Shanghai Daoqin Plastics Co., Ltd.

随 polymer/macromolecule molding process technology development, structure foaming injection molding parts and gas 体辅助 injection molding parts molding process add 完善, application areas expand large. is, 随 人们生 active water day improve/increase, for very more product more high requirements, ratio in 音响号筒 field/area large 家越 越关注音质效果以 and product resistant use property, appearance and other and other. injection molding parts already very difficult meet/satisfy this parts demand, low pressure structure foaming injection molding parts 诞生填补 传统 injection molding parts technology 空白. foaming injection molding parts development brief introduction foaming injection molding parts technology 渊源久远. most is 20世纪20 year 代初期 foam 胶木, use similar manufacturing foam methods made 取; 30 year 代出现 hard polyurethane ester foam and polystyrene (PS) foam; 40 year has polyethylene (PE), polyvinyl chloride (PVC), ring oxygen resin, aldehyde foam; 50 year has can property polystyrene (PS) foam and soft polyurethane ester foam. in, basic upper has plastics, thermoplastic property and hot solid property can foaming. industrial upper made methods has: extrusion foaming, injection molding parts foaming, foaming, calendering foaming, powder foaming and spray coating foaming and other and other. its in, injection molding parts foaming is most important molding methods 之一, is low pressure structure foaming injection molding parts front 身. low pressure structure foaming principle in plastics injection front, through nitrogen gas equipment toward mold cavity inner low pressure gas made foaming agent foaming, pressure to 0.8-2.0MPa时开始射胶 filling injection molding parts mold, meanwhile injection molding parts mold inner nitrogen gas through gas slow 排出, foaming agent in plastics internal foaming formed micro 孔. foaming reaction 式: 名称: nitrogen 二甲酰 amine; separation 子式: C2H4N4O2; molecular weight: 116. material property 质: color crystallization powder 末, positive 常情况 lower is stability; 无毒, 无臭, 无污染 property; easy solvent 于二甲基亚矾, 二甲基酰 amine and hydrogen oxidation solvent liquid; solvent acid, alcohol, ketone, 苯, and water. foaming agent Data Sheet structure foaming features structure foaming (Structural Foam Molding) belongs to chemical foaming method, 保留 传统 injection molding parts molding process many advantages, also rear 者 部 separation defect, products strong/high degree 不够, production cycle long, rate low and other. using/adopting structure foaming technology can large type complex products, use low cost injection molding parts mold, more mold cavity can meanwhile as, from reduce products production cost. structure foaming products is types tool has table/sheet 层 连体 foaming material, its mono weight strong/high degree and rigid degree ratio types foaming material high 3～4倍. low pressure foaming injection molding parts and injection molding parts difference in its injection molding parts mold mold cavity pressure relatively low, 约2～7MPa, 而普通 injection molding parts in 30～60MPa between. low pressure foaming injection molding parts generally using/adopting method, will amount （不注满 mold cavity ） plastics melt （含 has foaming agent ）注入 mold cavity, foaming agent separation understanding gas make plastics 膨胀而充满 mold cavity. in injection molding parts machine upper low pressure foaming injection molding parts, generally is will chemical foaming agent and plastics mixed combined, in machine inner 塑化, must using/adopting 自锁式射嘴. injection 时, due to gas expand dispersion speed degree very fast, formed products surface coarse 糙, therefore injection molding parts machine injection speed degree need fast. generally using/adopting increase pressure device improve/increase injection speed degree and injection amount, make injection as in 瞬间完 formed. process process/workflow （1） will 我们通 commonly used material 如: ABS, HIPS, PP and other （ attention/notes must is molding temperature degree and AC foaming agent foaming temperature degree plastics ）, and AC进行一定 ratio/proportion mixed combined, usually ratio/proportion is 0.5%-5%. （2） mixed combined uniform material through injection molding parts machine screw blending, nozzle 阀门关闭. （3） gas 体辅助 equipment toward injection molding parts mold inner low pressure nitrogen gas, made foaming agent in foaming. （4）当 mold cavity pressure to 0.8-2.0MPA时, 自锁式 nozzle 阀门打开开始 injection, melt plastics through injection molding parts mold inner hot runner add hot, let foaming agent to foaming temperature degree. （5） plastics will mold cavity 时（ usually in 90%-95% left right ）, gas 体辅助 equipment 开始排 gas, and meanwhile plastics parts internal separation foaming, most rear 添满整 mold cavity. Common defect and solutions （1） injection molding parts parts sink marks: due to filling saturated and 经常会造 formed foaming separation, 因而造 formed and sink marks. solution methods: decrease/reduce injection amount, reduce gas time, reduce gas pressure, improve/increase nozzle temperature degree. （2） injection molding parts parts 欠注: due to injection molding parts amount 不足经常会 has phenomenon. solution methods: increase injection molding parts amount. （3） melt 破裂, gas 痕: due to non-uniform or foaming machine for, in injection molding parts parts surface has orange peel defect or has similar 于熔接痕 defect. solution methods: adjustment injection molding parts parts balanced, reduce gate filling speed degree, reduce gas pressure, improve/increase gas 体排放 斜 rate, reduce material tube/pipe temperature degree, 避免材 material in material tube/pipe in front foaming. other defect 处理办 method and injection molding parts comparison 接近, in again heavy 复说明. main/primary is through gas 体辅助 equipment adjustment injection molding parts mold internal pressure, control foaming agent foaming machine. 结论 （1） low pressure foaming injection molding parts is gas 体辅助 control AC foaming agent foaming new type injection molding parts process. （2） low pressure foaming injection molding parts can solution thick 壁, 柱位, sink marks issues, meanwhile also tool has 节省材 material, improve/increase products 音质效果 and other function, widely used in industry in.