Injection molding parts with pinholes

摘要

A mold for molding thermoplastic parts having a plurality of pinholes wherein at least one of the mold cavities has a number of projections in the form of three-dimensional tapering shapes, for example, cones, which extend to a point near to but spaced from the confronting surface of the other mold half cavity. The taper of the angle of the projection and spacing between the apices of the projection and the surface of the other mold half are selected so that molten thermoplastic freezes before it covers the apices of the projections during the molding process to thereby form pinholes in the resulting plastic part. A method for molding plastic parts with pinholes with the use of the mold cavity with multiple projections is also disclosed.