Micro drilling characterization of the carbon and carbon–aramid (hybrid) composites

Abstract In this study, micro‐drilling tests were carried out on composite laminates reinforced with hybrid (aramid‐carbon) and carbon fibers. Thrust force, hole quality, tool wear, and temperature parameters were measured and assessed following each drilling test. The quality of holes includes circularity, overcut, hole damage factor (HDF), and taper ratio. Micro‐drilling was performed on a CNC milling machine using 0.6 mm drill diameter, 7500 rpm, and 0.5 mm/min feed parameters. The plates are 3.05 mm (carbon fiber) and 3.45 mm (hybrid) thick. According to the results, the maximum thrust force (29.8 N) was measured in the hybrid composite due to the high fracture toughness of the aramid. In addition, it was determined that the thrust force and drill wear were related. The increase in thrust force during drilling caused an increase in drill wear values. While the average wear of the drill in carbon composite was 0.013 mm, the average wear of the drill in hybrid composite was 0.021 mm. Thrust force and tool temperatures were found to have a similar trend. The highest tool temperature was measured as 86.7°C in the hybrid composite. Hole quality results showed that drilling in carbon composite was more successful than in hybrid composite. Holes drilled in carbon composite have lower values for overcut (0.017 mm), HDF (1.028), and taper ratio (0.008). It has been understood that hole quality depends on thrust force and damage formation. Highlights Carbon and hybrid (carbon‐aramid) composites were produced with a vacuum infusion process (VIP). Micro‐drilling of composites was investigated focusing on thrust force, tool temperature, and hole quality. Hybrid composites exhibited greater thrust forces due to their higher toughness compared to carbon composites. Hybrid composites showed higher maximum tool temperatures compared to carbon composites. The carbon composites exhibited better hole quality compared to the hybrid composites.