Experimental Study of the Effectiveness of Al ₂ O ₃ -SiO ₂ NPMEDM for Surface Topography of Stainless Steel 304L

Abstract Among the several machining techniques used in mold and die manufacture, electro-discharge machining (EDM) is a unique type of machining. One of the most recent developments in thermo-electric processes is nano powder-mixed electric discharge machining (NPMEDM), which involves suspending metallic nano powder in a dielectric. The purpose of this work is to investigate the effects on surface topography (outputs) of Al 2 O 3 -SiO 2 nano powders mixture, which were selected from several mixtures or individual nano powders, after reviewing previous research, as nano powder concentration and nano powder mixing ratio. At concentrations of (1, 2, 3, 4, 5 g/l) mixed into the dielectric fluid of EDM on stainless steel 304L, with a mixing rate that varies for each mixture from 30% to 70%, achieving 100% for the mixture as a whole with an interval of 10% at each level. Other electric parameters (inputs) include pulse on time (50, 100, 150, 200, 250 µs), current (20, 25, 30, 35, 40 A), and pulse off time (25, 50, 75, 100, 125 µs). Response Surface Methodology (RSM) has been utilized to determine the mathematical relationship between the input and output and the NPMEDM process. White Layer Thickness (WLT), Heat Affected Zone (HAZ), and Surface Crack Density (SCD) are used to gauge the effectiveness of the machining process. The experiments were conducted using 50 experiments using the Design Expert 11 program and Central Composite Design (CCD) methodology. The results obtained were analyzed to determine the extent of the influence of the inputs on the response of the stainless steel 304L surface; we received an improvement in surface response, decreasing WLT, HAZ, and SCD by 5.8%, 17.7%, and 2.6%, respectively.