Effects of Electrode and Workpiece Materials on the Sustainability of Micro-EDM Drilling Process

An analysis on the sustainability of micro-EDM drilling is presented in this paper. In particular, a sustainability index of the process was calculated taking into account the energy consumption and the tool wear during the drilling process. The machining accuracy was also taken into account to calculate the overall sustainability index. The index was validated considering the micro-EDM drilling of three different workpiece materials (stainless steel, tungsten carbide and aluminium) with two commonly used electrode materials (brass and tungsten carbide) and different process parameters, namely peak current, voltage and frequency. An analysis about the influence of workpiece and electrode materials on the sustainability index was carried out. In general, the tool wear has the highest impact on the sustainability of the process. Considering only the wear and the energy consumption, brass electrode can be considered much more sustainable than the tungsten carbide one for all the tested workpiece materials. This gap is less remarkable (or negligible) if the respect of dimensional tolerances and the consequent percentage of nonconformity is taken into account. From the point of view of the workpiece material, aluminium minimizes the environmental impact of the process. Finally, the effects on the index of the process parameters, the thermal and electrical characteristics of the electrode and the workpiece materials were evaluated. These results can be useful for approaching a more environmental-oriented strategy in manufacturing.