Additive manufacturing temperature controller/sensor apparatus and method of use thereof

• US 10,207,363 B2
• Filed: 03/23/2015
• Issued: 02/19/2019
• 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
• Primary Examiner(s): Shah, Manish S
• Application Number:
  US14/665,983
• Publication Number:
  US 20150268099A1
• Time in Patent Office: 1,429 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 determining a temperature of an object under construction, comprising the steps of:

providing an additive manufacturing device configured to construct the object comprising;

a working platform holding the object under construction; and

a temperature sensor, comprising;

a first two-dimensional detector array optically linked to a plane parallel to a surface of the working platform; and

a second two-dimensional detector array optically linked to the plane parallel to the working platform;

generating a first set of signals using said first two-dimensional detector array;

generating a second set of signals using said second two-dimensional detector array; and

using a controller to calculate a set of temperatures using said first set of signals and said second set of signals.

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

depositing a powder on the plane parallel to the surface of the working platform using a screed of said additive manufacturing device;

sintering the powder generating a melt pool of melted powder using a laser of said additive manufacturing device;

sensing the melt pool using said temperature sensor;

using the calculated set of temperatures in a step of at least one of;

controlling said laser; and

determining a quality of sintering of the object;

said controller using the calculated set of temperatures in a feedback control loop to redirect said laser to further lase a previously lased position of the object.

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

prior to said step of sensing, aligning said first two-dimensional detector array to image on a detector element by detector element level a same position of the object observed by said second two-dimensional detector, said set of temperatures corresponding to individual imaged locations of the object imaged by elements of the first two-dimensional detector.

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

within a period of less than one second, monitoring at least two locations of the object at least three millimeters apart using said first two-dimensional detector array and said second two-dimensional detector array, said at least two locations of the object comprising;

a first object location lased using a first laser and a second object location lased using a second laser.

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

multiplexing construction of the object via simultaneous use of a first laser, a second laser, and a third laser, respectively lasing a first position, a second position, and a third position of the object.

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

said controller using a-priori knowledge of shape of a spectrum of a blackbody radiator as related to the first set of signals and the second set of signals to determine the set of temperatures.

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

using said temperature sensor to monitor, within one-tenth of a second, at least two sintering locations sintered by a corresponding at least two lasers of said additive manufacturing device, wherein a first laser of said at least two lasers sinters a first location of said at least two sintering locations simultaneous with a second laser of said at least two lasers sintering a second location of said at least two sintering locations.

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

using each of said first-two dimensional detector array and said second two-dimensional detector array to simultaneously monitor a current sintering location at the head of a teardrop iso-temperature shape of a current melt pool of the object with a first set of pixels and at least one previously sintered location at a tail of the teardrop iso-temperature shape of the melt pool of the object with a second set of pixels to determine at least a cooling rate of a section of the object.

9. The method of claim 2, further comprising the step of:

recording data from both said first two-dimensional detector array and said second two-dimensional detector array; and

using said data to determine a cooling parameter of the melt pool of the object after lasing with a laser of said additive manufacturing device.