Investigation of Machining Characteristics and Parameter Optimization for Laser-Assisted Milling of CF/PEEK Composites.

Abstract

Carbon fiber/polyether ether ketone (CF/PEEK) is widely used in aerospace, transportation, and other high-end industries for its light weight, high strength, and recyclability. However, its inherently brittle-ductile two-phase structure presents challenges in processing CF/PEEK. This paper introduces a laser-assisted milling method, wherein four types of CF/PEEK unidirectional plates (0°, 45°, 90°, and 135°) are milled under varying laser powers and spindle speeds. The results are compared with conventional milling (CM) techniques, based on cutting forces, temperatures, surface roughness, and damage defects. The cutting force, temperature, and surface quality were optimal at a fiber direction of 0° and were least favorable at 90° under identical machining conditions. When the fiber direction was 90°, the milling temperatures at 400 W and 500 W laser power decreased by 19.8% and 7.9%, respectively, while the average values of Fx and Fy decreased by 20.5% and 9.55%, compared to conventional milling. Furthermore, the laser-assisted milling method significantly reduces surface defects and improves surface roughness. In CF/PEEK composites, brittle fracture is the primary material removal mechanism, with damage characteristics such as fiber fracture, fiber pullout, and fiber/matrix debonding. The optimal parameter combination is a 0° fiber orientation, 400 W laser power, and a spindle speed of 4000 rpm. This study provides theoretical and technical support for the high-quality processing of CF/PEEK composites.