Additive manufacturing system and method for printing three-dimensional parts using velocimetry
An additive manufacturing system that retains a print head for printing a three-dimensional part in a layer-by-layer manner using an additive manufacturing technique, where the retained print head is configured to receive a consumable material, melt the consumable material, and extrude the molten material. The system also includes a velocimetry assembly configured to determine flow rates of the molten material, and a controller assembly configured to manage the extrusion of the molten material from the print head, and to receive signals from the velocimetry assembly relating to the determined flow rates.
1. A method of calibrating a print head for use in an additive manufacturing system, the method comprising:
extruding a molten material from the print head as an extrudate;
routing a pulsed laser beam toward the extrudate to scatter light rays of the pulsed laser beam from the extrudate;
detecting at least a portion of the scattered light rays with a detector over multiple sequential captured frames captured at time intervals based upon a timing of the pulsing of the laser beam, wherein each captured frame has a speckle pattern;
processing the captured frames with a controller to generate speckle patterns;
comparing the speckle patterns of the sequential multiple captured frames;
determining a spatial shift in the speckle patterns;
calculating a velocity of the extrudate with the controller based on the determined spatial shift and the time intervals;
determining at least one average flow rate of the extrudate based at least on the calculated velocity; and
producing calibration information for the print head based upon the at least one average flow rate.
2. The method according to claim 1 , further comprising:
installing the print head in an additive manufacturing system; and
printing layers of a three-dimensional part using the print head based on the calibration information.
3. The method according to claim 2 , further comprising transmitting the calibration information to a controller assembly of the additive manufacturing system.
4. The method according to claim 2 , wherein:
extruding the molten material comprises:
feeding a consumable material to the print head using a drive mechanism based on a feed rate setting; and
melting the consumable material in the print head to produce the molten material; and
producing the calibration information for the print head includes producing the calibration information based upon the feed rate setting.
5. The method according to claim 2 , wherein extruding the molten material and routing the pulsed laser beam are performed before the print head is installed in the additive manufacturing system.
6. The method according to claim 2 , wherein extruding the molten material and routing the pulsed laser beam include installing the print head in a stand-alone station that is separate from the additive manufacturing system.
7. The method according to claim 2 , wherein installing the print head in the additive manufacturing system occurs before extruding the molten material from the print head.
8. The method of claim 1 , wherein determining the at least one average flow rate of the extrudate comprises:
calculating the at least one average flow rate of the extrudate with the controller based upon the calculated velocity and a precalculated cross-sectional area of the extrudate.
9. The method of claim 1 , wherein determining the at least one average flow rate of the extrudate comprises:
sensing a width of the extrudate for each sequential captured frame; and
calculating the at least one average flow rate of the extrudate with the controller based upon the calculated velocity and sensed width of the extrudate.
10. A method of calibrating a print head for use in an additive manufacturing system, the method comprising steps of:
feeding a consumable material to the print head using a drive mechanism based on a current feed rate setting having a predicted average flow rate;
melting the consumable material in the print head to produce a molten material;
extruding the molten material from the print head as an extrudate;
routing a pulsed laser beam toward the extrudate to scatter light rays of the pulsed laser beam from the extrudate;
detecting at least a portion of the scattered light rays with a detector over multiple sequential captured frames captured at time intervals based upon a timing of the pulsing of the laser beam, wherein each captured frame has a speckle pattern;
processing the captured frames with a controller to generate speckle patterns;
comparing the speckle patterns of the multiple captured frames;
determining a spatial shift in the speckle patterns;
calculating a velocity of the extrudate with the controller based on the determined spatial shift and the time intervals;
determining an average flow rate of the extrudate at the current feed rate setting based at least on the calculated velocity;
comparing the determined average flow rate to the predicted average flow rate;
updating calibration information for the print head based on the determined average flow rate;
changing the current feed rate setting to another feed rate setting having another predicted flow rate; and
repeating the steps a limited number of times.
11. The method according to claim 10 , further comprising:
installing the print head in an additive manufacturing system; and
printing layers of a three-dimensional part using the print head based on the calibration information.
12. The method according to claim 11 , further comprising transmitting the calibration information to a controller assembly of the additive manufacturing system.
13. The method according to claim 11 , wherein extruding the molten material and routing the pulsed laser beam are performed before installing the print head in the additive manufacturing system.
14. The method according to claim 13 , wherein extruding the molten material and routing the pulsed laser beam include installing the print head in a stand-alone station that is separate from the additive manufacturing system.
15. the method according to claim 11 , wherein installing the print head in the additive manufacturing system occurs before extruding the molten material from the print head.
16. The method of claim 10 , wherein determining the average flow rate of the extrudate comprises:
calculating the average flow rate of the extrudate with the controller based upon the calculated velocity and a precalculated cross-sectional area of the extrudate.
17. The method of claim 10 , wherein determining the average flow rate of the extrudate comprises:
sensing a width of the extrudate for each sequential captured frame; and
calculating the average flow rate of the extrudate with the controller based upon the calculated velocity and sensed width of the extrudate.