Numerical investigation on the damage mechanism of CFRP drilling under different pretreatment temperatures based on bevel cutting

Abstract The widespread use of CFRP components in the aerospace industry has led to a significant increase in the demand for assembly holes, for which drilling remains the primary machining method. To effectively mitigate drilling-induced damage, this study simplifies the CFRP drilling process as oblique cutting and develops a temperature-dependent, three-dimensional microscale oblique cutting model based on the Johnson–Cook constitutive law, which is validated using experimental data. The analysis reveals that resin behavior is critical to fiber fracture and identifies unsupported exit-side cutting as the primary cause of severe damage and demonstrates that cryogenic pretreatment significantly reduces subsurface damage and enhances surface quality. Further investigation into key parameters such as cutting depth, tool inclination, rake, and clearance angles under low-temperature conditions reveals that variable-parameter drilling strategies can improve hole quality without compromising efficiency. Parametric studies show that subsurface damage peaks at a cutting depth of 80 μm (126 μm, 2.34 times greater than at 30 μm) and is highly sensitive to the blade inclination angle (2.62 times greater at 45° than at 15°). A blade angle of 60° induces severe workpiece tearing. Additionally, optimized tool design – featuring localized negative or low inclination angles to suppress exit tearing and graded positive angles to minimize entry burrs and facilitate chip removal – can substantially enhance overall hole quality. These findings provide valuable insights for the development of low-damage drilling techniques and equipment for CFRP applications.