Methods and apparatus for additive manufacturing of glass
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.
1. An apparatus comprising:
(a) a crucible kiln that includes heating elements;
(b) a nozzle;
(c) an annealing kiln;
(d) a build platform that is located inside the annealing kiln; and
(e) a set of actuators that are configured (1) to cause the crucible kiln and the nozzle to move horizontally relative to the annealing kiln while the crucible kiln and the nozzle remain stationary relative to each other, and (2) to cause the build platform to move vertically relative to the nozzle;
wherein
(i) the heating elements of the crucible kiln are configured to melt and fine glass material in the crucible kiln, to produce a molten glass material,
(ii) the crucible kiln is positioned above and exterior to the annealing kiln, and
(iii) the apparatus is configured to cause the molten glass material to undergo an extruding, in which the molten glass material is extruded through the nozzle to form an object, in such a way that
(A) the molten glass material is, while exiting the nozzle, located inside the annealing kiln, and
(B) during the extruding
(I) temperature in the crucible kiln is higher than temperature in the annealing kiln,
(II) the object being formed rests on the build platform inside the annealing kiln, and
(III) the molten glass material travels downward from the crucible kiln, through the nozzle, and into the annealing kiln.
2. The apparatus of claim 1 , wherein the apparatus is configured to cause the molten glass material to be deposited layer-by-layer to form the object.
3. The apparatus of claim 1 , wherein:
(a) a first actuator, out of the set of actuators, is configured to actuate the kiln and the nozzle to move along a horizontal axis;
(b) a second actuator, out of the set of actuators, is configured to actuate the build platform to rotate; and
(c) a third actuator, out of the set of actuators, is configured to actuate the build platform to move along a vertical axis.
4. The apparatus of 1 , wherein the annealing kiln is configured to anneal extruded glass material.
5. The apparatus of claim 1 , wherein the extruding of the molten glass material through the nozzle is actuated by gravitational force and is not actuated by any other net force.
6. The apparatus of claim 1 , wherein:
(a) a region of the nozzle surrounds a nozzle tip of the nozzle; and
(b) the apparatus is configured to cause the region to undergo cooling, by circulating fluid through the region.
7. The apparatus of claim 6 , wherein an effect of the cooling is that less glass material sticks to the nozzle tip than would stick to the nozzle tip in the absence of the cooling.
8. The apparatus of claim 1 , wherein:
(a) the apparatus further comprises tubes or cavities that surround a nozzle tip of the nozzle; and
(b) the apparatus is configured to cause the tubes or cavities to undergo cooling, by circulating fluid through the tubes or cavities.
9. The apparatus of claim 8 , wherein an effect of the cooling is that less glass material sticks to the nozzle tip than would stick to the nozzle tip in the absence of the cooling.
10. The apparatus of claim 1 , further comprising a valve that is configured to control flow of molten glass material through the nozzle.
11. The apparatus of claim 10 , wherein the valve comprises a pair of shears that are configured to close in such a way that closing the shears:
(a) cuts a filament of the molten glass material that is exiting the nozzle, and
(b) blocks the flow of the molten glass material through an exit orifice of the nozzle.
12. The apparatus of claim 10 , wherein:
(a) the valve comprises a rod; and
(b) the rod is configured to stop the when the rod is moved into the nozzle and touches interior walls of the nozzle.
13. The apparatus of claim 1 , further comprising a plunger that is configured to:
(a) exert pressure on the molten glass material; and
(b) thereby push the molten glass material through the nozzle.
14. The apparatus of claim 1 , wherein:
(a) the apparatus further comprises an air pump and tubes; and
(b) the air pump is configured to pump air through the tubes, in such a way that the air exerts pressure on the molten glass material and thereby pushes the molten glass material through the nozzle.
15. The apparatus of claim 1 , wherein
(a) the apparatus further comprises an air pump and a tube; and
(b) the air pump is configured to pump air through the tube, in such a way that
(i) a column of air infiltrates a filament of the molten glass material as the filament is extruded through the nozzle, and
(ii) the column of air is trapped inside the filament and is co-axial with the filament.
16. The apparatus of claim 1 , wherein the object that is formed is optically transparent.