Methods and Systems for Coherent Imaging and Feedback Control for Modification of Materials

• US 20170120337A1
• Filed: 01/18/2017
• Published: 05/04/2017
• Est. Priority Date: 09/25/2010
• Status: Active Grant

• Current Assignee: IPG Photonics Corporation
• Original Assignee: Queen's University At Kingston
• Inventors: Webster, Paul J.L., Fraser, James M., Yang, Victor X.D., Kanko, Jordan
• Granted Patent: US 10,124,410 B2
• Time in Patent Office: Days
• CPC Class Codes: B22F 10/25 Direct deposition of metal particles, e.g. direct metal deposition [DMD] or laser engineered net shaping [LENS]
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/322 of the gas flow, e.g. rate or direction
• CPC Class Codes: B22F 10/36 of energy beam parameters
• CPC Class Codes: B22F 10/366 Scanning parameters, e.g. hatch distance or scanning strategy
• CPC Class Codes: B22F 10/80 Data acquisition or data processing
• CPC Class Codes: B22F 12/41 characterised by the type, e.g. laser or electron beam
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 12/49 Scanners
• CPC Class Codes: B22F 12/90 Means for process control, e.g. cameras or sensors
• CPC Class Codes: B22F 2203/03 for feed-back
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B23K 15/0013 Positioning or observing workpieces, e.g. with respect to the impact; Aligning, aiming or focusing electronbeams
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 31/125 Weld quality monitoring
• CPC Class Codes: B28B 1/001 Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material selective deposition modelling of metallic powder B22F10/00; rapid manufacturing of 3D objects in general and in particular of plastics B29C64/00
• CPC Class Codes: B28B 17/0081 Process control
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• 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 50/02 : for controlling or regulating additive manufacturing processes
• CPC Class Codes: G01B 9/02083 : characterised by particular signal processing and presentation
• CPC Class Codes: G01B 9/02091 : Tomographic interferometers, e.g. based on optical coherence
• CPC Class Codes: G01N 2021/8416 : and process controlling, not otherwise provided for
• CPC Class Codes: G01N 21/45 : using interferometric methods; using Schlieren methods
• CPC Class Codes: Y02P 10/25 : Process efficiency

Abstract

Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser, sintering, and welding applications. An imaging optical source that produces imaging light. A feedback controller controls at least one processing parameter of the material modification process based on an interferometry output generated using the imaging light. A method of processing interferograms is provided based on homodyne filtering. A method of generating a record of a material modification process using an interferometry output is provided.

Claims

1. An apparatus, comprising:

a material processing beam source that produces a material processing beam that is applied to a location of a material in a material modification process, wherein the material modification process is selected from sintering, welding, and brazing, or a combination thereof;

an imaging light source that produces imaging light;

a coherent imaging system including an optical interferometer that produces an interferometry output using at least a component of the imaging light that is delivered to a phase change region and/or a surrounding region created in the material before, during, and/or after the material modification process, the interferometry output based on at least one optical path length to at least one point in the phase change region and/or the surrounding region compared to another optical path length;

a detector that receives the interferometry output and produces a detector output that is indicative of a characteristic of the phase change region and/or the surrounding region during the material modification process, and

a record generator that generates at least one record based on the detector output at a plurality of times.

2. The apparatus of claim 1, wherein the material modification process is part of an additive manufacturing process, a subtractive manufacturing process, or a combination thereof.

3. The apparatus of claim 2, wherein the additive manufacturing process comprises laser sintering, selective laser sintering, laser melting, selective laser melting, direct metal laser sintering, electron beam melting, powder bed 3D printing, or powder bed fusion, or a variant, derivative, or combination thereof.

4. The apparatus of claim 2, wherein the additive manufacturing process comprises, a powder fed process, laser metal deposition, direct metal deposition, or laser cladding, or a variant, derivative, or combination thereof.

5. The apparatus of claim 1, further comprising a feedback processor that receives input from the coherent imaging system and/or the detector output and produces an output used as feedback to control one or more parameters of the material modification process.

6. The apparatus of claim 2, further comprising a feedback processor that receives input from the coherent imaging system and/or the detector output and produces an output used as feedback to control one or more parameters of the material modification process.

7. The apparatus of claim 1, further comprising one or more auxiliary optical sensor;

wherein the one or more auxiliary optical sensor receives at least one optical emission from the phase change region, or the surrounding region, or both, and produces one or more output;

wherein the one or more output is connected to at least one of a signal processor, a quality assurance signal generator, a feedback controller, and a record generator;

wherein at least one of the signal processor, quality assurance signal generator, feedback controller, and record generator generates at least one of a record, annunciation, and feedback output.

8. The apparatus of claim 2, further comprng one or more auxiliary optical sensor;

wherein the one or more auxiliary optical sensor receives at least one optical emission from the phase change region, or the surrounding region, or both, and produces one or more output;

wherein the one or more output is connected to at least one of a signal processor, a qua assurance signal generator, a feedback controller, and a record generator;

wherein at least one of the signal processor, quality assurance signal generator, feedback controller, and record generator generates at least one of a record, annunciation, and feedback output.

9. The apparatus of claim 1, further comprising:

a computer readable storage medium;

wherein the record generator stores the record on the computer readable storage medium.

10. The apparatus of claim 1, wherein the apparatus controls at least one processing parameter of the material modification process based on the at least one record.

11. The apparatus of claim 10, wherein the at least one processing parameter of the material modification process that is controlled comprises at least one of:

on/off state of the material processing beam;

average power of the material processing beam;

pulse duration of the material processing beam;

peak intensity of the material processing beam;

density of the material processing beam;

energy of the material processing beam;

particle species of the material processing beam;

wavelength of the material processing beam;

pulse repetition rate of the material processing beam;

pulse energy of the material processing beam;

pulse shape of the material processing beam;

scan speed of the material processing bea

focal diameter of the material processing beam;

focal position of the material processing beam;

spatial pattern of the material processing beam;

cooling media flow rate;

cover/assist gas flow rate;

cover/assist gas pressure;

cover/assist gas blend;

at least one process parameter selected from voltage and current;

additive material feed rate;

additive material feed geometry; and

additive material feed type.

12. The apparatus of claim 10, wherein the at least one processing parameter of the material modification process that is controlled comprises at least one of powder layer thickness, packing density, layer uniformity, additive material feed rate, and choice of deposited material.

13. The apparatus of claim 1, wherein the apparatus is configured to produce the material processing beam and the imaging light substantially co-axially when delivered into the phase change region and/or the surrounding region.

14. The apparatus of claim 2, wherein the additive manufacturing process manufactures, modifies, or repairs a three-dimensional object by modifyina an additive material with the material processing beam.

15. The apparatus of claim 1, wherein the material comprises at least one of metal, semiconductor, dielectric, glass, ceramic, polymer, plastic, and composite.

16. A method for controlling a material modification process that uses a material processing beam applied to a location of the material, comprising:

applying an imaging light to a phase change region and/or a surrounding region created in the material before, during, and/or after the material modification process;

using a coherent imaging system including an optical interferometer to produce an interferometry output using at least a component of the imaging light delivered to the phase change region and/ora surrounding region before, during, and/or after the material modification process, wherein the interferometry output is based on at least one optical path length to at least one point in the phase change region and/or the surrounding region compared to another optical path length;

wherein the interferometry output is indicative of a characteristic of the phase change region and/or the surrounding region during the material modification process;

using the interferometry output to control at least one processing parameterthe material modification process; and

wherein the material modification process is selected fro sintering, welding, brazing, and a conabination thereof.

17. The method of claim 16, wherein the material modification process is part of an additive manufacturing process, a subtractive manufacturing process, or a combination thereof.

18. The method of claim 17, wherein the additive manufacturing process comprises laser sintering, selective laser sintering, laser melting, selective laser melting, direct metal laser sintering, electron beam melting, powder bed 3D printing, powder bed fusion, a powder fed. process, laser metal deposition, direct metal deposition, or laser cladding, or a variant, derivative, or combination thereof.

19. The method of claim 16, further comprising disposing one or more auxiliary optical sensor to receive at least one optical emission from the phase change region, or the surrounding region, or both, and produce one or more output;

connecting the one or more output to at least one of a signal processor, a quality assurance signal generator, a feedback controller, and a record generator;

wherein at least one of the signal processor, quality assurance signal generator, feedback controller, and record generator generates at least one of a record, annunciation, and feedback output;

using at least one of the record, annunciation, and feedback output for one or more of controlling, monitoring, and adjusting the material modification process.

20. The method of claim 16, wherein controlling comprises providing additive manufacturing quality assurance information.

21. The method of claim 16, comprising controlling at least one processing parameter selected from on/off state of the material processing beam;

average power of the material processing beam;

pulse duration of the material processing beam;

peak intensity of the material processing beam;

density of the material processing beam;

energy of the material processing beam;

particle species of the material processing beam;

wavelength of the material processing beam;

pulse repetition rate of the material processing beam;

pulse energy of the material processing beam;

pulse shape of the material processing beam;

scan speed of the material processing bea

focal diameter of the material processing beam;

focal position of the material processing beam;

spatial pattern of the material processing beam;

cooling media flow rate;

cover/assist gas flow rate;

cover/assist gas pressure;

cover/assist gas blend;

at least one process parameter selected from voltage and current;

additive material feed rate;

additive material feed geometry; and

additive material feed type,

22. The method of claim 16, comprising controlling at least one of powder layer thickness, packing density, layer uniformity, additive material feed rate, and choice of deposited material.

23. The method of claim 16, comprising applying the material processing beam and the imaging light substantially co-axially to the phase change region and/or the surrounding region.

24. The method of claim 16, comprising controlling an additive manufacturing process used for manufacturing or repairing a three-dimensional object by modifying an additive material with the material processing beam.

25. The method of claim 16, comprising controlling an additive manufacturing process wherein the material comprises at least one of metal, semiconductor, dielectric, glass, ceramic, polymer, plastic, and composite.