Why use baked plastic raw materials?

Why use baked plastic raw materials?

ABS, PC, PA6 types of plastic raw materials need to be baked, but PP, TPO, POM types do not need to be baked?
In the injection molding process, the moisture content of the material must be in a relatively low range to ensure the normal injection molding and the normal physical properties of the product material. The moisture content of the injection material is too high. First, the surface will appear bad appearance such as silver wire. Second, the water vapor in the material will cause bubbles and holes in the product, which affects the strength. Third, the most important thing is that the high water content will cause the material to decompose when it melts.

Therefore, the material must be dried before injection. The moisture absorption rate of ABS, PC, PA6, PA66 and other materials is relatively large. The direct injection molding of the original packaging is not a big problem, but tens of kilograms of materials in the barrel cannot be done all at once. , In the process of several hours to ten hours, the moisture in the air will be absorbed by the material. However, PP, TPE, and POM have relatively low moisture absorption rates, and they will absorb less moisture for a long time under ambient temperature and humidity. The moisture absorbed can be within the allowable range of the injection molding machine working process and has little effect on injection molding.
Of course, a small impact does not mean that there is no impact, because although it does not absorb much moisture, it still absorbs water after all. In mass production, it is best to turn on the dryer for the stability of product quality when it has been produced continuously for many days.

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