Enhancing the Mechanical Properties and Forming Efficiency of Fused Granular Fabricated <scp>PETG</scp> ‐ <scp>CF</scp> Composites via Process Optimization and Heat Treatment

ABSTRACT To meet the dual demands for mechanical properties and forming efficiency of large‐sized structural components, fused granular fabrication (FGF) was adopted to form carbon fiber reinforced poly(ethylene terephthalate glycol‐co‐1,4‐cyclohexanedimethanol terephthalate) (PETG‐CF). A single‐factor experiment was designed to explore the effects of layer height ( h ), nozzle diameter ( d ), printing speed ( v ) and annealing on forming efficiency and mechanical properties. The combination of h = 0.2 mm, d = 0.4 mm and v = 50 mm/s was selected as the reference parameter. The results show that the layer thickness and nozzle diameter will significantly affect the interlayer and intra‐layer bonding, while the printing speed will affect the melting and cooling states of the material. Increasing the nozzle diameter (0.4–0.8 mm)/printing speed (50–100 mm/s) can not only significantly shorten the printing time (44.44%/38.89%), but also significantly improve the tensile strength (15.80%/12.24%). Annealing can promote the diffusion of pores and the rearrangement of molecular chains. Annealing at 65°C for 480 min can achieve a tensile strength of 53.8 MPa, 16.58% higher than unannealed. This study has achieved a synergistic improvement in the mechanical properties and forming efficiency of PETG‐CF.