Method for scanning the surface of metal workpieces

Patent metadata

Field	Value
Publication number	US-11642736-B2
Application number	US-202017777408-A
Country	US
Kind code	B2
Filing date	Nov 17, 2020
Priority date	Nov 18, 2019
Publication date	May 9, 2023
Grant date	May 9, 2023

Abstract

In a method for scanning the surface of metallic workpieces, during scanning, a welding torch with a consumable welding wire is moved over and towards the workpiece surface, until contact of the welding wire with the workpiece is detected, and the welding wire is subsequently moved away from the workpiece. Before scanning, slag-removal is carried out to remove slag at the welding wire end, wherein the welding current is lowered to a minimum, and the welding wire is moved cyclically with a rapid recurrent forward/backward movement over a specified path length toward the workpiece, and by a smaller distance away from the workpiece, until a short circuit between the welding wire and the workpiece is detected, whereupon slag-removal is ended, and upon the detection of no short circuit, slag-removal is repeated, and upon the detection of several short circuits one after the other, slag-removal is ended.

First claim

The invention claimed is:

1. A method for scanning a surface of a metallic workpiece, the method comprising the steps of:
during a scanning process, moving a welding torch with a consumable welding wire over the surface of the metallic workpiece, and moving the consumable welding wire towards the surface of the metallic workpiece at specified points in time at a forward speed, until a contact of the consumable welding wire with the metallic workpiece is detected by a welding current source, and subsequently moving the consumable welding wire away from the metallic workpiece again at a backward speed,
carrying out a slag-removal process to remove slag at an end of the consumable welding wire before the scanning process,
at a start of the slag-removal process, lowering a welding current to a minimum, and cyclically moving the consumable welding wire with a rapid recurrent forward/backward movement over a specified path length in direction of the metallic workpiece, and by a smaller distance away from the metallic workpiece again, so that a conveyance of the consumable welding wire to the metallic workpiece prevails, and upon a detection of no short circuit between the consumable welding wire and the metallic workpiece, repeating the slag-removal process, and upon a detection of several short circuits between the consumable welding wire and the metallic workpiece one after another, ending the slag-removal process, and
starting the slag-removal process when a wire feed speed sinks below a specified threshold value when moving the consumable welding wire at a specified wire feed speed in the direction of the metallic workpiece before the scanning process.

2. The method according to claim 1 , further comprising the step of ending the slag-removal process five short circuits between the consumable welding wire and the metallic workpiece are detected one after another.

3. The method according to claim 1 , further comprising the step of starting wherein the slag-removal process when no short circuit between the consumable welding wire and the metallic workpiece is detected during a defined time span before the scanning process.

4. The method according to claim 1 , further comprising the step of awaiting a specified time period before measuring whether the wire feed speed falls below the specified threshold value.

5. The method according to claim 1 , further comprising the step of starting the slag-removal process when a specified maximum value of a force on the consumable welding wire is exceeded.

6. The method according to claim 1 , further comprising the step of starting the slag-removal process when a specified threshold value of a change of a force over time on the consumable welding wire is exceeded.

7. The method according to claim 1 , further comprising the step of starting the slag-removal process when the wire feed speed sinks below a specified threshold value during the scanning process.

8. The method according to claim 1 , further comprising the step of starting the slag-removal process when a specified maximum value of a force on the consumable welding wire is exceeded during the scanning process.

9. The method according to claim 1 , further comprising the step of starting the slag-removal process when a specified threshold value of a change of a force on the consumable welding wire is exceeded during the scanning process.

10. The method according to claim 1 , further comprising the steps of determining an angle of attack of the welding torch to the surface of the metallic workpiece, and the slag-removal process when falling below a specified threshold value of the angle of attack.

11. The method according to claim 1 , further comprising the step of outputting an error message when no stable short circuit between the consumable welding wire and the metallic workpiece is detected after several repetitions of the slag-removal process.

12. The method according to claim 11 , further comprising the step of cutting off an end of the consumable welding wire in a cutting device after outputting the error message.

13. The method according to claim 11 , further comprising the step of outputting the error message when no stable short circuit between the consumable welding wire and the metallic workpiece is detected after 15 repetitions of the slag-removal process.

Assignees

• Fronius Int Gmbh

Inventors

• Mayer Manuel
• Waldhoer Andreas
• Binder Manuel

Classifications

• B23K9/095 Primary

  Monitoring or automatic control of welding parameters · CPC title

• B23K9/328

  Cleaning of weld torches, i.e. removing weld-spatter; Preventing weld-spatter, e.g. applying anti-adhesives · CPC title

• B23K9/235

  Preliminary treatment · CPC title

• B23K9/1278 Primary

  Using mechanical means · CPC title

• B23K9/125

  Feeding of electrodes (for stabilising arc B23K9/073) · CPC title