Additive Manufacturing Of Glass Using A Filament Fed Process

"There are many scientific and engineering applications of glass including optics, communications, electronics, and hermetic seals, there has been minimal research towards the Additive Manufacturing (AM) of transparent glass parts. The special thermal and optical properties of glasses make them hard to be printed using conventional AM techniques. In this dissertation, two different AM techniques for glass AM were developed, Selective Laser Melting (SLM) and filament fed process. Semi-transparent parts were printed with SLM process. However, the filament fed process was found to be more robust and promising for printing optically transparent glass parts. Therefore, this dissertation is focused on filament fed process for different types of glass, including soda lime glass, fused quartz and borosilicate glass. For soda lime glass, the optical quality of the best printed part was found to be as good as furnace cast glass part using the same type of filaments. Optical defects and refractive index inhomogeneity can be linked to the molten region temperature. Furthermore, the mechanism of bubble formation in soda lime glass printing was also studied. Different regimes of bubble formation were found corresponding with different process parameters. Though the melting temperature of fused quartz is very high (~2300 °C), 3D fully transparent cubes with high index homogeneity were printed. For borosilicate glass, 3D fully transparent parts were printed, and the optical quality of best printed sample is as good as conventionally manufactured borosilicate glass"--Abstract, page iv.