Shanghai Daoqin Plastics Co., Ltd.

        当塑 parts surface quality due to has 熔接痕达不 to design requirements 时, technology usually from material temperature degree, injection speed degree, pressure, amount, mold temperature degree and other 方面入手 solution.

         usually material temperature degree, injection speed degree, pressure, amount, mold temperature degree adjustment through equipment achieve, molding conditions standards small degree adjustment,逼近理想 value.

        显然,熔 material temperature degree, flow speed degree, pressure, amount, mold temperature degree this can through equipment adjustment project is comparison easy achieve, 一方面 adjustment 起 方便, 另一方面 can more 次反复. difficult in above already method solution 时, 就不 不 through mold methods achieve 预期效果, this is need discussion focus/key point.

         need mold can can has below/following types:

        (1)熔接痕处夹 has bubbles, need in for separation type increase gas 孔.

        (2) 熔接痕 deep degree ultra- 差, need adjustment parts mold type thick degree.

        (3) 熔接痕 位置偏 toward parts in 部, need adjustment gate 位置.

         lower for above 3 types improvement process separation 别进行叙述:

        熔接痕处 bubbles formed is due to 当两股熔 material 汇流时, gas has and troubleshooting, in parts internal, in 熔接痕 surface formed 凹坑, can 通俗 称之 is “困 gas ”.

        究 its causes, can can is for 应位置 separation type 面研配 紧, gas method 排出; can can is clamping rear, type high degree dimensions degree non-uniform (塑 parts thick versus relatively large) formed. for front types 情况, through increase or increase large gas improvement, currently inner application most PP material is 例, according to PP material material is 0. 03 mm this parameters, is 避免溢 material formed flash, gas 槽间隙 is 0. 01 ～ 0. 02 mm most 理想.

         is mold processing and molding process in type 腔 清理, gas 槽 位置 more 数情况会 selection in separation type upper, amount in type most rear 充满处. for/regarding type high degree dimensions degree non-uniform 情形, can through “补焊” and “打 abrasion ” methods adjustment type dimensions, this is difficult degree most large, is mold technology in debugging in most to, it adjustment methods and lower need to 熔接痕 high degree ultra- 差 adjustment methods 一致.

        当 through adjustment equipment process parameters and gas methods method improvement or remove parts due to 熔接痕导致 quality defect 时, very can can 不 不 adjustment type dimensions, need for parts versus thick degree 进行准确 测 amount rear, in design scope/range inner as 业.

        保险杠塑 parts thick in different 部位并不 is and other value, is 一 渐变 amount, its causes is to parts specific and melt plastics flow property, 渐变 壁 thick has molding. thick usually in 2. 60～3. 50 mm.

         mold type dimensions separation 2 types 情况一 types is increase large type dimensions, types is decrease small type dimensions. for/regarding types achieve relatively easy, according to testing data for mold type versus 应部位实施打 abrasion can. types 情形就 comparison complex, is to decrease small type dimensions 目, need in mold type upper 堆焊, rear abrasion. lower specific introduction decrease small mold type dimensions methods.

         from as difficult easy degree upper, 首先考虑 selection in upper 进行“补焊” and “打 abrasion ”会 ratio in upper easy more. due to injection 模 定模 type quality effect/influence to parts appearance, welding process in has a large amount of hot generate, has separation process measures ensure 时, this hot amount 往往会改变 type 腔面 组织 formed separation, type hardness different, effect/influence parts appearance, in need amount 避免定模 type 腔面 修改.

        动模 type 腔面修改 generally steps lower:

        (1) through in type 腔面贴胶 methods mold trial, large 致 出 type need increase decrease thick degree.

        (2) 实施“补焊” and “打 abrasion ” as 业.

        (3) again mold trial, according to molding adjustment type dimensions.

         its in 第二步 is difficulty/challenge and key/critical, below/following is type 腔面修补 detailed process:   

        a.选定 and versus welding material, 并确定 welding scope/range, 预留并保护 good abrasion 基准.

        b. separation 区交替堆焊, attention/notes need from to 尾, internal stress formed mold type 腔面裂 loss.

        c. for 照预留基准, 开始打 abrasion, attention/notes good related 部位 保护.

        d.测 amount 补焊面 high degree, to requirements rear, will 基准空位焊满, molding 腔面 修改.

        熔接痕 defect analysis

        熔 melt plastics in type in due to to parts, 孔洞, speed 不连贯 区域, material in 断 区域而以 more 股形式汇 combined and gate 喷射充模时, can full melt combined generate 线状 熔接痕. 熔接痕 存 in large low products machine strong/high degree. 克服熔接痕 办 method and decrease/reduce products methods basic same.

        一, equipment 方面

        塑化 defect, melt temperature degree 不均, can long cycle, make more full, necessary more 换塑化容 amount large machine.

        二, mold 方面   

        (1) mold temperature degree low, 应适当 improve/increase mold temperature degree or has improve/increase 熔接缝处 local temperature degree.

        (2) runner fine small, or shallow, cold material small. increase runner dimensions, improve/increase runner efficiency, meanwhile increase cold material 井 容积.

        (3) expand large or shrink small gate 截面, gate 位置. gate need amount melt in parts, 孔洞 周围 flow. 发生喷射充模 gate need method positive, or add block 缓冲. amount use or less use more gate.

        (4)排 gas defect or has gas 孔. 应开设, expand or hydrophobic gas 通道, its in utilizing parts, 顶针缝隙排 gas.

        三, process 方面  

        (1) improve/increase injection pressure, long injection time.

        (2)调 good injection speed degree: high speed can make material and drop temperature to combined 处, low speed can let type inner gas has time 排出.

        (3)调 good machine and nozzle temperature degree: temperature degree high plastics degree small, 流态通畅, 熔接痕变 fine; temperature degree low, decrease/reduce gas material separation understanding.

        (4) demolding agent amount less use, especially is silicon demolding agent, 否则会 make material can melt combined.

        (5) reduce clamping force, 以利排 gas.

        (6) improve/increase screw speed, make plastics degree decline; increase back pressure pressure, make plastics density improve/increase.

        四, raw materials 方面  

        (1) raw materials drying amount decrease/reduce formulation in liquid additives.

        (2) for flow property or hot property high plastics 适当添 add lubricant and stabilizer, necessary use flow property good or heat resistant property high plastics.

        五, products design 方面  

        (1)壁 thick small, add thick made parts 以免 早 solid 化.

        (2)嵌 parts 位置不当, adjustment.