3. Study drilling with commercially available tools

The tools selected for this study are made of K20 grade micro-grain tungsten carbide with a diameter of 6 mm, and feature a helical geometry. Some tools are designed for machining aluminum alloys, while others are dedicated to machining carbon/epoxy composites. As mentioned in Table 2 , we used both thin-coated and uncoated tools. Three types of coating were tested. The first two coatings are available on the market (more specifically from major drill manufacturers such as Dormer, Secotools, Sandvik...). The first coating is TiAlN aluminum titanium nitride, a multi-layer ceramic coating recommended for dry machining on the tools we have named Ref. 1. The second coating is Dialub diamond, particularly recommended for aluminum alloys on the tools we have named Ref. 2.