Assessment and Comparison of Machining Performance in Rotary and Stationary Tool EDM for Machining AISI D3 Tool Steel

Abstract

The Electric Discharge Machining (EDM) is a well-established and one of the most primitive unconventional manufacturing processes, that is used worldwide for the machining of geometrically complex or hard and electrically conductive materials which are extremely difficult-to-cut by any other conventional machining process. One of the major flaws of EDM, over all its advantages, is its very slow Material Removal Rate (MRR). In order to enhance this slow machining rate, various researchers have proposed various methods like; providing rotational motion to the tool or workpiece or to both, mixing of conducting additives (such as SiC, Cr, Al, graphite etc.) powders in the dielectric, providing vibrations to the tool or workpiece or to both etc. Present work is a comparative study of Rotary and Stationary Tool EDM, which deals with providing rotational motion to the copper tool for the machining of AISI D3 Tool Steel and the results have been compared with stationary tool EDM. It has been found that the tool rotation substantially increases the average MRR up to 49 %. The average surface finish increases around 9-10 % by using the rotational tool EDM. The average tool wear increment is observed to be around 14 % due to the tool rotation. Apart from this, the present work also focusses on the recast layer analysis, which is being re-deposited on the workpiece surface during the operation. The recast layer thickness is less in the case of rotary tool EDM and more for stationary tool EDM.