Apparatus and method for forming a plastic sheet

摘要

A method and apparatus for forming a continuous extrudate of a heated soft thermoplastic material into a continuous sheet of a cooled rigid thermoplastic material having a plurality of recesses formed in one surface thereof and a plurality of projections formed on the other surface thereof by feeding successive portions of a heated soft extruded thermoplastic material onto successive portions of a forming cylinder having a generally cylindrical outer peripheral surface having a plurality of recesses formed therein and applying a vacuum through the recesses to draw areas of successive portions opposite to the recesses into conformation with the recesses and cooling the thermoplastic material by moving a cooling fluid over the inner peripheral surface of the forming cylinder and removing the successive portions to form a continuous sheet of a rigid thermoplastic material having a plurality of recesses formed in one surface thereof and a plurality of projections formed on the other surface thereof.