Shanghai Daoqin Plastics Co., Ltd.

  gate is system in very key/critical material 流通道, remove runner type gate outer, large more gate is system in 截面积 most small 部位, its value generally has separation runner 截面积 3％～9％.
for/regarding from flow plastics melt 说, due to its viscosity and speed rate 无关, large gate 截面积 can reduce flow retardant force, improve/increase melt speed, this for/regarding and molding quality comparison has 利. for/regarding large more 数不服 from flow plastics melt, using/adopting decrease small gate 截面积, 却经常 has can can make melt speed rate increase large, due to hot function, will 会导致 melt table/sheet viscosity large degree decline has can can ratio large gate more has 利于充模. using/adopting small gate molding increase large flow retardant force pressure drop, can in scope/range inner use improve/increase injection pressure methods 补偿. generally 讲, using/adopting small gate injection molding 时, tool has below/following advantages.
① small gate front rear 两端存 in relatively large pressure 差, can has increase large melt speed rate generate relatively large hot, from 而导致 melt table/sheet viscosity decline, flow property reinforcement, has 利于充模. small gate this type of features for/regarding thin products or belt/tape has fine products and polyethylene (PE) （PE）, polypropylene (PP) （PP）, polystyrene (PS) （PS） and other viscosity for speed rate comparison plastics molding, tool has very large 裨益.
② in injection molding process in, holding pressure shrink stage/phase generally need to gate melt is 止, mold cavity in melt toward outer 倒流. if gate dimensions relatively large, holding pressure shrink time will comparison long, therefore has can can make large separation orientation degree and flow deformation increase large, in products inner, especially is in gate 附近造 formed very large shrink force, products most 终出现 warpage deformation. if using/adopting small gate, has can can through mold trial or adjustment small gate 容积, make gate melt in holding pressure process in 适时冻结, from 而恰当 control shrink time, upper phenomenon 发生.
③ due to small gate small, fast, therefore production certain products 时, can in small gate rear must products internal full solid 化, need external solid tool has strong/high degree and rigid degree can will products demolding, from shrink short molding cycle, improve/increase production efficiency.
④ in more mold cavity non balanced system in if using/adopting small gate, gate for plastics melt flow retardant force will ratio separation runner more melt flow retardant force large more, therefore has can can in melt runner 并建立起足够 pressure rear, mold cavity can in same time material 充模. therefore, small gate in more mold cavity in can balanced mold cavity material speed degree, has 利于浇注 system balanced.
⑤ if use relatively large gate molding products, in products surface quality requirements relatively high lower, need 适当 工 tool or machine for products rear processing can remove gate 疤痕, especially is gate large 时, gate material also must 锯, and other methods remove. however, using/adopting small gate can this type of 麻烦. 例如, small gate material can use fast speed remove, or in demolding utilizing mold structure 自动切 remove. another, small gate remove rear relatively small, generally need or need 稍许修整 abrasion light as can. therefore, using/adopting small gate not only has 利于浇注 system material and products 脱离, but also has products 修整.
但应 attention/notes, tube/pipe small gate tool has upper types types advantages, small gate formed very large flow retardant force, 导致进 material time long. therefore, for certain high viscosity or speed rate for table/sheet viscosity effect/influence very small plastics melt （如 poly acid ester and polysulfone (PSU) and other ）, 均不宜 using/adopting small gate molding. another, molding large type products 时, attention/notes will gate 截面积 versus large, has 时甚至 need will gate high degree large to products most large thick degree, can improvement melt flow property. remove upper 述情况之 outer, for/regarding thick relatively large, shrinkage rate relatively large products, generally requirements has 足够 补 shrink time, therefore in this type of lower, gate 截面积也不 can design small.