High‐Performance CCF / PETG Filaments for Additive Manufacturing Prepared by Melt Impregnation

ABSTRACT Continuous carbon fiber‐reinforced polymers (CCFRPs) exhibit superior mechanical properties compared with short‐fiber‐reinforced composites, while additive manufacturing (AM) enables the fabrication of complex geometries. Among various material systems, continuous carbon fiber‐reinforced polyethylene terephthalate glycol (CCF/PETG) produced by AM is particularly attractive due to its good processability and chemical resistance. In this work, a custom melt‐impregnation setup was developed to manufacture CCF/PETG prepreg filaments. The filament properties were systematically tuned by adjusting key processing parameters, especially impregnation temperature, impregnation pressure, and winding speed. By increasing the impregnation temperature and pressure while reducing the winding/stretching speed, stable forming and enhanced impregnation quality were achieved. Under optimized conditions, the prepared filaments reached a peak tensile strength of 1103.25 MPa, with a fiber volume fraction of 39.13%, a dense microstructure (porosity < 1%), and good geometric fidelity (circularity of 0.95). The practical printability of these filaments in fused deposition modeling (FDM) was further demonstrated: printed CCF/PETG components achieved a tensile strength of 715.16 MPa and a flexural strength of 457.44 MPa along the fiber direction. These results confirm that the proposed melt‐impregnation route can produce high‐quality continuous‐fiber thermoplastic feedstocks and enable the fabrication of high‐performance composites by AM.