Machining Performance of Cryogenically Treated Electrodes in Microelectric Discharge Machining: A Comparative Experimental Study

Micro machining processes are becoming popular in this modern era of miniaturization. Microelectric discharge machining (MEDM) is one of the micromachining processes capable of machining all electrically conductive materials. The overall machining performance of electricdischarge machining (EDM) process depends on the electrical, thermal properties of both tool and workpiece materials. Cryogenic treatment has a history of improving mechanical, electrical, and thermal properties of materials. Recently, very few researchers applied cryogenic cooling in conventional EDM and found notable improvement in machining performance. In the present work, a comparative study on machining performance of both cryogenically treated and untreated micro electrodes in MEDM were analyzed alongwith electrical resistivity, crystallite size, microhardness and microscopic analysis. From the study, it is evident that there is significant reduction of 58% in tool wear rate (TWR) for Tungsten electrode followed by brass and copper electrodes with 51% and 35%, respectively. Electrical conductivity and microhardness of Tungsten electrodes exceptionally improved, while that of brass and copper electrodes also remarkably increased. Material removal rate (MRR) almost proportionally decreased with respect to decrease in TWR for all the three cryogenically treated electrodes.