Investigation of performance characteristics amid nano powder mixed electrical discharge micro-milling on Hastelloy C 276

Abstract

Powder mixed electrical discharge micro-milling (EDMM) has been introduced as a novel variant of EDM operation, which can generate complex 3D micro features by CNC programming through the rotating micro-tool. It enhances the material removal rate (MRR), decreases the tool wear rate (TWR) and provides superior surface characteristics. The present work investigates the impact of powder concentration, gap voltage, and capacitance on the micro-hardness (MH), material removal rate (MRR), tool wear rate (TWR), surface roughness (SR), overcut (OC), taper angle (TA) and surface morphology during graphene nano powder added EDMM of Hastelloy C 276. The powder concentration of 0.25 g/L significantly enhanced the MRR and decreased the TWR, respectively. A drastic reduction in SR has been observed for 0.4 g/L concentration compared to plain dielectric. Lower OC and higher TA has been found for plain dielectric system. Field emission scanning electron microscopy (FESEM) is used in both cases to examine the surface morphology and recast layer of the milled micro-channels. The MH of the milled micro-channels is raised by 2.3 times at 0.4 g/L concentration. Energy-dispersive X-ray spectroscopy (EDS) confirms the migration of materials from the dielectric and graphene nano powder to the milled micro-channels on HC 276.