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 ø2 mm x 35 mm length rod of tungsten carbide, a 3x3 array of microelectrodes was fabricated with a 230 µm diameter hole in a copper sheet, providing a depth of 1.5 mm. Increasing the process parameters from 10nF capacitance, 90V voltage, and 0.3 mm/min feed to 100nF capacitance, 130V voltage, and 0.9 mm/min 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 10nF, a voltage of 130V, and a feed rate of 0.3 mm/min 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. 

Reverse micro electrical discharge machining (reverse µEDM) is becoming more popular as a novel method for creating array microelectrodes with a high aspect ratio without profile restrictions. Surface roughness is an essential quality characteristic or parameter determining the product's final shape and is more determinant when the size of the product is small. The objective of this work is to create a mathematical model based on dimensional analysis that uses Buckingham's µ-theorem to quantify the surface roughness of microrods. Surface roughness has been explored through experiments based on the Taguchi design, considering the process parameters such as voltage, feed, capacitance, flushing pressure, and material properties (thermal conductivity, electrical conductivity, melting temperature, and specific heat). The surface roughness of tungsten carbide (WC) micro rods increases by approx. 58% when the capacitance increases from 10nF to 100nF. FESEM is used to analyze the crater size variation of WC micro rods. The surface roughness predicted by dimensional analysis supports the experimental results with an error of 3.45%.

The high demand for compact and multitasking devices in the market has been a driving force behind the growing interest in microfabrication techniques. These techniques have wide-ranging applications in many industries, including aerospace, automobile, electronics, and defense. Micro electrical discharge machining (µEDM) techniques have the unique ability to produce highly precise and intricate features on small components, which has further fueled the demand for such products. However, with the increasing demand for micro-featured products, there is a pressing need to enhance the process capability of µEDM process. This work aims to address this need by focusing on enhancing the performance of µEDM by varied process parameters and materials such as copper, brass, and tungsten carbide for the drilling of blind micro holes. Surface roughness (SR) and material removal rate (MRR) are the main performance factors taken into account in this investigation. Notably, the minimum SR was achieved on tungsten carbide, while the maximum MRR was achieved using copper electrodes. For SR and MRR, artificial neural network (ANN) models have been constructed that predict with more than 90% accuracy. These findings have significant implications for the future of microfabrication using µEDM.