Investigation of the potential of nano-powder mixed surfactant based waste oil for reducing tool wear and dimensional errors in electro-erosion process

Electric Discharge Machining (EDM) is indispensable in industrial applications for machining hard-to-process materials like Inconel 617. However, tool wear and dimensional deviations remain significant challenges that limit the efficiency and quality of the EDM process. This study investigates the potential of using nanopowder-enhanced, surfactant-based waste cooking oil (WCO) as a dielectric fluid to mitigate these issues. The research aims to optimize process parameters, focusing on reducing electrode wear rate (EWR) and overcut (OC), while maintaining dimensional accuracy and sustainability. A systematic experimental design using the Taguchi method was employed, with process parameters such as powder type, electrode material, powder concentration, surfactant type and concentration, peak current, and pulse ratio. The optimization was followed by a comprehensive analysis involving main effects plots, analysis of variance (ANOVA), optical and scanning electron microscopy (SEM), and multi-response optimization using Grey Relational Analysis (GRA). The findings revealed that the optimal parameters for minimizing EWR and OC included SiC powder, copper electrode, a powder concentration of 1.5 g/L, S80 surfactant at 8 %/L, peak current of 6 A, and a pulse ratio of 0.5. The multi-objective optimization resulted in a remarkable reduction of 96.57 % in EWR and 86.77 % in OC compared to the initial DOE setup. These results highlight the superior performance of WCO-based dielectrics with nanopowder additives over conventional petroleum-based oils, contributing to both process efficiency and environmental sustainability. This work demonstrates the applicability of a green dielectric for advanced EDM applications, offering significant improvements in machining performance and reduced environmental impact, aligning with industry trends towards eco-friendly manufacturing.