Scanning bevels in preparation for welding

1. A method of facing an edge of a workpiece to prepare that edge for welding, the method comprising scanning the edge with at least one scanning tool mounted on a moving head of an edge-facing machine while that moving head is moved along said edge, and cutting or grinding the edge using an edge-facing tool of the edge-facing machine to face said edge.

2. The method of claim 1 , wherein at least one edge-facing tool is also mounted on said moving head of the edge-facing machine.

3. The method of claim 1 , comprising:

fixing the edge-facing machine in a facing-ready position relative to the workpiece; and

while the edge-facing machine is in the facing-ready position, moving the or each scanning tool along said edge of the workpiece to measure said edge.

4. The method of claim 3 , comprising, after measuring said edge end while the edge-facing machine remains in the facing-ready position:

advancing the or each edge-facing tool of the edge-facing machine into engagement with said edge; and

moving the or each edge-facing tool along said edge to face said edge.

5. The method of claim 3 , comprising, before measuring said edge and while the edge-facing machine is in the facing-ready position;

advancing the or each edge-facing tool of the edge-facing machine into engagement with said edge; and

moving the or each edge-facing tool along said edge to face said edge.

6. The method of claim 5 , further comprising retracting the or each edge-facing tool of the edge-facing machine out of engagement with said edge before measuring said edge.

7. The method of claim 5 , comprising measuring said edge while moving the or each edge-facing tool along said edge to face said edge.

8. The method of claim 4 , comprising controlling facing of said edge in accordance with measurements of said edge taken by the or each scanning tool.

9. The method of claim 3 , further comprising moving the or each scanning tool along said edge of the workpiece to measure said edge, after facing said edge and while the edge-facing machine remains in the facing-ready position.

10. The method of claim 1 , comprising wirelessly communicating edge measurement data from the or each scanning tool to a data store.

11. The method of claim 1 , comprising tracking the position of the or each scanning tool relative to said edge of the workpiece during scanning.

12. The method of claim 11 , wherein the or each scanning tool is biased into tracking contact with the workpiece.

13. The method of claim 1 , performed on a circumferential edge of a tubular workpiece and comprising moving the or each scanning tool circumferentially relative to the tubular workpiece on a rotary moving head of the machine.

14. The method of claim 1 , comprising scanning the edge with the at least one scanning tool before, while or after an edge-facing tool of the edge-facing machine cuts or grinds the edge.

15. An edge-facing machine comprising at least one edge-facing tool configured to cut or grind an edge of a workpiece to face said edge, and further comprising at least one scanning tool mounted on a movable head of the machine, which head is movable relative to a support frame of the edge-facing machine along the edge of the workpiece, wherein

at least one edge-facing tool is mounted on the movable head adjacent to the or each scanning tool;

the or each scanning tool and the or each edge-facing tool are positioned on a distal side of the movable head;

and the or each scanning tool is oriented to emit an edge-scanning beam distally.

16. The machine of claim 15 , wherein the or each scanning tool is positioned between two or more edge-facing tools on the movable head.

17. The machine of claim 15 , further comprising a wireless data link for transmitting edge measurement data from the or each scanning tool for storage or processing.

18. The machine of claim 15 , wherein the or each scanning tool comprises an encoding wheel positioned to engage the workpiece during scanning to track the position of said scanning tool relative to said edge of the workpiece during scanning.

19. The machine of claim 15 , comprising a movable or removable mounting for the or each scanning tool on the movable head.

20. The machine of claim 15 , wherein the movable head is a rotary head arranged to turn about an axis of rotation.

21. The machine of claim 20 , further comprising a mounting head that is cooperable with a tubular workpiece to anchor the machine relative to the workpiece by radial movement of at least one clamping element relative to the axis of rotation of the rotary head.