Shanghai Daoqin Plastics Co., Ltd.

        一, what is crazing 汽白?

         crazing 汽白: crazing is plastics products relatively Common types defect, made parts surface filament cracks, micro 裂, 顶白, cracking and made parts mold sticking, runner mold sticking formed 创伤, cracking time separation is demolding cracking and application cracking.

         generate main/primary causes is due to force deformation 致(main/primary has residual stress, external force and external ring generate force deformation). 如图 示

        二, how to improvement?

        1.材 material 方面:

        适当 use demolding agent, attention/notes 经常消 remove 模面附 gas and other material 质;

         molding processing front for material material 进行充 separation drying 处理;

         attention/notes selection 不会发生 cracking coating material and dilute agent.

        2. molding process:

        避免塑化 stage/phase material defect 而卷入空 gas;

         improve/increase melt temperature degree and mold temperature degree, ensure melt flow upper, amount reduce injection molding pressure;

         reduce screw speed, injection speed degree, decrease melt through gate speed degree, using/adopting more grade injection molding;

         adjustment mold opening speed degree and pressure, 避免因 fast speed strong/high products formed demolding cracking;

        避免 due to 熔接痕, plastics degradation formed strong/high degree 遍 而出现 cracking;

         through in molding rear 立即进行退火处理 消 remove internal stress decrease/reduce cracks generate.

         if parts surface already generate crazing, can 考虑采取退火 办 method 予以消 remove. 退火处理 make low parts heat deflection temperature (HDT) 5℃ left right temperature degree, separation add thermoplastic parts 1 small left right, rear will its slow cooling, most good is will generate crazing parts molding rear 立即进行退火处理, this has 利于消 remove crazing. crazing in has residual stress, coating material in solvent agent very easy make 裂痕处 development formed is cracks.