Shanghai Daoqin Plastics Co., Ltd.

        一, what is thin injection molding

         thin injection molding technology is thin parts injection molding technology. about/regarding its has below/following types:

         its 一: flow long degree and thick degree ratio L/T, 即 from melt mold to melt must type most flow long degree L and versus 应平均壁 thick T ratio in 100 or 者150 above injection molding is thin injection molding;

         its 二: molding parts thick degree small 于1 mm, meanwhile parts 投影面积 in 50 c㎡ above injection molding methods;

         its 三: molding parts thick small 于1 mm（ or 1.5mm）, or t/d (塑 parts thick degree t, parts 直径d, for type parts ） in 0.05 below/following injection molding is thin injection molding.

        由此 can 看出, thin injection molding 定义 临界 value will 发生变化, it is versus for concept.

        二, raw materials selection

         for raw materials requirements: large flow long degree, high impact strong/high degree, high heat deflection temperature (HDT), high heat stabilized property, low direction property and good dimensional stability; also need plastics raw materials low temperature impact rigid property, flame retardant property, machine assembly property and appearance quality and other.

         currently commonly used thin injection molding raw materials has: polycarbonate (PC) (PC), propylene 睛— butadiene — styrene (ABS), PC /ABS blending material and PA6 and other. 随 壁 thick reduce, need use tool has more good physical properties plastics products strong/high degree.

        三, Common defect analysis

         although parts thin has very more advantages, reduce parts can molding property, 以致于 use injection molding methods method molding this thin parts. in thin parts molding 时, in lower Common issues:

        1, short 射

         short is due to mold type filling full formed parts 不完整 quality defect, melt in formed filling front already 经凝结.

        常规 injection molding filling process and cooling process is in 一起. polymer melt flow 时, melt front to versus for temperature degree relatively low type surface or type 腔壁, in its surface formed cold 凝层. melt in cold inner toward front flow, cold thick degree increase, type runner narrow, cold thick degree for polymer flow has significantly effect/influence. is injection molding parts thick degree relatively thick, therefore cold for injection molding effect/influence also is very large. in thin injection molding in, cold thick degree and parts thick degree ratio 随 塑 parts thick degree thin increase 时, this effect/influence very large. especially is dimensions can versus comparison more is 突出.

        当塑 parts thick degree decrease small 时, cold for flow effect/influence will 会以指数形式 increase, this more cold in thin injection molding in effect/influence large. if from injection molding 考虑, need injection molding machine has high injection speed rate, make plastics melt filling type speed rate ultra- cold formed long speed rate (or make cold formed long speed rate slow), this can in flow 截面封闭 front formed filling as, thin parts injection molding.

        当 flow long degree is 300mm, parts thick is 3.0 mm 时, L/T is 100, use injection molding technology very easy to;但当塑 parts thick decline 至1.0mm below/following 时, this very easy to long thick degree ratio (100)就变 non difficult to.

        2, warpage deformation

         warpage deformation is non-uniform internal force 导致 塑 parts defect. warpage deformation generate causes is shrinkage non-uniform, orientation non-uniform and cooling non-uniform.

          improvement methods: can through balanced cooling system, adjustment cooling time, holding pressure pressure and holding pressure time and other measures improvement parts warpage deformation defect.

        3, weld lines

         weld lines is type inner or more melt flow front combined formed 界线. in weld lines easy generate force in, low parts machine strong/high degree, for parts especially is thin parts mechanical properties is 不利, outer force rear parts non easy in weld lines cracking.

          improvement methods: in design can through decrease/reduce gate or gate decrease/reduce or weld lines 位置, meet/satisfy parts design requirements.

        4, material

         formed product fine small 部位, 角落处无 method full molding, mold processing to or is gas 不畅, molding upper due to injection agent amount or pressure and other causes, formed design defect （肉 thick 不足）.

         improvement methods: can positive material mold, or 改良排 gas measures, add thick, gate improvement (add large gate, increase gate), add large injection agent amount, increase injection pressure and other measures improvement.

        5, sink marks

        常发生于 formed product thick or thick 不均处, hot plastics cooling or solid shrinkage different 而致. 如肋 背面, has 侧壁 边缘, BOSS柱 背面偷肉, less 保留2/3 肉 thick.

           improvement methods: can through add coarse runner, add large gate, add gas, rise high material temperature, add large injection pressure, long holding pressure time and other measures improvement.

        6, surface 影像

        常发生于经 偷肉 BOSS柱, or 筋 背面, or is due to type 芯, design high formed force reduce.

         improvement methods: can through positive type 芯, 顶针, 母模面喷砂 and other methods 处理, using/adopting reduce 模面亮 degree, reduce injection speed degree, decrease small injection pressure and other methods.

        7, gas marks

        发生于进 gate 处, more due to mold temperature high, injection speed degree, pressure high, gate 设置不当, 进浇时 plastics to structure.

         improvement methods: can through more gate, runner light, runner cold material add large, gate add large, surface add 咬花(through machine or 修模赶结 combined can), rise high mold temperature, reduce injection speed degree, decrease small injection pressure and other methods solution.

        8, combined 线

        发生于两股 material combined 处, 如两 进 gate material combined, type material combined, is due to material temperature decline, gas defect 致.

          improvement methods: can through more gate, add cold material 井, gas or 公模面咬花 and other methods, can rise high material temperature, rise high mold temperature and other.

        9, flash/burrs

        常发生公母模 结 combined 处, due to clamping defect 致, or is 模面边角 processing 不当, molding upper due to clamping force 不够, material temperature, pressure high and other.

          improvement methods: can mold positive, heavy new clamping, increase clamping force, reduce material temperature, decrease small injection pressure, decrease/reduce holding pressure time, reduce holding pressure pressure and other.

        10, deformation

         fine long parts, large thin parts, or is structure for relatively large formed product due to molding cooling force or ejection force 不一 致.

         improvement methods: can 进行修 positive 顶针, 设置起张紧 function material and other, necessary 时公模 add adjustment deformation, adjustment 公母模 mold temperature reduce holding pressure and other, small parts deformation adjustment main/primary pressure large small and time, large parts deformation adjustment generally mold temperature.

        11, surface 不洁

         is due to mold surface coarse 糙.

         improvement methods: for/regarding PC material, has due to mold temperature high, has 残胶, 油渍, and 时进行清理模面, light 处理, reduce mold temperature and other.

        12, whitening on ejection

         easy 发生于 formed product thin 壁转角处 or is thin 壁RIB根部, is due to demolding force defect formed, 顶针设置不当 or is 拔模斜 degree 不够.

         improvement methods: add large 转角处R角, increase large demolding degree, increase or is add large its 截面积, 模面打 light, or 斜销打 light, reduce speed, decrease small injection pressure, reduce holding pressure and time and other.

        13, 拉模

         performance is demolding defect or 模伤, 拉花. main/primary due to 拔模斜 degree or coarse 糙, molding conditions has effect/influence.

         improvement methods: increase large 拔模角 degree, 模面打 light, viscous 母模面时 can increase or more material 销, 牛角进 material attention/notes 牛角直径, add 咬花, decrease small injection pressure, reduce holding pressure and time and other.

        14, gas 孔

         transparent formed product PC material formed 形时容 easy 出现. due to injection molding process in gas 体未排尽, mold design or is molding conditions 不当都 has effect/influence.

         improvement methods: increase gas, more gate (进 gate increase large), PC material runner must light, 严格烘 material conditions, increase injection pressure, reduce injection speed degree and other.

        15, 断差

        发生于公母模 block, slip block, and other combined 处, performance is combined 面 层次不齐 and other, due to clamping or is mold issues.

          improvement methods: 修 positive mold, or heavy new clamping.

        16, dimensions ultra- 公差

         mold issues, or is molding conditions 不当造 formed molding shrinkage combined 适.

         improvement methods: usually holding pressure time, injection pressure (第二段) for dimensions effect/influence most large. 例如: improve/increase pressure, improve/increase holding pressure shrink function can obvious add large dimensions, reduce mold temperature can, add large gate or increase gate can improvement adjustment 效果.