Pressing of reinforced thermosetting polymer articles

The process of pressure molding a charge of reinforced thermosetting polymeric material into a molded piece comprising exerting pressure by relative movement of a pair of mold elements toward one another and said charge of material within a mold cavity, substantially simultaneously subjecting said charge of material to internal heating by dielectric losses under high frequency, maintaining said internal heating during formation of a molded piece under pressure, and until said molded piece is cured, all the while bringing the core of said molded piece to a prescribed temperature, said mold elements being thermally isolated from outside ambient conditions and having a calorific capacity at least equal to that of the material from which said molded piece is formed whereby heat transmitted from the mold cavity by conduction is stored in said mold elements, and using the mold elements as an external heat source to at least partially heat the next charge of said material as soon as it is introduced to said mold cavity after removal of said molded piece.