Prediction model in drilling of unidirectional thermoplastic CF/PEEK composite laminates considering the chisel edge

Carbon fiber reinforced thermoplastic composites (CFRTP) are increasingly becoming critical lightweight and high-efficiency materials in manufacturing fields such as aerospace and defense technology, owing to their high strength, high modulus, and environmentally friendly recyclability. As a high-performance CFRTP, carbon fiber reinforced polyetheretherketone (CF/PEEK) composites are typically joined with other materials through drilling, where the thrust force is a key parameter affecting hole quality. A novel predictive model for the thrust force in unidirectional CF/PEEK (UD-CF/PEEK) composites was established based on the two-parameter elastic foundation theory and Hertz contact, taking into account tool structure and material characteristics. Experimental validation results showed that the prediction errors for the thrust forces of the chisel edge and the main cutting edge were 1.46% and 8.89%, respectively, and the prediction error for the total thrust force was 6.27%. Furthermore, by investigating the influence of different drilling parameters on the thrust force of UD-CF/PEEK, it was found that at a constant spindle speed, an increase in the feed rate leads to a rising trend in the thrust forces of both the chisel edge and the main cutting edge. This finding provides theoretical guidance for low-damage hole-making in thermoplastic CF/PEEK composites.