There are several techniques for 3D printing glass by sequentially fusing molten tracks. We investigate a process feeding cool glass filament into a CO2 laser to provide local heating. Unlike most crystalline materials, glasses retain significant viscosity when molten. In filament-fed laser heated processing the feed exerts a significant stress on the laser heated region which strongly influences on final track geometry. This introduces challenges but also allows the creation of fully dense glass volumes and free-standing structures. The stress field on the molten region is controlled by using pneumatics and orienting the feed in the moving deposition coordinate system.
Additive Manufacturing (AM) of low-profile 2.5D glass structures is demonstrated using a fiber-fed laser-heated process. In this process, glass single mode optical fibers with diameters 90-125 μm are fed into the intersection of a workpiece and CO2 laser beam. The workpiece is positioned by a four-axis CNC stage. Issues unique to the process are discussed, including the thermal breakdown of the glass and index inhomogeneity. Scanning electron microscopy reveals that the core/cladding structure of the fiber remains intact during printing and can be used to guide light for photonic applications.