Systems and methods for measuring radiated thermal energy during an additive manufacturing operation

• US 10,479,020 B2
• Filed: 08/01/2018
• Issued: 11/19/2019
• Est. Priority Date: 08/01/2017
• Status: Active Grant

• Current Assignee: Divergent Technologies, Inc.
• Original Assignee: Sigma Labs, Inc.
• Inventors: Madigan, R. Bruce, Jacquemetton, Lars, Wikle, Glenn, Cola, Mark J., Dave, Vivek R., Beckett, Darren, Castro, Alberto M.
• Primary Examiner(s): Evans, Geoffrey S
• Application Number:
  US16/052,488
• Publication Number:
  US 20190039318A1
• Time in Patent Office: 475 Days
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/31 Calibration of process steps or apparatus settings, e.g. before or during manufacturing
• CPC Class Codes: B22F 12/90 Means for process control, e.g. cameras or sensors
• CPC Class Codes: B22F 2203/11 temperature, temperature profile
• CPC Class Codes: B23K 15/0086 welding for purposes other than joining, e.g. built-up welding
• CPC Class Codes: B23K 15/02 Control circuits therefor
• CPC Class Codes: B23K 2101/001 Turbines
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/082 Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• CPC Class Codes: B23K 26/342 Build-up welding
• CPC Class Codes: B23K 26/70 Auxiliary operations or equipment
• CPC Class Codes: B23K 31/125 Weld quality monitoring
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B29C 64/268 using laser beams; using electron beams [EB]
• CPC Class Codes: B29C 64/393 for controlling or regulating additive manufacturing processes
• 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 50/00 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

This disclosure describes various methods and apparatus for characterizing an additive manufacturing process. A method for characterizing the additive manufacturing process can include generating scans of an energy source across a build plane; measuring an amount of energy radiated from the build plane during each of the scans using an optical sensor; determining an area of the build plane traversed during the scans; determining a thermal energy density for the area of the build plane traversed by the scans based upon the amount of energy radiated and the area of the build plane traversed by the scans; mapping the thermal energy density to one or more location of the build plane; determining that the thermal energy density is characterized by a density outside a range of density values; and thereafter, adjusting subsequent scans of the energy source across or proximate the one or more locations of the build plane.

Claims

1. An additive manufacturing method, comprising:

generating a plurality of scans of an energy source across a build plane;

measuring an amount of energy radiated from the build plane during each of the plurality of scans using an optical sensor monitoring the build plane;

determining an area of the build plane traversed during one or more scans of the plurality of scans of the energy source;

determining a thermal energy density for the area of the build plane traversed by the one or more scans of the plurality of scans based upon the amount of energy radiated and the area of the build plane traversed by the plurality of scans;

mapping the thermal energy density to one or more locations of the build plane;

determining that the thermal energy density is characterized by a density outside a range of density values; and

thereafter, adjusting subsequent scans of the energy source across or proximate the one or more locations of the build plane.

2. The additive manufacturing method of claim 1 wherein the measuring an amount of energy comprises receiving sensor readings from the optical sensor.

3. The additive manufacturing method of claim 1 wherein determining the area of the build plane traversed comprises

determining a start point of a first scan of the plurality of scans;

determining an end point of the first scan; and

determining a length of the first scan by calculating a distance between the start point and the end point.

4. The additive manufacturing method of claim 1 wherein determining that the thermal energy density is characterized by a density outside a range of density values further comprises:

receiving a baseline;

determining one of more thermal energy density scan values are substantially different than the baseline; and

outputting at least one of a graph and a point cloud.

5. The additive manufacturing method of claim 4, wherein determining that the thermal energy density is characterized by a density outside a range of density values further comprises:

transmitting a control signal associated with a process parameter.

6. The additive manufacturing method of claim 1 wherein the energy source corresponds to at least one of a laser and an electron beam.

7. The additive manufacturing method of claim 1 wherein mapping the thermal energy density comprises:

receiving energy source drive signal data indicating a path of the energy source across the build plane; and

determining a location of each of the plurality of scans using the energy source drive signal data.

8. The additive manufacturing method of claim 1 further comprising:

receiving position data associated with the energy source.

9. The additive manufacturing method of claim 1, further comprising:

receiving energy source drive signal data, wherein the energy source drive signal data indicates when the energy source is turned on and when the energy source is turned off.

10. An additive manufacturing method, comprising:

dividing a build plane into a plurality of grid regions, wherein each of the grid region has a grid area;

generating a plurality of scans of an energy source across the build plane;

generating sensor readings during each of the plurality of scans using an optical sensor;

determining a total amount of energy radiated from the build plane during the plurality of scans using the sensor readings;

computing a thermal energy density associated with a grid region of the plurality of grid regions based upon the total amount of energy radiated from the grid region and the grid area of the grid region;

determining that the thermal energy density associated with the grid region is characterized by a thermal energy density outside a range of thermal energy density values; and

thereafter, adjusting an output of the energy source.

11. The additive manufacturing method of claim 10, wherein the thermal energy density is determined by dividing the total amount of energy radiated from the grid region by the grid area.

12. The additive manufacturing method of claim 10, wherein a width of the grid region is sized in accordance with a length of each of the plurality of scans.

13. The additive manufacturing method of claim 10, determining a grid region including the plurality of scans comprises:

receiving energy source drive signal data indicating a path of the energy source across the build plane; and

defining a location, shape and size of the grid region based upon the energy source drive signal data.

14. The additive manufacturing method of claim 13, wherein the energy source drive signal data includes a distance between two or more scans of the plurality of scans.

15. An additive manufacturing method, comprising:

dividing at least a portion of a build plane into a plurality of grid regions each having a grid area;

generating a plurality of scans of an energy source across the build plane;

generating sensor readings during each of the plurality of scans using an optical sensor;

for each of the plurality of scans, mapping portions of each of the sensor readings to a respective one of the plurality of grid regions;

for each of the plurality of grid regions;

summing the sensor readings mapped to each grid region; and

computing a thermal energy density based on the summed sensor readings and the grid area;

determining that the thermal energy density associated with one or more of the plurality of grid regions is characterized by a thermal energy density outside a range of thermal energy density values; and

thereafter, adjusting an output of the energy source.

16. The additive manufacturing method as recited in claim 15, further comprising:

providing a powder layer across the build plane;

generating an additional plurality of scans of the energy source across the powder layer, wherein characteristics of at least some of the additional plurality of scans are based on the computed thermal energy density of one or more of the plurality of grid regions.

17. The additive manufacturing method of claim 15 wherein one or more input parameters of the energy source is changed during at least a portion of one of the plurality of scans based on the computed thermal energy density.

18. The additive manufacturing method of claim 15 wherein mapping portions of each of the sensor readings comprises mapping all of the sensor readings for one of the plurality of scans to one or more of the plurality of grid regions.

19. The additive manufacturing method of claim 15, wherein the plurality of grid regions extend across an entirety of the build plane.

20. The additive manufacturing method of claim 15, wherein the grid regions are distributed evenly across the build plane.