High Fiber Content 3D Printed Dry Continuous Carbon Fiber Reinforce Composites Based on Coaxial Dual‐Aperture Nozzle

Abstract In traditional in‐situ impregnation 3D printing of dry continuous carbon fiber reinforced polymer composites (CFRPCs) with high fiber content, various printing defects caused by the fiber exposure limit the further increase of fiber content. In this study, a coaxial dual‐aperture nozzle printing method is proposed by improving in‐situ impregnation process, realizing matrix uniformly wrapping fibers to avoid fiber exposure at high fiber content (up to 40 vol%). Morphological characterization indicates that the coaxial dual‐aperture nozzle printing approach effectively improves the fiber damage, debonding, dislocation, and dispersion in traditional in‐situ impregnation process, exhibiting better printing quality and molding accuracy. A similar level of fiber‐resin impregnation as the pre‐impregnation process is achieved by the dual‐impregnation effect of the coaxial dual‐aperture nozzle. Mechanical property test results show that the tensile and flexural strengths of the CFRPCs by the coaxial dual‐aperture nozzle are 758.92 ± 40.05 and 534.46 ± 32.10 MPa, which reach performance levels comparable to those of pre‐impregnated CFRPCs with similar fiber contents. Furthermore, the high fiber content also provides possibilities to improve some functional properties of 3D printed CFRPCs. Overall, this study provides a simple method to fabricate high fiber content in‐situ impregnated CFRPCs with excellent properties.