On performance evaluation of textured tools during micro-channeling with ECDM

Abstract

Electrochemical discharge machining (ECDM) is an emerging technique for machining of micro-channels on non-conductive materials. It utilizes a combination of chemical as well as thermal energies to machine the materials. The configuration of tool electrode plays important role to channelize these energies from tool electrode to work material. Thus, the appropriate selection of tool electrode configuration is essential to effectively utilize the energies during ECDM for achieving machining accuracy. The present investigation reports on textured tools for machining of micro-channels on borosilicate glass with ECDM. The underlying process mechanism is investigated. Textured tools provides micro gaps between the tool electrode and the workpiece surface and results in thin and stable gas films. The breakdown of thin and stable gas films produces high frequency low intensity discharges and consequently improves the machining performance. The textured tools in comparison with smooth surfaced tools exhibits improvements in material removal rate (MRR) by 19.27% and depth by 64.81%. Also the width overcut (WOC) and surface roughness were reduced by 122.26% and 26.96%, respectively. The flexibility to develop textured as well as smooth micro-channel surfaces by textured tools provides wider scope for fabrication of various micro fluidic devices. The effect of ECDM process parameters (voltage, pulse on-time, pulse off-time, feed rate and electrolyte concentration) with the use of textured tools was investigated. Multi criteria optimization using desirability approach predicted the parametric combination of applied voltage of 59 V, pulse on-time of 3 ms, pulse off-time of 3 ms, feed rate of 12 m m/min. and electrolyte concentration of 21%wt./vol., the optimum setting for micro-channelling by ECDM using textured tools.