Problematic areas in micro-electrochemical milling of HSTR alloys

Abstract

Micro-electrochemical milling has capability to fabricate intricate micro-features for fulfilling the rising needs of modern manufacturing industries. Electrochemical milling is an advanced version of the ECM process, and micro-electrochemical milling is just a scaled-down approach of it. Due to the formation of a passive oxide layer on the machinable surface, electrochemical dissolution of titanium and its alloy is very much difficult and it is much more challenging with this downscaled approach. Since the last few years, researchers are trying to get the best solution for successful machining of different high-strength temperature-resistant (HSTR) alloys, e.g. titanium, nickel and cobalt alloys, etc. In this research, an attempt has been made to identify the issues that arise during micro-electrochemical milling of three different HSTR alloys which are now-a-days extensively used in the modern manufacturing industries. Furthermore, this study also deals with the best possible remedial approaches for minimizing these problems. Finally, considering all the problematic areas and their best possible remedial approaches in this study, high aspect ratio (> 10) 3D micro-features have been successfully fabricated on HSTR alloys, e.g. nickel (Nimonic-263) and cobalt alloy (Haynes-188) at the most suitable parametric combination of 7.5 V of constant DC voltage, 0.4 mm/min of feed rate and 750RPM of tool rotation.