Recent developments in the reverse micro-electrical discharge machining in the fabrication of arrayed micro-features

High aspect ratio arrayed micro-structures and textured surfaces are required in diversified applications such as electrical contacts, printing heads, electrodes for micro-batteries, injection nozzles, nano-material delivery systems, biomedical implants, and hydrophobic surfaces. Reverse micro-electrical discharge machining (R-MEDM) process has a capability to fabricate such arrayed features on a variety of workpiece materials irrespective of their mechanical properties. R-MEDM is a variant of micro-electrical discharge machining (MEDM) process, key difference being, extruded arrayed features are fabricated in the R-MEDM process against the micro-cavities that are machined in MEDM. This article highlights the recent advances in process characterization and modelling of mechanics of the R-MEDM process. The focus of discussion is on comparing the process with the other micromachining processes presently available for the fabrication of arrayed micro-features. In addition, R-MEDM process characteristics in the fabrication of arrayed features on ‘easy’ and ‘difficult’ to erode materials are presented. It is understood that R-MEDM has comparable or in some cases better performance in the fabrication of arrayed features than the processes like micro-milling, micro-wire EDM, micro-wire electrical discharge grinding (EDG) and block EDG.