plastic 3D printing--3d Printing Rapid Prototype,plastic 3D printing Rapid Prototype. Plastic mold is a combination mold used for compression molding, extrusion molding, injection molding, blow molding, and low foam molding. The coordinated changes between the convex and concave molds of the mold and the auxiliary forming system can process a series of plastic parts with different shapes and sizes. Plastic Mould Start from part design analysis.