Electrochemical Discharge Machining

Abstract

With the advancement in the miniaturization of electronic components, the requirement for the micromachining of electrically non-conductive substrates has become more important. Among the different methods employed for micromachining of the non-conductive substrates, electrochemical discharge machining (ECDM) has gained significant popularity over the last two decades. Among the non-conductive materials, micromachining of silica-based substrates such as quartz, sodalime, and borosilicate glass has tremendous applications in microfluidics and biomedical devices due to their optical transparency and biocompatible nature. In the ECDM process, electrochemical discharges are generated between the tool electrode and the electrolyte by the dielectric breakdown of the thin gas film. The material removal in the ECDM process occurs by melting and vaporization and high-temperature chemical etching of the workpiece. A detailed description of the different steps involved in the formation of the gas film is elucidated. The different mechanisms of sparking and varying approaches for the theoretical/numerical simulations of the ECDM process are also discussed. The effects of the tool–workpiece gap, tool roughness/texture, and tool feed rate during fabrication of the microfeatures in the glass workpiece are discussed. Finally, the applications of the array tool electrode in creating simultaneous microholes and microchannels using the ECDM process are reported.