Determination of surface roughness of micro rods fabricated by reverse µEDM using dimensional analysis

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 micro rods. 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 10 to 100 nF. 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%.