Influence of tool electrode feed rate in the electrochemical discharge drilling of a glass substrate

Abstract

ABSTRACT The tool electrode feed rate (TEFR) is a parameter of vital importance for velocity-feed electrochemical discharge drilling (ECDD). The tool electrode will hit the workpiece and may even cause to crack if higher TEFR is used, while a lower TEFR will curtail the material etch rate. Hence, a comprehensive experimental study into the TEFR effects on the ECDD performance is presented. The top and bottom sizes of micro-holes, eccentricity, circularity, heat-affected zone, and tool electrode wear are the important features considered in this experimental work. Cylindrical-shaped tungsten carbide tool electrodes with 70 μm and 300 μm sizes were utilized. The TEFR in the range of 1–9 μm s−1 were selected. The stable and uniform EC discharges were observed for the TEFR < 5 μm s−1. The minimal hole size and HAZ were obtained for the TEFR in the range of 3–4 μm s−1. The eccentricity and circularity of micro-holes were found to be lower for the TEFR < 5 μm s−1. Higher tool wear was noticed for the TEFR < 2 μm s−1. Based on the overall experimental evaluation, TEFR in the range of 3–4 μm s−1 is recommended.