STUDY OF CONCENTRATOR IN MICROWAVE MACHINING OF MATERIALS

Abstract

Drilling is one of the important secondary manufacturing processes, which is used in industries to machine materials to produce holes such as through holes, blind holes etc. ranging from macro to micro sizes. The machining of brittle materials such as glass is quite challenging owing to its poor thermal properties and brittle in nature. In order to overcome inherent processing challenges in drilling of glass, various non-conventional machining techniques were. reported. However, development of holes containing required accuracy, surface finish, tool wear and cracks free surfaces are still a concern to be solved. Moreover, time required, energy saving and eco-friendly aspects (dust, fumes, noise etc.) are some of the issues associated with these processes which are yet to be addressed. Some of these processing issues can be solved by using microwave energy for drilling holes. It is reported by many researchers that use of microwave for material processing reduces significant time, improves energy saving and environmental pollution. Microwave drilling is based on thermal ablation process to generate holes in materials using metallic concentrator. This dissertation reports on preliminary results of microwave drilling on borosilicate glass at 2.45 GHz and various power level (90-180 W) using various metallic concentrators (Nichrome, Copper, Low carbon steel, Nickel-plated steel and Aluminium). The effects of concentrator materials have been investigated in terms of time and power required, cracks developed and tool wear during microwave drilling process with and without preheating the workpiece. It was observed that the thermal and material related properties of metallic concentrator affect accuracy and cracks developed on drilled samples.