Selective deposition-based additive manufacturing device and method of printing 3D parts with semi-crystalline materials

1. A selective deposition-based additive manufacturing system capable of building a three-dimensional (3D) part utilizing a semi-crystalline polymeric material, the system comprising:

at least one electrostatographic engine configured to develop one or more layers including particles of semi-crystalline polymeric material corresponding to one or more slices of a 3D model of a 3D part or their corresponding supports;

a transfer medium configured to receive the one or more layers of particles of the semi-crystalline polymeric material on a front side from the at least one electrostatographic engine and to move the one or more layers away from the electrostatographic engine;

a platen configured to carry the 3D part or support being printed;

a gantry coupled to the platen and configured to move the platen into registration with the one or more layers;

a heater configured to heat a top surface of the 3D part being printed to a transfuse temperature;

a layer transfer assembly comprising:

a roller contacting a back side of the transfer medium; and

a driver configured to cause the layer to transfer from the front side of the transfer medium to the heated top surface of the part; and

a cooler configured to cool the heated semi-crystalline polymeric material at a rate of at least 20° C. per second such that the semi-crystalline material is in a super-cooled state wherein the semi-crystalline polymeric material does not completely initially crystallize.

2. The system of claim 1 , wherein the cooler is configured to cool the heated semi-crystalline polymeric material at a rate of at least 30° C. per second.

3. The system of claim 1 , wherein the cooler comprises an air tunnel that shears cooling air across the top surface of the 3D part as the material cools to the super-cooled state.

4. The system of claim 1 , wherein the cooler comprises an air tunnel or an air knife.

5. The system of claim 1 , wherein the transfer medium comprises a continuous belt.

6. A method of printing a 3D part in a layer-wise manner with a semi-crystalline polymeric material utilizing a selective-deposition-based additive manufacturing system:

developing a first partial layer of semi-crystalline polymeric material using at least one electrostatotographic engine;

conveying the first partial layer from the at least one electrostatographic engine to a transfusion assembly with a transfer medium;

moving a platen carrying a 3D part being printed with a gantry to a location upstream from the transfusion assembly;

heating a top layer of the 3D part to a transfusion temperature;

registering the layer with the 3D part;

moving the 3D part and the layer through a transfusion assemble to thermally transfer the layer to the top surface of the 3D part while applying a pressure to a back surface of the transfer medium;

cooling the transfused layer to a temperature below a cold crystallization temperature at a rate of least 20° C. per second such that the semi-crystalline material is super-cooled; and

repeating the above steps until the 3D part is printed.

7. The method of claim 6 , wherein the cooling step comprises cooling the heated layer to super-cool the semi-crystalline material at a rate of least 30° C. per second.

8. The method of claim 6 , wherein the cooling step allows for less than 50% of full crystallization.

9. The method of claim 6 , wherein the cooling step allows for less than 30% of full crystallization.

10. The method of claim 6 , wherein the applying pressure step comprises applying between about 0.5 psi and about 200 psi to the back surface of the transfer medium.

11. The method of claim 6 , and further comprising:

subjecting the printed part to one or more post build processes to increase a volume percent crystallinity in the printed part.

12. The method of claim 6 , and further comprising:

developing a second partial layer of a second polymeric material using a second electrostatographic engine;

depositing the second partial layer onto the transfer medium with the first partial layer to form the first layer; and

conveying the first layer from the at least one electrostatographic engine to a transfusion assembly with a transfer medium.

13. The method of claim 12 , wherein the second polymeric material is semi-crystalline.

14. The method of claim 12 , wherein the second polymeric material is amorphous.

15. The method of claim 6 , wherein the cooling the part comprises varying cooling rate to adjust the initial crystallinity of the part being printed.

16. The method of claim 6 , wherein conveying the first partial layer comprises utilizing a continuous belt.