Experimental Investigation of Magnetic Field Assisted Powder Mixed Electric Discharge Machining

Abstract

Electric discharge machining (EDM) is the most promising modern machining process amongst all the modern machining processes. This paper presents the application of metal powders that are mixed in dielectric medium during EDM to improve process performance like material removal, tool wear, surface finish, overcut, and microhardness. An external magnetic field is provided to further assist the machining process which affects differently for different output characteristics. Taguchi's design of experimentation and analysis of variance is used for analysis of results. Current, pulse on time, workpiece, and powders show significant effect on different responses Results showed that the material removal rate increases with the field strength at low values of current, while increase in overcut is observed with increase in field strength. Tool wear rate is observed to increase with the field strength at lower current values while microhardness is observed to enhance with increase in magnetic field strength. Surface finish is observed to improve at lower current with increase in field strength. Different optimal parameters are characterized for machining purpose in terms of current, powder, powder concentration, and tool for machining different workpiece materials. Results are further supported by selected microstructure and x-ray diffraction results.