Tool wear and surface finish analysis after drilling Al-SiC metal matrix composite with DLC-coated tools at varying feed

Metal matrix composites (MMCs) show enhanced mechanical and physical properties compared to monolithic alloys, which make them attractive for various engineering applications. However, their actual use in industry is limited due to their low machinability. The hard reinforcements present in the matrix may lead to high tool wear and poor surface integrity. In this context, the paper aims at studying the drillability of an Al-SiC MMC when using DLC-coated tungsten carbide tools at varying feeds. After the machining trials, a quantitative evaluation of the tool wear as well as the analysis of the hole surface roughness and damage was carried out. The results demonstrate that, at increasing feed, the tool wear, surface roughness, and surface defect density decrease, leading to the counterintuitive conclusion that increasing feed when drilling causes an increase in the MMC drillability.