Investigation of reverse micro-EDM process for generating high aspect ratio micro-electrode arrays

Abstract

Deep arrayed micro-hole arrays find applications in air-bearings, inkjet nozzles, micro filters, and single cell manipulation devices. Typically, high aspect ratio micro-electrodes are required for creation of deep blind/through holes. Reverse micro-EDM has the potential for generating high aspect ratio arrayed micro-electrodes. It involves reverse replication of arrayed micro-holes in a plate on to a larger diameter bulk electrode thereby creating high aspect ratio micro-rod arrays. While the process is well-known for its application in the macro-domain, there have been extremely limited studies in its application in the micro-domain. In this work, micro-electrode arrays having different cross-sections and dimensions have been fabricated. A micro-electrode 60 mu m in diameter and an aspect ratio of 33 has been successfully fabricated. Machined micro-electrodes are assessed for geometrical accuracy, surface finish, and surface morphology. The chemical composition of machined rods has been investigated via Energy Dispersive Spectroscopy (EDS).