Shanghai Daoqin Plastics Co., Ltd.

        01, mold temperature degree setting

         mold temperature degree for crystallization degree and molding shrinkage has effect/influence, mold temperature scope/range in 80~120℃.

         selection high mold temperature, crystallization degree high, wear resistance, hardness, elastic property modulus increase, water property decline, products molding shrinkage increase, combined for strong/high degree and rigid property requirements relatively high products; products thin difficult molding 时, need using/adopting relatively high mold temperature, for mold 进行一定 add temperature control.

         selection low mold temperature, crystallization degree low, tough property good, elongation relatively high, shrinkage rate decline, combined transparent property good or for flexibility property requirements relatively high products.

         if thick large 于3mm, use 20~40℃ low temperature mold. for/regarding glass fiber reinforcement nylon material, mold temperature degree large 于80℃.

        02, material temperature degree setting

         generally lower, PA6 material temperature degree most low is 220℃, PA66 is 250℃. material temperature low, material can full melt, its hard pellets or fiber can can loss mold and screw, material temperature high easy make made parts color 变, and silver streaks and other. injection molding selection material temperature degree comprehensive resin property can, add pellets or fiber, equipment, products factors and other.

         due to nylon heat stabilized property relatively 差, therefore high temperature long time in material in 停留, 以免引起 material material color 发黄, meanwhile due to nylon melt flow property relatively good, therefore can using/adopting relatively fast injection speed degree.

        03, glass fiber (GF) content and shrinkage rate 关系

         in nylon injection molding process in, reduce mold temperature degree, add large injection pressure, reduce material temperature in 一定程 degree upper decrease small nylon shrinkage rate, most significantly methods is add glass fiber (GF).

        例如PA66 shrinkage rate in 1.5-2% between, PA6 shrinkage rate is 1%~1.5%, in add glass fiber (GF) rear can make shrinkage rate reduce to 0.3% left right.

         glass fiber (GF) add amount more, nylon molding shrinkage small. is glass fiber (GF) add amount more formed surface fiber exposure, versus property and other rear 果, glass fiber (GF) content generally in 30% left right 时效果 versus for relatively good. lower table/sheet is 一份由 experience to “ glass fiber (GF) content - molding shrinkage ” table/sheet.

        04, gate and gas

         gate 孔径不 need small 于0.5×t(t is parts thick degree), use 潜入式 gate, gate most small 直径应当 is 0.75mm.

         nylon resin value is 0.03mm left right, therefore gas dimensions control in 0.025mm below/following.

        05, its it precautions

        (1) recycled material use most good ultra- 三次, 以免引起 products color or machine physical properties decline, recycled material add amount control in 25% below/following, more 会引起 process conditions 波动, recycled material and new material mixed combined must drying.

        (2) use a small amount of demolding agent has for bubbles and other defect has improvement and remove function. nylon products demolding agent can selection hard acid zinc and and other, can mixed combined formed use, use must amount less uniform, 以免造 formed products surface defects.

        (3)开 machine 时应首先开启 nozzle temperature degree, rear in to material add temperature, nozzle retardant 塞时, 切忌面 for 喷孔, anti material inner solvent pressure poly 集而突然释放, 发生危险. in machine need screw, anti lower production 时, 因残存 material 而发生扭断 screw phenomenon.

         modified nylon injection molding products rear 处理

        01, hot 处理

         hot can remove products internal stress, can utilizing material 油, 甘油, liquid wax and other high liquid for products hot 处理, hot temperature degree high use temperature degree 10~20℃, time products thick 而异, thick degree in 3mm below/following is 10~15 separation 钟, thick degree is 3~6mm time is 15~30 separation 钟, hot products attention/notes slow cooling room temperature, anti cold products in internal stress heavy new formed.

        02, wet 处理

        调 wet main/primary is for use ring wet degree relatively large products 而进行, its method has types: is 自然调 wet method;二 is acid water solvent liquid wet method (醋 acid and water ratio/proportion is 1.25:1, 沸点121℃).

        自然调 wet method 简便, need will products in wet degree is 65% ring lower, make its to balanced wet amount can, time relatively long;而醋 acid water solvent liquid wet method temperature degree is 80~100℃, time main/primary products thick, thick is 1.5mm时约2 small 时, 3mm时约8 small 时, 6mm时约16~18 small 时.

         modified nylon products Common defect and 处理

        01, injection molding pressure unstable

         generally injection molding machine 射嘴孔 small has 关. mold temperature degree generally is 20~90℃, temperature degree generally is 240~280℃, easy hot 交换. 当射嘴 temperature degree drop to nylon melting point below/following 时, 射嘴孔 by 冻结, again injection 时, need more large injection molding pressure 冲开, formed pressure loss 失. from phenomenon is injection molding machine injection molding unstable, its is 射嘴孔 small. add large 射嘴孔, this type of phenomenon 就会消失. Common 于PA, POM, ABS production process.

        02, 波浪形 flow marks

         melt in mold cavity inner speed slow, rear material has method mold.

        (1) improve/increase injection speed degree;

        (2) improve/increase mold temperature degree and material temperature degree;

        (3) increase 射嘴孔径 or gate.

        03, silver streaks

        塑化 good material in has gas 体, in injection gas in mold surface by strong/high pressure 出, in products surface white filament 纹.

        (1)检查 is raw materials wet or 污染;

        (2)检查 raw materials is in material separation understanding;

        (3)检查射嘴孔 is small;

        (4)检查 is mold temperature low;

        (5) mold gas defect;

        (6) gate dimensions is small.

        04, 熔接痕

         flow 末端胶 material temperature degree very low, pressure low, material combined property relatively 差, material combined 不紧密.

        (1) improve/increase injection pressure and speed degree;

        (2) improve/increase mold temperature and material temperature;

        (3) improvement mold.

        05, 焦斑

         injection material high speed mold cavity, mold cavity inner gas 体 不 and troubleshooting 时, this separation gas by pressure shrink, gas pressure shrink rear rise temperature products 烧焦.

        (1) reduce injection molding speed degree or pressure;

        (2) reduce melt temperature degree;

        (3) improvement mold gas;

        (4) decrease small clamping force;

        (5) increase large 射嘴孔径.

        06, demolding difficult

        (1) mold temperature control 不当, shrinkage 不均造 formed force 不均;

        (2) products inner injection residual stress large, generate large force make demolding difficult;

        (3)检查 mold 拔模斜 degree.

        07, warpage deformation

        (1) reduce injection pressure and time, reduce holding pressure pressure and time;

        (2) improve/increase material temperature and mold temperature degree.

        08, nozzle 流涎

        (1) add large screw rear 抽;

        (2) reduce material temperature and nozzle temperature degree;

        (3) raw materials separation drying;

        (4) screw add ring.