Fabrication of array microelectrodes: achieving geometrical characteristics using reverse micro-EDM process

Reverse micro-EDM is the most suitable method for fabricating circular cross-section array microelectrodes. This work presents an experimental investigation into the effect of process parameters such as capacitance, voltage, and feed on the geometrical characteristics (diameter, length, and taper) of tungsten carbide (WC) array microelectrodes. Using a o2 mm x 35 mm length rod of tungsten carbide, a 3 x 3 array of microelectrodes was fabricated with a 230 & mu;m diameter hole in a copper sheet, providing a depth of 1.5 mm. Increasing the process parameters from 10 nF capacitance, 90 V voltage, and 0.3 mm min(-1) feed to 100 nF capacitance, 130 V voltage, and 0.9 mm min(-1) feed decreased the diameter by 6.75% and increased the taper of the electrodes by 3%. The ANOVA analysis indicates that capacitance, voltage, and feed significantly affect the geometrical characteristics of array microelectrodes. Using the multi-objective optimization technique grey relational analysis (GRA), it was found that at a capacitance of 10 nF, a voltage of 130 V, and a feed rate of 0.3 mm min(-1) achieved the minimum deviation in the geometrical characteristics of WC array microelectrodes. This paper will help determine the hole size required to achieve the specific dimensions on the array microelectrodes and select optimal process parameters.