Electrophotography-based additive manufacturing with solvent-assisted planarization

1. An electrophotography-based additive manufacturing system for printing a three-dimensional part, the electrophotography-based additive manufacturing system comprising:

one or more imaging engines configured to develop layers of powder part material of the three-dimensional part;

a printing assembly configured to print the three-dimensional part from the developed layers utilizing heat and pressure; and

a planarizer comprising:

a plurality of rollers;

a belt retained by the plurality of rollers, wherein the belt comprises a porous substrate configured to accept and retain a liquid solvent;

a solvent dispenser configured to transfer a hydrocarbon based liquid solvent onto intermediate build surfaces of the three-dimensional part after one or more of the developed layers are printed wherein the liquid solvent softens the printed material and wherein the planarizer is configured to apply pressure to flatten a softened top surface of the intermediate build surfaces.

2. The electrophotography-based additive manufacturing system of claim 1 , wherein the hydrocarbon based liquid comprises a fluorinated hydrocarbon liquid solvent.

3. The electrophotography-based additive manufacturing system of claim 1 , wherein the printing assembly comprises:

a heater configured to heat the developed layers;

a build platform; and

a pressing element configured to engage with the transfer assembly to press the heated developed layers into contact with the intermediate build surfaces of the three-dimensional part on the build platform in a layer-by-layer manner.

4. The electrophotography-based additive manufacturing system of claim 3 , wherein the pressing element comprises a nip roller, and wherein the planarizer is located downstream from the nip roller.

5. An electrophotography-based additive manufacturing system for printing a three-dimensional part, the electrophotography-based additive manufacturing system comprising:

one or more imaging engines configured to a develop layer of the three-dimensional part;

a rotatable transfer belt configured to receive the developed layer from the one or more imaging engines;

a build platform;

a nip roller configured to engage with the rotatable transfer belt to press the developed layers into contact with an intermediate build surface of the three-dimensional part on the build platform in a layer-by-layer manner;

a rotatable planarization belt assembly located downstream from the nip roller;

a solvent dispenser configured to dispense a hydrocarbon based liquid solvent to the rotatable planarization belt assembly to transfer the hydrocarbon based liquid solvent onto intermediate build surfaces of the three-dimensional part being printed wherein the hydrocarbon based liquid solvent softens at least an upper surface of the intermediate build surfaces and wherein the rotatable planarization belt is configured to apply pressure to the upper surface such that the upper surface of the intermediate build surfaces is flattened; and

a gantry configured to move the build platform to engage the three-dimensional part with the nip roller and the rotatable planarization belt.

6. The electrophotography-based additive manufacturing system of claim 5 , and further comprising a heater configured to heat the developed layers on the rotatable transfer belt.

7. The electrophotography-based additive manufacturing system of claim 5 , wherein the rotatable planarization belt comprises a porous substrate.

8. The electrophotography-based additive manufacturing system of claim 5 , wherein the hydrocarbon based liquid solvent comprises a halogenated hydrocarbon liquid solvent.

9. The electrophotography-based additive manufacturing system of claim 8 , wherein the hydrocarbon based liquid solvent comprises a fluorinated hydrocarbon liquid solvent.

10. The electrophotography-based additive manufacturing system of claim of claim 5 , wherein the rotatable planarization belt is configured to move in an opposing rotational direction relative to a movement direction of the build platform.

11. A method for printing a three-dimensional part with an electrophotography-based additive manufacturing system, the method comprising:

producing a developed layer of a part material with one or more imaging engines of the electrophotography-based additive manufacturing system;

transferring the developed layer from the one or more imaging engines to a transfer assembly of the electrophotography-based additive manufacturing system;

pressing the developed layer into contact with an intermediate build surface of the three-dimensional part;

entraining a hydrocarbon based liquid solvent in a porous substrate of a rotatable planarization assembly for transferring the liquid solvent onto intermediate build surfaces of the three-dimensional part after one or more of the developed layers are printed to soften at least a top surface of the intermediate build surface; and

engaging the three-dimensional part having the pressed layer with the rotatable planarization assembly comprising:

a plurality of rollers;

a belt retained by the plurality of rollers, wherein the belt comprises a porous substrate configured to accept and retain a liquid solvent to apply pressure to the top surface and planarize the three-dimensional part by solvation and abrasive shearing.

12. The method of claim 11 , and further comprising heating the developed layer at the transfer assembly.

13. The method of claim 11 , wherein engaging the three-dimensional part having the pressed layer with the rotatable planarization assembly comprises:

moving the three-dimensional part in a first linear direction; and

rotating the rotatable planarization belt in a direction that is opposite of the first linear direction.

14. The method of claim 11 , wherein the solvation causes a portion of the liquid solvent to penetrate into the three-dimensional part.

15. The method of claim 11 , wherein the liquid solvent comprises a fluorinated hydrocarbon.

16. The method of claim 11 , and further comprising evaporating a portion of the liquid solvent off from the planarized three-dimensional part.