Laser machining systems and methods

Patent metadata

Field	Value
Publication number	US-11420288-B2
Application number	US-201916426414-A
Country	US
Kind code	B2
Filing date	May 30, 2019
Priority date	Jan 19, 2015
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

A laser machining method includes directing, from an F-theta lens having a long focal length of greater than about 250 millimeters, a laser beam at a non-perpendicular beam tilt angle from an optical axis of the lens having a top-hat profile and a narrow beam divergence angle of between about 1 degree and about 3 degrees towards a workpiece on a stage movable in at least an X-direction and a Y-direction, engaging the directed laser beam with the workpiece disposed in the usable field of view, moving the workpiece and the directed laser beam relative to each other, and removing portions of the workpiece with the directed laser beam to define a machined surface.

First claim

The invention claimed is:

1. A laser machining system for laser machining a workpiece, said laser machining system comprising:
a laser operable to generate a laser beam having a Gaussian profile;
a converter to convert the laser beam having the Gaussian profile into the laser beam having a top-hat profile;
an F-theta lens having a long focal length of greater than about 250 millimeters;
a stage operable to support and move the workpiece movable in at least an X-direction and a Y-direction;
a beam steering device to receive the laser beam having the top-hat profile and directing the laser beam through the F-theta lens at an angle from an optical axis of the F-theta lens towards the workpiece on the stage, the laser beam being directable over a range of angles from the optical axis of the F-theta lens defining a usable field of view having a perimeter and having a narrow beam divergence angle of about 1 degree and less than 3 degrees; and
a controller operable to control motion of said stage and/or said beam steering device to orientate the laser beam having the top-hat profile through the F-theta lens and onto the workpiece removing portions of the workpiece with the directed laser beam to define a machined surface,
wherein said beam steering device is operable to direct the laser beam at a non-perpendicular beam tilt angle of between 3 degrees and 6 degrees so that the machined surface has generally a zero taper relative to a Z-direction.

2. The laser machining system of claim 1 , wherein said focal length of said F-theta lens comprises greater than about 420 millimeters.

3. The laser machining system of claim 1 , wherein said system is operable to engage the directed laser beam with the workpiece disposed in the usable field of view with an axis of the directed laser beam spaced apart from the perimeter of the usable field so that the machined surface has a zero taper relative to the Z-direction.

4. The laser machining system of claim 1 , wherein said system is operable with an axis of the directed laser beam spaced apart between 15 millimeters to about 30 millimeters from the perimeter of the usable field so that the machined surface on the workpiece has a zero taper relative to the Z-direction.

5. The laser machining system of claim 1 , wherein said system is operable to engage the directed laser beam with the workpiece disposed in the usable field of view with an axis of the directed laser beam being spaced apart from the perimeter of the usable field so that the machined surface has generally a negative taper relative to the Z-direction.

6. The laser machining system of claim 1 , wherein said system is operable with an axis of the directed laser beam being within a range of about 15 millimeters from the perimeter of the usable field so that the machined surface has a generally negative taper relative to the Z-direction.

7. The laser machining system of claim 1 , wherein the converter comprises an optical fiber device.

8. The laser machining system of claim 1 , wherein said controller is operable to determine a shift distance and a direction from a center of the usable field of view based on the angle of a cut, and control moving said stage to locate the portion of the workpiece to be machined a predetermined distance and direction from the center of the usable field of view.

9. The laser machining system of claim 1 , wherein said system is operable to removing portions of the workpiece comprising a ceramic workpiece.

10. The laser machining system of claim 1 , wherein said system is operable to remove portions of the workpiece comprising a line cut or a slot.

11. The laser machining system of claim 1 , wherein the converter comprises a refractive element.

12. The laser machining system of claim 1 , wherein the converter comprises a diffractive element.

13. The laser machining system of claim 1 , wherein the focal length of said F-theta lens comprises less than 420 millimeters.

14. The laser machining system of claim 8 , wherein moving said stage comprises tilting the stage about an X axis and/or a Y axis and/or a Z axis.

15. The laser machining system of claim 1 , wherein the controller is operable to control motion said beam steering device to steer the laser beam to the F-theta lens at a scanning angle to the optical axis.

16. The laser machining system of claim 1 , wherein the controller is operable to control motion of said beam steering device to reflect the laser beam off a mirror.

17. The laser machining system of claim 16 , wherein the controller is further operable to control motion of the mirror.

18. The laser machining system of claim 1 , wherein the slot comprises a grooved slot.

19. The laser machining system of claim 1 , wherein the slot comprises a seal slot.

Assignees

• Gen Electric

Inventors

• Chen Hongqiang
• Hayashi Steven Robert
• Zhang Xi

Classifications

• B23K26/40

  taking account of the properties of the material involved · CPC title

• B23K26/0648 Primary

  comprising lenses · CPC title

• B23K26/38

  by boring or cutting · CPC title

• B23K26/0853

  Devices involving movement of the workpiece in at least two axial directions, e.g. in a plane · CPC title

• B23K26/048

  by controlling the distance between laser head and workpiece · CPC title