Effect of EDM Parameters on MRR, Surface Roughness and Tool Wear

Electrical discharge machining (EDM) is widely used for shaping hard, electrically conductive materials such as hardened tool steels and tungsten carbide, but the quality of the finished part depends strongly on how the electrical settings are chosen. This paper looks at three of those settings: pulse current, spark frequency (set through the pulse-on and pulse-off times) and spark gap. Their effect on material removal rate (MRR), surface roughness and tool wear is examined by comparing results from published experimental studies and review articles on die-sinking EDM. No new experiments were carried out. The comparison shows that pulse current is the most consistent influence: higher current generally raises MRR, but it also roughens the surface and thickens the thermally affected layer. The effect of pulse duration is less consistent, and studies on tool steels and on tungsten carbide report different tool-wear behaviour. The spark gap is not set directly. It is controlled through the servo reference voltage, and it governs discharge stability and debris removal. The paper also gives a summary table of reported trends, a roughing-versus-finishing comparison, and a Taguchi-based experimental plan that is proposed for future work but has not been carried out.