Analysis of fabrication of arrayed micro-rods on tungsten carbide using reverse micro-EDM

Reverse micro-EDM (R-MEDM) has evolved as process for the fabrication of high aspect ratio arrayed micro-features. A detailed characterisation of R-MEDM process has been carried out using Taguchi method-based experimentation in the fabrication of micro-rods of size Φ 80 µm and Φ 200 µm of 1.5 mm length on WC. Response parameters were erosion rate, tool wear, surface finish and dimensional accuracy, whereas voltage, capacitance, threshold, feed and electrode thickness were the processing parameters. Erosion rate of process improves over a period of time. A lower thickness plate electrode was found to provide better erosion rates and better surface finish on the fabricated micro-rods; reducing the plate thickness from 500 µm to 300 µm results in 20% and 11% improvement in the surface finish at the tip of 80 µm and 200 µm rods, respectively. Notable differences were observed in the dimensional accuracy and surface finish of the fabricated.