Influence of lay-up configuration and feed rate on surface integrity when drilling carbon fibre reinforced plastic (CFRP) composites

Experimental data is presented relating to surface roughness (2D and 3D) and workpiece integrity when drilling unidirectional CFRP laminates with varying lay-up configurations (Type 1, 2 and 3) at different feed rates (0.2 and 0.4 mm/rev) using diamond coated carbide tools. Drill feed rate was ramped down to 0.01 mm/rev for the final 0.5 mm in all trials. Surface roughness at hole exit was typically lower (up to 4.04 μm Ra) compared with the entry section in all tests due to the lower feed rate applied. High resolution SEM micrographs and 3D topographic maps showed that Type 2 ([45/0/135/0/90/0/135/0/45]2S) lay-up gave the lowest roughness of ∼1.16 μm Sa after 384 holes at a cutting speed and feed rate of 90m/min and 0.4 mm/rev respectively. Cavities, smearing of matrix material and adhered/deposited fibre dust were observed near the exit location at test cessation.