Blind-hole drilling of Al2O3/6061Al composite using rotary electro-discharge machining

This work optimizes the blind-hole drilling of Al2O3/6061Al composite using rotary electro-discharging machining by using Taguchi methodology. Experimental results confirm that the revised copper electrode with an eccentric through-hole has the optimum performance for machining from various aspects. Three observed values, MRR, EWR, and SR, verify this optimization of the machining technique. In addition, seven independent parameters are chosen as variables in evaluating the Taguchi method and are categorized into two groups: (1) electrical parameters, e.g., polarity, peak current, pulse duration, and powder supply voltage, and (2) non-electrical parameters, e.g., rotational speed of the electrode, injection Bushing pressure of the dielectric fluid, and the number of eccentric through-holes in the electrode. Moreover, analysis of the Taguchi method reveals that the electrical group has a more significant effect than the non-electrical group on the machining characteristics. Furthermore, either the polarity or the peak current most prominently affects the MRR, SR or EWR amongst all of the parameters, whereas none of the non-electrical group has an equal affect. Also derived herein are semi-empirical equations that contain all of the machining characteristics. (C) 2000 Elsevier Science S.A. All rights reserved.