Optimal cutting parameters and tool geometry in drilling of CFRP/CFRP stack laminates for aeronautical applications

Drilling stands out as the most widespread machining process of carbon fibre reinforced plastic (CFRP) composite parts, primarily in the aerospace industry due to the extensive use of mechanical assembly using fasteners such as rivets or bolts. In this paper, drilling of CFRP/CFRP stacks for aeronautical applications is investigated using two different types of drilling tools, a traditional twist drill and an innovative step drill, under different spindle speed and feed rate conditions to evaluate the optimal drilling parameters and the most suitable drill bit geometry for one-shot stack drilling. Automatic image processing is applied to evaluate the hole quality parameters and the relationship between tool wear and hole quality is studied for both tool types.