Techniques for depowdering additively fabricated parts via gas flow and related systems and methods
Techniques for depowdering in additive fabrication are provided. According to some aspects, techniques are provided that separate powder from parts by directing gas onto, or near to, the powder. While fragile green parts, such as green parts produced by binder jetting, may be fragile with respect to scraping or impacts, such parts may nonetheless be resistance to damage from directed gas, even if directed at a high pressure. Techniques for depowdering through directed application of gas may be automated, thereby mitigating challenges associated with manual depowdering operations.
1. A method for extracting one or more additively fabricated parts from a powder bed comprising a powder and the one or more additively fabricated parts, the method comprising:
inserting at least part of the powder bed into a chamber, the chamber comprising one or more inlets and one or more outlets, wherein the one or more inlets comprise one or more openings into the chamber;
forming a hermetic seal around the at least part of the powder bed;
directing, using one or more nozzles, one or more jets of gas onto a surface of the powder bed within the chamber; and
producing, concurrently with said directing the one or more jets of gas onto the surface of the powder, a continuous flow of gas through the chamber from the one or more inlets to the one or more outlets such that powder from the powder bed is transported through at least some of the one or more outlets.
2. The method of claim 1 , wherein the powder bed is held within a build box, and wherein forming the hermetic seal around the at least part of the powder bed comprises forming the hermetic seal around the build box.
3. The method of claim 1 , wherein the powder bed comprises a metal powder and wherein the one or more additively fabricated parts comprise particles of the metal powder and at least one binding agent.
4. The method of claim 1 , wherein a vacuum is coupled to the one or more outlets to, at least in part, produce the continuous flow of gas through the chamber.
5. The method of claim 1 , further comprising moving the one or more nozzles relative to the surface of the powder bed while directing the one or more jets of gas onto the surface of the powder bed.
6. The method of claim 5 , wherein the one or more nozzles are part of a movable structure and moving the one or more nozzles relative to the surface of the powder bed comprises moving the movable structure over the surface of the powder bed.
7. The method of claim 1 , wherein the one or more inlets pass through one or more planet gears of a planetary gear train.
8. The method of claim 1 , further comprising raising the powder bed and thereby pushing additional parts of the powder bed into the chamber.
9. The method of claim 1 , wherein the one or more jets of gas directed using the one or more nozzles comprises air.
10. The method of claim 1 , wherein the continuous flow of gas comprises a continuous flow of air.
11. The method of claim 1 , wherein the one or more inlets are part of a closed loop with the one or more outlets.
12. The method of claim 1 , wherein the one or more inlets includes a first inlet, wherein the one or more outlets includes a first outlet, and wherein the first inlet is arranged on an opposing side of the chamber from the first outlet.
13. The method of claim 5 , further comprising moving at least part of the one or more nozzles into the powder bed while directing the one or more jets of gas into the powder bed.
14. The method of claim 1 , wherein the continuous flow of gas through the chamber from the one or more inlets to the one or more outlets generates an ambient pressure difference within the chamber between the one or more inlets and the one or more outlets.