Active corrosion control in wire EDM of carbide punches

In conventional wire electrical discharge machining (WEDM), WC-Co machined pieces can stay for hours in the worktank. In the pH range of the dielectric Co actively dissolves and thus corrosion can occur affecting the mechanical properties and lifetime of those pieces. This study demonstrates how applying cathodic polarization through the implementation of auxiliary electrodes in the work zone helps reducing in-depth propagation of the corrosion attacks on WC-Co hardmetals during storage in the dielectric. Our experimental findings were supported by a prediction model that helps visualizing the electrical field distribution during machining and storage and identifying the critical engineering parameters.