Effect of tool-electrode material in through-hole formation using ECDM process

Abstract

ABSTRACT An experimental investigation comparing the effect of tool electrode materials on the formation of microholes in glass by the pulse electrochemical discharge machining is presented. Two different materials, i.e., Molybdenum and High carbon steel (HCS), were used in the experiments carried out in 10% wt KOH electrolyte. Other parameters such as machining voltage, pulse frequency, tool feed rates were systematically varied. A lower mean discharge current was noticed when the molybdenum tool having higher electrical conductivity was used. The average reductions in the hole overcut, taper angle, and the heat-affected zone in the microholes were 30%, 55%, and 58%, respectively, when the Molybdenum tool was used compared to the HCS tool. For both tool materials, the hole overcut was measured to be minimum when a tool feed rate of 4 µm s−1 was used. The microhole diameter and heat-affected zone were increasing with the increment in the applied voltage irrespective of the tool electrode material. Due to the higher melting point, molybdenum electrodes had less tool erosion and, therefore, more suitable than the HCS tools for electrochemical discharge machining applications.