Additive manufacturing of carbon fiber reinforced polymers (CFRP) provides the advantage of quick prototyping of complex geometries, while maintaining light-weight characteristics and keeping structural integrity. This paper presents flexural strength data from 3D printing of an onyx and carbon fiber composites. A MarkForged Mark 2 3D printer, with a dual printer head, is used to 3D print several configurations of CFRP composites. The configurations are set to examine the extreme parameters of the rectangular fill pattern, including fill density, roof and floor layers, and wall layers. The print angle along with the fill pattern stays consistent. Each sample comprises twenty- four layers of CFRP and undergoes a three-point bend test. Test data of load, deflection, and maximum stress are compared among the different configurations. Results show that the roof/floor layer has the largest impact on the flexural strength for each configuration. The configurations with less roof/floor layers are able to take on a larger load, because there are more CFRP layers present; while specimens with more roof/floor layers withstand less load and behave more ductile. These results show that the amount of roof/floor layers can change the CFRP composite from its usual brittle characteristic to a ductile behavior.
A novel device to simply 3D print bulk green ceramic components by stereolithography employing viscous slurries