ADDITIVE MANUFACTURING SYSTEM AND METHOD FOR PRINTING THREE-DIMENSIONAL PARTS USING VELOCIMETRY

• US 20170100888A1
• Filed: 12/21/2016
• Published: 04/13/2017
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Stratasys Incorporated
• Original Assignee: Stratasys Incorporated
• Inventors: Batchelder, J. Samuel
• Granted Patent: US 10,369,776 B2
• Time in Patent Office: Days
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/118 using filamentary material being melted, e.g. fused deposition modelling [FDM]
• CPC Class Codes: B29C 64/209 Heads; Nozzles
• CPC Class Codes: B29C 64/273 pulsed; frequency modulated
• CPC Class Codes: B29C 64/321 Feeding
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: G01F 1/661 using light

Abstract

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.

Claims

1. An additive manufacturing system comprising:

a print head for printing a three-dimensional part in a layer-by-layer manner using an additive manufacturing technique, wherein the print head is configured to receive a consumable material, melt the consumable material, and extrude the molten material;

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.

2. The additive manufacturing system of claim 1, wherein the velocimetry assembly comprises:

a light source, and optionally, one or more optical lenses, which are configured to route a light beam from the light source towards the molten material, wherein the molten material causes light rays of the light beam to scatter;

a detector having a sensor configured to receive at least a portion of the scattered light rays, and to transmit the signals relating to the determined flow rates to the controller assembly.

3. The additive manufacturing system of claim 2, wherein the detector is positioned relative to the light source to receive the scattered light rays in a transmission-forward-scatter pattern.

4. The additive manufacturing system of claim 2, wherein the detector is configured to receive the portion of the scattered light rays over multiple captured frames, wherein each captured frame has a speckle pattern, and wherein the velocimetry assembly is configured to compare the speckle pattern of the multiple captured frames to determine velocities of the molten material.

5. The additive manufacturing system of claim 4, wherein the detector of the velocimetry assembly further comprises a second sensor configured to receive at least a portion of the scattered light rays, wherein the detector is further configured to determine the flow rates as volumetric flow rates of the molten material from the scattered light rays received by the second sensor and the determined velocities of the molten material.

6. The additive manufacturing system of claim 1, wherein the velocimetry assembly is configured to determine velocities of the molten material after the molten material exits a nozzle of the print head as an extrudate.

7. The additive manufacturing system of claim 1, and further comprising a purge station, wherein the velocimetry assembly is retained by the purge station.

8. The additive manufacturing system of claim 1, wherein the velocimetry assembly is configured to route a pulsed laser beam into an extrusion nozzle of the print head.

9. A method for using an additive manufacturing system, the method comprising:

providing a print head retained by the additive manufacturing system;

feeding a consumable material to the print head;

melting the consumable material in the print head to produce a pre-extrudate of the molten consumable material;

extruding the pre-extrudate from the print head as an extrudate; and

determining flow rates of the pre-extrudate or the extrudate with a velocimetry assembly.

10. The method of claim 9, and further comprising determining velocities of the consumable material being fed to the print head with a second velocimetry assembly.

11. The method of claim 9, wherein determining the flow rates of the pre-extrudate or the extrudate with the velocimetry assembly comprises:

routing a pulsed light beam toward the pre-extrudate or extrudate to scatter light rays from the pre-extrudate or extrudate; and

detecting at least a portion of the scattered light rays with a first detector over multiple captured frames that are synchronized in time with a pulsing of the light beam.

12. The method of claim 11, wherein the first detector is positioned to receive the scattered light rays in a transmission-forward-scatter pattern.

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

detecting at least a portion of the scattered light rays with a second detector over multiple captured frames that are synchronized in time with the detecting at the first detector;

determining cross-sectional areas of the extrudate or pre-extrudate based on the scattered light rays detected with the second detector; and

determining the flow rates as volumetric flow rates from the determined velocities and the determined cross-sectional areas.

14. The method of claim 9, wherein the extrudate or pre-extrudate comprises the extrudate, wherein the pulsed light beam comprises a pulsed laser beam, and wherein routing the pulsed laser beam toward the extrudate comprises positioning a focal volume of the pulsed laser beam at a position at which velocities of a core region and a surface of the extrudate are substantially the same.

19. The method of claim 9, wherein the detector is positioned to receive the scattered light rays in a transmission-forward-scatter pattern.

15. A method for using an additive manufacturing system, the method comprising:

extruding a molten material from a print head retained by the additive manufacturing system 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 captured frames, wherein each captured frame has a speckle pattern; and

comparing the speckle pattern of the multiple captured frames to determine flow rates of the extrudate.

16. The method of claim 15, wherein routing the pulsed laser beam toward the extrudate comprises positioning a focal volume of the pulsed laser beam at a position at which velocities of a core region and a surface of the extrudate are substantially the same.

17. The method of claim 15, and further comprising:

detecting at least a portion of the scattered light rays with a second detector over multiple captured frames;

determining cross-sectional areas of the extrudate or pre-extrudate based on the scattered light rays detected with the second detector; and

determining the flow rates as volumetric flow rates from the determined velocities and the determined cross-sectional areas.

18. The method of claim 15, wherein the detector is retained at a purge station of the additive manufacturing system.

20. The method of claim 15, wherein the detecting step is performed while the print head is printing layers of a three-dimensional part using an additive manufacturing technique.