Experimental measurement and evaluation of circularity, cylindricity, and perpendicularity in Al₂O₃ nanoparticle-enriched EDM of Ti-5553

Abstract

Electrical Discharge Machining (EDM) is used extensively in machining hard to cut alloys, but due to poor discharge control, non-uniform heat, and poor debris removal with conventional dielectric fluids, achieving high geometric accuracy proves to be hard. Past work suggested that nanoparticle enriched dielectrics can enhance discharge stability and surface integrity, but their effect on improving three-dimensional geometric accuracy like circularity, cylindricity and perpendicularity is not well studied, especially on advanced titanium alloys. The impact of Al
2
O
3
(optimized 1% concentration) nanoparticle-enriched dielectric on the geometric accuracy of Ti-5553 alloy in EDM is experimentally analyzed in the current study. A Taguchi L27 orthogonal array utilized for designing experiments considering 5 process variables; voltage, current, pulse-on time (TON), pulse-off time (TOFF), and flushing pressure in three levels. The findings indicate a great sensitivity of the geometric accuracy due to the combined effects of electrical parameters and flushing conditions. Circularity was primarily controlled by current and voltage, cylindricity by pulse-on time and current and perpendicularity by strong interaction effects on the flushing pressure. Intermediate discharge energy and optimal pulse timing were associated with stable plasma generation and even material removal, whereas a greater flushing pressure enhanced the evacuation of debris and decreased angular dispersion. The combination of parameters which produced minimum errors in circularity, cylindricity and perpendicularity were 70 V, 2.3 A, 65mTON, 18mTOFF and maximum flushing pressure and had a total desirability of 0.93. The results indicate that the dielectric with Al
2
O
3
nanoparticle enrichments produces greatly high geometric accuracy in comparison with EDM, and it is a viable procedure of achieving high-precision machining on titanium alloys that need high adherence of both dimensions and shape.