Electrical Discharge Machining (EDM) is the most commonly used technique in mold and die manufacturing. The purpose of this investigation was to optimize the machining parameters of EDM on zirconium dioxide (ZrO2) and aluminum oxide (Al2O3). During the EDM process, the surface of electrically nonconductive ceramic was covered with adhesive conductive copper (Cu) and aluminum (Al) foils to attain the threshold of electrical conductivity for the EDM process. The machining characteristics associated with the EDM process such as material removal rate (MRR) and surface roughness (SR) were explored through the experimental study according to an L18 orthogonal array using the Taguchi method. The analysis of variance (ANOVA) was conducted to examine the significant machining parameters which affect the machining characteristics. As the experimental results show, peak current and pulse duration significantly affected MRR and SR. In addition, the optimal combination levels of machining parameters were also determined from the response graph of signal-to-noise (S/N) ratios for each level of machining parameters. A practical and convenient process for shaping the electrically nonconductive ceramics was developed which featured high efficiency, high precision, and high-quality of surface integrity.

Keywords: EDM, Taguchi method, Material removal rate, Surface roughness, Nonconductive ceramics, ANOVA.