Techniques for releasing parts in additive fabrication and related systems and methods

1. A build platform configured to be removably attached to an additive fabrication device, the build platform comprising:

a rigid structure; and

an actuation structure coupled to the rigid structure and comprising at least two sheet handles and a flexible sheet, wherein the at least two sheet handles are attached to the flexible sheet,

wherein a first surface of the flexible sheet forms a build surface on which the additive fabrication device is configured to form layers of material, and

wherein the at least two sheet handles are configured to be actuated by moving the at least two sheet handles relative to one another, thereby causing at least a part of the flexible sheet to deform away from the rigid structure.

2. The build platform of claim 1 , further comprising one or more magnets that couple the actuation structure to the rigid structure.

3. The build platform of claim 2 , wherein a second surface of the flexible sheet is configured to be coupled to a first surface of the rigid structure, and wherein the first surface of the rigid structure includes:

a first magnetic zone exerting a first amount of magnetic force per area on the actuation structure, and

a second magnetic zone exerting a second mount of magnetic force per area on the actuation structure; and

wherein the first amount is different from the second amount.

4. The build platform of claim 1 , wherein the at least two sheet handles include a first sheet handle attached to a first side of the flexible sheet and a second sheet handle attached to the flexible sheet at a second side of the flexible sheet, opposite to the first side.

5. The build platform of claim 1 , wherein the rigid structure includes a mounting device configured to be removably attached to the additive fabrication device.

6. The build platform of claim 1 , wherein the at least two sheet handles each comprises a drip-prevention structure to catch liquid that drips from the flexible sheet when the build platform is oriented with the flexible sheet above the at least two sheet handles.

7. The build platform of claim 1 , wherein the build platform is configured to be removed from the additive fabrication device and to be removably attached to a mount for the actuation of the at least two sheet handles.

8. The build platform of claim 1 , wherein the rigid structure includes one or more troughs at its edges, and wherein a part of each of the at least two sheet handles rests in one of the one or more troughs.

9. The build platform of claim 2 , wherein during actuation of the at least two sheet handles to apply a force to the flexible sheet:

during a first phase of the actuation, an elastic force experienced by a first part of the flexible sheet is smaller than a magnetic force exerted on the first part of the flexible sheet by the one or more magnets;

during a second phase of the actuation, the elastic force experienced by the first part of the flexible sheet is greater than the magnetic force exerted on the first part of the flexible sheet by the one or more magnets.

10. The build platform of claim 1 , wherein the at least two sheet handles are configured to be actuated while at least a part of the actuation structure remains attached to the rigid structure.

11. The build platform of claim 1 , wherein the actuation structure is coupled to the rigid structure through mechanical retaining means.

12. An additive fabrication device configured to form layers of material on a build surface, the additive fabrication device comprising:

a build platform comprising:

a rigid structure; and

an actuation structure coupled to the rigid structure and comprising at least two sheet handles and a flexible sheet, wherein the at least two sheet handles are attached to the flexible sheet,

wherein a first surface of the flexible sheet forms a build surface on which the additive fabrication device is configured to form layers of material, and

wherein the at least two sheet handles are configured to be actuated by moving the at least two sheet handles relative to one another, thereby causing at least a part of the flexible sheet to deform away from the rigid structure.

13. The additive fabrication device of claim 12 , wherein the build platform further comprises one or more magnets that couple the actuation structure to the rigid structure.

14. The additive fabrication device of claim 13 , wherein a second surface of the flexible sheet is configured to be coupled to a first surface of the rigid structure, and wherein the first surface of the rigid structure includes:

a first magnetic zone exerting a first amount of magnetic force per area on the actuation structure, and

a second magnetic zone exerting a second mount of magnetic force per area on the actuation structure; and

wherein the first amount is different from the second amount.

15. The additive fabrication device of claim 12 , wherein the at least two sheet handles include a first sheet handle attached to a first side of the flexible sheet and a second sheet handles attached to the flexible sheet at a second side of the flexible sheet, opposite to the first side.

16. The additive fabrication device of claim 12 , wherein the rigid structure includes a mounting device configured to be removably attached to the additive fabrication device.

17. The additive fabrication device of claim 12 , wherein the at least two sheet handles each comprises a drip-prevention structure to catch liquid that drips from the flexible sheet when the build platform is oriented with the flexible sheet above the at least two sheet handles.

18. The additive fabrication device of claim 12 , wherein the build platform is configured to be removed from the additive fabrication device and to be removably attached to a mount for the actuation of the at least two sheet handles.

19. The additive fabrication device of claim 12 , wherein the rigid structure includes one or more troughs at its edges, and wherein a part of each of the at least two sheet handles rests in one of the one or more troughs.

20. The additive fabrication device of claim 13 , wherein during actuation of the at least two sheet handles to apply a force to the flexible sheet:

during a first phase of the actuation, an elastic force experienced by a first part of the flexible sheet is smaller than a magnetic force exerted on the first part of the flexible sheet by the one or more magnets;

during a second phase of the actuation, the elastic force experienced by the first part of the flexible sheet is greater than the magnetic force exerted on the first part of the flexible sheet by the one or more magnets.

21. The additive fabrication device of claim 12 , wherein the at least two sheet handles are configured to be actuated while at least a part of the actuation structure remains attached to the rigid structure.

22. The additive fabrication device of claim 12 , wherein the actuation structure is coupled to the rigid structure through mechanical retaining means.

23. The build platform of claim 1 , wherein the at least two sheet handles are configured to be actuated by moving the at least two sheet handles toward one another, thereby causing the at least a part of the flexible sheet to deform away from the rigid structure.

24. The additive fabrication device of claim 12 , wherein the at least two sheet handles are configured to be actuated by moving the at least two sheet handles toward one another, thereby causing the at least a part of the flexible sheet to deform away from the rigid structure.