An investigation of drilling high-strength CFRP composites using specialized drills

Machining of high-strength carbon fiber reinforced polymers (CFRPs) has faced great challenges in quality control and tool wear management due to their inherent heterogeneity and high abrasiveness leading to serious workpiece damage and rapid tool wear. The present paper contributes to an experimental investigation of evaluating the machinability of one type of high-strength T800/X850 CFRPs representative of aircraft components. The novelty of this work lies in identifying the effects of different specialized drills on the drilling process of the high-strength CFRPs by covering a variety of aspects involving the drilling forces, hole morphologies, workpiece damage, hole dimensional accuracy, and tool wear. Both the in-situ and post-process measuring results were correlated with the input process parameters and the used drill bits. A particular focus was placed on the inspections of the resulting tool morphologies and wear mechanisms governing the drilling of the high-strength CFRPs. The results highlight the importance of using functionally designed drills and optimum cutting conditions in realizing the damage-free drilling of T800/X850 composites.