A Truing Mechanism for Flattening Diamond Grains on the Working Surface of an Electroformed Diamond Tool

Abstract

A truing test was conducted to clarify the truing mechanism for flattening diamond grains on the hemispherical working surface of an electroformed diamond tool with a mesh size of #1 000 and a tip radius of 0.2 mm. A polycrystalline diamond disc of 0.5 μm primary grain size and 15 mm diameter was used as a truer. A concentric groove with a reverse profile relative to the hemispherical tool and a surface roughness of 0.5 μm Rz was preformed on the truer by laser machining and wet lapping. Truing was then performed by placing the tool in elastic contact with the preformed groove on the truer. It was verified through a truing test that primary diamond grains on the guide groove acted as multiple minute cutting edges so that 93% of the diamond grains on the tool working surface could be flattened when the tool was placed in contact with a groove of 50 μm depth and the contact load was set at 5.2 N.