Impact of cooled compressed air and high-speed cutting on the drilling of hybrid composite-metal stacks

Abstract Hybrid composite-metal stacks (HCMS) are used to manufacture and maintain aircraft combining metal alloys and composite materials. Drilling stands out due to its high use for installing rivets in fuselages. This work sought to identify the influence of cooled compressed air and high-speed cutting (HSC) on drilling multi-material joints with different configurations. Among the factors observed are the composite type (carbon- or glass-fiber-reinforced polymer), joint type with 2024 aluminum alloy (simple or composed), presence or absence of cooled air, cutting speed (40 and 220 m/min), and feed rate (0.02 and 0.08 mm/rev) in HCMS drilling. Adjusted delamination factor, hole wall roughness, hole roundness, and thrust force were evaluated. The combined effect between cutting speed and cooled air did not significantly impact the defects generated, making it possible to use HSC without harming the joint. Cooled air showed a tendency to decrease defects in HCMS drilling.