Experimental comparison of near-dry and cryogenically cooled near-dry machining in wire-cut electrical discharge machining processes

In this research, the wire wear ratio (WWR), material removal rate (MRR) and surface roughness (SR) of cryogenic cooled near dry wire-cut electrical discharge machining (NDWEDM) is compared with the existing NDWEDM process. Cryogenic cooled and un-cooled molybdenum wires and Inconel 718 alloy have been used as the electrodes and work-material respectively. The novel experimental setup has been fabricated to mix the minimum amount of water with pressurized air as a dielectric fluid. The control variables such as Air pressure (P), Flow rate (F), Current (I), Pulse width (PW), and Pulse Interval (PI) are measured to conduct both NDWEDM experiments using the L27 Taguchi method. It was revealed from systematic studies that WWR of cryogenic cooled NDWEDM is reduced to 29%, MRR is increased to 15.6% and SR is reduced to 7.23% than existing NDWEDM due to an increase in electric conductivity and effective spark strengths by cryogenic cooled wire. It was revealed from SEM images that the macro crater in the existing NDWEDM and the micro crater of wire in the cryogenic NDWEDM process have been studied.