Provided is a method and apparatus for building a structure of glass using additive manufacturing technology. The apparatus incorporates a method of depositing molten glass material in discrete droplets rather than as a continuous fused filament. The additive manufacturing of glass material relies on the surface tension, the high viscosity of the molten glass, and droplet formation to control deposition by melting the glass filament directly without the use of a needle or crucible.

In illustrative implementations of this invention, a crucible kiln heats glass such that the glass becomes or remains molten. A nozzle extrudes the molten glass while one or more actuators actuate movements of the nozzle, a build platform or both. A computer controls these movements such that the extruded molten glass is selectively deposited to form a 3D glass object. The selective deposition of molten glass occurs inside an annealing kiln. The annealing kiln anneals the glass after it is extruded. In some cases, the actuators actuate the crucible kiln and nozzle to move in horizontal x, y directions and actuate the build platform to move in a z-direction. In some cases, fluid flows through a cavity or tubes adjacent to the nozzle tip, in order to cool the nozzle tip and thereby reduce the amount of glass that sticks to the nozzle tip.

A glass manufacturing apparatus is disclosed including a vessel configured to convey molten glass, a conduit extending from the vessel, the conduit including a distal end with a concave heating member joined thereto, a first electrical flange joined to the conduit, and a second electrical flange joined to the concave heating member. A method of preventing devitrification of a molten glass forming material is also described.

A glass manufacturing apparatus is disclosed including a vessel configured to convey molten glass, a conduit extending from the vessel, the conduit including a distal end with a concave heating member joined thereto, a first electrical flange joined to the conduit, and a second electrical flange joined to the concave heating member. A method of preventing devitrification of a molten glass forming material is also described.