What is the reason for the black spots in the plastic granulation process of the twin-screw extruder

Why does the twin-screw granulator encounter black spots during the granulation production process? I think many friends are quite annoying when they encounter this problem. In this way, our production progress will be affected, and more raw materials will be wasted, and the time and energy will be spent in vain, which is not worth it. Let's analyze it with you below.

​

​There are several reasons for the black spots of the twin-screw granulator:

1. The quality of the raw material itself is relatively poor, and there are too many black spots;

2. Partial overheating of the screw or too strong shearing, resulting in aggravated carbonization of the material;

3. The pressure of the technical head is too high, and the carbonization of the material is aggravated when there is too much reflow material;

4. The service life of the machine is relatively long, the gap between the screw and the barrel increases, and the carbides adhered to the barrel wall increase;

5. Die cleaning is not clean;

6. The outlet is not smooth enough, and the accumulated material may be gradually carbonized for a long time;

7. Part of the original thread is damaged, resulting in increased carbonization of the material at the dead corner.

In fact, the main reasons for the black spots are these reasons. In addition to these reasons, it is also very important to choose a suitable twin-screw granulator.

Nanjing Tengda Machinery Co., Ltd. is a gaint manufacturer of Application, which is one of the most outstanding product produced from us.
Nanjing Tengda Machinery Co., Ltd. aims to hire several additional experienced marketing professionals that can add to our existing talent-pool and help continue the steady growth of our business.
Nanjing Tengda Machinery Co., Ltd. really created a whole persona around Application’s manufacturing and selling, and it's so innovative that people really respond to it.