after heat treatment, the machined inserts are finished, ground and polished to obtain a good surface quality,because the surface conditions of a cavity are, in the end, responsible for the surface quality of a plastic part and its ease of release. Defects in the surface of the cavity are reproduced to different extends depending on the molding material and processing conditions. Deviation from the ideal geometrical contour of the cavity surface, such as ripples and roughness, which increase the necessary release forces.