聚苯乙烯(EPS)头盔内衬垫发泡模结构设计

摘要

由于头盔内衬垫应具有保温、隔热、缓冲抗震等性能上的要求,故采用可发性聚苯乙烯(EPS)材料和二步浸渍工艺,将可发性聚苯乙烯珠粒通过预发泡后,再放进蒸气室双层壁的发泡模中再发泡而成型.发泡模是成型头盔内衬垫的关键工艺装备,通过对头盔内衬垫的形体分析,找出了影响头盔内衬垫脱模的凸台、弓形高和许多微形凸疱的3种“障碍体”,它们会对制品分型、脱模产生阻碍作用.针对这种情况,在采用将头盔内衬垫逆时针旋转10°后,发泡模又采用了二次分型的三模结构形式,有效地避免了3种“障碍体”对模具分型与脱模的影响,同时型腔中制作出许多用于通入蒸汽的小孔.这些措施使得头盔内衬垫能够顺利地进行成型加工、分型与脱模.%Due to the thermal insulation,cushioning and shock resistance of the inner liner,the EPS material and the two step impregnation process are adopted.After pre-foaming,the expandable polystyrene beads were then put into the double wall foam mould in steam chamber and foaming.Foaming mould is the key equipment to form helmet liner.Though the shape analysis of helmet liner,three kinds of "obstacle",including boss,bow high and many micro convex bleb,influencing mould releasing of helmet liner were found out,which will hinder the mould parting and releasing.Measures like 10°counterclockwise rotation of inner liner,and triple mould structure with twice parting were adopted to effectively avoid the effects of three kinds of "obstacle" to die parting and demoulding.Also,a lot of holes were made in cavity for steaming.By taking these measures,the inner liner of the helmet is produced smoothly.