Injection solid freeforming of polymer and ceramic composite materials

Abstract

Solid freeform fabrication processes (SFF) have been the subject of much research and discussion within recent years. Unlike other near net shape manufacturing processes (i.e. conventional injection molding, casting, or bulk machining), SFF techniques fabricate parts "from the ground up" by the sequential deposition and curing of raw material slurry layers upon each other until the final part results. Precise spatial control of deposited layers is achieved through CAD software and hardware interfaced with the SFF apparatus. The development of suitable SFF compatible raw material formulations and appropriate processing parameters are discussed in this dissertation. In particular, a wide range of materials have been fabricated and characterized at AML and ACR using this technique including alumina., crosslinked acrylate, and high molecular weight Nylon 6 thermoplastics. Comparisons are made between the mechanical properties of the SFF and corresponding commercial conventionally processed materials. Finally, the heat transfer and polymerization kinetics associated with three model SFF resin formulations are discussed and compared to corresponding empirical SFF process observations.