Shanghai Daoqin Plastics Co., Ltd.

PVC is hot property material, its injection molding parts molding process property relatively 差, causes is high temperature degree or long hot time very easy make PVC separation understanding, therefore control melt temperature degree is injection molding parts PVC product key/critical. 熔化PVC raw materials hot 源 自两方面即 screw generate for plastics hot and machine outer electrical retardant filament add hot, main/primary is screw 运动 剪切 hot, machine outer add hot main/primary is machine 起动时 provide hot 源. due to PVC hot property can 差, therefore in add hot process in, outer plastics already add hot, in material still cold 凝状态, outer separation already hot separation understanding, internal can can also has 未熔部 separation. has types types causes must in product design, injection molding parts mold design, injection molding parts process and other as separation attention/notes, especially need selection excellent injection molding parts processing PVC specialized injection molding parts machine, can manufacturing 出理想 product. lower injection molding parts PVC时应 attention/notes as introduction, can for has 帮助. （一）, product design and injection molding parts mold design upper attention/notes below/following 几点: 1． product amount need has or 突变, thick degree force 求变化不 large, anti 止出现PVC understanding drop 变质. 2． injection molding parts mold has 10 above 拔模斜 degree, 予留约0.5% shrinkage amount. 3． injection molding parts mold runner design attention/notes a）, injection molding parts mold injection ratio 射咀孔略 large, ratio runner 交错处直径 large, make PVC material mold cavity 不滞留 and pressure balanced. b）, amount using/adopting gate, make 熔渣不会流入 product and runner in temperature degree reduce, easy molding. C）, gate design in product most thick 壁处, degree 足够, long degree most good in 6—8mm between, make PVC material 流入畅顺. d）, is active pressure decline and easy demolding, runner most good is 圆形, product large small and weight in 6—10mm间 selection. 4． injection molding parts mold temperature degree has cooling water control plant/unit, make mold temperature can in 30℃~60℃ between can 控. 5． injection molding parts mold surface light 洁, anti 腐蚀. （二）, injection molding parts process attention/notes below/following 事项: 1． back pressure control in 1Mpa left right, high back pressure generate large force, make PVC hot separation understanding. meanwhile in process using/adopting more grade back pressure control. 开始时, screw has long degree long, back pressure relatively low, screw has long degree decrease/reduce, 应适当 increase back pressure hot amount decrease/reduce. material front small 段, also reduce back pressure, anti 止漏涎. 2． screw speed 应因直径 different 而异. generally 直径＜60mm, speed is 50-70rpm; 直径＞70mm, speed is 20-50rpm, anti 止剪切 force large 而出现PVC degradation. 3． is make plastics injection 入查腔 inner, speed degree 均一, generally injection speed degree need more control, its is slow injection, molding 面积 逐渐 increase large separation must increase injection speed rate, cracks and sink marks is 止, can injection fast, anti product surface 变剥蚀. 4． injection process in machine temperature degree control in 170-190℃ between. material temperature degree to setting temperature degree 时, 应起动鼓风 machine cooling drop temperature, rise temperature 时, again 停止吹风 add hot, anti 止PVC hot 变质. due to PVC property can 特殊, therefore selection specialized PVC injection molding parts machine production, its in need attention/notes below/following 几点: 1． screw long ratio is 20: 1 relatively good, pressure shrink ratio in 1: 1.6-1: 1.2 between. 2． screw and 射咀应 is is PVC manufacturing, surface 镀铬. 3． injection pressure, speed degree, back pressure, temperature degree can more grade, precision control. （本 company production 四缸直锁二 sheet/plate 式PVC injection molding parts machine tool has above property can, 欢迎客房 selection ） most rear in raw materials upper attention/notes below/following requirements: 1． 必 must has other plastics PVC raw materials in, 引起PVC raw materials 变质. especially is injection molding parts other raw materials 时, need 先清洗 dry machine and screw inner plastics, can injection molding parts PVC product. （ use PEPPPS material screw, machine 筒） 2． 停 machine front need will PVC material full 打净, long time machine, is anti 止PVC腐蚀 machine, application material dry screw, machine 筒. 3． 当PVC material time ultra- 6 month, ring high temperature, wet, use front application 60-80℃ temperature degree dry 2-5 small can use.