Microwave Drilling of Polymer Based Composite: Challenges and Opportunities

Microwave drilling is an advanced machining process in which electromagnetic energy converted into thermal energy with the help of a metallic concentrator is used to create the desired shape in the work material. High strength electric field developed around the tooltip ionizes the dielectric media around the tooltip and results in plasma formation. High-temperature plasma ablates the material just beneath the tool tip to create the desired hole in the workpiece. In the present research work, micro-hole drilling on thermoset and thermoplastic-based composites using microwave energy in the air and transformer oil has been investigated. The drilling characteristics have been investigated in terms of the heat-affected zone, and overcut; a comparison has been made in air and transformer oil. The study revealed that drilling in the presence of dielectric-like transformer oil reduces the defects like HAZ and overcut significantly. It was also observed that thermal damage was more in thermoset-based composites as compared to thermoplastic-based composites.

Keywords: Composite, Heat affected zone, Microwave drilling, Micro-hole, Overcut.