Dalian hollow molding plastic products commonly used molding material: Polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), poly (ethylene terephthalate) (PET), polystyrene (PS), polycarbonate (PC), and linear low density polyethylene (LLDPE), high molecular weight polyethylene (DPIM) etc. resin. After molding cooling shrinkage and the compact core package, in order to facilitate mold release, to avoid the appearance of white top, top injury and drag phenomena, WIP inner and outer wall parallel to the parting direction should be with certain ejection angle. The release angle is related to the properties of the rubber, the shape of the rubber and the surface. Plastic products, such as lubricants, plasticizer, etc., the release angle ratio does not contain a small number of.