Effects of Machining Parameters on Performance of Electrical Discharge Surface Grinding of AISI D2 die Steel with Composite Tool Electrode

Abstract

Electrical Discharge Surface Grinding (EDSG) is much like electrical discharge machining except that the electrode is a rotating metal matrix composite (MMC) tool, processed by reinforcing abrasive particles in a conducting metal matrix by powder metallurgy route. The tool electrode is fed into the work material by a servo-controlled mechanism. The work material is machined and grinded by the combined action of electric sparks (thermal interaction) between the tool electrode and the work material, immersed in a dielectric fluid, and the abrasion (mechanical interaction) due to the abrasives mixed in the matrix. Each spark discharge melts or vaporizes a small amount of metal from the work surface, producing a small crater at the localized spot, followed by grinding by the abrasives, producing a ground surface. This paper focusses on understanding the mechanism of material removal in abrasion-assisted EDSG, for the machining of AISI D2 die steel. The rotary motion imparted to the metal matrix Cu/SiCp tool electrode using rotating spindle assembly mounted on electric discharge machine was employed to study the EDSG technology. Powder metallurgy route was adopted to fabricate the MMC electrode with different proportion of abrasives as SiC in copper powder. During the EDSG operation, the hump of material melted by the EDM is forcibly removed by the grinding/abrasion mechanism from the work surface, which enhances the material removal rate (MRR) of this hybrid process.