Shanghai Daoqin Plastics Co., Ltd.

in specific design plastics products 时, is has dispersion internal stress, 应遵循 this 样 原则: products outer 形应尽 can can maintain property, 避免锐角, 直角, and expand large or shrink small.

for/regarding plastics products 边缘处应 design formed 圆角, its in inner semi large versus 邻两壁 in thin thick degree 70% above; outer semi according to products 形状而确定.

for/regarding thick versus relatively large 部位, cooling speed degree different, easy generate cooling internal stress and orientation internal stress. therefore, design formed thick can can uniform made parts, must thick non-uniform, need 进行壁 thick 差异 渐变 渡.

plastics and metal thermal expansion coefficient versus 差5~10倍, belt/tape metal parts plastics products in cooling 时, 两者形 formed shrinkage degree different, plastics shrinkage comparison large 而紧紧抱住 metal parts, in parts plastics inner pressure force, outer 层受拉应 force function, generate force in phenomenon.

in specific 设汁嵌 parts 时, attention/notes lower 几点, 以帮助 decrease small or remove internal stress:

   a.尽 can can selection plastics parts as is parts.

   b.尽 can can selection and plastics thermal expansion coefficient versus small metal material parts material, aluminum, aluminum alloy and copper and other.

   c. in metal parts upper coating 一层橡胶 or polyurethane ester elastic property 缓冲层, ensure molding coating 层不熔化, can reduce shrinkage 差.

   d. for metal parts surface 脱脂化处理, can anti 止油脂 accelerated products force cracking.

   e. metal parts 进行适当 preheating 处理.

   f. metal parts plastics thick degree need 充足. 例如, parts outer is D, parts plastics thick degree is h, for aluminum parts plastics thick degree h≥0.8D; for/regarding copper parts, plastics thick degree h≥0.9 D.

   g. metal parts design formed slip 形状, most good belt/tape 精致 滚花纹.

plastics products upper 孔 形状, and 孔 位置都会 for internal stress in degree generate very large effect/influence.

is 避免应 force cracking, in plastics products upper 开设棱形, 矩形, or more 边形孔. can can 开设圆形孔, its in 椭圆形孔 效果 most good, make 椭圆形孔 long 轴平行于 outer force function direction.

如开设圆孔, can increase and other process 圆孔, make versus 邻两圆孔 in 心连接线平行于 outer force function direction, this can and 椭圆孔 versus 似 效果; also has types methods, in 圆孔周围开设 for 称 槽孔, dispersion internal stress.