Surface integrity study of high-speed drilling of Al–Si alloy using HSS drill

Abstract

The motivation to replace steel and cast iron with Al–Si alloys for automotive components is part of the attempt to improve fuel economy and reduce emissions. In relation to that, the application of high-speed drilling is considered one of the most-used operations in hole making for automotive parts due to its ability to reduce lead time without sacrificing the hole quality. However, this advantage was offset by the creeping problems encountered during high-speed drilling. Although this issue is addressed accordingly, problems like uncontrollable surface integrity and poor hole quality still exist. Surface integrity studies involved the investigation of surface roughness, metallurgical changes and microhardness of the subsurface of the drilled hole. Significant alternations with respect to the loss of mechanical properties have been observed from the microhardness and microstructure analysis of the drilled hole. Results from this study showed that, in general, drilling parameters have significant effects on the surface quality and integrity of the drilled hole during high-speed drilling of Al–Si using an HSS drill.