Influence of different grades of CuW electrodes when die sinking ED-machining of cemented carbide

This work investigates the influences of two different grades of copper–tungsten (CuW) electrodes with 65% and 85% of tungsten when sinking ED-machining cemented carbide (WC-Co) with 10% Co. In EDM, literature research works evaluating the influence of different grades of CuW electrodes when ED-machining the same WC-Co workpiece material were not found. In this work, rough, semi-finish, and finish EDM regimes were applied to evaluate process performance aspects as material removal rate (V w ) and volumetric relative wear (ϑ). Workpiece surface integrity was evaluated in terms of surface roughness, hardness, and chemical composition. From the results, the CuW85 electrode presented lower volumetric relative wear (ϑ) and higher material removal rate (V w ) than that of CuW65 electrode. Micro-cracks, from recast layer in direction to heat affected zone, were observed for both grades of CuW electrodes for rough ED-machining. Nanoindentation showed a hardness reduction of about 10% in heat-affected zone in relation to the base material for finishing regime with both CuW electrode grades. EDS revealed that the presence of Co and WC was not altered in recast layer and heat-affected zone.