Damage Reduction Mechanism in Drilling Carbon Fiber Reinforced Polyetheretherketone Composite With Double‐Angle Drill Based on Cutting‐Edge Decomposition

ABSTRACT Drilling of carbon fiber reinforced polyetheretherketone (CF/PEEK) is prone to burr and delamination damage due to coupled thermal‐mechanical effects. A double‐angle drill featuring a double‐top angle and an outer‐edge tip is developed based on cutting‐edge decomposition to mitigate such damage. The drilling process of this drill is analyzed, and drilling experiments are conducted on CF/PEEK composites. Results demonstrated that the double‐angle drill demonstrated the best cutting performance. In comparison with the traditional twist drill, the double‐angle drill reduces the average thrust force and drilling temperature by 45.09% and 10.54%, respectively. This reduction is attributed to the shortened contact length between the cutting edge and chips, as well as the progressive cutting achieved by multiple cutting edges. Moreover, the double‐angle drill generated a lower delamination and burr factor, which can be attributed to its independent cutting tips. This design minimizes extrusion and thermal effects during the formation of the machined surface, thereby reducing hole‐making damage. This study presents a new methodology for improving the drilling quality of CF/PEEK composite.