Improvements to Large Scale Additively Manufactured Components via In-situ and Post Process Composite Modifications

Conference Abstract: Large Scale Additive Manufacturing (LSAM) has revolutionized the manufacturing industry by enabling the production of large, complex structures with unprecedented speed and precision. This work evaluates the viability of a simplified in-situ process and post-print modifications for improved mechanical performance and light-weighting. LSAM components often struggle in attaining the performance criteria of more traditional manufacturing methods due to the time-based deposition and macro-scale voids. The incorporation of unidirectional carbon fiber reinforcement, polyurethane foam infill, and post-printing composite wrapping allow for significant changes in performance with minimal increase to cost or adjustment of process parameters. While the advantages of integrating fiber and foam materials into additively manufactured components are widely acknowledged, existing approaches frequently involve intricate or costly methods that necessitate extra planning and effort for their integration into LSAM-produced components. This approach investigates the addition of foam and fiber inlays by hand placement and evaluates the impact of the rudimentary placement on performance and material properties. Test samples were fabricated using Poly-Lactic Acid (PLA) as the base material with combinations of five 1.5-inch-wide unidirectional carbon fiber strips, 25 vol% 6 lb/ft3 polyisocyanurate foam, and 40 oz/yd2 tri-axial E-glass fibers as reinforcement. Samples were evaluated for flexural and tensile strength to characterize changes in performance for deformation and z-axis adhesion. LSAM parts containing uni-directional fibers, foam inserts, and post processing wraps demonstrated an 82% increase in flexural strength while simultaneously reducing weight by 9.5%, whereas the placement of unidirectional fibers alone increased the flexural strength by 26%. The addition of reinforcing materials to LSAM components via hand application provides significant benefit to performance without changing the manufacturing process.