Welding system

• US 5,923,555 A
• Filed: 06/02/1997
• Issued: 07/13/1999
• Est. Priority Date: 06/02/1997
• Status: Expired due to Fees

• Current Assignee: Areva NP Incorporated (AES Corporation)
• Original Assignee: Framatome Technologies Incorporated (AES Corporation)
• Inventors: Bryant, James Patterson, Overby, Steven Darrell, Bailey, William Eastham
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): MILLER, CRAIG S
• Application Number:
  US08/867,050
• Time in Patent Office: 771 Days
• Field of Search: 395/94, 356/3.1, 348/90, 364/148, 364/138, 364/167.01, 364/468.01, 364/468.21, 702/94, 702/150, 702/188
• US Class Current: 700/114
• CPC Class Codes: B23K 2101/06 Tubes
• CPC Class Codes: B23K 9/044 Built-up welding on three-dimensional surfaces

Abstract

A welding system for automatically welding two workpieces together at a joint. The system includes a welding box having an electrode for welding the workpieces together; a camera assembly for viewing selected regions of the workpieces including a first edge and a second edge of the joint; and a controller connected to the camera assembly and the welding box for receiving the location of the first edge and the second edge of the joint and calculating the centerline of the joint and providing an output signal representative of the difference of the relative position of the centerline of the joint and the centerline of the fusing element. In the preferred embodiment, a 2-axis light source illuminates the surface of the workpieces to better locate the centerline of the joint.

Claims

1. A welding system for automatically welding two workpieces together at a joint, said system comprising:

(a) a welding box having a fusing element for welding said workpieces together;

(b) a camera assembly for viewing selected regions of said workpieces; and

(c) a control system connected to said camera assembly and said welding box for locating the centerline of said joint with respect to the centerline said fusing element and providing an output signal representative of the difference of their relative positions.

2. The apparatus according to claim 1, further including a 2-axis light source for illuminating the surface of said workpieces to locate said centerline of said joint.

3. The apparatus according to claim 2, wherein said 2-axis light source is L-shaped.

4. The apparatus according to claim 3, wherein said 2-axis light source includes a plurality of lights arranged in rows.

5. The apparatus according to claim 4, wherein said plurality of lights arranged in rows are oriented in one direction on one portion of said L-shape and another direction on another portion of said L-shape.

6. The apparatus according to claim 2, further including a backlight for illuminating the surface of said fusing element to locate said centerline of said fusing element.

7. The apparatus according to claim 6, wherein said backlight includes a light source and a diffuser located between said light source and said camera assembly.

8. The apparatus according to claim 1, wherein said camera assembly includes a borescope attached to said welding box and a camera attached to said borescope.

9. The apparatus according to claim 8, wherein said camera is a video camera having video pulse synchronization.

10. The apparatus according to claim 8, wherein said borescope includes a vacuum sheath.

11. The apparatus according to claim 8, wherein said borescope includes a set-up light source.

12. The apparatus according to claim 1, wherein said fusing element is an electrode and a power supply.

13. The apparatus according to claim 1, wherein said fusing element is a laser and a power supply.

14. The apparatus according to claim 1, wherein said welding box includes means for moving said fusing element and said workpieces with respect to one another.

15. The apparatus according to claim 1, wherein said welding box includes a chamber for containing a cover gas.

16. The apparatus according to claim 15, wherein said welding box includes an air lock for allowing said workpieces to be inserted into said chamber containing a cover gas.

17. A control system for a welding box including a fusing element for welding two workpieces together at a joint, said system comprising:

(a) a camera assembly for viewing selected regions of said workpieces including a first edge and a second edge of said joint; and

(b) a controller connected to said camera assembly and said welding box for receiving the location of said first edge and said second edge of said joint and calculating the centerline of said joint and providing an output signal representative of the difference of the relative position of the centerline of said joint and the centerline of said fusing element.

18. The apparatus according to claim 17, wherein said fusing element is an electrode and said camera assembly views selected regions of said electrode including a first edge and a second edge and said controller calculates the center of said electrode.

19. The apparatus according to claim 17, wherein said fusing element is an electrode and said camera assembly views selected regions of said electrode including a first lower edge and a second lower edge and a first upper edge and a second upper edge and said controller calculates the centerline of said electrode.

20. The apparatus according to claim 17, wherein said fusing element is an electrode and said camera assembly views selected regions of said electrode including its tip and a first edge of one of said workpieces and said controller calculates the positions of said tip and said first edge of one of said workpieces and provides an output signal representative of the difference of the relative position of said tip and said first edge of one of said workpieces.

21. A welding system for automatically welding two workpieces together at a joint, said system comprising:

(a) a welding box having a fusing element for welding said workpieces together;

(b) a camera assembly for viewing selected regions of said workpieces including a first edge and a second edge of said joint;

(c) a controller connected to said camera assembly and said welding box for receiving the location of said first edge and said second edge of said joint and calculating the centerline of said joint and providing an output signal representative of the difference of the relative position of the centerline of said joint and the centerline of said fusing element; and

(d) a 2-axis light source for illuminating the surface of said workpieces to locate said centerline of said joint.

22. The apparatus according to claim 21, wherein said 2-axis light source is L-shaped.

23. The apparatus according to claim 22, wherein said 2-axis light source includes a plurality of lights arranged in rows.

24. The apparatus according to claim 23, wherein said plurality of lights arranged in rows are oriented in one direction on one portion of said L-shape and another direction on another portion of said L-shape.

25. The apparatus according to claim 21, further including a backlight for illuminating the surface of said fusing element to locate said centerline of said fusing element.

26. The apparatus according to claim 25, wherein said backlight includes a light source and a diffuser located between said light source and said camera assembly.

27. The apparatus according to claim 21, wherein said camera assembly includes a borescope attached to said welding box and a camera attached to said borescope.

28. The apparatus according to claim 27, wherein said camera is a video camera having video pulse synchronization.

29. The apparatus according to claim 27, wherein said borescope includes a vacuum sheath.

30. The apparatus according to claim 27, wherein said borescope includes a set-up light source.

31. The apparatus according to claim 21, wherein said fusing element is an electrode and a power supply.

32. The apparatus according to claim 21, wherein said fusing element is a laser and a power supply.

33. The apparatus according to claim 21, wherein said welding box includes means for moving said fusing element and said workpieces with respect to one another.

34. The apparatus according to claim 21, wherein said welding box includes a chamber for containing a cover gas.

35. The apparatus according to claim 34, wherein said welding box includes an air lock for allowing said workpieces to be inserted into said chamber containing a cover gas.

36. The apparatus according to claim 21, wherein said fusing element is an electrode and said camera views selected regions of said electrode including a first edge and a second edge and said controller calculates the center of said electrode.

37. The apparatus according to claim 21, wherein said fusing element is an electrode and said camera assembly views selected regions of said electrode including a first lower edge and a second lower edge and a first upper edge and a second upper edge and said controller calculates the centerline of said electrode.

38. The apparatus according to claim 21, wherein said fusing element is an electrode and said camera assembly views selected regions of said electrode including its tip and a first edge of one of said workpieces and said controller calculates the positions of said tip and said first edge of one of said workpieces and provides an output signal representative of the difference of the relative position of said tip and said first edge of one of said workpieces.

39. A method for automatically welding two workpieces together at a joint using a fusing element, said method comprising the steps of:

(a) viewing selected regions of said workpieces using a camera;

(b) locating the centerline of said joint with respect to the centerline of said fusing element and providing an output signal representative of the difference of their relative positions using a control system connected to said camera;

(c) using said output signal to control the position of said fusing element; and

(d) welding said workpieces together.

40. A method for controlling the position of a fusing element for welding two workpieces together at a joint, said method comprising the steps of:

(a) viewing selected regions of said workpieces including a first edge and a second edge of said joint using a camera; and

(b) receiving the location of said first edge and said second edge of said joint and calculating the centerline of said joint and providing an output signal representative of the difference of the relative position of the centerline of said joint and the centerline of said fusing element.

41. A method for automatically welding two workpieces together at a joint using a fusing element, said method comprising the steps of:

(a) illuminating the surface of said workpieces to locate said centerline of said joint using a 2-axis light source;

(b) viewing selected regions of said workpieces including a first edge and a second edge of said joint using a camera;

(c) receiving the location of said first edge and said second edge of said joint and calculating the centerline of said joint and providing an output signal representative of the difference of the relative position of the centerline of said joint and the centerline of said fusing element using a control system connected to said camera;

(d) using said output signal to control the position of said fusing element; and

(e) welding said workpieces together.