INVESTIGATION ON CRYOGENIC COOLING OF MICRO EDM DRILLING PROCESS ON AISI 304 STAINLESS STEEL

In this experimental work, the cryogenic cooling of the Micro-EDM (mu EDM) drilling process for improving the performance and quality of micro holes. The controllable parameters such as the current (I-p), pulse on time (T-on), Pulse off time (T-off) and gap voltage (V-g) were chosen for further investigation. The Taguchi L-27 orthogonal array is preferred to achieve the best experimental runs. Case hardened AISI 304 stainless steel is selected to perform the experiments. The overall machining performances of geometrical characterization such as taper angle, Overcut, Circularity at the entry and exit and the performance evaluation such as the material removal rate and electrode wear rate are analyzed. It is found that the taper angle improved by 91%, overcut improved by 17 to 66%, Circularity improved up to 70% and 68% respectively, material removal rate increased from 9 to 70% and electrode wear rate reduced up to 76%. It is found that pulse off time plays a vital role in the quality of micro holes drilled in both conventional and cryogenic micro-EDM (C mu EDM) processes.