Abstract

While the majority of extrusion-based additive manufacturing (AM) technologies rely on a single point of extrusion, this design choice creates a limitation in that the resolution---the minimum feature size printable by a nozzle of a specific diameter---is quadratically proportional to the overall rate of material extrusion and thus the speed of printing. While this relationship is less limiting when printing at small scales, it emerges as a significant limitation in the case of large-format additive manufacturing (LFAM). The volume of a printed object scales cubically, while the printing speed only increases quadratically in proportion to nozzle size, creating a mismatch in effective resolution as the scale of the print increases. This dissertation presents a novel material extrusion process, Selective Sheet Extrusion (SSE), that decouples these parameters. SSE utilizes a very wide nozzle through which flow is controlled by an array of dynamically actuated teeth at the nozzle outlet, allowing the system to print an entire layer or subsection of a print in a single pass. In this work, we explore the theoretical and experimental performance of the SSE technology, as well as topics such as the increased strength of joints formed with this method and preliminary work on concepts for flow-balancing and the conversion of the lab-based process into a continuous process that could be used commercially. We close with a discussion on the promise of LFAM in building and construction as well as some of the challenges still faced in its adoption.