Methods and apparatus for additive manufacturing of glass

• US 9,896,368 B2
• Filed: 11/30/2016
• Issued: 02/20/2018
• Est. Priority Date: 04/25/2014
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Klein, John, Franchin, Giorgia, Stern, Michael, Kayser, Markus, Inamura, Chikara, Dave, Shreya, Oxman, Neri, Houk, Peter
• Primary Examiner(s): Hindenlang, Alison L
• Assistant Examiner(s): Ahmed Ali, Mohamed K
• Application Number:
  US15/365,577
• Publication Number:
  US 20170081236A1
• Time in Patent Office: 447 Days
• Field of Search: 65127, 65129, 65164, 65326
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: C03B 17/00 Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
• CPC Class Codes: C03B 17/025 Tubes or rods
• CPC Class Codes: C03B 17/04 Forming tubes or rods by drawing from stationary or rotating tools or from forming nozzles
• CPC Class Codes: C03B 19/00 Other methods of shaping glass manufacture or treatment of flakes, fibres or filaments from softened glass, minerals or slags C03B37/00
• CPC Class Codes: C03B 19/02 by casting molten glass, e.g. injection moulding
• CPC Class Codes: C03B 25/02 in a discontinuous way
• CPC Class Codes: C03B 3/00 Charging the melting furnaces
• CPC Class Codes: C03B 5/021 by induction heating
• CPC Class Codes: C03B 5/0334 Pot furnaces; Core furnaces
• CPC Class Codes: C03B 5/0336 Shaft furnaces C03B5/0338 takes precedence
• CPC Class Codes: C03B 5/26 Outlets , e.g. drains, siphons; Overflows , e.g. for supplying the float tank, tweels
• CPC Class Codes: C03B 7/088 Outlets, e.g. orifice rings
• CPC Class Codes: C03B 7/094 Means for heating, cooling or insulation
• CPC Class Codes: C03B 7/098 electric
• CPC Class Codes: C03B 7/12 Cutting-off or severing a free-hanging glass stream , e.g. by the combination of gravity and surface tension forces

Abstract

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.

Claims

1. A method comprising, in combination:

(a) melting and fining glass material in a crucible kiln due to heat produced by heating elements of the crucible kiln, which melting and fining produces a molten glass material; and

(b) extruding the molten glass material through a nozzle to form an object;

wherein

(i) the molten glass material is, while exiting the nozzle during the extruding, located inside an annealing kiln, and

(ii) during the extruding

(A) temperature in the crucible kiln is higher than temperature in the annealing kiln,

(B) the object being formed rests on a build platform inside the annealing kiln,

(C) the crucible kiln is positioned above and exterior to the annealing kiln, such that the molten glass material travels downward from the crucible kiln, through the nozzle, and into the annealing kiln, and

(D) a set of actuators causes

(I) the crucible kiln and the nozzle to move horizontally relative to the annealing kiln and to remain stationary relative to each other, and

(II) the build platform to move vertically relative to the nozzle.

2. The method of claim 1, wherein the molten glass is deposited layer-by-layer to form the object.

3. The method of claim 1, wherein:

(i) a first actuator, out of the set of actuators, actuates the kiln and the nozzle to move along a horizontal axis, and

(ii) a second actuator, out of the set of actuators, actuates the build platform to rotate, and

(iii) a third actuator, out of the set of actuators, actuates the build platform to move along a vertical axis.

5. The method 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 method of claim 1, wherein:

(a) a region of the nozzle surrounds or is adjacent to an exit orifice of the nozzle;

(b) the method further comprises cooling the region by causing fluid to flow through the region; and

(c) the fluid is cooler than molten glass material exiting the exit orifice.

7. The method of claim 6, wherein an effect of the cooling is that less glass material sticks to a tip of the nozzle than would stick to the nozzle in the absence of the cooling.

8. The method of claim 1, wherein:

(a) tubes or cavities surround or are adjacent to an exit orifice of the nozzle;

(b) the method further comprises cooling the region by causing fluid to flow through the tubes or cavities; and

(c) the fluid is cooler than molten glass material exiting the exit orifice.

9. The method of claim 8, wherein an effect of the cooling is that less glass material sticks to a tip of the nozzle than would stick to the nozzle in the absence of the cooling.

10. The method of claim 1, further comprising a valve controlling flow of molten glass material through the nozzle.

11. The method of claim 10, wherein:

(a) the valve comprises a pair of shears; and

(b) closing the shears

(i) cuts a filament of the molten glass material that is exiting the nozzle, and

(ii) blocks the flow.

12. The method of claim 10, wherein:

(a) the valve comprises a rod; and

(b) the rod stops the flow when the rod is moved into the nozzle and touches interior walls of the nozzle.

13. The method of claim 1, further comprising a plunger:

(a) exerting pressure on the molten glass material; and

(b) thereby pushing the molten glass material through the nozzle.

14. The method of claim 1, further comprising air:

(a) exerting pressure on the molten glass material; and

(b) thereby pushing the molten glass material through the nozzle.

15. The method of claim 1, further comprising blowing air through a tube, such that:

(a) a column of air infiltrates a filament of the molten glass material as the filament is extruded through the nozzle; and

(b) the column of air is trapped inside the filament and is co-axial with the filament.

16. The method of claim 1, wherein the object that is formed is optically transparent.

4. The method of 1, wherein after the extruding, the annealing kiln anneals extruded glass material.