Overmolding Insert molding in China

Cnmoulding12 Dec, 2025Technology

In plastic injection molding, a sink mark is a surface defect that appears as a depression, dimple, or dent on the surface of a molded part. It typically occurs in thicker sections of the part or near features like ribs, bosses, or other areas where there is a significant variation in wall thickness. Sink marks are caused by uneven cooling and shrinkage of the plastic material during the molding process.