Surface integrity of tungsten carbide microelectrodes fabricated using reverse micro-EDM by varying electrode materials

Abstract

Recently, there has been a notable trend towards miniaturizing components across diverse industries. The reverse micro electrical discharge machining (reverse micro-EDM) process has gained prominence for microelectrodes array fabrication. However, this process often induces undesirable surface attributes on microelectrodes, including rough topography, elevated residual tensile stresses, increased surface roughness, microcracks, recast layers, and heat-affected zones (HAZ). Consequently, assessing the influence of tool materials on microelectrode surface integrity becomes crucial. This study systematically investigates the effect of distinct tool materials on the surface roughness of microelectrodes fabricated using reverse micro-EDM. Three tool materials were considered: copper, brass C38500, and aluminum 3003. The results robustly establish copper as the most efficient tool material for reverse micro-EDM applications, showcasing superior productivity and performance. Employing copper as the tool material under specific conditions yielded a remarkable achievement, a minimal surface roughness of 0.38 µm on tungsten carbide microelectrodes at 90 V, 10nF, and 5 µm/sec. These findings underscore the potential of copper as a promising tool material for fabricating microelectrodes via reverse micro-EDM.