Silicon-based Nozzles for Controlled Fiber Alignment in Composite 3D Printing

3D printing is often constrained by the properties of traditional filament materials like PLA. While fiber-reinforced composites improve performance, the magnitude of these improvements is affected by the orientation of the fibers. Parts with most fibers aligned in an ideal direction will outperform a part with a random distribution of fiber orientations. Currently, fiber orientation control during printing requires expensive equipment. Using inexpensive, easily scalable techniques developed for fabricating MEMS devices, we produce silicon nozzles that encourage passive alignment of fibers in any chosen direction. A single crystal silicon wafer, processed through photolithography and anisotropic etching, creates a nozzle with a non-circular interior cross-section that induces fiber rotation as the filament is extruded through it. Through the ability to control and vary the fiber orientation in different parts of a 3D printed component, our method provides an alternate pathway to enhancing electrical, thermal or mechanical performance. Compatible with materials like glass and carbon fibers, this technique enables stronger, more functional 3D-printed parts at affordable costs.