Three-dimensional printing

1 . A surface treatment method, comprising:

exposing a final three-dimensionally printed polyamide object to benzyl alcohol, wherein the final three-dimensionally printed polyamide object is formed from a solid polyamide build material composition; and

exposing the three-dimensionally printed polyamide object to microwave irradiation after the benzyl alcohol exposure, thereby reducing a surface roughness of the final three-dimensionally printed polyamide object;

wherein exposing the three-dimensionally printed polyamide object to the benzyl alcohol involves soaking the three-dimensionally printed polyamide object in the benzyl alcohol; and

wherein the soaking is performed for a time period ranging from about 1 hour to about 25 hours;

wherein the surface treatment method is a post-print finishing technique.

2 . The surface treatment method as defined in claim 1 wherein the soaking is performed for a time period ranging from about 2 hours to about 10 hours.

3 . The surface treatment method as defined in claim 1 wherein exposing the three-dimensionally printed polyamide object to the microwave irradiation is performed for a time period sufficient to initiate melting at a surface of the three-dimensionally printed polyamide object and avoid melting of a bulk of the three-dimensionally printed polyamide object.

4 . The surface treatment method as defined in claim 3 wherein the time period for microwave irradiation exposure ranges from about 30 seconds to about 4 minutes.

5 . The surface treatment method as defined in claim 1 wherein the microwave irradiation is performed with a microwave having a wattage ranging from about 500 W to about 2000 W.

6 . The surface treatment method as defined in claim 1 wherein exposing the three-dimensionally printed polyamide object to the benzyl alcohol is performed at a temperature ranging from about 18° C. to about 27° C.

7 . The surface treatment method as defined in claim 1 , further comprising at least partially drying the three-dimensionally printed polyamide object after exposing the three-dimensionally printed polyamide object to the benzyl alcohol and prior to exposing the three-dimensionally printed polyamide object to the microwave irradiation.

8 . The surface treatment method as defined in claim 7 wherein the at least partially drying involves air drying.

9 . A method, comprising:

forming a final 3D printed polyamide object by:

iteratively applying a solid polyamide build material composition to form respective build material layers;

based on a 3D object model, selectively applying a fusing agent on the respective build material layers to form respective patterned portions; and

exposing the respective build material layers to electromagnetic radiation to selectively coalesce the patterned portions and form the final 3D printed polyamide object;

exposing the final 3D printed polyamide object to benzyl alcohol; and

exposing the 3D printed polyamide object to microwave irradiation after the benzyl alcohol exposure, thereby reducing a surface roughness of the final 3D printed polyamide object;

wherein exposing the 3D printed polyamide object to the benzyl alcohol involves soaking the 3D printed polyamide object in the benzyl alcohol; and

wherein the soaking is performed for a time period ranging from about 1 hour to about 25 hours;

wherein the exposing to benzyl alcohol and to microwave irradiation is a post-print finishing technique.

10 . The method as defined in claim 9 wherein the soaking is performed for a time period ranging from about 2 hours to about 10 hours.

11 . The method as defined in claim 9 wherein exposing the 3D printed polyamide object to the microwave irradiation is performed for a time period sufficient to initiate melting at a surface of the 3D printed polyamide object and avoid melting of a bulk of the 3D printed polyamide object.

12 . The method as defined in claim 11 wherein the time period for microwave irradiation exposure ranges from about 30 seconds to about 4 minutes.

13 . The method as defined in claim 9 wherein exposing the 3D printed polyamide object to the benzyl alcohol is performed at a temperature ranging from about 18° C. to about 27° C.

14 . The method as defined in claim 9 , further comprising at least partially drying the 3D printed polyamide object after exposing the 3D printed polyamide object to the benzyl alcohol and prior to exposing the 3D printed polyamide object to the microwave irradiation.

15 . A three-dimensional printed polyamide object generated by the method of claim 9 .

16 . The surface treatment method as defined in claim 1 wherein a percent change in the surface roughness of the final three-dimensionally printed polyamide object from prior to the post-print finishing technique, to after the post-print finishing technique ranges from −14.9% to −16.5%.

17 . The method as defined in claim 9 wherein a percent change in the surface roughness of the final 3 D printed polyamide object from prior to the post-print finishing technique, to after the post-print finishing technique ranges from −14.9% to −16.5%.