Every use of the diamond PCD tool wears out some of it, and we need to run it in for longer use. Among them, the principle of discharge sharpening can achieve such requirements.
The discharge sharpening is to melt and vaporize the tool material by generating a transient high temperature by discharging between the grinding wheel electrode and the tool electrode separated by the dielectric. When sharpening a diamond PCD tool, since the diamond is not electrically conductive, the tool electrode is a conductive network composed of a metal phase in the diamond. Thus, the discharge sharpening is a thermal erosion process. In addition, due to the high temperature of the spark discharge, diamond PCD cutters may cause heat loss and graphitization during sharpening, especially at the interface between diamond and cemented carbide substrate, because discharge grinding is a non-contact. During the sharpening process, the grinding force is negligibly small, so the sharpening efficiency is high.
In contrast, the principle of discharge sharpening is fundamentally different from the traditional abrasive grinding principle and is currently one of the main sharpening methods for diamond PCD tools.