Black spots are black spots or stripes on the surface of injection molded parts.
Reasons for the formation of black spots on injection molded parts

(1) Plastic overheating decomposition leads to black spots or streaks. Plastic in the closed barrel, screw surface stays too long, will lead to carbonization degradation, so in the injection molding process to produce black spots or stripes;

(2) The presence of dirty recycled materials in the plastic, foreign materials, other colors of materials or easy to degrade low molecular materials, may cause injection molded parts processing with black spots.
Injection molding parts processing black spot solution
1. Injection molding machine:
1) Choose the appropriate tonnage of the injection molding machine;

2) Check whether the inner surface of the barrel and the surface of the screw are scratched with accumulated material.

2. process conditions.
1)Reduce the temperature of barrel and nozzle;
2) Clean all parts of the injection molding process to avoid the black spot injection molded parts that have been produced to be recycled.