A decision-making model for tool material selection in electrical discharge machining

Abstract

Electrical discharge machining (EDM) has emerged as an essential process for machining dies/moulds in electrically conductive materials. Apart from workpiece erosion, the inherent characteristic of the process leads to tool wear. Thus, selecting EDM tool material is critical for achieving higher efficiency and accuracy. The present study deals with framing a decision-making model to facilitate the selection of tool material for the EDM process. Key factors such as density, electrical resistivity, thermal conductivity, linear expansion coefficient, melting point, specific heat and cost are chosen as criteria. The concept of fuzzy logic has been applied to assign the weightage of each criterion by taking experts’ decisions in linguistic terms. Thereafter, the TOPSIS method is applied to rank the alternatives, wherein tungsten evolved as the best material, followed by copper graphite, copper, copper tungsten and tellurium copper. Further, sensitivity analysis is conducted to check the robustness of the developed model.