Common thermoplastic 3D Printed parts have reduced mechanical properties in the build direction of the print, and are generally weaker and less stiff than their equivalent injection-molded or machined parts. A promising solution to increase the stiffness and strength is investigating the addition of continuous carbon fibers in the print. Reinforcement of the inter-layer bonding may come through the addition of continuous fiber reinforced material deposited on an existing structure in the build direction, which implies stepping away from layer-by-layer manufacturing using true 3D deposition and tool-pathing. This is possible by exploiting the full benefits of a 6 degree of freedom Fused Filament Fabricated / Fused Deposition Modeled system. For this research, an industrial robotic platform is equipped with a continuous fiber deposition end effector capable of deposition with engineering thermoplastics. Using previously developed application-driven software to generate the toolpaths for the printer, a variety of parts were printed. The parts range from traditional, horizontal layer-by-layer parts to multi-axis overprinted parts. During ASTM tensile testing of coupons, a sixfold tensile strength-to-weight increase and a sixteenfold increase in tensile stiffness are observed when compared to unreinforced thermoplastic properties. The potential of the system and software capabilities are further demonstrated though sample complex multi-axis 3D printed parts.
展开▼
