection setting is: grade injection amount （即 injection 终止位置） is system gate 终点. remove gate, its 余 几乎都 using/adopting in pressure, in speed or in pressure low speed; grade injection 终止位置 is from gate 终点开始至整 type 腔1/2-2/3 空间, grade injection using/adopting high pressure, high speed, high pressure, in speed or in pressure, in speed. products structure and use material 而定; below/following injection grade 别, using/adopting in pressure in speed or in pressure low speed, is good 充满剩余 type 腔空间. this injection process is belongs to versus scope/range. most rear grade injection belongs to increase pressure versus scope/range, holding pressure 切换点就 in this grade injection 终止位置 between, 切换点 selection methods is:

计时 and 位置两 types methods. injection shot 开始时, meanwhile injection shot 计时也 meanwhile 计算各 grade injection shot 终止位置, if injection shot parameters 不变, raw materials flow property different, flow property relatively 佳, most rear grade 终止位置 ratio 计时先 to holding pressure 切换点, this formed 充填, increase pressure versus 充模, injection shot holding pressure （补偿 versus ）, to 计时则不 again 计时直接进入 holding pressure, if flow property relatively 差, 计时完 formed most rear grade injection shot 终止位置 also to 达切换点, 一样不 and other to 达, 直接进入 holding pressure. therefore attention/notes below/following 几点:                                                1, raw materials flow property relatively 平均, can in holding pressure rear, again time add 几秒, as is 补偿. 2, raw materials flow property material 佳, mixed combined material, low viscosity material, injection shot relatively unstable, use relatively 佳, will holding pressure 切换点 decrease small （ generally 终止位置 setting is 零）, 以计时 control, 自动切换进入 holding pressure.       3, raw materials flow property relatively 差, 以位置 control holding pressure 切换点 relatively 佳, will add long, to setting 切换点 rear holding pressure.

（4）    holding pressure 切换点即 mold type already 充填满 位置, injection shot already difficult again front 进, 数字变换 very slow, this must pressure can make products full molding, 该位置 in as upper can to （计算 machine 语言）. 至于三 grade holding pressure use is this 样确定: 骨位不 more, dimensions combined products and high viscosity raw materials products use grade holding pressure, holding pressure pressure ratio increase pressure versus high, holding pressure time short. 凡骨位（ add strong/high 筋） relatively more, requirements has 公差配 combined products, 一定启 use more grade holding pressure.

more grade injection setting methods

（1）计算 weight method

injection shot 行程（S）=（ products quality + water quality ）/ screw 截面积*材 material density

screw 截面积=（D/2）2Π=Π/4D2=0.875* D2

S=0.875* D2*材 material density

我们就 force group production 250t below/following more grade injection machine 举例说明

（2） debugging method

main/primary is using/adopting “ molding water sheet/plate ” methods （观察主画面计算 machine table/sheet 达 语言）, 寻找位置转换点, according to 自己 初步估计, will lower grade injection speed degree setting is 0, or will holding pressure 切换位置 setting is lower grade injection speed degree 切换位置, meanwhile will holding pressure or holding pressure time setting is 0, again molding water sheet/plate （ injection molding machine 主画面）, through 观察实际射胶 位置, again according to 实际情况进行 adjustment, 直至找 to combined 适 位置. this type of methods in mold trial use comparison more, but also relatively methods （1） more is fast use, in by application