What Is The Reason For The Black Spots Produced By The Plastic Pellet Machine?

The problem of black spots in the processing process of plastic granules is a common machine error, especially for colorful and light-colored products. In the granulation process, it is a very common problem to encounter black spots from the extracted granules. How to treat the problem of black spots in the granulation process of plastic granulator?

One: There are printing ink compounds on the surface of the plastic

If there are printing ink compounds on the surface, when passing through the stainless steel screen, if the size of the screen is too small, the printing ink can pass through the stainless steel screen, causing the particles to be pumped to produce black spots visible to the human eye. Solution: Replace the stainless steel screen with a larger mesh, or install the stainless steel screen carefully and carefully, so that there is no gap between the stainless steel screen and the template.

Two: There are miscellaneous spots in plastic materials, especially black raw materials

This black plastic is cut, mixed and melted in the pelletizing ball screw, which will produce black-like marks on the surface or inside of the pellets. Solution: Before granulation, the black plastic is picked out manually or by a color picker.

Three: The carbonization of plastic in the plastic granulator causes black spots

This kind of situation is more serious, why sometimes the granulation of raw materials modified materials also produces black spots? This is because the plastic melt has a strong adsorption effect on the plastic granulator, and it is unlikely to be eliminated every time it is turned off, and then there will always be a thin layer of plastic melt that is firmly adsorbed on the plastic granulation of the plastic extruder. Inside the machine and the engine and on the ball screw, after the shutdown, the system will automatically evaporate and cool down and in the next heating process, it will gradually turn yellow and focus to become cementite. Solution: According to the traditional shutdown method, no corresponding closing measures have been taken on both sides of the die opening and the discharge opening of the engine, which causes the air to enter the machine and causes oxidation, which promotes the thermal deterioration of the residual plastic in the machine, and provides favorable conditions for carbonization.