Tooling aspects of micro electrochemical machining (ECM) technology: Design, functionality, and fabrication routes

The era of advanced manufacturing involves the parallel development of sophisticated miniature products as well as novel materials which have necessitated research into electrochemical micromachining technology (micro-ECM) where the material removal is achieved in an athermal manner through the controlled anodic dissolution of the workpiece. High-quality micromachining is obtained through the controlled application of electric and flow fields. The development of micro-ECM is backed by several industries including aerospace, mold, space, automotive, microelectronics, consumer goods, and biomedical industries. In micro-ECM technology, the tool serves as one of the main factors influencing processing accuracy and capability. This aspect has not been covered in detail in existing review articles. Therefore, this review article focuses on tooling aspects of micro-ECM technology. It incorporates all the aspects of tooling from functional design, structures, and materials to fabrication routes in a single manuscript. This article also attempts to highlight the development of composite micro-tools to deliver multiple process energies, ECM tools fabricated through additive manufacturing routes, proposes future research directions and the associated challenges involved with the use of micro- and nano-tools in ECM technology. This review article seeks to address both the academic and industrial audience thereby leading to further tooling innovations for micro-ECM technology.