CONTINUOUS FIBER 3D PRINTING FOR COMPRESSION OVER MOLDING

Due to fiber alignment along the deposition direction, additive manufacturing systems have the capability to produce parts with distinct anisotropic properties. Oak Ridge National Laboratory (ORNL) has developed an innovative Additive Manufacturing - Compression Molding (AM-CM) system that combines the advantages of AM and CM. By creating preforms using AM and subsequently utilizing CM, parts can be fabricated with optimized fiber alignment along the component. This advanced technology allows for the rapid production of parts, meeting the fast-rate process requirements of the automotive industry, with a cycle time of just three minutes. To further enhance the mechanical performance of these components, continuous fiber can be incorporated on top of the mold before the preforming process. Alternatively, the continuous fiber can be pre-printed separately and placed along the mold to over-mold it into the structure during CM. This fusion of materials during CM results in the creation of built-in stiffeners along the loading direction. These modifications enable the precise placement of continuous carbon fiber within the mold, achieving a bend radius that was previously unattainable through traditional methods. The introduction of these fibers has proven to significantly increase flexural strength by 57% and flexural modulus by 49%. Additionally, incorporating continuous fibers along the joints of several parts through over-molding enhances the strength between these components. In summary, the AM-CM system, combined with the integration of continuous carbon fibers, offers an innovative approach to fabricating high-performance parts with unique anisotropic properties, meeting the demands of the automotive industry and beyond.