Method for additively manufacturing an object and additively manufactured object

1. A method of additively manufacturing an object, the method comprising:

successively forming a plurality of powder layers by depositing powder;

successively forming a binder shell by bonding select regions of each one of the plurality of powder layers before forming each successive one of the plurality of powder layers,

such that

the binder shell is formed of bonded powder and

the binder shell encloses a powder core formed of unbonded powder;

tamping at least a portion of the unbonded powder bound by the binder shell to apply a compression force for packing the unbonded powder bound by the binder shell; and

fusing the unbonded powder of the powder core and the bonded powder of the binder shell together to form a finished object.

2. The method of claim 1 , further comprising subjecting-at least the portion of the unbonded powder bound by the binder shell to vibratory energy.

3. The method of claim 1 , wherein:

successively forming the plurality of powder layers is performed using a powder-deposition apparatus; and

successively forming the binder shell is performed using a binder-delivery apparatus; and

tamping at least-the portion of the unbonded powder bound by the binder shell is performed using a tamping mechanism.

4. The method of claim 1 , wherein successively forming the binder shell comprises delivering binder at the select regions of each one of the plurality of powder layers to successively form the bonded powder of a plurality of shell layers of the binder shell that enclose the unbonded portion of the powder bound by the binder shell.

5. The method of claim 4 , further comprising subjecting the unbonded portion of the powder bound by the binder shell to vibratory energy.

6. The method of claim 5 , wherein subjecting the unbonded portion of the powder bound by the binder shell to the vibratory energy occurs before forming each successive one of the plurality of shell layers of the binder shell.

7. The method of claim 1 , wherein the binder shell comprises a contour that matches a net shape of the object.

8. The method of claim 1 , further comprising removing binder from the binder shell,

wherein:

removing the binder and fusing the unbonded powder and the bonded powder together comprises sintering the object; and

the finished object comprises a unified, solid structure.

9. The method of claim 2 , wherein subjecting at least the portion of the unbound powder bound by the binder shell to the vibratory energy comprises transmitting ultrasonic vibrations to the at least the portion of the unbound powder bound by the binder shell.

10. The method of claim 1 , wherein tamping the unbonded portion of the powder bound by the binder shell occurs after forming each successive one of the plurality of shell layers of the binder shell.

11. The method of claim 10 , further comprising forming a fill layer by depositing powder on at least the portion of the unbonded powder bound by the binder shell before forming a successive one of the plurality of shell layers of the binder shell.

12. The method of claim 11 , wherein forming the fill layer occurs after densifying tamping at least the portion of the unbonded powder bound by the binder shell.

13. The method of claim 1 , wherein the binder shell comprises a closed cross-sectional shape.

14. The method of claim 1 , wherein the binder shell comprises a thickness of less than 0.0625 inch.

15. An additively manufactured object made according to the method of claim 8 .

16. An additively manufactured object made according to the method of claim 1 .

17. The method of claim 1 , further comprising forming a fill layer by depositing powder on at least the portion of the unbonded powder bound by the binder shell after tamping and before forming a successive one of the plurality of shell layers of the binder shell.

18. The method of claim 1 , further comprising positioning a tamping mechanism relative to the unbonded powder bound by the binder shell,

wherein tamping the unbonded powder bound by the binder shell comprises applying the compression force using the tamping mechanism.

19. The method of claim 18 , wherein:

the tamping mechanism comprises a plurality of tamping pins; and

tamping the unbonded powder bound by the binder shell comprises actuating select ones of the plurality of tamping pins to apply the compression force at a plurality of locations within a boundary formed by the binder shell.

20. The method of claim 18 , wherein:

the tamping mechanism comprises a tamping head; and

tamping the unbonded powder bound by the binder shell comprises actuating the tamping head to apply the compression force to a location within a boundary formed by the binder shell.