Laser processing systems capable of dithering

Patent metadata

Field	Value
Publication number	US-2016228988-A1
Application number	US-201415024177-A
Country	US
Kind code	A1
Filing date	Sep 24, 2014
Priority date	Sep 24, 2013
Publication date	Aug 11, 2016
Grant date	—

Abstract

Laser processing systems and methods are capable of moving a laser beam while maintaining consistent laser beam characteristics at processing locations. The laser processing systems generate a collimated laser beam having a consistent Z axis power density along at least a portion of a length of the laser beam and dither the collimated laser beam along one of the X and Y axes. The dithering of the collimated laser beam facilitates consistent laser processing on a three-dimensional surface, for example, to provide consistent deposition of a coating in a laser cladding process. A laser processing system may include a beam delivery system that provides both the collimation and the dithering of the collimated laser as well as an adjustment of the beam diameter of the collimated beam.

First claim

What is claimed is:

1 . A method for laser processing a workpiece, the method comprising:
generating a collimated laser beam having a consistent Z axis power density along at least a portion of a length of the collimated laser beam; directing the collimated laser beam toward a workpiece to form a beam spot on the workpiece; moving the workpiece such that the beam spot facilitates processing on the surface of the workpiece as the workpiece moves; and dithering the collimated laser beam along one of the X and Y axes such that the beam spot is dithered on the workpiece as the workpiece is moved.

2 . The method of claim 1 wherein generating the collimated laser beam includes passing a laser output through at least two collimating lenses.

3 . The method of claim 2 wherein at least one of the collimating lenses is movable in the Z axis to change a diameter of the beam spot on the workpiece.

4 . The method of claim 1 wherein processing includes cladding.

5 . The method of claim 1 wherein processing includes welding.

6 . The method of claim 1 wherein processing includes surface cleaning.

7 . The method of claim 1 wherein the workpiece has a three-dimensional surface, and wherein the collimated laser beam provides the consistent Z axis power density at different processing locations on the three-dimensional surface.

8 . The method of claim 7 wherein the workpiece is a turbine blade.

9 . The method of claim 7 wherein the workpiece is a valve seat.

10 . The method of claim 1 wherein dithering the collimated laser beam includes moving optics in a beam delivery system without moving a laser output optically coupled to the beam delivery system.

11 . The method of claim 1 wherein dithering the collimated laser beam includes moving a fiber laser output without moving optics of a beam delivery system optically coupled to the fiber laser output.

12 . The method of claim 1 wherein the collimated laser beam is dithered in coordination with movement of the workpiece such that the beam spot moves in a continuous pattern on the surface of the workpiece.

13 . The method of claim 12 wherein the pattern is a serpentine pattern.

14 . The method of claim 12 wherein the pattern is a spiral pattern.

15 . A laser processing system comprising:
a fiber laser system; a beam delivery system optically coupled to a fiber laser output of the fiber laser system, the beam delivery system including collimating lenses to produce a collimated laser beam, wherein at least one of the collimating lenses is movable in the Z axis to change a diameter of the collimated beam; means for moving the fiber laser output relative to the collimating lenses to dither the collimated laser beam in one of the X and Y axes; a workpiece holder for supporting and moving a workpiece; and a motion control system for controlling motion of the workpiece holder and the means for moving the fiber laser output relative to the collimating lenses.

16 . The laser processing system of claim 15 wherein the means for moving the fiber laser output relative to the collimating lenses includes an optics X-Y stage for moving the collimating lenses without moving the fiber laser output.

17 . The laser processing system of claim 15 wherein the means for moving the fiber laser output relative to the collimating lenses includes a fiber laser output X-Y stage for moving the fiber laser output without moving the collimating lenses.

18 . An optical head comprising:
a housing; a fiber laser connector for connecting a fiber laser output to the housing at one end of the housing; a beam delivery system located in the housing and optically coupled to the fiber laser output, the beam delivery system comprising:
first and second collimating lenses for providing a collimated laser beam, at least one of the first and second lenses movable in a Z axis to change a diameter of the collimated laser beam; and
a final collimating lens for providing a final collimation of the collimated laser beam; and
an optics X-Y stage located in the housing and supporting the collimating lenses for movement in X and Y axes.

19 . The optical head of claim 18 further comprising a sacrificial window located at another end of the housing for allowing the collimated laser beam to pass out of the housing.

20 . The optical head of claim 18 further comprising a support structure and a first and second lens carriages slidably mounted on the support structure for movement in the Z axis, wherein the first and second collimating lenses are mounted on the first and second lens carriages, respectively, and wherein the support structure is mounted on the optics X-Y stage.

21 . The optical head of claim 18 wherein the first and second collimating lenses include concave and convex lenses, respectively.

22 . A laser cladding method for depositing a cladding layer on a workpiece, the method comprising:
generating a collimated laser beam having a consistent Z axis power density along at least a portion of a length of the collimated laser beam; directing the collimated laser beam toward a workpiece to provide a beam spot on the workpiece; directing a cladding material toward the workpiece such that the cladding material impinges the surface of the workpiece on a region heated by the beam spot; and moving the workpiece such that the cladding material forms a cladding layer on the surface of the workpiece as the workpiece moves.

23 . The laser cladding method of claim 22 further comprising:
dithering the collimated laser beam along one of the X and Y axes such that the beam spot is dithered on the workpiece as the workpiece is moved.

24 . The laser cladding method of claim 23 wherein the workpiece has a three-dimensional surface, and wherein the collimated laser beam provides the consistent Z axis power density at different processing locations on the three-dimensional surface.

25 . The laser cladding method of claim 22 wherein the workpiece has a three-dimensional surface, and wherein the collimated laser beam provides the consistent Z axis power density at different processing locations on the three-dimensional surface.

26 . The laser cladding method of claim 25 wherein the workpiece is a turbine blade.

27 . The laser cladding method of claim 22 wherein generating the collimated laser beam includes passing a laser output through at least two collimating lenses.

28 . The laser cladding method of claim 27 wherein at least one of the collimating lenses is movable in the Z axis to change a diameter of the beam spot on the workpiece.

29 . The laser cladding method of claim 22 wherein dithering the collimated laser beam includes moving optics in a beam delivery system without moving a laser output optically coupled to the beam delivery system.

30 . The laser cladding method of claim 22 wherein dithering the collimated laser beam includes moving a fiber laser output without moving optics of a beam delivery system optically coupled to the fiber laser output.

31 . The laser cladding method of claim 22 wherein the collimated laser beam is dithered in coordination with movement of the workpiece such that the beam spot moves in a continuous pattern on the surface of the workpiece.

32 . The laser cladding method of

Assignees

• Ipg Photonics Corp

Inventors

• Dallarosa Joseph Leo
• Amar Ben
• Squires David

Classifications

• B23K26/0622

  by shaping pulses · CPC title

• B23K2101/001

  Turbines · CPC title

• B23K26/0869

  Devices involving movement of the laser head in at least one axial direction · CPC title

• F05D2230/90

  Coating; Surface treatment · CPC title

• B23K26/0648

  comprising lenses · CPC title