ADDITIVE MANUFACTURING TEMPERATURE CONTROLLER/SENSOR APPARATUS AND METHOD OF USE THEREOF

• US 20170151628A1
• Filed: 02/10/2017
• Published: 06/01/2017
• Est. Priority Date: 03/24/2014
• Status: Active Grant

• Current Assignee: James Eldon Craig, Thomas Ross Wakeman
• Original Assignee: James Eldon Craig, Thomas Ross Wakeman
• Inventors: Craig, James Eldon, Wakeman, Thomas Ross
• Granted Patent: US 10,603,742 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 2103/08 Non-ferrous metals or alloys
• CPC Class Codes: B23K 26/034 Observing the temperature of the workpiece
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• 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 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: G01J 2005/106 Arrays
• CPC Class Codes: G01J 2005/607 on two separate detectors
• CPC Class Codes: G01J 5/0003 for sensing the radiant heat transfer of samples, e.g. emittance meter
• CPC Class Codes: G01J 5/004 by molten metals
• CPC Class Codes: G01J 5/602 using selective, monochromatic or bandpass filtering

Abstract

An additive manufacturing temperature controller/temperature sensor uses one or more spectrophotometric sensors to monitor temperature of successive layers and preferably localized sections of successive layers of a melt pool, and transients thereof, of an object being generated for the purpose of dynamic control of the additive manufacturing device and/or quality control of the generated object manufactured with the additive manufacturing device. Generally, the additive manufacturing temperature controller/sensor apparatus monitors temperature of a section of the object during manufacture as a function of wavelength, time, position, and/or angle to determine melt extent in terms of radius and/or depth.

Claims

1. A method for monitoring a temperature of an object under construction, comprising:

providing an additive manufacturing device, comprising;

a working platform configured to hold the object under construction;

providing a temperature sensor, comprising;

a two-dimensional detector array; and

at least one intervening optic, said two-dimensional detector array optically coupled, through said at least one intervening optic, to a plane parallel said working platform; and

determining a temperature of the object under construction at at least two positions on said plane parallel said working platform using photons emitted from the object under construction.

2. The method of claim 1, further comprising the steps of:

said additive manufacturing device using a first laser to generate a first melt pool, at a first location of said plane, from material applied via a screed.

3. The method of claim 2, said step of determining further comprising the step of:

monitoring a temperature of the first melt pool using a first bandpass filter and a second bandpass filter.

4. The method of claim 3, further comprising the step of:

repeatedly monitoring the first location using said temperature sensor until the first melt pool at the first location freezes.

5. The method of claim 3, further comprising the step of:

determining a cooling rate of the object under construction at the first position through repeatedly monitoring the first location using said temperature sensor as the laser interacts with non-overlapping second, third, and fourth positions of the object under construction.

6. The method of claim 5, further comprising the step of:

using the determined cooling rate in determination of a depth of the melt pool.

7. The method of claim 5, further comprising the step of:

a controller, based on the cooling rate, directing the laser to return to the first position for additional heating.

8. The method of claim 3, further comprising a step of:

repeatedly monitoring the first location as said first laser interacts with at least eight new positions of the object under construction along a longitudinal axis of the plane parallel said working platform.

9. The method of claim 8, said step of determining a temperature further comprising the step of:

as the first laser interacts with the at least eight new positions along the longitudinal axis, monitoring a position along a radial axis, the radial axis perpendicular to the longitudinal axis and passing through the first location.

10. The method of claim 3, said step of determining the temperature further comprising the steps of:

measuring a temperature at a first location using said at least one intervening optic, said at least one intervening optic comprising said first optical filter; and

measuring a temperature at a second location using said at least one intervening optic, said at least one intervening optic comprising a second optical filter.

11. The method of claim 10, said step of determining the temperature further comprising the step of:

imaging the plane parallel the working platform using said at least one intervening optic, said at least one intervening optic comprising an achromatic lens optically coupled to said two-dimensional detector array.

12. The method of claim 11, further comprising the step of:

said two dimensional detector array and said achromatic lens imaging first photons passing through said first filter and second photons passing through said second filter.

13. The method of claim 12, further comprising the step of:

determining a color temperature of the object under construction using a first signal related to the first photons and a second signal related to the second photons.

14. The method of claim 13, wherein said first photons comprise a first mean wavelength at least one hundred nanometers longer than a second mean wavelength of said second photons.

15. The method of claim 13, a majority of said first photons absorbed by said second filter.

16. The method of claim 11, further comprising the steps of:

said additive manufacturing device building a set of layers using said screed and said first laser;

a controller generating a three-dimensional data cube using said temperature sensor and output of said two-dimensional detector array associated with each layer of said set of layers; and

using said three-dimensional data cube to determine a cooling rate of a sub-layer volume of the object under construction.

17. The method of claim 10, further comprising the steps of:

said additive manufacturing device using a second laser to generate a second melt pool from the material applied via said screed; and

simultaneously monitoring the first melt pool and the second melt pool using said two-dimensional detector array.

18. The method of claim 1, further comprising the step of:

using said two dimensional detector array to simultaneously monitor a current sintering location of the object with a first set of pixels and at least one previously sintered location of the object with a second set of pixels to determine at least a cooling rate of a section of the object.

19. An apparatus for monitoring a temperature of an object under construction, comprising:

an additive manufacturing device, comprising;

a working platform configured to hold the object under construction; and

a temperature sensor, comprising;

a two-dimensional detector array;

at least one intervening optic, said two-dimensional detector array optically coupled, through said at least one intervening optic, to a plane parallel said working platform, said temperature sensor configured to determine a temperature of the object under construction at at least two positions on said plane parallel said working platform using photons emitted from the object under construction.