Enhancing mechanical properties of CCF/PEEK composites by rotary 3D printing with Co-regulation of hot compaction and fiber tension

Continuous fiber-reinforced thermoplastic composites (CFRTPCs) fabricated by fused deposition modelling (FDM) methods often suffer from insufficient in-situ consolidation, resulting in interfacial voids, fiber waviness, and limited mechanical performance. In this work, a rotary 3D printing platform with real-time closed-loop co-regulation of hot compaction and fiber tension was developed to enhance the consolidation quality of CCF/PEEK composites. The closed-loop force feedback enables stable compaction control during deposition, significantly improving interlayer integrity compared with conventional fixed-height printing. The microstructural evolution is governed by the coupled competition between compaction-induced resin flow and tension-mediated anchoring. Hot compaction promotes matrix flow, effectively suppressing void defects and reducing porosity from 0.99% to 0.2%. However, excessive compaction induces strong hydrodynamic drag and fiber deviation, disrupting fiber alignment. In contrast, increasing fiber tension provides an axial stabilizing constraint, improving fiber collimation (misalignment reduced from 7.46° to 4.84°) and increasing fiber mass fraction from 17.51% to 24.81%. A friction-induced amplification mechanism further links compaction and effective tension, highlighting their intrinsic coupling during rotary consolidation. An optimal synergistic processing window was identified at 60 N compaction and 500 mN tension, delivering peak tensile strength, interlaminar shear strength, and modulus of 257.56 MPa, 31.37 MPa, and 3.24 GPa, respectively. These results establish a quantitative process–structure–property framework for compaction–tension co-regulation, providing guidance for high performance thermoplastic composite manufacturing of curved structural components.