Shanghai Daoqin Plastics Co., Ltd.

         speed degree injection

        当 mold cavity 未填满 front, injection pressure (from pressure table/sheet 读出) is very low, is need 克服喷咀, runner and mold cavity inner melt flow retardant force can. this 情况持续 to mold cavity 填满100% is 止.

         injection molding machine pressure control is pressure upper control, certain injection pressure is 90 bar, table/sheet pressure can ultra- 90 bar, in 90 bar below/following is pressure, is melt retardant force 决定. this pressure can in injection from pressure table/sheet 读出. 故此, in mold cavity 未填满 front, injection molding machine can pressure control, can use speed degree control.

         pressure retardant force, retardant force is injection molding machine control.

         injection molding product stability property and injection speed degree stability property 则息息 related. full ring injection is 以每段 injection need to injection speed degree is 目. injection pressure 设置, using/adopting system pressure, is 如140 bar or 160 bar most high pressure. has pressure can ensure injection can has control speed degree.

         due to mold cavity 未满, high pressure 设置不会 is generate flash/burrs causes.

         mold cavity rear table/sheet injection process 就结束, also need pressure. its injection and its it molding methods most different 之处便 is high injection pressure. 此 pressure usually is in 1000 to 2000 bar between. need in upper most deep deep 渊底, water pressure and 2000 bar.

        挤 pressure is melt pressure shrink amount and screw injection generate, can formed is ultra- 满充填, versus mold cavity several separation 点 熔 melt in mold cavity rear again by 挤进, make pressure rise.

        挤 pressure its is most rear injection, has pressure need control injection pressure, 设置一 upper 限, anti flash/burrs generate. pressure 结束, to holding pressure.

         holding pressure function

         holding pressure function is its melt cooling or solid shrinkage 时, maintain pressure, 继续注入熔 melt shrinkage 空间, decrease/reduce or 避免凹痕 generate.

         holding pressure setting pressure can ultra- 挤 pressure setting pressure, flash/burrs has can can in holding pressure generate. more holding pressure pressure is decline, 而理想 decline is property drop, non grade property decline, combined shrinkage need.

         due to shrinkage slow, screw front speed degree is slow, 2% speed degree 便足够. injection molding machine energy saving, main/primary is in holding pressure will 泵 流 amount low to 3% left right, amount is 100% 定 amount ratio, 节省 97%.

         holding pressure time long （壁 thick ultra- large ）, electrical consumption more. from can 知, holding pressure 时 需 control pressure can control amount, shrinkage rate is injection molding machine control. this is and injection front rigid good versus 反.

         about/regarding holding pressure time more long, production weight again upper rise, holding pressure can 停止. lower 一步便 is 塑化. it and cooling time is meanwhile 开始.

        判断 mold cavity 填满, can holding pressure is separation injection (含挤 pressure) and holding pressure screw 位置. as need holding pressure 点, is mold cavity 填满时 screw 位置, has below/following types methods:

        1, 理论计算

        如 d= screw 直径, s= screw 行程, w=塑 parts weight (含 cold runner weight), ρ= plastics room temperature density

        则 has: w=(πd2) / (400) × s / 10 × 0.85 × ρ (its in 0.85 is 系数).

        故 s = (4000w) / (0.85ρπd²) = (1497.9w) / (ρd²)

        而 holding pressure h = p - s, p=塑化完 screw 位置

        2, mold cavity 填满时, screw front speed degree 会骤然 drop lower

         this can from injection molding machine screw (machine 械)指针 in injection and holding pressure 时观察出, from rear 面 纸尺读出 slow lower that screw 位置, will this setting is holding pressure value.

        3, in injection and holding pressure 时, system pressure table/sheet

        当 mold cavity 填满时, pressure pressure rise. 此时读出指针 or electrical 脑显示 screw 位置, will this 位置设置 is holding pressure value. this methods 适宜于 injection speed degree slow thick injection molding.

         pressure and speed degree control selection

         injection molding machine as

         from as 层面, injection and holding pressure has lower same 之处.

        1, remove use injection 伺服阀, injection direction in injection and holding pressure is 打开, its 间不会关闭(当然亦不会转 toward).

        2, in electrical 脑屏幕 upper, injection and holding pressure has speed degree and pressure control.

        3, injection separation 段, although screw 位置区 separation most is 准确, can use time separation (称 is time injection), and holding pressure separation same.

        故 has as use holding pressure use injection rear or rear 几段做 holding pressure.

         attention/notes: injection and injection selection time injection, this made injection and injection 二(挤 pressure 段) can using/adopting time injection, can use relatively 精确 位置 injection separation.

         electrical injection molding machine has below/following function:

        1, in 位置+ time 模式 lower, can injection time upper 限. injection upper time to rear screw also to holding pressure 点, process also is to holding pressure. this in more injection molding has mold cavity runner 堵塞便会出现. using/adopting holding pressure 段时, use upper 此模式, can use time injection.

        2, in holding pressure 点 front rear scope/range outer has 两 报警区, screw to 位区称 is 欠注区, screw holding pressure 点 称 is material 区. 两者都 has machine generate waste product, notice as 员于以处理. using/adopting holding pressure use upper function.

        如 electrical can provide holding pressure 段 线 property drop pressure, using/adopting holding pressure use upper function. precision and thin injection molding using/adopting ring control. ring control injection use speed degree control, pressure pressure upper control, holding pressure use pressure control.