Multi-objective Optimization Using Taguchi's Loss Function-Based Principal Component Analysis in Electrochemical Discharge Machining of Micro-channels on Borosilicate Glass with Direct and Hybrid Electrolytes

Machining of hard and brittle materials like borosilicate glass has imposed challenges due to its low machinability. Among various non-traditional machining methods, electrochemical discharge machining (ECDM) or spark-assisted chemical engraving (SACE) is proved as a potential method to machine such low machinable and non-conducting engineering materials. ECDM combines the features of electric discharge machining (EDM) and electrochemical machining (ECM) to machine electrically non-conducting materials. In the present study, direct (NaOH) and hybrid (NaOH + KOH) electrolytes were used to machine micro-channels on borosilicate glass with in-house developed prototype constant velocity tool-feed ECDM experimental set-up. The experiments were conducted based on L-9 orthogonal array with electrolyte concentration, voltage and duty factor as control factors. The overcut (OC) and heat-affected zones (HAZ) were considered as responses. Taguchi's loss function-based principal component analysis (PCA) was utilized for simultaneous optimization of responses. Analysis of variance (ANOVA) was performed, and electrolyte concentration was found as the most significant factor for both the cases. Confirmation tests with three replications were conducted at optimum factor levels and validated experimental results.