Machinability Analysis of CF / PEEK Composites Under Laser‐Ultrasonic Coupling‐Assisted Milling

ABSTRACT Carbon fiber‐reinforced polyether ether ketone (CF/PEEK) is extensively utilized in aerospace and transportation for its low weight, high strength, recyclability, and reparability. The coexistence of a brittle reinforcement phase and a ductile matrix phase in CF/PEEK complicates processing and fabrication. Milling performance under conventional, laser‐assisted, ultrasonic vibration‐assisted, and laser‐ultrasonic‐assisted milling is analyzed, considering fiber orientation angles and spindle speeds, with evaluation based on milling forces, surface roughness, and defect formation. Milling force reaches its minimum and surface quality its maximum at a 0° fiber orientation, while 90° results in the poorest performance. At a fiber orientation of 90°, laser‐ultrasonic‐assisted milling (LAM‐UAM) reduces the normal milling force ( F n ) by 31.5%, 35.8%, and 38.6% and the tangential milling force ( F t ) by 47.6%, 45.4%, and 51.6% compared to conventional milling (CM) at spindle speeds of 2000, 4000, and 6000 r/min, respectively. LAM‐UAM enhances surface quality, minimizing defects in topography. Damage mechanisms in CF/PEEK laminates comprise brittle fiber fracture, PEEK resin smearing, fiber/matrix debonding, and fiber pullout. The optimal machining strategy for minimal damage involves a 0° fiber orientation, laser‐ultrasonic‐assisted milling, and a spindle speed of 6000 r/min. This study offers theoretical insights and technical guidance for CF/PEEK precision machining.