Why do injection molded parts suffer from scratch marks

Q: Why do injection molded parts suffer from scratch marks?

Answer: The bad appearance of scratch marks in the injection parts is mainly caused by excessive friction between the wall and the corners of the mold in the demoulding process after the completion of the injection molding.Plastic parts produce excessive friction reasons, most of the plastic parts with insufficient demoulding slope, insufficient structural strength of the mold, mold damage, or injection molding machine efficiency and injection parameters adjustment.