Building material enclosure comprising a thermal break
According to some aspects, degradation of material in a sintering additive fabrication process may be mitigated or avoided by fabricating parts within a chamber that includes one or more thermal breaks. The thermal break may be implemented using a variety of structures, but generally allows material in the chamber close to the surface to be maintained at different temperatures than the material further from the surface. For instance, as a result of the thermal break, parts located within the material of the chamber that were formed earlier during fabrication may be kept cooler to avoid damage to the parts yet the upper surface (sometimes called the “build surface”) of unconsolidated material may be heated enough so as to require minimal additional energy exposure to trigger consolidation.
1. An additive fabrication device configured to produce three-dimensional objects by sintering a source material, the additive fabrication device comprising:
a chamber comprising a first section that extends to a top of the chamber, a second section, and a thermal break arranged between the first section and the second section, the thermal break being formed from a different material than the first section or the second section, wherein the first section of the chamber comprises metal;
a fabrication platform arranged within the chamber, configured to receive source material and to be lowered into the chamber as progressive layers of source material are deposited over the fabrication platform;
a material deposition mechanism configured to deposit a layer of the source material over the fabrication platform, such that the layer of source material is arranged at the top of the chamber; and
one or more heaters configured to heat at least the source material deposited by the material deposition mechanism.
2. The additive fabrication device of claim 1 , wherein the first section and the second section of the chamber each have a thermal conductivity that is lower than a thermal conductivity of the thermal break.
3. The additive fabrication device of claim 1 , wherein the first section and the second section of the chamber are joined together by the thermal break.
4. The additive fabrication device of claim 1 , wherein the thermal break is arranged at least 15 mm from a top of the chamber.
5. The additive fabrication device of claim 1 , wherein the thermal break has a height of at least 20 mm.
6. The additive fabrication device of claim 1 , wherein the second section of the chamber extends to a bottom of the chamber.
7. The additive fabrication device of claim 1 , wherein the second section of the chamber comprises metal.
8. The additive fabrication device of claim 1 , wherein the thermal break comprises plastic and/or ceramic.
9. The additive fabrication device of claim 8 , wherein the thermal break comprises Polyetheretherketone (PEEK).
10. The additive fabrication device of claim 1 , wherein the thermal break has a height that is greater than 0.5% and less than or equal to 4% of a height of the chamber.
11. The additive fabrication device of claim 1 , wherein the first section of the chamber, the second section of the chamber, and the thermal break each has a cross-sectional shape of a square or a rectangle with rounded corners.
12. The additive fabrication device of claim 1 , wherein the thermal break has a wall thickness that is greater than a wall thickness of the first section or a wall thickness of the second section.
13. The additive fabrication device of claim 1 , wherein the thermal break is coupled to the first section of the chamber and coupled to the second section of the chamber.
14. The additive fabrication device of claim 1 , wherein the thermal break is coupled to and extends over part of the first section of the chamber.
15. The additive fabrication device of claim 14 , wherein the thermal break is further coupled to and extends over part of the second section of the chamber.