MACHINING OF SIC MATERIALS USING ECSM PROCESS

Abstract

Currently, composites and ceramic materials are replacing the metals owing to their properties such as high hardness, brittleness, strength and electrical insulation. The application of Travelling Wire Electrochemical Spark Machining (TW-ECSM) assists in machining of this non-conducting composites and ceramics. Since silicon carbide (SiC) has range of applications from heat exchangers, seals, bearings, fixed and moving turbine components. Besides, it has hugely influenced the electronic as well as automobile market. That makes the research in the area of SiC compelling not only in macro but also in micro domain. SiC material (non-oxide ceramic) which is semiconducting in nature has been used as workpiece material to study its material removal rate (MRR), surface roughness (SR) and frontal oversize (OS). The brass wire with 0.25mm diameter has been used as tool electrode. The experiments have been performed in two different sets with only change of magnetic field application i.e. one set without application of magnetic field (MF) and other one with application of magnetic field (MF). The MF is employed with the help of neodymium based permanent magnet having disc shape. The quantitative study in terms of above mentioned output parameters as well as comparison between two sets of experiments have been presented in this thesis. It was found that MRR increases whereas SR and OS values experienced depreciation due to magnetic field application. Application of magnetic field provided more accuracy and precision than the application of non-magnetic field. Field Emission Scanning Electron Microscope (FESEM) images has been utilized to compare the surface profiles in the both cases. Application of MF in the direction perpendicular to the electric field produces Lorentz force which aids in the movement of ions. Magnetohydrodynamic (MHD) convection provides stirring effect to an electrolyte which helps to remove trapped debris particles inside the narrow gap even at high current density applications. Thus, highly hard and brittle materials not only of non-conducting nature but also of semiconducting nature can be machined with the help of TW-ECSM process. The further enhancement of above mentioned output parameters can be achieved with the application of magnetic field