Surface integrity analysis in Heat Sink-based Dry Drilling of Titanium Alloy

Abstract The aerospace structural components made of titanium alloys being manufactured require no. of holes for their assembly. In the dry drilling of titanium alloy, excessive heat is generated at the cutting zones, which results in high mechanical and thermal damage to the surface integrity. The surface integrity of the machined component is an important characteristic, which influences functional behavior of the components being manufactured. Therefore, in this work, a unique heat sink-based dry drilling approach has been prepared to compare its effectiveness over dry drilling (without heat sink) of titanium alloys. In this approach, a highly conductive copper plate was used as a heat sink below the titanium work surface being machined. Drilled surfaces were analyzed for surface roughness, sub-surface deformation and surface defects. It is observed that the average surface roughness was reduced from 4 μm Ra to 1.5 μm Ra in heat sink-based drilling approach. An average sub-surface deformation thickness was reduced by 21% in the heat sink approach as compared to dry drilling. The drilled surface defects were found to be comparatively lower in the heat sink-based drilled surfaces.