On modes of electrochemical machining: a comprehensive review

Abstract

ABSTRACT Conventional (C) electrochemical machining (ECM) is an established toolroom process to remove controlled materials from conductive materials, including composites that are otherwise difficult to machine. Several variants of ECM with different modes/mechanisms of material removal are commercially available. However, hitherto, little has been reported on the comprehensive review of the mechanisms for different modes (such as pulsed, hybrid, air/water jet, laser-assisted, mask, etc.) of the ECM process. In this work, an effort has been made to review the different ECM modes/mechanisms employed for mass transfer (from the bulk electrolyte solution to the electrode surface), electron transfer at the electrode surface, and chemical reactions preceding or following the electron transfer and other surface reactions, such as adsorption, desorption, or crystallisation in diverse procedures for machining various materials. Some investigations from the broad field of CECM and modified (M) ECM developed to improve the overall process for high-quality tool rooms are also reported. Finally, the advancements in MECM, its associated problems, and future research prospects have been presented. The study highlights significant research gaps in material reaction metrics, circularity, cylindricity, dimensional stability, and surface properties in various modes of ECM.