Interface layers for removable supports
Support structures are used in certain additive fabrication processes to permit fabrication of a greater range of object geometries. For additive fabrication processes with materials that are subsequently sintered into a final part, an interface layer is formed between the object and support in order to inhibit bonding between adjacent surfaces of the support structure and the object during sintering.
1. A method of fabricating a metallic three-dimensional object having a separable support, comprising the steps of:
forming a plurality of successive layers of build material into a desired shape of the three-dimensional object and a support structure, the build material including a binder system and a metal powder;
wherein during the step of forming a plurality of successive layers, forming an interface of non-sinterable material between the desired shape of the three-dimensional object and the support structure;
debinding at least a portion of the binder system; and
sintering the shape of the three-dimensional object into a densified final object and the support structure into a densified support structure separable at the interface of non-sinterable material.
2. The method of claim 1 wherein the step of forming a plurality of successive layers of build material includes extruding the build material through a nozzle that is moved relative to a build plate.
3. The method of claim 2 wherein the step of extruding the build material through a nozzle includes delivering discrete billet units of the build material through an intermediary channel via a drive train.
4. The method of claim 1 wherein during the step of forming a plurality of successive layers the support structure is disposed on a surface of a build plate and extends upwards therefrom such that it is disposed below the desired shape of the three-dimensional object.
5. The method of claim 1 wherein the build material is adapted from a metal injection molding (“MIM”) feedstock.
6. The method of claim 1 wherein the densified final object is includes at least two nested parts.
7. A method of fabricating a three-dimensional object having a separable support, comprising the steps of:
forming a plurality of successive layers of build material into a desired shape of the three-dimensional object and a support structure, the build material including a binder system and a sinterable powder;
wherein during the step of forming a plurality of successive layers, forming an interface of non-sinterable material between the desired shape of the three-dimensional object and the support structure;
debinding at least a portion of the binder system; and
sintering the shape of the three-dimensional object into a densified final object and the support structure into a densified support structure separable at the interface of non-sinterable material.
8. The method of claim 7 wherein the step of forming a plurality of successive layers of build material includes extruding the build material through a nozzle that is moved relative to a build plate.
9. The method of claim 8 wherein the step of extruding the build material through a nozzle includes delivering discrete billet units of the build material through an intermediary channel via a drive train.
10. The method of claim 7 wherein during the step of forming a plurality of successive layers the support structure is disposed on a surface of a build plate and extends upwards therefrom such that it is disposed below the desired shape of the three-dimensional object.
11. The method of claim 7 wherein the build material is adapted from a metal injection molding (“MIM”) feedstock.
12. The method of claim 7 wherein the densified final object is includes at least two nested parts.
13. A method of fabricating a metallic three-dimensional object, comprising the steps of:
depositing a build material into a desired shape of the three-dimensional object and a support structure, the build material including a binder system and a sinterable powder;
wherein the support structure at least partially underlies the three-dimensional object and provides structural support to at least a portion of a feature thereof against gravity-induced deformation;
wherein during the step of depositing the build material, depositing a non-sinterable material between the desired shape of the three-dimensional object and the support structure;
debinding at least a portion of the binder system;
sintering the shape of the three-dimensional object into a densified final object and the support structure into a densified support structure; and
applying a mechanical force sufficient to separate the densified final object and the support structure at the non-sinterable material without damage to the densified final object.
14. The method of claim 13 wherein the step of forming a plurality of successive layers of build material includes extruding the build material through a nozzle that is moved relative to a build plate.
15. The method of claim 13 wherein the step of extruding the build material through a nozzle includes delivering discrete billet units of the build material through an intermediary channel via a drive train.
16. The method of claim 13 wherein during the step of forming a plurality of successive layers the support structure is disposed on a surface of a build plate and extends upwards therefrom such that it is disposed below the desired shape of the three-dimensional object.
17. The method of claim 13 wherein the densified final object is includes at least two nested parts.