Build material extraction using vibration and airflow

1. An additive manufacturing platform, comprising:

a vibrating bed on which a volume of build material is to be disposed, wherein the vibrating bed is to vibrate to remove excess build material;

a non-vibrating frame to support the vibrating bed;

ports in the vibrating bed through which the excess build material is removed when the vibrating bed vibrates;

a sensor to measure an amount of build material removed; and

a controller to:

receive an object build file;

set extraction parameters based on the object build file, wherein the extraction parameters comprise at least one of an extraction start time, a length of extraction, vibration characteristics, and an air flow rate; and

selectively activate the vibrating bed and ports based on a measured rate of extraction falling below a threshold value.

2. The additive manufacturing platform of claim 1 , wherein:

the vibrating bed operates in at least two extraction modes during a build material extraction period; and

the at least two extraction modes differ in vibrating characteristics.

3. The additive manufacturing platform of claim 2 , wherein:

a first extraction mode operates at a first vibrating mode; and

a second extraction mode operates at a second vibrating mode that is different than the first vibrating mode.

4. The additive manufacturing platform of claim 3 , wherein:

the vibrating bed operates in the first extraction mode prior to operating in the second extraction mode to remove loose excess build material; and

the vibrating bed operates in the second extraction mode following operating in the first extraction mode to remove agglomerated excess build material from a finished object.

5. The additive manufacturing platform of claim 1 , wherein excess build material is removed to a chamber through vibration of the vibrating bed and then extracted to a reservoir using a vacuum system.

6. The additive manufacturing platform of claim 1 , wherein the vibrating bed vibrates in a horizontal plane.

7. The additive manufacturing platform of claim 1 , further comprising

a vacuum system to create an airflow through ports in the vibrating bed,

wherein the vibrating bed is vibrated and the vacuum system is operated simultaneously to remove excess build material by a combination of vibration and airflow.

8. An additive manufacturing system, comprising:

a build material distributor to successively deposit layers of build material into a build area;

at least one agent distributor including at least one liquid ejection device to selectively distribute fusing agent onto the layers of build material; and

a platform that defines a build area, wherein the platform comprises:

a vibrating bed on which a volume of build material is to be disposed, wherein the vibrating bed is to vibrate:

to remove excess build material into a chamber; and

in sequentially more intense extraction modes;

a non-vibrating frame to support the vibrating bed;

a vacuum system to draw excess build material from the chamber to the reservoir;

a sensor to measure an amount of excess build material removed; and

a controller to:

receive an object build file;

set extraction parameters based on the object build file, wherein the extraction parameters comprise at least one of an extraction start time, a length of extraction, vibration characteristics, and an air flow rate;

control extraction modes during a build material extraction period; and

selectively activate the vibrating bed and vacuum system based on a measured rate of extraction falling below a threshold value.

9. The additive manufacturing system of claim 8 , wherein the extraction modes comprise at least two different extraction modes which differ in regards to at least one of:

vibration frequency;

vibration intensity;

vibration duty cycle.

10. The additive manufacturing system of claim 9 , wherein the at least two different extraction modes are based on at least one of the build material and a selected extraction sensitivity.

11. The additive manufacturing system of claim 9 , wherein:

the platform comprises walls that extend from the platform; and

the walls, in addition to the platform, vibrate to remove excess build material.

12. The additive manufacturing system of claim 9 , wherein the at least two extraction modes differ in air flow rates.

13. The additive manufacturing system of claim 8 , wherein the controller is to select vibration characteristics based on a build material type.

14. The additive manufacturing system of claim 8 , wherein the controller is to select vibration characteristics based on a size and dimension of a three-dimensional (3D) printed object.

15. The additive manufacturing system of claim 8 , wherein:

an airflow in a first extraction mode is the same as an airflow in a second extraction mode; and

a vibration characteristic in the first extraction mode is different than a vibration characteristic in the second extraction mode.

16. A method, comprising:

receiving an object build file for a three-dimensional object;

setting extraction parameters for an extraction of excess build material based on the object build file, an object build material, and a desired extraction sensitivity, wherein the extraction parameters comprise at least one of an extraction start time, a length of extraction, vibration characteristics, and an air flow rate;

measuring, with a sensor, an amount of build material removed;

selectively activating a vibrating bed based on a measured rate of extraction falling below a threshold;

controlling the vibrating bed of an additive manufacturing platform in accordance with the extraction parameters; and

vibrating the bed to remove excess build material through ports in the vibrating bed.

17. The method of claim 16 , wherein the build file indicates an object height.

18. The method of claim 16 , further comprising:

acquiring the build file for the three-dimensional object;

receiving input indicating the object build material and the desired extraction sensitivity; and

deactivating the vibrating bed and vacuum system based on a rate of extraction falling below a threshold value.

19. The method of claim 16 , further comprising:

controlling the vibrating bed of an additive manufacturing platform and a vacuum system in accordance with the extraction parameters,

wherein the vibrating bed is vibrated and the vacuum system is operated simultaneously to remove excess build material by a combination of vibration and airflow.