Sustainable developments in near-dry electrical discharge machining process using sunflower oil-mist dielectric fluid

Abstract

Abstract In this study, a near-dry electrical discharge machining (NDEDM) process has been conducted using compressed air mixed with a low quantity of biodegradable refined sunflower oil (called oil-mist) to investigate the machining characteristics. The influences of oil flow rate (OR), air pressure (AR), spark current (SC), and pulse width (PW) on gas emission concentration (GEC), machining rate (MR), and surface roughness (SR) by the Box-Behnken method. The TOPSIS (The Technique for Order of Preference by Similarity to the Ideal Solution) technique estimates the parameter optimal set for the best machining characteristics. The optimal machining parameters have been used to examine the microstructure of the machined surfaces using a scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. The 0.981 mg/min of GEC, 55.145 mg/min of machining rate, and 2.43 µm of surface roughness have been attained by the 14 ml/min flow rate, 7 bar of air pressure, 10 A spark current, and 48 µs pulse duration of the sun-flower oil-mist NDEDM process.