Shanghai Daoqin Plastics Co., Ltd.

        随 automotive industrial development, plastics parts in automotive upper application 越 越广泛. automotive plastics parts application for/regarding reduce automotive quality, 节约燃油, promote environmental protection and can recycling utilizing and other 方面都 has significantly advantages. automotive plastics parts large more using/adopting injection molding, 虎皮纹, surface made defect, shrink 痕, weld lines, warpage deformation and other, is automotive injection molding parts Common defect, this defect not only and material has 关, also and structure design, mold design and molding process has very large 关系. 今天就 and large 家一起 separation several 保险杠 injection molding Common issues and solutions!

        一, pressure 线

        如图 示, 保险杠雾灯周围 has obvious pressure 线, effect/influence products appearance and surface quality, due to 保险杠 belongs to automotive outer surface parts, for table/sheet quality requirements comparison 严格, generate pressure for its table/sheet quality generate heavy effect/influence.

        1. material main/primary process parameters

        名称: 保险杠

        材 material: PP

         color: 黑

         mold temperature degree: 35℃

         gate methods: 针阀式 gate

        2. can can causes analysis and improvement measures

         mold 方面: 本案例 products in 雾灯周围 孔附近设置 has gate G5, gate 打开时, due to effect/influence, formed 孔两侧 pressure heavy new to balanced formed pressure 线.

        3. improvement rear 效果

        案例 in pressure is 潜流线, 往往出现 in is 熔接痕 in 区域, this category of pressure 线出现 mechanism lower 图 示, solution methods is amount make 熔接痕周围 pressure decrease small, or make pressure 差不足以推动 positive in solid melt 移动.

        二, 虎皮纹

        虎皮纹经常出现 in 保险杠, table/sheet sheet/plate, sheet/plate and and other relatively large automotive injection molding parts upper, is types 波浪形 strip/profile surface defects, large 约垂直于 melt flow direction, in made parts surface upper formed gloss different 刻印, 看起 就像老虎皮 upper 花纹一样, 俗称虎皮纹.

        1.虎皮纹 generally in what 方出现?

        虎皮纹容 easy generate in thick relatively thin, process/workflow relatively large made parts upper, it tool has below/following 特征: (1) injection molding parts surface 出现呈 cycle property 变化 明 dark strip/profile 纹;(2) strip/profile large 致垂直于 melt flow direction;(3) strip/profile separation is and dark 区, gloss degree high, dark gloss degree 差;(4) if made parts positive is 亮区, 则背面 is dark 区, 两者交替出现.

        2. is easy 出现虎皮纹?

        材 material in toughened system more, 虎皮纹 phenomenon easy 出现”. tough property 差 材 material very less 会出现虎皮纹 phenomenon, reinforcement material, non toughened nylon, PBT and other material molding process in very less has 虎皮纹 generate. used for automotive injection molding parts PP材 material, due to requirements has relatively high impact property can, add EPDM, POE and other toughened formed separation, non easy 出现虎皮纹 defect.

        3. how to improvement 虎皮纹?

        1) in mold design increase runner 直径, expand large gate thick degree and wide degree is remove 虎皮纹 has measures. gate thick degree most good to thick 0.7～0.8倍. 此举 目 is reduce melt in runner and gate in pressure loss 失, decrease small type 腔时 出模膨胀效应.

        2) in injection molding process improve/increase melt temperature degree and mold temperature degree, adjustment injection speed degree, has 利于消 remove 虎皮纹. generally lower, using/adopting relatively low speed has 利于消 remove 虎皮纹, is low speed lower melt flow more stability.

        三, material 花

         automotive 保险杠附近 material cold material not only effect/influence made parts table/sheet quality, effect/influence its mechanical properties. automotive 保险杠 is absorption and outer impact force, anti 护车身 front rear safety plant/unit. generally selection machine strong/high degree relatively good PP.

        1. 材 material main/primary process parameters

        名称: automotive 保险杠

        材 material: PP color: black mold temperature degree: 55℃ gate methods: gate

        2. can can causes analysis and improvement measures

         products mold 方面: 本案例 products using/adopting mold in separation 别包含 hot runner and cold runner, cold runner upper has design cold material 井, 直接连通 in made parts upper.

         molding process 方面: for/regarding injection molding process 方面, 观察发现 has gate 封胶不严, gate upper has cold material, 封闭针阀 gas pressure very low, to function. 本案例 through use gas pressure increase pressure improve/increase gas pressure, hot gate again material rear cold material 消失.

        3. improvement front rear 效果图 comparison

        4. focus/key point 提示

         lower is type hot runner nozzle structure, can to, its nozzle front and sheet/plate 接触, although 接触面积 has 限, nozzle front hot amount also is toward relatively cold sheet/plate 传导; in addition, nozzle due to cooling need, has also in cooling 回路, this 样进一步 increase nozzle front temperature degree low can can property. nozzle front temperature degree relatively low, its front in less separation cold material, especially is 封针封胶不严时, melt 溢出, more easy formed cold material, therefore hot runner nozzle cold runner 时, in cold runner upper 也设置 cold material 井.

        四, peeling

         automotive 保险杠 made parts surface large, defect defect rate low, very difficult peeling defect, defect heavy effect/influence made parts appearance quality. lower is certain project 保险杠 surface delamination peeling, defect rate 3-5%, machine in made parts surface. due to made parts surface large, defect defect rate low, therefore very difficult 发现, heavy effect/influence made parts appearance quality.

        1. material main/primary process parameters

        2. can can causes analysis and improvement measures

         molding process 方面: for/regarding 本案例 products can can is due to cold material 引起. through 检查发现 material temperature and hot runner temperature degree positive 常, mold using/adopting 开放式 hot runner positive 常. due to production 时采取手动取 parts, parts time relatively long 时, formed hot 嘴均出现 different degree 流涎. through shrink short parts time rear 发现, hot 嘴流涎 phenomenon to has improvement. therefore, has can can is generate cold material by to type in formed delamination peeling, 而现场也发现 positive is 工人取 parts time long short lower product is generate delamination peeling. for/regarding 此, 本案例 products solution measures is: will injection molding machine 射退距离 from 16mm改至20mm, hot again generate 流涎, made parts upper has again delamination peeling.

        3. improvement front rear 效果图 comparison

        4. focus/key point 提示

         cold material type can can 会引起 delamination peeling. cold material can can is material temperature low, nozzle temperature degree low, runner has cold material or cold material long degree 不足, hot runner temperature degree low, mold temperature degree low and other.

        五, 鼓包

         automotive 保险杠, surface has 鼓包, large solid 定, 位于行李箱 cover/cap sheet/plate for 应 转折位置, generate rate very high, generate 鼓包会 for its table/sheet quality generate defect effect/influence.

        1. material main/primary process parameters

        名称: automotive rear 保险杠材 material: PP+EPDM+TD15 color: black weight: 3800G gate methods: gate

        2. can can causes analysis and improvement measures

        1) products structure 方面: 观察鼓包位于行李箱 cover/cap sheet/plate for 应圆弧位置, left right 两边 圆弧都出现鼓包, rate has 差异;鼓包 has obvious 鼓起, has is light micro 凹凸不平, very difficult 发现, rear non obvious; using/adopting electrical in 600℃ lower 烘烤, light micro 鼓包迅 speed 鼓起. surface has light micro 凹凸不平 product, 剖开断面都看 to has 孔.

        2) products mold 方面: 鼓包位置 for mold separation has 开设排 gas 槽, injection molding process in gas difficult 以排出. therefore in mold upper increase gas 槽.

        3) molding process 方面: to 鼓包部位 for screw 位置, using/adopting low speed injection molding. most solution issues.

        3. improvement front rear 效果图 comparison

        4. focus/key point 提示

         using/adopting electrical 吹风烘烤, is types 辨别引起鼓包 causes methods. in, using/adopting electrical in 600℃ lower 烘烤, light micro 鼓包迅 speed 鼓起, is bubbles 引起.