TEMPERATURE SENSING APPARATUS, LASER PROCESSING SYSTEM, AND TEMPERATURE MEASURING METHOD

• US 20160096236A1
• Filed: 10/02/2014
• Published: 04/07/2016
• Est. Priority Date: 10/02/2014
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Cho, Chia-Hung, Hsieh, Yi-Chen, Chou, Sen-Yih, Lin, Chun-Jen, Chuang, Kai-Ping
• Granted Patent: US 9,533,375 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/368 Temperature or temperature gradient, e.g. temperature of the melt pool
• 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: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/034 Observing the temperature of the workpiece
• 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 26/707 for monitoring laser beam transmission optics
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: G01J 2005/106 Arrays
• CPC Class Codes: G01J 5/08021 Notch filters
• CPC Class Codes: G01J 5/0803 Arrangements for time-dependent attenuation of radiation signals
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors
• CPC Class Codes: G01J 5/0846 having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A temperature sensing apparatus configured to measure a temperature distribution of a surface to be measured is provided. The temperature sensing apparatus includes a lens set, a filtering module, a plurality of sensor arrays, and a processing unit. The lens set is configured to receive radiation from the surface to be measured. The filtering module is configured to filter the radiation from the lens set into a plurality of radiation portions respectively having different wavelengths. The sensor arrays are configured to respectively sense the radiation portions. The processing unit is configured to calculate an intensity ratio distribution of the radiation between the different wavelengths according to the radiation portions respectively sensed by the sensor arrays and determine the temperature distribution according to the intensity ratio distribution. A laser processing system and a temperature measuring method are also provided.

Claims

1. A temperature sensing apparatus configured to measure a temperature distribution of a surface to be measured, the temperature sensing apparatus comprising:

a lens set configured to receive radiation from the surface to be measured;

a filtering module configured to filter the radiation from the lens set into a plurality of radiation portions respectively having different wavelengths;

a plurality of sensor arrays configured to respectively sense the radiation portions; and

a processing unit configured to calculate an intensity ratio distribution of the radiation between the different wavelengths according to the radiation portions respectively sensed by the sensor arrays and determine the temperature distribution according to the intensity ratio distribution.

2. The temperature sensing apparatus according to claim 1, wherein a refresh rate of each of the sensor arrays is greater than or equal to 1 kHz.

3. The temperature sensing apparatus according to claim 1, wherein each of the sensor arrays comprises a plurality of optical sensors arranged in a one-dimensional array or in a two-dimensional array.

4. The temperature sensing apparatus according to claim 1, wherein the surface to be measured is a surface of a melt pool of a powder layer scanned by a laser beam, and the processing unit is configured to monitor a scanning direction of the laser beam according to the temperature distribution.

5. The temperature sensing apparatus according to claim 1, wherein the filtering module comprises:

a beam splitter disposed on a path of the radiation from the lens set and splitting the radiation into a plurality of partial radiation beams; and

a plurality of optical filters respectively disposed on paths of the partial radiation beams and respectively filtering the partial radiation beams into the radiation portions.

6. The temperature sensing apparatus according to claim 1, wherein the filtering module comprises:

a first optical filter disposed on a path of the radiation from the lens set and splitting the radiation into a plurality of partial radiation beams respectively having different wavelength ranges; and

a plurality of second optical filters respectively disposed on paths of the partial radiation beams and respectively filtering the partial radiation beams into the radiation portions.

7. The temperature sensing apparatus according to claim 1, wherein the sensor arrays respectively sense the radiation portions successively, and the processing unit determine the temperature distribution successively.

8. The temperature sensing apparatus according to claim 1, wherein the surface to be measured is a surface of a melt pool of a powder layer scanned by a laser beam, and the processing unit is configured to monitor a shape of the melt pool according to the temperature distribution.

9. The temperature sensing apparatus according to claim 1, wherein the processing unit is configured to interpolate temperature distribution data according to the temperature distribution.

10. A laser processing system comprising:

a laser source configured to emit a laser beam;

a scanning unit configured to cause the laser beam to scan a surface; and

a temperature sensing apparatus configured to measure a temperature distribution of the scanned surface, the temperature sensing apparatus comprising;

a lens set configured to receive radiation from the scanned surface;

a filtering module configured to divide the radiation from the lens set into a plurality of radiation portions respectively having different wavelengths;

a plurality of sensor arrays configured to respectively sense the radiation portions; and

a processing unit configured to calculate an intensity ratio distribution of the radiation between the different wavelengths according to the radiation portions respectively sensed by the sensor arrays and determine the temperature distribution according to the intensity ratio distribution.

11. The laser processing system according to claim 10, wherein a refresh rate of each of the sensor arrays is greater than or equal to 1 kHz.

12. The laser processing system according to claim 10, wherein each of the sensor arrays comprises a plurality of optical sensors arranged in a one-dimensional array or in a two-dimensional array.

13. The laser processing system according to claim 10, wherein the scanned surface is a surface of a melt pool of a powder layer scanned by the laser beam, and the processing unit is configured to monitoring a scanning direction of the laser beam according to the temperature distribution.

14. The laser processing system according to claim 10, wherein the filtering module comprises:

a beam splitter disposed on a path of the radiation from the lens set and splitting the radiation into a plurality of partial radiation beams; and

a plurality of optical filters respectively disposed on paths of the partial radiation beams and respectively filtering the partial radiation beams into the radiation portions.

15. The laser processing system according to claim 10, wherein the filtering module comprises:

a first optical filter disposed on a path of the radiation from the lens set and splitting the radiation into a plurality of partial radiation beams respectively having different wavelength ranges; and

a plurality of second optical filters respectively disposed on paths of the partial radiation beams and respectively filtering the partial radiation beams into the radiation portions.

16. The laser processing system according to claim 10, wherein the sensor arrays respectively sense the radiation portions successively, and the processing unit determine the temperature distribution successively.

17. The laser processing system according to claim 10, wherein the scanned surface is a surface of a melt pool of a powder layer scanned by the laser beam, and the processing unit is configured to monitor a shape of the melt pool according to the temperature distribution.

18. The laser processing system according to claim 10, wherein the processing unit is configured to interpolate temperature distribution data according to the temperature distribution.

19. The laser processing system according to claim 10, wherein the scanning unit is disposed on a path of the radiation between the scanned surface and the lens set.

20. The laser processing system according to claim 19 further comprising a beam splitter configured to cause the laser beam from the laser source to be transmitted to the scanning unit and configured to cause the radiation from the scanning unit to be transmitted to the lens set.

21. The laser processing system according to claim 20, wherein the laser beam and the radiation share a substantially same path between the scanned surface and the beam splitter.

22. A temperature measuring method comprising:

receiving radiation from a surface to be measured;

filtering the radiation into a plurality of radiation portions respectively having different wavelengths;

sensing the radiation portions to respectively obtain a plurality of intensity distributions;

calculating an intensity ratio distribution of the radiation between the different wavelengths according to the intensity distributions; and

determining a temperature distribution of the surface to be measured according to the intensity ratio distribution.

23. The temperature measuring method according to claim 22, wherein a refresh rate of sensing the radiation portions is greater than or equal to 1 kHz.

24. The temperature measuring method according to claim 22, wherein each of the intensity distributions is a one-dimensional or two-dimensional distribution data of intensity.

25. The temperature measuring method according to claim 22, wherein the surface to be measured is a surface of a melt pool of a powder layer scanned by a laser beam, and the the temperature measuring method further comprises monitoring a scanning direction of the laser beam according to the temperature distribution.

26. The temperature measuring method according to claim 22, wherein the surface to be measured is a surface of a melt pool of a powder layer scanned by a laser beam, and the the temperature measuring method further comprises adjusting the laser beam according to a feedback of the temperature distribution.

27. The temperature measuring method according to claim 22 further comprising interpolating temperature distribution data according to the temperature distribution.

28. The temperature measuring method according to claim 22, wherein the radiation portions are successively sensed, and the temperature distribution is successively determined.

29. The temperature measuring method according to claim 22, wherein the surface to be measured is a surface of a melt pool of a powder layer scanned by a laser beam, and the temperature measuring method further comprises monitoring a shape of the melt pool according to the temperature distribution.