Surface roughening of powder metal parts

Abstract

It has been found that metal parts having rough surfaces can be manufactured by (1) compacting a metal powder under high pressure in a mold to make a green part, wherein at least one face of the mold is roughened by electrical discharge machining to have an Ra of 10 to 200 micro-inches, as measured with a profilometer having a stylus tip, (2) heating the green metal part to a temperature of at least 1500° F. to sinter the green metal part to produce the metal part having at least one rough surface, wherein the rough surface has an Ra which is within the range of 10 to 200 micro-inches, as measured with a profilometer having a chisel tip, and (3) optionally, buffing, classifying, deburring and/or washing the metal part. This method can be beneficially used in manufacturing clutch plates, pressure plates, and cam shaft sprockets.

Dependencies are inferred from the claim text.