Shanghai Daoqin Plastics Co., Ltd.

injection molding processing 时 辅 injection molding process is outer year research formed 功, year to application 一项实 use type injection molding new process, its principle is utilizing high pressure property gas injection to melt plastics in formed true 空截面并推动熔 material front 进, achieve injection, holding pressure, cooling and other process. due to gas tool has high pressure property, can make gas internal pressure maintain 一致, can remove internal force, anti products deformation, meanwhile can large degree reduce mold cavity inner pressure, therefore in molding process in need very high clamping force, remove outer, gas injection molding also tool has decrease light products weight, remove shrink 痕, improve/increase production efficiency, improve/increase products design degree and other advantages. in recent years, in home appliances, automotive, furniture and other industry, gas injection molding to 越 越广泛 application, outlook/prospects good. group 于98 year 引进一 sleeve/set gas equipment used for production electrical 冰箱, device injection molding parts .   

      gas equipment   

      gas equipment gas control mono and nitrogen gas plant/unit. it is 独立于 injection molding machine outer sleeve/set system, its and injection molding machine 唯一接口 is injection 信号连接线. injection molding machine will injection injection or screw 位置传递 to gas control mono rear, 便开始一 注 gas process, and other lower injection process 开始时 to 出另一 injection 信号, 开始另一 循 ring, 如此反复进行.   

      gas injection molding use gas must is property gas 体（ usually is nitrogen gas ）, gas most high pressure is 35MPa, 特殊者 can 达70MPa, nitrogen gas pure degree ≥98％.   

      gas control mono is control gas time and gas pressure plant/unit, it tool has more gas design, can meanwhile control more injection molding machine gas production, gas control mono has gas recycling function, can can reduce gas consumption use amount.   

      in the future gas equipment development trend is will gas control mono inner injection molding machine inner, as is injection molding machine new function.   

      gas process control   

      1．注 gas parameters   

      gas control mono is control stage/phase gas pressure large small plant/unit, gas parameters has value: gas time （秒） and gas pressure （MPa）.   

      2． gas injection molding process is in mold inner plastics melt meanwhile high pressure gas 体, melt and gas between in complex versus function, therefore process parameters control versus important, lower 面就讨论一 lower parameters control methods: 　 

      a． injection amount   

      gas injection molding is using/adopting 谓 “ short 射” methods （short size）, in mold cavity inner 注入一定 amount material （ usually is 满射时 70－95％）, rear again gas 体, achieve full process. injection amount and mold gas large small and mold cavity structure most large. gas 道截面越 large, gas easy 穿透, rate high, 适宜于 using/adopting relatively large “ short rate ”. this if use more material amount, very easy 发生熔 material 堆积, material more 方会出现 shrink 痕. if material less, 则会导致吹穿.   

      if gas and material direction full 一致, that most has gas 体 穿透, gas 道 掏空 rate most large. therefore in mold design can can will gas and material direction maintain 一致.   

      b． injection speed degree and holding pressure   
      in ensure products performance 不出现 defect lower, can can use relatively high injection speed degree, make material fast mold cavity, this material temperature degree still maintain relatively high, has gas 体 穿透 and 充模. gas in 推动熔 material mold cavity rear still maintain pressure, versus 当于传统 injection molding in holding pressure stage/phase, therefore generally gas injection molding process can use injection molding machine holding pressure process. has products due to structure causes still use injection molding holding pressure ensure product performance quality. can use high holding pressure, is holding pressure high make gas 针封死, inner gas can recycling, mold opening easy generate 吹爆. holding pressure high make gas 体穿透受 retardant, add large injection molding holding pressure has can can make products performance more large shrink 痕.   

      c． gas pressure and gas speed degree   

      gas pressure and material flow property most large. flow property good material （如PP） using/adopting relatively low gas pressure. types material recommendation pressure lower:   

      plastics types type 熔纸(g/10min) use gas pressure (MPa)  

      PP 20~30 8~10  

      HIPS 2~10 15~20  

      ABS 1~520~25  

      gas pressure large, easy 于穿透, easy 吹穿; gas pressure small, can can 出现充模不足, 填不满 or products surface has shrink 痕; gas speed degree high, can in material temperature degree relatively high lower mold cavity. for process/workflow long or gas small mold, improve/increase gas speed degree has 利于熔胶 充模, can improvement product surface quality, gas speed degree fast has can can 出现吹穿, for gas coarse large products can can generate surface flow marks, gas marks.   

      d．延迟 time   

      time is injection molding machine 射胶开始 to gas control mono 元开始注 gas time 段, can understanding is 反映射胶 and gas “同步 property ” parameters. time short, in also relatively high temperature degree lower 开始注 gas, has gas 体穿透 and 充模, 但延迟 time short, gas easy dispersion, 掏空形状不佳, rate 亦不够.   

      gas mold   

      gas mold and injection molding mold more large 差别, increase gas parts （称 is gas 针）, increase gas design. 谓“ gas 道” can simple understanding is gas 体 通道, gas 体进入 rear 流经 部 separation, gas has is products separation, has is is gas 流而专门 design 胶位.   

      gas is gas mold very key/critical parts, it effect/influence process stability and product quality. gas core separation is more fine small 缝隙组 formed 圆柱体, large small effect/influence gas amount. large, gas amount large, for injection molding has 利, 但缝隙太 large by 熔胶堵塞, gas amount decline.   

      gas application 实例  

      gas injection molding most 适宜于 tool has coarse large or thick products and coarse large internal has products （如手柄 type, type ）, inner large type electrical machine 厂家都 using/adopting gas injection molding process production electrical machine front frame, can Raw Materials 10％～20％并 large degree reduce clamping force.   

      冰箱顶 cover/cap sheet/plate is large type sheet/plate injection molding parts, quality requirements high, its mold using/adopting gate 入胶, in injection molding easy generate deformation, effect/influence assembly. using/adopting gas rear, deformation amount to has control, deformation amount 由原 1．7～2 mm decrease/reduce to 0．5mm below/following.   

      device toward sheet/plate is long strip/profile type structure, 截面形状“不规则”, due to surface 不允许 has 熔接痕, mold mono water 口入胶, material process/workflow long, use injection molding easy generate deformation, shrink 痕, in device upper effect/influence toward electrical machine 转动, heavy 者甚至会烧毁 electrical machine, therefore improvement deformation amount 显 尤 is important. using/adopting gas process rear issues 迎刃而 understanding, deformation amount 由原 3～4mm drop is 1 mm以 inner.   

      手柄则 is type type products, in gas 辅出现 front it is parts products assembly formed, need 做两付 mold but also assembly rear strong/high degree 不够, overall 也不够美观. gas rear can “ combined is 一”, 省略一付 mold and assembly 工序.   

      gas injection molding is year 兴起 一项 new process, in outer already to application, in inner 尚处于初始 stage/phase, currently large type home appliances already 陆续开始 application this new process, versus 信随 各厂商 for gas process add deep, this new process application 越 越普遍