Shanghai Daoqin Plastics Co., Ltd.

black spots, defect is in positive production process in generate waste product rate most important factors. it main/primary is effect/influence products appearance from 而导致报 waste. and large more black spots is outer material 质, and raw materials 本身无关, less separation black spots, is raw materials 本身造 formed.

black spots, 杂质特征 is pellets relatively small, 呈黑褐 color, generally light, pellets large 时杂质呈层状, 脆, easy 碎, rear more 孔, its distribution has large features: 1, has overall property random dispersion distribution, has is local random dispersion distribution, has 时则仅偶尔出现 in certain local 区域; 2, this category of black spots, has 时仅出现 in products table/sheet 层, has 时则不论 table/sheet deep shallow has, 不 距 table/sheet relatively internal black spots ratio table/sheet black spots color need shallow, more deep black spots 则根本看不 to. has is will this 两点联系起 会发现, 仅出现 in certain local 区域 杂质必然 is table/sheet black spots, black spots distribution table/sheet deep shallow is overall property random dispersion distribution. this is due to internal in 杂质必然 is molding front in, molding 时才出现 杂质必然 distribution in surface. this 样, 杂质就 separation is molding front and molding formed large type:

molding front black spots, formed 因:

raw materials processing 时, due to types types causes, material dry make raw materials black spots;

pelletizing pure formed black spots;

raw materials mixed masterbatch or belt/tape powder material block, material 屑;

material pure, low melting point material in mixed high melting point material 粒;

packaging, 运输, process in can can 出现杂质 mixed 入, it obvious is raw materials rear, fine 观察, can to in material pellets surface has material, 杂质;

add material process in 杂质, material lower is or upper material device and material 斗 简图;

造 formed products black spots, 杂质. 污染源包括: gas in 灰尘, material 状悬浮 material, material material 屑, material material 粒, powder masterbatch, color agent and other. is 杜绝异 material 杂质造 formed black spots, must add strong/high tube/pipe 理, control from raw materials 进厂至 add material step/link （包括回 use process ）. material 时, must fine can can material or 屑滞留 部位, especially material 箱, material 斗, 漏斗, lower 摆夹扣紧处 and other. positive production 时, need especially attention/notes add material material 箱 清洁. production rear, will add material system for outer ring 境暴露处 upper material tube/pipe upper material 端口密封, anti 污染, to ring ring versus 扣, tube/pipe 理.

raw materials carbon 化, this type of black spots generally relatively large, large black spots appearance can formed 12mm, more 数“ black spots ” relatively thick, has or relatively thin. this type of 情况就 is raw materials long material or local high hot, separation understanding, 焦化, carbon formed block. in screw or is nozzle and other flow 受剪切破碎 rear formed.

raw materials carbon causes has:

melt temperature degree high, material temperature high formed hot separation understanding, formed carbon material, especially is for hot property material temperature degree scope/range narrow, must control material 筒味部 temperature degree can high.

积 material 焦化: if melt plastics certain time long, 会出现焦化积 material, black spots, can can material 滞留 区域, has and 螺筒 连接处, 螺筒壁, ring, and gate 接触部位, hot runner 拐弯处, runner and other 部位.

material 筒间隙 large, and screw 间隙太 large, make material in material in 滞留, 而滞留 material long hot separation understanding, generate black spots.

additives drop, separation understanding color, additives anti-static agent, 紫/红 outer absorption agent and generally color agent, its property generally in ratio raw materials active 泼, in processing temperature degree force function lower, raw materials separation understanding 时, it already separation understanding, formed dark color, color black, molding formed black spots, 杂质.

production in outer causes generate black spots, non 常普遍, but also rear separation solid.

1, mold 材质不 good, separation type or molding or 碰穿面都会掉 iron powder, formed black spots.

2, coarse easy 烧, iron powder, formed black spots.

3, slip block abrasion iron powder, formed black spots.

4, slip block 里面漏 water or its it 污渍, and by slip block active 动飞出, in products upper formed black spots.

black spots 辨别:

如 black spots in products surface upper, made parts deep has black spots, belongs to molding front black spots; black spots in surface, molding in black spots. meanwhile distribution in surface 特定区域, belongs to molding in black spots 无疑; black spots relatively large （ generally in 0.5~1mm）, belongs to raw materials carbon black spots; meanwhile black spots dark, 脆, more 孔, can is carbon black spots: black spots density especially large, raw materials obvious 杂质, generally rigid material rear material dry phenomenon, 否则应查 material causes.

solution measures:

for molding 杂质, is material mixed material in formed black spots, must control production, packaging, 贮藏, 运输, 开报, mixed material material 筒 各 step/link 清洁.

for carbon black spots, 应严格 control processing temperature degree, production in, table/sheet processing temperature degree and processing temperature degree is has 差别. for equipment 而言, different back pressure, different cycle time, different one-time property injection shot amount, different hot electrical 偶插放位置, formed processing temperature degree lower material carbon 化, degradation trend different. specific 说, table/sheet temperature degree versus meanwhile, back pressure small, cycle short, one-time property injection shot amount large, hot electrical in upper 部时, material drop / separation understanding trend low, easy generate carbon black spots.

anti carbon black spots meanwhile need anti material, need remove 螺筒, nozzle, runner in 死角, make its 转弯处 has 平缓 渡, remove can can has material 滞留 区域.

for/regarding additives degradation or already has carbon material in 螺纹面 and 螺筒壁 upper black spots. generally production 进行, this black spots in inner various strong/high force function lower its 原先附 面进入熔 material in by 排出. this type of “排出” process is products black spots, process. material color production in, this type of “排出”杂质 process is 必然, need force shrink short this type of process. is “清洗”. lower is types methods:

（1） for 空熔胶清洗 screw （熔胶 rear 空射）.

（2）进射台熔胶, for 空射胶, again 进射台熔胶, for 空射胶, 如此反复进行, 实践证明: in, back pressure to very large function, material and screw strong/high force 剪切. speed degree slow, therefore time long. this 样 效果 good, 清理异 material speed. attention/notes: back pressure in 没定时 has 原则尽 amount high, high to rigid good 不会自动 rise temperature is 止.

（3） for/regarding molding in black spots, molding in black spots 必定先附于 type surface, rear by material solid products surface, therefore this type of black spots remove method and has let it in type in. for 确定材质 defect mold, also need 先确定 causes, 确定位置. has has versus for type 腔, 模芯包括 slip block, in 子, 顶针/ block, has can can 烧伤, 确定烧伤 rear, need 修复破 loss 部位, another need decrease small sliding 部位 摩 scratch, add lubricated 油. another, need decrease small sliding versus for speed degree, 如顶进/退, clamping, slip block 移动时尽 amount need slow, slip block and sheet/plate 间生锈 and its it 污渍, need lower slip block, will and its it 污渍清 remove dry 净, will water 咀扎紧. for/regarding or water to mold cavity light slip molding 面, formed black spots 应该经常 scratch easy 出油, water 处, its in molding upper 出现.