a compression molding process for forming an article , preferably a preform or closure , is provided . the process includes the steps of forming thermoplastic resin into a precursor , wherein the precursor fits in a compression mold and has a shape for allowing the precursor to be supported in a predetermined or dimensionally preheld manner in a cavity of the compression mold prior to being compressed into a final shape , which shape is the shape of the compression mold ; heating the precursor ; and compression molding the precursor into the article while said precursor is heated . the step of forming may include the steps of extruding the resin into sheets ; cutting discs from the sheets ; and stacking the discs to form the precursors .