Study of the Material Removal Mechanism and Surface Damage in Laser-Assisted Milling of CF/PEEK.

Carbon-fiber-reinforced polyetheretherketone (CF/PEEK) composites are being increasingly used in aerospace, biomedical, and other industries due to their superior mechanical properties. However, CF/PEEK structural components require secondary processing after curing and molding to meet connection and assembly precision requirements. This process, however, often results in defects such as burrs and pits, which significantly compromise the mechanical performance and assembly quality of the structural components. This study first employed finite element simulations to analyze the laser-assisted milling of CF/PEEK composites, investigating the material removal mechanism under thermal coupling, which was then experimentally validated. Variations in the cutting force, cutting heat, surface damage, and fiber fracture mechanisms during milling were investigated. During laser-assisted milling, the fibers fractured mainly in bending at a cutting angle of 0°, in bending shear at a cutting angle of 45°, in compression at a cutting angle of 90°, and in compression shear at a cutting angle of 135°. The experimental findings were generally consistent with the simulation results. In addition, laser-assisted milling effectively reduced the cutting forces, cutting temperatures, and surface damage compared to conventional milling; laser-assisted milling reduced the cutting forces in the 90° fiber direction by 24.8% (total cutting forces) and 16.3% (feed-cutting forces). The fiber integrity was further increased with increasing spindle speed.