MULTIPLE-BEAM LASER PROCESSING USING MULTIPLE LASER BEAMS WITH DISTINCT WAVELENGTHS AND/OR PULSE DURATIONS

• US 20150246412A1
• Filed: 02/27/2015
• Published: 09/03/2015
• Est. Priority Date: 02/28/2014
• Status: Active Grant

• Current Assignee: IPG Photonics Corporation
• Original Assignee: IPG Photonics Corporation
• Inventors: Mendes, Marco, Sercel, Jeffrey P., Song, Xiangyang, Porneala, Cristian, Sarrafi, Rouzbeh, Schoenly, Joshua, Van Gemert, Roy
• Granted Patent: US 9,956,646 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B23K 2103/12 Copper or alloys thereof
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B23K 26/0604 by a combination of beams

Abstract

Multiple-beam laser processing may be performed on a workpiece using at least first and second laser beams with different characteristics (e.g., wavelengths and/or pulse durations). In some applications, an assist laser beam is directed at a target location on or within the workpiece to modify a property of the non-absorptive material. A process laser beam is directed at the target location and is coupled into absorption centers formed in the non-absorptive material to complete processing of the non-absorptive material. Multiple-beam laser processing may be used, for example, to drill holes in a substrate made of alumina or other transparent ceramics. In other applications, multiple-beam laser processing may be used in melting applications such as micro-welding, soldering, and forming laser fired contacts. In these applications, the assist laser beam may be used to modify a property of the material or to change the geometry of the parts.

Claims

1. A method of multiple-beam laser processing of a workpiece made of a non-absorptive material, the method comprising:

generating an assist laser beam with a first wavelength and a first pulse duration, wherein the non-absorptive material of the workpiece is sufficiently absorptive of the assist laser beam with the first wavelength and the first pulse duration to modify a property of the non-absorptive material;

generating a process laser beam with a second wavelength and a second pulse duration, wherein at least one of the first and second wavelengths and the first and second pulse durations are different, and wherein the process laser beam alone is not sufficiently absorbed in the non-absorptive material to complete processing the non-absorptive material; and

directing the assist laser beam and the process laser beam at a target location on the workpiece such that the assist laser beam modifies a property of the non-absorptive material of the workpiece at the target location forming absorption centers and such that the process laser beam is coupled into the absorption centers formed in the non-absorptive material at the target location to complete processing of the non-absorptive material at the target location.

2. The method of claim 1 wherein the assist laser beam is generated by an assist laser, and wherein the process laser beam is generated by a process laser.

3. The method of claim 2 wherein the assist laser beam from the assist laser and the process laser beam from the process laser are combined and directed at the target location on the workpiece simultaneously.

4. The method of claim 1 wherein the first wavelength is shorter than the second wavelength, and wherein the first pulse duration is shorter than the second pulse duration.

5. The method of claim 1 wherein the first wavelength is in a visible spectral range and wherein the second wavelength is in an infrared spectral range.

6. The method of claim 1 wherein the first wavelength is in an ultraviolet (UV) spectral range and wherein the second wavelength is in a visible spectral range.

7. The method of claim 1 wherein the first wavelength is in an ultraviolet (UV) spectral range and wherein the second wavelength is in an infrared spectral range.

8. The method of claim 1 wherein the first pulse duration is in a range of less than 10 ns, and wherein the second pulse duration is in a range of greater than 1 microsecond.

9. The method of claim 1 wherein the first wavelength and the second wavelength are both in an infrared spectral range, and wherein the first pulse duration is in a range of less than 1 ns and the second pulse duration is in a range of greater than 1 microsecond.

10. The method of claim 1 wherein the non-absorptive material includes a transparent ceramic.

11. The method of claim 1 wherein the non-absorptive material includes sapphire or glass.

12. The method of claim 11, wherein the first wavelength is in a spectral range of 514-532 nm and the second wavelength is in a spectral range of 1040 -1070 nm, and wherein the first pulse duration is about 1 ns and the second pulse duration is greater than 10 μ

s.

13. The method of claim 2 wherein the assist laser and the process laser are rare-earth-doped fiber lasers.

14. The method of claim 1 wherein directing the assist laser beam and the process laser beam includes focusing the laser beams.

15. The method of claim 1 wherein the process laser beam drills a hole through the non-absorptive material at the target location.

16. The method of claim 15 wherein the hole has a diameter less than 30 μ

m and a length greater than 300 μ

m.

17. The method of claim 1 wherein a single pulse of the process laser beam at the target location drills a hole through the non-absorptive material at the target location.

18. The method of claim 1 wherein the non-absorptive material is a reflective material to be welded to another material, wherein the assist laser beam increases a temperature of the reflective material such that reflectivity is lower, and wherein the process laser beam completes welding of the reflective material to the other material.

19. A multiple-beam laser processing system for processing a workpiece made of a non-absorptive material, the multiple-beam laser processing system comprising:

an assist laser for generating an assist laser beam with a first wavelength and a first pulse duration, wherein the non-absorptive material of the workpiece is sufficiently absorptive of the assist laser beam with the first wavelength and the first pulse duration to modify a property of the non-absorptive material;

a process laser for generating a process laser beam with a second wavelength and a second pulse duration, wherein at least one of the first and second wavelengths and the first and second pulse durations are different, and wherein the process laser beam alone is not sufficiently absorbed in the non-absorptive material of the workpiece to complete processing of the non-absorptive material; and

a beam combiner for directing the assist laser beam from the assist laser and the process laser beam from the process laser at a target location on the workpiece such that the assist laser beam with the first wavelength and the first pulse duration modifies a property of the non-absorptive material of the workpiece at the target location forming absorption centers and such that the process laser beam with the second wavelength and the second pulse duration is coupled into the absorption centers formed in the non-absorptive material at the target location to complete processing of the non-absorptive material at the target location.

20. The multiple-beam laser processing system of claim 19 further including a focusing lens for focusing the assist laser beam from the assist laser and the process laser beam from the process laser at the target location.

21. The multiple-beam laser processing system of claim 19 wherein the assist laser is a green fiber laser, and wherein the process laser is an IR fiber laser.

22. The multiple-beam laser processing system of claim 19 further comprising an assist laser beam delivery system for controlling divergence of the assist laser beam such that the assist laser beam and the process laser beam have the same focal plane.

23. A method of multiple-beam laser processing of a workpiece including at least one layer of material, the method comprising:

generating an assist laser beam with a first wavelength and a first pulse duration, wherein the assist laser beam at the first wavelength and the first pulse duration, by itself, is not able to complete processing of the workpiece;

generating a process laser beam with a second wavelength and a second pulse duration, wherein at least one of the first and second wavelengths and the first and second pulse durations are different, and wherein the process laser beam at the second wavelength and the second pulse duration, by itself, is not able to complete processing of the workpiece; and

directing the assist laser beam and the process laser beam at a target location on the workpiece such that the assist laser beam modifies a property and/or a geometry of the at least one layer of material to facilitate the process laser beam completing processing of the workpiece at the target location.

24. The method of claim 23 wherein the workpiece includes at least first and second layers of material, and wherein completing processing includes welding the first layer of material to the second layer of material.

25. The method of claim 24 wherein the assist laser beam modifies a property of the first layer of material by increasing a temperature of the first layer of material and lowering reflectivity, and wherein the process laser beam causes the first layer of material to melt and weld to the second layer of material.

26. The method of claim 24 wherein the assist laser beam modifies a geometry of the first layer of material by forming an opening in the first layer of material, and wherein the process laser beam propagates through the opening to the second layer of material and causes the first layer of material and the second layer of material to be welded.

27. The method of claim 23 wherein the workpiece includes at least first and second layers of material, and wherein completing processing includes forming at least one laser fired contact between the first layer of material to the second layer of material.

28. The method of claim 23 wherein the workpiece includes at least first and second layers of material, and wherein completing processing includes melting at least one of the first and second layers of material.

29. The method of claim 23 wherein the assist laser beam and the process laser beam are directed at the target location at the same time.

30. A multiple-beam laser processing system for processing a workpiece, the multiple-beam laser processing system comprising:

a first laser for generating a first laser beam with a first wavelength and a first pulse duration, wherein the first laser beam at the first wavelength and the first pulse duration, by itself, is not able to complete processing of the workpiece;

a second laser for generating a second laser beam with a second wavelength and a second pulse duration, wherein at least one of the first and second wavelengths and the first and second pulse durations are different, and wherein the second laser beam at the second wavelength and the second pulse duration, by itself, is not able to complete processing of the workpiece; and

a beam combiner for directing the first laser beam from the assist laser and the second laser beam from the process laser at a target location on the workpiece such that the first laser beam with the first wavelength and the first pulse duration modifies a property and/or a geometry of the at least one layer of material to facilitate the second laser beam completing processing of the workpiece at the target location.

31. The multiple-beam laser processing system of claim 30 wherein the first laser is a green fiber laser, and wherein the second laser is an IR fiber laser.

32. The multiple-beam laser processing system of claim 30 further comprising at least a third laser for generating a third laser beam with a third wavelength and a third pulse duration.