Discharge energy based optimisation of sinking EDM of cemented carbides

The Electrical Discharge Machining (EDM) of cemented carbides is anticipated to enhance in order to allow more efficient machining. However, it is important that an optimisation does not deteriorate the surface integrity of the cemented carbide workpiece, since they are particularly sensitive to tensile stresses as they are caused by EDM. In order to allow for a safe optimisation, the surface integrity of every machining step has been examined before the optimisation regarding surface roughness, recast layer, heat affected zone and crack length. The same parameters have been examined for the optimised machining steps and the resulting workpiece. It was found that machining can be shortened without a significant detrimental effect.