Preparation of Continuous Carbon‐Fiber/Polycarbonate Prepreg Filaments With Low Damage Based on a Synergistic Suspension Pre‐Impregnation and Melt‐Impregnation Process

ABSTRACT Continuous carbon‐fiber reinforced polycarbonate ( CCF / PC ) prepreg filaments are promising feedstocks for 3D printing, yet their fabrication remains challenging due to the high melt viscosity of PC , which hampers resin infiltration and commonly requires high processing tension, resulting in void defects and fiber damage. In this work, a synergistic suspension pre‐impregnation and melt‐impregnation process is proposed to uniformly deposit PC powders onto carbon fiber prior to melt consolidation, thereby improving infiltration efficiency without the need for damage caused by mechanical broadening and high tension traction. The effects of melt‐impregnation temperature (270°C–300°C) and drawing speed (7–21 mm/s) on microstructure, porosity, and tensile properties were systematically investigated. Under the optimized condition (290°C, 7 mm/s), the prepreg filament achieved a low porosity of 8 × 10 −3 and a tensile strength of approximately 1550 MPa , which is only 3% lower than the theoretical value, indicating effective mitigation of fiber damage. 3D printing using the optimized filament produced unidirectional specimens with a tensile strength of about 875 MPa and a modulus of 78 GPa , demonstrating the feasibility of the proposed route for high‐performance continuous‐fiber thermoplastic additive manufacturing.