Surface Integrity Study Using Small Area EDM

Abstract

Electro-Discharge Machining (EDM) nds widespread application in aerospace in-dustry, Micro Electro Mechanical Systems (MEMS), tool and mould industry. Themachining technique now plays an indispensable role in the fabrication of wide va-riety of components. The Small Erosion Area (SEA) machining is one of the mostproblematic forms of EDM since the integrity of the EDM surface is degraded by theunstable arcing which always occurs during the machining process.The present study performs the small area Electro-Discharge Machining (EDM) pro-cess with a copper electrode of diameter 2 mm to establish the inuence of EDMparameters on various aspects of the surface integrity of AISI 52100 die steel. Theeectiveness of EDM process is evaluated in terms of material removal rate, relativewear ratio and surface nish quality of the workpiece produced. The input parametersare current, pulse-on-time, pulse-o-time and gap.The development of a comprehensive mathematical model for correlating the interac-tive and higher order inuences of various electrical discharge machining parametersthrough Response Surface Methodology (RSM), utilizing relevant experimental dataobtained by experimentation. The adequacy of the above models has been testedthrough the Analysis of Variance (ANOVA). The MRR, EWR and SR predictionmodel has been optimized using genetic algorithms. The genetic algorithm programgives maximum values of MRR, minimum values of EWR and SR and their respectiveoptimal conditions. The EDMed surface morphology was examined with a ScanningElectron Microscope (SEM).