針閥式熱流道模進料點處有白化現(xiàn)象,原因分析！

　　模具用的是mold master的閥針式熱流道。一模16穴，材料：PET%2B15%GF,產(chǎn)品澆口處經(jīng)常出現(xiàn)白色雜質(zhì)?，F(xiàn)我們采用降低螺桿溫度和主流道溫度，而增加熱流道嘴頭溫度，此問題有輕微改善，但連續(xù)生產(chǎn)中又會出現(xiàn)白色雜質(zhì)，求解方法！

　　什么樣的情況會發(fā)白，有氣體產(chǎn)生，

　　什么樣的情況會有氣體產(chǎn)生：

　　1：進點設計不合理，導致進點進膠速度較快，溫度過高，產(chǎn)生剪切稀化作用，塑膠分解產(chǎn)生氣體；

　　2：可以查看設計圖檔，看看進點處是否存在截面過小的現(xiàn)在；

　　3：料溫過高，還是導致塑膠在螺桿中產(chǎn)生熱裂解，產(chǎn)生氣體；降低料溫；

　　4：可能是優(yōu)先模的冷料打模面上，產(chǎn)生痕跡；后面每模都有復印現(xiàn)場產(chǎn)生；待擦拭母模面后再試模；

　　熱流道問題：

　　1.入點處溫度過高，熱咀隔熱不良。

　　2.熱嘴頭部溫度影響模具表面，測一下模具母模面溫度是否均勻

　　3.熱嘴本身溫度不均，造成塑膠流出模面，塑膠溫度不均，表面就會有熱影

　　The die is used the needle valve type hot runner mold master. A mold 16cavity, material: PET%2B15%GF, the gate of the product often appear whiteimpurity. We use lower screw temperature and the sprue runner tiptemperature, increasing temperature, the problem is slightly improved, but the continuous production will appear white impurity, solving method!

　　What kind of situation will be white, the gas is generated,

　　What kind of situation will have a gas generation:

　　1: the design is unreasonable, resulting into the point of glue feeding speed,the temperature is too high, the shear thinning effect, plastic decompositiongases;

　　2: you can view the design drawing, have a look into the point is too small nowexisting section;

　　3: the material temperature is too high, or cause plastic produce thermal cracking, in the screw to produce gas; reduce the material temperature;

　　4: may be generated traces of cold material first die mold surface, behind eachmodule has a copy; produce; to wipe mold surface and try again;

　　Heat flow problem:

　　1 into the high point temperature, hot nozzle insulation performance.

　　2 hot nozzle head temperature affect the mold surface, check whether the uniform mold mold surface temperature

　　3 hot nozzle itself caused by uneven temperature, plastic flow mold, plastictemperature is uneven, the surface will be hot.