The mechanical performance of the 3D printed composites produced with continuous carbon fiber reinforced filaments obtained via melt impregnation

Abstract Additive manufacturing of the continuous fiber-reinforced thermoplastic (CFRTP) composites with fused deposition modeling is an up-and-coming production method because of their exceptional mechanical properties, even though these values are still relatively low when compared with conventional thermoset products. In this respect, the additive manufacturing of continuous fiber-reinforced thermoplastic composites with high mechanical properties based on PLA thermoplastic polymer was investigated in this study. At the first stage, a polymer impregnation line was designed for manufacturing pre-preg forms of the continuous fiber-reinforced thermoplastic filaments with different fiber fractions. Afterward, standard tensile and three-point bending test specimens were printed with the fused deposition modeling (FDM) method using these filaments. Test results showed approximately 989 MPa tensile strength for pre-preg filaments. Maximum tensile strength of 544 MPa and maximum flexural strength of 310 MPa were achieved for CFRTP specimens with a 40% fiber fraction. In addition, scanning electron microscope (SEM) inspection showed a quite homogenous impregnation in both the filaments and the printed parts. Obtained results indicate that this manufacturing method could be a promising approach for printing CFRTP parts with improved mechanical properties.