Magnetically assisted electrochemical discharge machining of advanced insulating materials: a review

Abstract

Micro-featured devices composed of insulating brittle materials such as silicon wafers, silicon dioxide, glass, ceramics, and composites are becoming more and more important in microfluidics, optics, semiconductors, and biomedical equipment as technology advances. Electrochemical discharge machining (ECDM) is a novel, unconventional micromachining technique designed for the precise fabrication of intricate three-dimensional geometries in difficult-to-machine insulating materials owing to the inherent limitations of current technologies. However, conventional ECDM is limited by unstable gas film formation, erratic discharge occurrence, and poor electrolyte circulation. Such conditions adversely affect material removal rate (MRR), surface quality and process stability. To overcome these drawbacks, the concept of magnetic field-assisted ECDM (MF-ECDM) is discussed, where magnetohydrodynamic convection plays an important role by improving electrolyte circulation, stabilizing the gas film, reducing OC, and providing better surface integrity and accuracy. In this respect, an assessment of the potential of MF-ECDM compared to the conventional ECDM is carried out, focusing on improved discharge stability and machining accuracy, along with limitations related to the enhancement of MRR. Current review systematically analyses recent advancements in MF-ECDM based on published literature, focusing on machining mechanisms, process parameters, modeling approaches, and performance characteristics. Furthermore, the present work mentions current problems faced and future research directions to enhance the process capabilities based on published research in the MF-ECDM process.