High-throughput extrusion-based additive manufacturing

Abstract

Additive manufacturing (AM), the process of building objects layer by layer from a three dimensional digital model, is gaining significance due to its ability to create unique geometries and/or novel material compositions while spanning a wide range of length scales. However, the viability of using AM for the production of end-use parts hinges on improvements to production speed without making sacrifices to quality. This thesis seeks to understand the rate-limits to extrusion-based AM, commonly referred to as fused deposition modeling (FDM), and to demonstrate this understanding via the design and fabrication of a high-throughput extrusion AM platform. Three subsystems - the pinch wheel extruder, the conduction liquefier, and the open loop series gantry - were identified as rate limiting to conventional FDM systems via module level experimentation and analysis. These limitations motivated the development of three alternate mechanisms -a screw-feed extruder, a laser-heated extruder, and H-frame gantry - which are designed to overcome the limitations of conventional techniques. These mechanisms are combined into a high-throughput desktop-scale prototype, called FastFDM. Using the FastFDM system, test parts are fabricated at twice the material deposition rate of state-of-the-art machines while maintaining comparable accuracy and resolution. The FastFDM approach has promising future applications to the extrusion AM of nanocomposite polymer resins, high-throughput AM of high performance thermoplastics, and adaptation to large-scale extrusion AM systems.