Application of the sheet electrode to enhance the geometric characteristics of micro-holes fabricated by electrochemical discharge machining

The electrochemical discharge machining (ECDM) is an advanced machining technology used to fabricate micro-holes in glass. In this study, a sheet tool electrode is employed to increase electrolyte circulation in machining zone. The effect of pulse voltage, frequency, duty cycle, electrolyte concentration, and tool rotation speed on the geometric properties of micro-holes were evaluated. The results showed that when using a sheet tool electrode, the machining depth increased by 42.9 %, and the machining efficiency increased by 51.1 %, while the entrance diameter was reduced by 13.9 % than cylindrical tool electrode. Additionally, the heat-affected zone (HAZ) and entrance hole surface quality is improved. On the other hand, the Taguchi method was employed to analyze the relative importance of the machining parameters on geometric characteristics of micro-holes (i.e. drilled depth and entrance diameter of micro-holes). Finally, the entrance hole overcut of 148 µm was successfully fabricated with a depth of 2520 µm. It was discovered that using a sheet tool electrode is a simple method for machining a deep micro-hole with high machining efficiency and a range entrance hole diameter overcut that is acceptable.