Continuous Fiber Additive Manufacturing of US Navy Propulsion Shafting

Continuous Fiber 3D (CF3D) manufacturing is a cutting-edge composite manufacturing technology that has the potential to enable higher-performing (e.g., specific stiffness, dimensional stability) and lower-cost (e.g., less material waste, minimized part count, reduced touch labor) structures for future Navy applications. CF3D works by combining dry fiber tows with liquid snap-curing thermoset resin inside of a print head on the end of a six-axis robotic arm. As the green composite is discharged and consolidated, it is snap-cured into place enabling the manufacturing of complex composite structures (e.g., fiber steering, stacking, tight contours) with high fiber volume fractions (>50%) and low void volume fractions (<2%). The Navy continues its use of innovative propulsion shaft designs, which will benefit from advanced manufacturing techniques such as CF3D. The proposed innovation is to enable large, thick walled shafts to be made using the emerging CF3D® manufacturing process that is suitable for Navy submarine use. This proposal endeavors to advance and characterize the CF3D materials and process through testing of torsional strength, property scaling, and manufacturing processes. Testing will be conducted at the coupon and representative structure sub-scale. The equipment manufactured and processes developed by Continuous Composite will enable many innovators and manufacturers to develop hardware for the Navy and customers with unique composite needs. Phase I Base will include cylindrical coupon testing and larger shaft builds. Phase I Option with include further development, FEA and test planning for Phase II.