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.
