a machine for molding bonded plastics material , in particular expanded or foamable polystyrene in combination with rigid sheet polystyrene , wherein the rigid material is preformed in a preforming station in a preforming mold while simultaneously separating by a cutter the preformed portion from the rigid sheet of starting material to produce separate preformed pieces , the preformed pieces are moved by a transfer table to a molding station while retained on preforming half - mold , foamable material is fed to molding mold and molded and bonded on the preformed pieces with sintering by pulse action of steam and , the final molded articles are discharged at discharge station . the half - mold is moved alternately between the preforming station and molding station , and cooperates with respective counter - molds . the scrap is recovered without being involved in the molding stage . the various parts of the machine are controlled by a control device for continuous synchronous cyclical operation .