substantially sulfur free thermoplastic pmma containing molding compositions are utilized with non - ferrous metal tools for the manufacture of molded articles . the use of such molding materials having a sulfur content of less than 50 ppm reduces the wear on the non - ferrous metal tools , particularly when utilized with injection molding and pressure molding . as a result of the use of sulfur free molding masses where it necessary to utilize tools of non - ferrous metal , there is a substantial economic advantage in the use thereof .