ANISOTROPIC IMPACT TOUGHNNESS OF CHOPPED CARBON FIBER REINFORCED NYLON FABRICATED BY MATERIAL-EXTRUSION-BASED ADDITIVE MANUFACTURING

3D printed polymer composites are gaining more interest due to weight reduction and high geometrical complexity freedom especially for highly demanding applications such as aerospace and defense. Using the material-extrusion based processes, polymer matrix composite parts with complex geometries can be designed and realized to improve the mechanical properties of pure thermoplastic parts. However, in addition to porosity found at the fracture interfaces, the layered nature additive manufacturing processes may become a limitation for the direct replacement for functional applications. In this study, the results of Charpy impact testing of chopped carbon fiber reinforced nylon fabricated by fused deposition modeling (FDM) are reported. The effects of the build direction and customized density by different infill strategies on the obtained toughness are presented in comparison to the one of nylon without any reinforcement. The toughness results show a severe anisotropy in toughness and high dependence on the infill strategy.