Method for printing three-dimensional parts wtih crystallization kinetics control

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

providing a part material compositionally including one or more semi-crystalline polymers and one or more secondary materials that are configured to retard crystallization of the one or more semi-crystalline polymers, wherein the one or more secondary materials are substantially miscible with the one or more semi-crystalline polymers;

melting the part material in the additive manufacturing system;

forming at least a portion of a layer of the three-dimensional part from the melted part material in a build environment; and

maintaining the build environment at an annealing temperature that is between a glass transition temperature of the part material and a cold crystallization temperature of the part material.

2. The method of claim 1 , wherein the one or more secondary materials comprise one or more amorphous polymers.

3. The method of claim 2 , wherein the one or more amorphous polymers constitute from about 50% by weight to about 85% by weight of a combined weight of the one or more semi-crystalline polymers and the one or more amorphous polymers.

4. The method of claim 1 , wherein the one or more semi-crystalline polymers comprise one or more semi-crystalline polyamides, and wherein the one or more secondary materials comprise one or more amorphous polyamides.

5. The method of claim 1 , wherein the one or more semi-crystalline polymers comprise one or more one or more polyaryletherketones, and wherein the one or more secondary materials comprise one or more polyetherimides.

6. The method of claim 1 , and further comprising performing a post-printing crystallization step on the printed three-dimensional part.

7. The method of claim 1 , wherein the one or more semi-crystalline polymers are polymerized from one or more base monomers, and wherein the one or more secondary materials comprise one or more second semi-crystalline polymers polymerized from one or more monomers that are isomers of the one or more base monomers.

8. The method of claim 7 , wherein the one or more semi-crystalline polymers and the one or more second semi-crystalline polymers each comprise one or more polylactic acid polymers, one or more polyetherketoneketone polymers, or one or more polyesters.

9. A method for printing a three-dimensional part from with an additive manufacturing system, the method comprising:

providing a part material that compositionally comprises one or more semi-crystalline polymers and one or more amorphous polymers that are substantially miscible with the one or more semi-crystalline polymers;

maintaining a build environment of the additive manufacturing system, at least in a deposition region of the build environment, at an annealing temperature that is between a glass transition temperature of the part material and a cold crystallization temperature of the part material;

feeding the part material to a print head retained by of the additive manufacturing system;

melting the part material in the print head;

extruding the melted part material from the print head; and

depositing the extruded part material onto a build surface in the deposition region to form at least a portion of a layer of the three-dimensional part from the extruded part material.

10. The method of claim 9 , wherein the one or more semi-crystalline polymers comprise one or more semi-crystalline polyamides, and wherein the one or more amorphous polymers comprise one or more amorphous polyamides.

11. The method of claim 10 , wherein the one or more amorphous polymers constitute from about 50% by weight to about 85% by weight of a combined weight of the one or more semi-crystalline polymers and the one or more amorphous polymers.

12. The method of claim 8 , and further comprising selecting the annealing temperature to achieve a predetermined crystallinity level for the part material of the printed three-dimensional part.

13. The method of claim 8 , wherein the one or more amorphous polymers are configured to retard crystallization of the one or more semi-crystalline polymers.

14. The method of claim 8 , and further comprising performing a post-printing crystallization step on the printed three-dimensional part.

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

providing a part material that compositionally comprises one or more semi-crystalline polymers and one or more amorphous polymers that are substantially miscible with the one or more semi-crystalline polymers;

melting the part material in the additive manufacturing system;

forming layers of the three-dimensional part from the melted part material using an additive manufacturing technique, wherein the layers are formed in a region that is maintained at an annealing temperature that is within 10° C. of a glass transition temperature of the part material; and

reheating the printed three-dimensional part to one or more temperatures that are within about 10° C. of a cold crystallization temperature of the part material.

16. The method of claim 15 , wherein a re-crystallization temperature is within about 5° C. of the cold crystallization temperature of the part material.

17. The method of claim 15 , wherein reheating the printed three-dimensional part to the one or more temperatures is performed for at least about 30 minutes.

18. The method of claim 15 , wherein the reheating step is performed in a separate oven from the additive manufacturing system.

19. The method of claim 18 , and further comprising separating the three-dimensional part from a build sheet used to received the formed layers of the three-dimensional part.

20. The method of claim 15 , wherein the one or more semi-crystalline polymers comprise one or more semi-crystalline polyamides, and wherein the one or more amorphous polymers comprise one or more amorphous polyamides.