Lapping apparatus and process with raised edge on platen

Abstract

Lapping or polishing at high speeds with fine abrasive particles offers significant advantages in the speed of lapping, savings of time in lapping, and smoothness in the finished articles. An improved lapping system comprises a lapper platen system comprising a rotatable platen having I) a back surface and ii) a front surface, wherein the front surface of the rotating platen facing a work piece has a flat plateau or raised area which is continuous around a perimeter of the front side of said platen and the plateau is elevated with respect to a central area on the front surface. The front surface optionally has vents for air, the platen optionally has a back side to which a shaft is connected (directly or through intermediate connections) to rotate the platen and there is a front side on the platen to which is secured an abrasive sheet by reduced air pressure conveyed through said vents. The back side of the work piece holder is also optionally pivotally connected to a rotating joint which is in turn connected to a shaft which rotates said work piece. It is preferred that a frame for the system has a total weight of at least 200 kg supporting a work piece holder. It is also preferred that the work piece holder is movable on said frame. It is most preferred that the platen is rotated at a rotational velocity sufficient to generate a surface speed of at least 4,000 surface feet per minute (or even more than 20,000 surface feet per minute).