Machining of ZrO2 using wire EDM: an experiment based investigation via assisted electrode

Machining of electrically insulating ceramic materials has been a challenging task for ceramic industries. Assisted electrode method (AEM) based wire electrical discharge machining (WEDM) process emerged as an advanced option to machine insulating ceramics. This study deals with the machining of yttrium (Y2O3) stabilised zirconia (ZrO2) ceramic using copper (Cu) and stainless steel (SS) assisted electrode (AE) in presence of alumina (Al2O3) powder, ethylene glycol and demineralised water mixed dielectric fluid. The effect of different AE materials, pulse on time (T-ON), peak current (I-P) on length of cut (L-C), surface roughness (Ra), and average micro-hardness (MH) were investigated. Further, the comparison was made between minimum and maximum L-C, and Ra (case-(i) and case-(ii)), respectively. SEM and EDS were carried out to analyse the surface characteristics and distribution of elements of the machined surface. Experimental results show that machining with SS AE at high levels of T-ON and I-P provides high spark energy that results in higher value of L-C (1300.910 mu m), Ra (24.520 mu m) and MH (1401.713 HV). Increasing T(ON )and I-P significantly increases the L-C and Ra. Moreover, hardness near the lower junction was higher than the hardness near the upper junction and middle region of the machined surface.