Dielectric Velocity Research Articles

On finite element analysis of material removal rate in microwave drilling of borosilicate glass

Abstract In the present work, microwave drilling of borosilicate glass has been investigated at 2.45 GHz using experimental and simulation tools. Microholes were produced on glass (Thickness = 1.3 mm) using a graphite concentrator (Diameter = 500 µm) at different dielectric velocity (0.2 ms−1, 1.0 ms−1, 1.8 ms−1, 2.6 ms−1). Effect of power and dielectric velocity has been studied on material removal rate. A model of the same was developed using the finite element method. Experimental results were found in reasonable agreement with the simulation results. Study on distribution of input microwave energy during microwave drilling indicated that maximum usable energy is utilized in heating the workpiece, whereas, rest of the usable energy is absorbed by the dielectric and concentrator. Material removal rate increases with increase in power but also attracts defects like crack around the hole. It was observed that increase in dielectric velocity up to 1 ms−1 improves material removal rate due to the efficient flushing of glass residue. However, further increase in dielectric velocity decreases the material removal rate due to the loss of excess heat flux from the machining zone.