MRR, EWR and KERF Analysis in cold work tool steel machining in EDM method by copper and brass electrode

In this study, holes were drilled on the Sleipner cold work tool steel with a hardness of 60-62 HRC by copper and brass electrodes using three different current values (50, 25, 12.5 A), pulse on times (3, 6, 9 μs) and pulse off times (4, 6, 8 μs) parameters in the EDM method; the effects of these working parameters on machining times, material removal rate (MRR), electrode wear rate (EWR), the hole inlet-outlet diameters of the machined parts, the kerf on workpiece and electrode were analyzed. As a result of the analyzes made, in the use of copper electrodes, the MRR increased by 311.25% on average compared to the use of brass electrodes, while the EWR and machining time decreased by 42.01% and 38.46%, respectively. The increase in sparking and thermal effects between the workpiece and the electrode resulted in an increase in the MRR and a decrease in the machining time. In the use of copper and brass electrodes with different processing parameters, the inlet diameters of the drilled holes were found to be larger than the outlet diameters as well as an irregular kerf formation was observed due to debris evacuation due to worn electrodes.