a process for manufacturing moldings of plastic material includes successive cycles of conveying a succession of mobile molding tool parts independently of each other along lateral and vertical guideways of a conveyor to a work station holding a basic molding tool part . each cycle includes the steps of joining the mobile molding tool part and the basic molding tool part together at the work station to close the mold cavity in the mobile tool part , dispensing the plastic material into the closed mold cavity from a dispensing device , imparting a predetermined temperature to the mold cavity to permit the plastic material in the mold cavity to harden into a shape - retaining molding , separating the basic molding tool part from the mobile molding tool part after the molding has hardened , conveying the mobile molding tool part holding the molding in the mold cavity thereof independently of succeeding mobile molding tool parts to at least one succeeding work station for further treatment , and ejecting the molding from the mold cavity .