System and method for delivering an energy beam to selected impinge points on a work piece

• US 20040245227A1
• Filed: 06/21/2004
• Published: 12/09/2004
• Est. Priority Date: 07/26/2001
• Status: Abandoned Application

• Current Assignee: The GSI Group Inc
• Original Assignee: The GSI Group Inc
• Inventors: Caiger, Simon George, Grafton-Reed, Clive
• Application Number:
  US10/484,873
• Publication Number:
  US 20040245227A1
• Time in Patent Office: Days
• US Class Current: 219/121.83
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/04 Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
• CPC Class Codes: B23K 26/043 along the beam path, i.e. alignment of laser beam axis relative to laser beam apparatus
• CPC Class Codes: G02B 6/4237 Welding

Abstract

A system for laser processing a work piece surface with a laser processing beam includes a processing beam delivery source (205) optics (210, 230) for focusing the processing beam at a surface of the work piece, a viewing camera (250) configured coaxially and coincidently focused with the processing beam (207) at beam impinge point (245) on the work piece (100). The system further includes a computer (510) and processor (512) for displaying an image of the work piece (100) and a cursor (600) superimposed thereon on a monitor (560). One or more movable mirrors (320, 325) are provided movably mounted on galvanometers (335, 340) controlled by the processor (512) to direct the processing beam to selected points on the work surface for processing, (e.g. by laser spot welding). The system further includes an input device such as a mouse (520) for positioning a movable cursor (600) on image points of the work piece image and for selecting the image point for laser processing. The image points may be stored in a memory (514) as a pattern of image points laser processed as a patter under automatic control by the processor (512).

Claims

1. An automated system for directing an energy beam to a desired impinge point on a surface of a work piece for processing the work piece, comprising:

a moveable beam reflecting mirror for receiving the energy beam from an energy beam source Band for movably directing the energy beam onto the surface of the work piece;

an imager having a field of view with a line of sight that is substantially centered with respect to the field of view, said imager being configured to provide an image of at least a portion of the surface of the work piece and for providing a video signal corresponding thereto;

a display monitor for displaying the image with an operator movable pointer superimposed thereon;

an input device configured to move the pointer with respect to the image in response to operator movement inputs from the input device and further configured to provide a first operator command signal when an operator selects a first point of the image for directing the energy beam; and

a processor configured to receive the first operator command signal and to determine the image coordinates of the selected first point of the image, and to direct movement of the movable beam reflecting mirror so as to direct the energy beam to the surface of the work piece at an energy beam impinge point that corresponds to the selected first point of the image; and

a memory operatively coupled to the processor and configured to store a pattern of target locations selected using the image, the pattern including the first point as one of the target locations and a plurality of stops.

2. A system according to claim 1 wherein the system is further configured with the line of sight of the imager movably directed onto the surface of the work piece by the movable beam reflecting mirror such that any movement of the reflecting mirrors redirects the line of sight of the imager with respect to the surface of the work piece.

3. A system according to claim 1 wherein the system is further configured with the line of sight of the imager and the energy beam impinge point is substantially coincident at the surface of the work piece.

4. A system according to claim 1 wherein the display monitor includes a fixed location identifier having a position that identifies the energy beam impinge point.

5. A system according to claim 1 further comprising optical elements for focusing the energy beam at the surface of the work piece.

6. A system according to claim 1 further comprising a movable support table and a z-axis motion control device in communication with the processor for moving the work piece along a z-axis.

7. A system according to claim 1 further comprising an energy beam focus sensing device comprising:

a sensor for sensing energy of a focus sensing beam reflected by the surface of the work piece and for providing a sensor output indicative of a focus condition;

wherein the sensor output is delivered to the processor thereby enabling the processor to make a focus correction in response to a poor focus condition.

8. A system according to claim 1 further comprising means for delivering a plurality of energy beams to the surface of the work piece and wherein each of the plurality of energy beams is focused on the surface and directed over the work piece by movement of the moveable beam reflecting mirror.

9. A system according to claim 1 further comprising a visible laser for providing a visible beam impinging onto the work piece at a point coincident with the energy beam impinge point and wherein the visible laser beam is directed over the work piece by movement of the reflecting mirror while remaining coincident with the energy beam impinge point.

10. A system according to claim 1 further comprising a weld quality sensor for providing a weld quality signal indicative of the quality of a weld being performed to the system, and wherein the processor is configured to respond to a bad weld signal from the weld quality sensor.

11. A system according to claim 1, wherein:

the movable pointer is a cursor;

the input device is a mouse having a button;

the operator movement inputs are provided by moving the mouse and thereby moving the displayed cursor with respect to the image to select the first point as a desired energy beam impinge point; and

the first operator command signal provided to select the first point of the image includes pressing the button.

12. A system according to claim 1 wherein the job is a welding job and the target locations are weld locations.

13. A system according to claim 1 wherein the system is further configured to have a drag mode such that:

the first operator input command signal initiates the drag mode;

further operator movement inputs generated by moving the input device move the pointer and the beam reflecting mirror in response thereto, wherein the pointer moves from the first point of the image to a second point of the image; and

,

a second operator input command signal is provided when the operator selects the second point, thereby stopping movement of the beam reflecting mirrors and ending the drag mode.

14. A system according to claim 1 wherein:

the processor is configured to generate a thumb nail image showing a larger portion of the work piece than the image generated by the imager; and

,

the display monitor is configured, to display the image and the thumb nail image simultaneously.

15. A system according to claim 1 wherein

the processor is further configured to generate symbols for displaying the pattern of target locations in accordance with display signals sent to the monitor.

16. A system according to claim 1 wherein the energy beam comprises a laser beam.

17. A system according to claim 1 wherein the moveable beam reflecting mirror comprises two mirrors configured to direct the energy beam over the surface of the work piece in mutually perpendicular axes.

18. A system according to claim 5 wherein at least one of the optical elements is movable for adjusting the location of a focal point location of the energy beam.

19. A system according to claim 15 wherein

the pattern is changeable by moving a displayed symbol to a new selected location using the input device.

30. A system according to claim 1 wherein the system allows an operator to inspect the pattern and make changes as required during a job that uses the pattern.

20. A method for directing an energy beam to impinge a work piece at a selected first point, comprising:

displaying an image of the work piece, with a pointer superimposed on the image such that the pointer is movable with respect to the image in response to operator movement commands;

selecting the first point on the image;

providing a first operator command signal to a processor when the first point is selected;

performing a logical operation in the processor for determining an angle for rotating a beam reflecting mirror positioned between the energy beam source and the surface of the work piece, the angle being selected for directing the energy beam to impinge the surface at an impinge point corresponding to the selected point;

repeating the selecting providing and performing for each of one or more additional points thereby defining a pattern of target locations; and

selecting a stop between at least two of the selected points included in the pattern.

21. A method according to claim 20, further comprising:

displaying a spot indicator superimposed on the image at the selected point locations.

22. A method according to claim 20 further comprising

storing a location of each of the selected points in a memory;

and,

operatively coupled to the processor.

23. A method according to claim 22 further comprising displaying an impinge spot indicator superimposed on the image at each of the selected points.

24. A method according to claim 20 further comprising:

directing a visible laser beam coaxially with the energy beam so that the visible laser beam and the energy beam impinge the work piece at a coincident impinge point; and

,

configuring a camera to display the visible laser beam on a display monitor.

25. A method according to claim 20 further comprising:

directing a focus beam onto the work piece;

sensing focus beam energy reflected from the surface of the work piece with a focus sensor;

providing a focus sensor output signal to the processor;

analyzing the focus sensor output signal with the processor to determine a focus condition; and

,

initiating a focus correction action if the focus condition is unacceptable.

26. A method according to claim 20 further comprising:

controlling the z-axis position of the surface of the work piece in accordance with commands received from the processor.

27. A method according to claim 20 further comprising:

determining a focus condition of the energy beam at the surface of the work piece; and

,

adjusting a z-axis position of the surface of the work piece to optimize the focus condition prior to processing.

28. A method according to claim 20 further comprising:

directing a plurality of processing beams at the work piece with a plurality of impinge points; and

,

processing the plurality of impinge points simultaneously.

29. A method according to claim 20 further comprising:

sensing a quality of the energy beam by providing an energy beam quality sensor in a position to receive radiation reflected from the work piece during processing;

providing a process quality signal to the processor; and

,

performing corrective action according to commands generated by the processor in response to receiving a process quality signal from the weld quality sensor indicative of a bad weld.

31. A method according to claim 20 wherein selecting a stop between at least two of the selected points included in the pattern allows an operator to inspect the pattern and make changes as required during a job that uses the pattern.

32. An automated system for directing an energy beam to a desired impinge point on a surface of a work piece for processing the work piece, comprising:

a processor configured to determine coordinates of a user selected first point on an image of the work piece, and to control a movable beam reflecting mirror so as to direct an energy beam to the surface of the work piece at an impinge point that corresponds to the user selected point on the image; and

a memory operatively coupled to the processor and configured to store a pattern of user selected points on the image, the pattern including the first point and a stop between at least two of the selected points.

33. The system of claim 32 wherein the system enables both the image and a thumb nail image showing a larger portion of the work piece to be displayed simultaneously on a monitor coupled to the system, thereby enabling a continuing display of the larger portion during system operation.

34. The system of claim 32 wherein the processor is further configured to generate symbols for displaying the pattern of user selected points on the image, where symbols of processed points are distinguished from symbols of non-processed points as the system executes the pattern.

35. The system of claim 34 wherein the pattern is changeable by moving a displayed symbol to a new selected location using an input device.

36. The system of claim 32 further comprising optical elements for focusing the energy beam at the surface of the work piece, wherein at least one of the optical elements is movable for adjusting a focal point location of the energy beam.

37. The system of claim 32 further comprising a z-axis motion control device in communication with the processor for moving the work piece along a z-axis.

38. The system of claim 32 wherein the system allows a user to inspect the pattern and make changes as required during a job that executes the pattern.