Drill-milling process and novel drill-milling tool for making a hole on carbon fiber–reinforced plastics

Abstract

During carbon fiber–reinforced plastic (CFRP) hole-making, exit damages such as burrs and delamination frequently occur. Some hole-making technologies are invented to cater to the demands of the high hole quality for CFRP laminates. To adequately eliminate the process-induced damages, a novel dill-milling tool is designed, and a series of drill-milling experiments are conducted on CFRP by using this novel drill-milling tool. Theoretical and experimental analyses of the drill-milling process and the performance of the novel drill-milling have been conducted. The result indicates that compared with the drilling process, using the new drill-milling process, the burrs can be thoroughly removed and the delamination can be reduced significantly, even removed. The changes of the hole quality and the exit damages are different with the variations of the helical milling parameters. Therefore, by comprehensive consideration, proper helical milling parameters should be chosen adequately. Furthermore, in theory, the right-handed helix angles βy should be raised, which is favorable for improving the hole accuracy and reducing the exit damages.