Multi-scale characterization of the effect of point angle on material damage during drilling of UD-CFRP

This study investigates the effect of tool point angle on cutting efficiency during the drilling of carbon fiber-reinforced plastic (CFRP). A fully three-dimensional finite element model of CFRP drilling (including both macro and micro models) was established and validated using experimental data. The macroscopic analysis simulated the drilling process under different tool point angles (90°, 118°, 140°). The results indicate that the tool point angle significantly influences cutting force levels. Tools with smaller point angles exhibited lower cutting forces due to their efficient cutting geometry, whereas tools with larger point angles resulted in higher peak cutting forces due to the increased contact area. The study also evaluated the impact of tool point angle on delamination damage. Tools with smaller point angles were more effective in cutting fibers and breaking the resin matrix, whereas tools with larger point angles were more prone to causing peel-up and push-out delamination, potentially compromising material integrity. The microscopic-level simulations focused on the influence of different tool rake angles (45° and 59°) on fiber fracture and matrix tearing mechanisms. Overall, the findings suggest that selecting an appropriate tool point angle is crucial for optimizing cutting efficiency and minimizing CFRP drilling damage. Tools with smaller point angles are recommended for their lower cutting forces and reduced delamination, whereas larger point angles should be used cautiously to maintain material integrity and surface quality. This study provides valuable insights for optimizing CFRP drilling processes and improving machining performance.