INDEPENDENT FABRICATION OF OBJECTS AND OBJECT SUPPORTS
Additive fabrication systems generally use support structures to expand the available range of features and geometries in fabricated objects. For example, when a vertical shelf or cantilever extends from an object, a supplemental support structure may be required to provide a surface for fabrication thereon. This process may become more difficult when, e.g., a part will be subjected to downstream processing steps such as debinding or sintering that impose different design rules. To address these challenges and provide a greater range of flexibility and processing speed, it may be useful in certain circumstances to independently fabricate the object and support structures, and then assemble these structures into a composite item for debinding and sintering. This approach also advantageously facilitates various techniques for spraying, dipping, or otherwise applying a release layer between the support structure and the part so that these separate items do not become fused together during sintering.
1 . A method comprising:
fabricating a support structure for an object from a first material;
fabricating the object from a second material, the object including a surface positionable adjacent to and supportable by the support structure, wherein the second material includes powdered material for forming a final part and a binder system including one or more binders, wherein the one or more binders resist deformation of a net shape of the object during processing of the object into the final part;
applying an interface layer to a least one of the support structure and object at a location corresponding to the surface of the object positionable adjacent to and supportable by the support structure, wherein the interface layer resists bonding of the support structure to the object during sintering; and
assembling the support structure and the object together with the surface positioned adjacent to and supported by the support structure, thereby providing an assembled workpiece.
2 . The method of claim 1 wherein the first material and the second material are substantially similar compositions.
3 . The method of claim 1 wherein the first material and the second material are deposited from a single source.
4 . The method of claim 1 wherein the first material and the second material are a single build material extruded from a single extruder of a fused filament fabrication system.
5 . The method of claim 1 wherein the first material and the second material have substantially matched shrinkage rates during debinding and sintering of the first material.
6 . The method of claim 1 wherein the powdered material includes a metal powder.
7 . The method of claim 1 wherein the powdered material includes a ceramic powder.
8 . The method of claim 1 wherein the powdered material is a sinterable material.
9 . The method of claim 1 wherein the binder system includes a first binder and a second binder, the first binder selected to resist deformation of the net shape of the object during debinding of the object and a second binder selected to resist deformation of the net shape of the object during a thermal sintering cycle used to sinter the object.
10 . The method of claim 9 further comprising removing the first binder in a first debind process prior to assembling the support structure.
11 . The method of claim 1 wherein fabricating the support structure includes additively manufacturing the support structure using at least one of fused filament fabrication, binder jetting, and optical curing of a powder-loaded resin.
12 . The method of claim 1 wherein fabricating the object includes additively manufacturing the object using at least one of fused filament fabrication, binder jetting, and optical curing of a powder-loaded resin.
13 . The method of claim 1 wherein fabricating the interface layer includes applying the interface layer using at least one of fused filament fabrication, binder jetting, and optical curing of a powder-loaded resin.
14 . The method of claim 1 wherein applying the interface layer includes applying a ceramic-loaded slurry onto the support structure.
15 . The method of claim 1 wherein applying the interface layer includes applying a ceramic suspension onto the support structure.
16 . The method of claim 1 wherein applying the interface layer includes spraying the interface layer onto at least one of the support structure and the object.
17 . The method of claim 1 wherein applying the interface layer includes dipping at least one of the support structure and the object into an interface material.
18 . The method of claim 1 wherein applying the interface layer includes micropipetting the interface layer onto at least one of the support structure and the object.
19 . The method of claim 1 further comprising positioning the assembled workpiece on a build plate configured to shrink at a substantially equal rate to the object during at least one of debinding and sintering.
20 . The method of claim 1 further comprising debinding the assembled workpiece.
21 . The method of claim 1 further comprising sintering the assembled workpiece.
22 . A method comprising:
receiving a support structure for an object from a first material and an object from a second material, the object including a surface positionable adjacent to and supportable by the support structure, wherein the second material includes powdered material for forming a final part and a binder system including one or more binders, wherein the one or more binders resist deformation of a net shape of the object during processing of the object into a final part;
applying an interface layer to a least one of the support structure and object at a location corresponding to the surface of the object positionable adjacent to and supportable by the support structure, wherein the interface layer resists bonding of the support structure to the object during sintering;
assembling the support structure and the object together with the surface positioned adjacent to and supported by the support structure, thereby providing an assembled workpiece; and
processing the assembled workpiece to form the object into the final part, wherein processing includes at least one of debinding the assembled workpiece and sintering the assembled workpiece.