Experimental Evaluation of a Microwave Drilling Process in Perspex

Abstract An attempt was made to investigate the practicability of drilling sub-millimeter holes in the low–melting-point Perspex using microwave energy. However, a complete characterization study of the microwave drilling process occurs through the characterization of the drill concentrator and the drilled hole in the Perspex specimen. In the present study, a commercial steel-alloyed drill tool has been used as a microwave concentrator and was characterized after the microwave drilling process. The key objective was to understand the capability of the drill tool in concentrating the microwave energy for effective hole drilling in Perspex specimens. A method based on mutual material interaction inside a customized applicator was employed to drill a hole in Perspex by thermal ablation. Energy dispersive spectroscopy using a field emission scanning electron microscopy was performed on a drill tool and workpiece to understand the composition variation during microwave drilling. A Dewinter optical microscope with material and software was used for macroscopic studies (Dewinter, New Delhi, India). Often, a precise weighing machine, jiffy digital clock, and fluke infrared thermometer were used for basic preparation. Thermal analyses based on thermogravimetric analysis (thermogravimetric analysis, differential thermal analyzer, and derivative thermogravimetric) were attempted in order to understand the thermal losses and heat energy influencing the performance of the microwave drilling process. Thermal characterization was carried out for the high heating rates of individual materials as well as the interaction with other materials. The results confirm the drilling of a hole at a low power (90–360 W) setting by a steel alloy drill bit concentrator. It was observed that the melting of the drill bit increased with an increase in the power beyond 180 W. A quality hole of 0.9 mm was drilled with a 0.8 mm drill bit after material characterization at optimized parametric settings.