Shanghai Daoqin Plastics Co., Ltd.

injection molding speed degree ratio/proportion control already by injection molding machine manufacturing 商广泛 using/adopting. although electrical control injection molding speed degree separation control system already in, due to related material has 限, this type of machine advantages very less to 发挥. will system application more speed degree injection molding advantages, 并概括 introduction its in remove short 射, gas, sink marks and other products defect upper applications.
    speed degree and products quality 密切关系 make it formed is injection molding key/critical parameters. through filling speed degree separation 段 开始, in 间, 终,并 achieve 一 设置点 to 另一 设置点 light slip 渡, can ensure stability melt surface speed degree manufacturing 出期望 separation 子取问 and most small internal stress. 我们建议 using/adopting below/following this type of speed degree separation 段原则: 1）流体 surface speed degree is 常数. 2）应 using/adopting fast speed anti 止射胶 process in melt 冻结. 3）射胶 speed degree 设置应考虑 to in 临界区域（如 runner ） fast speed meanwhile in water decrease slow speed degree. 4）射胶 speed degree ensure mold cavity rear 立即停止以 anti 止出现 filling, flash and residual stress.

    setting speed degree separation based on must to mold 几何形状, its it flow made and unstable factors. speed degree setting must for injection molding process and material Knowledge has relatively 清楚 认识, 否则, products quality will difficult control. is melt speed difficult 以直接测 amount, can through amount screw front speed degree, or type pressure 间接推算出（确定止逆阀没 has 泄漏）.

    material features is non important, is polymer can can due to force different degradation, increase temperature degree can can 导致剧烈 oxidation and chemical structure degradation, meanwhile 由剪切引起 degradation small, is high temperature reduce material viscosity, decrease/reduce 剪切应 force. 无疑, more 段射胶 speed degree for molding 诸如PC, POM, UPVC and other for hot 敏感 材 material and it 们 调配 material very has 帮助.

    mold 几何形状也 is factors: thin need most large injection speed degree; thick parts need slow — fast — slow type speed degree 曲线以避免出现 defect; is ensure parts quality combined standards, injection molding speed degree 设置应 ensure melt front speed 不变. melt flow speed degree is non important, is it effect/influence parts in separation 子排列 direction and surface 状态; melt front to 达交叉区域 structure 时, decrease speed; for/regarding 辐射状 expand dispersion complex mold, ensure melt through amount increase; long runner must fast speed filling decrease/reduce melt front cooling, injection high viscosity material,如PC is outer 情况, is fast speed degree will cold material through water belt/tape type 腔.

    adjustment injection molding speed degree can 帮助消 remove due to in water 口位出现 flow slow 而引起 defect. melt 经 射嘴 and runner to water 口时, melt front surface can can already cooling solid, or due to runner 突然变 narrow formed melt 停滞, to 建立起足够 pressure melt 穿 入 water 口, this make through water pressure 出现峰形. high pressure will loss material formed flow marks and water 口烧焦 and other surface defects, this type of can through rigid good in water front decrease speed methods upper defect. this type of decrease speed can anti water degree 剪切, rear again will speed improve/increase to 原 数 value. is control speed in water decrease slow is non difficult, therefore in runner decrease speed is relatively good solution/scheme.

    can through control 末段射胶 speed degree or decrease/reduce flash, 烧焦, gas and other defect. filling decrease speed can anti type degree filling, 避免出现 flash and decrease/reduce residual stress. due to mold 流径末端排 gas defect or filling issues 引起 困 gas, can through reduce gas speed degree, especially is 射胶末段 排 gas speed degree add solution.

    short is due to water speed degree slow or melt solid formed local flow retardant and other causes generate. in rigid rigid through water or local flow retardant add fast speed degree can solution this issues.

flow marks, water 口烧焦, separation 子破裂, 脱层, and other in hot property material upper defect is due to through water degree 剪切造 formed.

    light slip made parts 取决于 injection molding speed degree, glass fiber filling material especially 敏感, especially is nylon. dark 斑（ waviness ） is due to viscosity 变化造 formed flow unstable 引起. flow can waviness or non-uniform 雾状, generate types defect 取决于 flow unstable degree.

    melt through water high speed injection 会导致 high 剪切, hot property plastics will 出现烧焦, this type of 烧焦 材 material type 腔, to flow front 锋, in parts surface.

    is anti 止射纹, speed degree 设置必 must ensure fast speed filling runner 区域然 rear slow speed through water 口. this speed degree 转换点 is issues essence. if 太早, filling time degree increase, if 太迟, large flow property will 导致射纹 出现. melt viscosity low, material temperature degree high this type of 射纹出现 trend obvious. due to small water need high speed high pressure injection, therefore is flow defect important factors.

    sink marks can through more has pressure 传递, more small pressure drop improvement. low mold temperature and screw speed degree slow large shrink short flow long degree, must through high speed 补偿. high speed flow decrease/reduce hot amount loss 失, and due to high hot generate abrasion scratch hot, formed melt temperature degree rise high, decrease slow parts outer increase thick speed degree. type 腔交叉位必 must has thick degree 以避免太 large pressure drop, 否则就会出现 sink marks.

    总之, large more injection molding defect can through adjustment injection molding speed degree to solution, therefore adjustment injection molding process tips/techniques is combined 理 设置射胶 speed degree and its separation 段.