Heating techniques in additive fabrication and related systems and methods
Substantially equal amounts of thermal energy may be provided over a build area of an additive fabrication device using as few as one heat source by selectively attenuating thermal energy emitted by the heat source. The thermal energy may be selectively attenuated by a structure that blocks portions of the thermal energy from being directly incident upon the build area such that the heat is normalized over the build area. The heat distribution over the build area may, in some embodiments, approximate the heat distribution produced by a flat field heating element, yet may be produced at comparatively lower cost and with less complex engineering.
1. An additive fabrication device configured to fabricate objects by forming layers of solid material from a source material, the additive fabrication device comprising:
a build region into which source material may be disposed;
at least one source of electromagnetic radiation configured to direct radiation onto the source material in the build region to thereby form a layer of solid material from the source material;
a first heater configured to direct thermal radiation onto at least a first portion of the source material in the build region; and
a first thermal attenuation structure arranged between the first heater and the build region, the first thermal attenuation structure formed from a solid material having a plurality of apertures therein, wherein a density of apertures of the plurality of apertures within a first region of the first thermal attenuation structure that is proximate to the first heater is lower than a density of apertures of the plurality of apertures within a second region of the first thermal attenuation structure that is distal to the first heater.
2. The additive fabrication device of claim 1 , further comprising a material deposition mechanism configured to move over the build region and to deposit source material onto the build region.
3. The additive fabrication device of claim 1 , further comprising a second heater configured to direct thermal radiation onto at least a second portion of the source material in the build region.
4. The additive fabrication device of claim 3 , further comprising a second thermal attenuation structure arranged between the first heater and the build region and/or between the second heater and the build region.
5. The additive fabrication device of claim 1 , wherein the at least one source of electromagnetic radiation includes a laser.
6. The additive fabrication device of claim 1 , wherein the first thermal attenuation structure is planar.
7. The additive fabrication device of claim 1 , wherein the first thermal attenuation structure comprises metal.
8. The additive fabrication device of claim 1 , wherein the plurality of apertures of the first thermal attenuation structure includes a plurality of circular holes.
9. The additive fabrication device of claim 1 , wherein the first thermal attenuation structure comprises a mesh structure and wherein the plurality of apertures of the first thermal attenuation structure are gaps of the mesh structure.
10. The additive fabrication device of claim 1 , wherein the plurality of apertures have a plurality of different sizes.
11. The additive fabrication device of claim 1 , wherein the first heater is an infrared tube heater.
12. The additive fabrication device of claim 1 , wherein the thermal radiation directed from the first heater onto the build region and attenuated by the first thermal attenuation structure is incident on the build region with a uniform intensity distribution.
13. A method of additive fabrication, the method comprising:
depositing a source material into a build region;
directing thermal radiation, using a first heater, onto at least some of the source material in the build region, wherein a first thermal attenuation structure is arranged between the first heater and the build region, the first thermal attenuation structure formed from a solid material having a plurality of apertures therein, wherein a density of apertures of the plurality of apertures within a first region of the first thermal attenuation structure that is proximate to the first heater is lower than a density of apertures of the plurality of apertures within a second region of the first thermal attenuation structure that is distal to the first heater; and
directing radiation, using at least one source of electromagnetic radiation, onto the source material in the build region to thereby form a layer of solid material from the source material.
14. The method of claim 13 , wherein depositing the source material comprises controlling a material deposition mechanism to move over the build region and to deposit source material onto the build region.
15. The method of claim 13 , wherein directing the thermal radiation onto the build region comprises attenuating the thermal radiation by the first thermal attenuation structure such that thermal radiation is incident on the build region with a uniform intensity distribution.