Welding device and welding method with self-setting welding wire feed speed

Patent metadata

Field	Value
Publication number	US-11872659-B2
Application number	US-201917276603-A
Country	US
Kind code	B2
Filing date	Sep 16, 2019
Priority date	Sep 17, 2018
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

Abstract

In order to easily regulate the supply of welding wire to the welding point during a welding process, the electrical potential produced by the welding current around the electrode is tapped with the welding wire and the control of the welding wire feed speed is carried out on the basis of the tapped potential and this control results in an average welding wire feed speed being established.

First claim

The invention claimed is:

1. A welding method using a welding torch having an electrode and using a welding wire that is supplied to a welding point at a welding wire feed speed, said welding method comprising:
creating an arc to be maintained between the electrode and a workpiece to be welded by way of a welding current flowing through the electrode, said welding current producing a distribution of an electrical potential in the vicinity of the electrode;
tapping the electrical potential in the vicinity of the electrode with the welding wire;
controlling the feed speed of the welding wire according to a tapped electrical potential, said controlling resulting in establishing an average welding feed speed; and
applying, before welding an electrical voltage to the welding wire to detect the electric voltage as the electrical potential before ignition of the arc and to determine a position of the welding wire in relation to the workpiece from the detected electrical potential before the ignition of the arc.

2. The welding method according to claim 1 , further comprising:
the welding wire that is supplied to the welding point comprises supplying the welding wire to the welding point at a first welding wire feed speed until a short circuit between the welding wire and the workpiece is detected via the tapped electrical potential;
when the short circuit is detected, the supplying of the welding wire to the welding point is stopped or changed to a second welding wire feed speed; and
when, via the tapped electrical potential and a specified limit value of the electrical potential, a determination is made that the welding wire has stopped and has melted to a certain extent causing an elimination of the short circuit, supplying of the welding wire to the welding point is restarted at the first welding wire feed speed.

3. The welding method according to claim 2 , wherein:
the supplying of the welding wire is started with a specified start delay time and/or the welding wire is stopped with a specified stop delay time.

4. The welding method according to claim 2 , wherein:
stopping and restarting of the supplying of the welding wire is repeated cyclically during welding.

5. The welding method according to claim 4 , wherein:
a cycle frequency of a cyclical repetition is used to control a desired distance between the electrode and the workpiece.

6. The welding method according to claim 5 , wherein:
starting from a desired distance between the electrode and the workpiece, the desired distance is increased when the cycle frequency decreases and the distance is reduced when the cycle frequency increases.

7. The welding method according to claim 1 , wherein:
the electrical voltage or the electrical current with respect to the electrical potential of the workpiece, or a related electrical variable, is detected as the electrical potential.

8. The welding method according to claim 7 , wherein:
a short circuit is identified when the electrical voltage or the electrical current drops to zero.

9. The welding method according to claim 8 , wherein:
when the supplying of the welding wire is stopped, a value of the electrical voltage or the electrical current rises from zero due to melting of the welding wire, and an associated loss of contact between the welding wire and the workpiece and, with further melting of the welding wire, a specified limit voltage or a specified limit current as a limit value of the electrical potential is reached, whereby the supplying of the welding wire to the welding point is restarted.

10. The welding method according to claim 1 , wherein:
the average welding wire feed speed is used to control a desired distance between the electrode and the workpiece.

11. The welding method according to claim 10 , wherein:
starting from a desired distance between the electrode and the workpiece, the distance is increased when the average welding wire feed speed or a cycle frequency decreases, and the distance is reduced when the average welding wire feed speed or a cycle frequency increases.

12. The welding method according to claim 1 , wherein:
an arc voltage between the electrode and the welding point is detected and the supplying of the welding wire is stopped when the detected arc voltage, or an average value of the arc voltage over a specified period of time, falls below a specified limit voltage.

13. The welding method according to claim 12 , wherein:
the supplying of the welding wire is restarted when the detected arc voltage, or the average value of the arc voltage over the specified period of time, rises above a specified starting voltage.

14. The welding method according to claim 1 , wherein:
during a short circuit between the welding wire and the workpiece, a resistance is determined from the detected electrical potential and the welding current as a measure of a state of a line between an electrical potential measurer for determining the detected electrical potential and the workpiece.

15. A welding device comprising:
a welding torch having an electrode;
a welding wire feed configured to supply welding wire at a welding wire feed speed into a region of the electrode of the welding torch;
for performing welding, a welding current through the electrode causes an arc to burn between the electrode and a workpiece, said welding current causes a distribution of an electrical potential in the vicinity of the electrode;
an electrical potential measurer is configured to detect, with the welding wire, the electrical potential generated by the welding current in the vicinity of the electrode;
a feed controller configured to evaluate a detected electrical potential and to control a welding wire feed speed via the detected electrical potential so that an average welding wire feed speed is established;
the electrical potential measurer comprises a high-impedance voltage source configured:
to apply an electrical voltage to the welding wire before welding to detect the electrical voltage as the electrical potential before ignition of the arc; and
to determine a position of the welding wire in relation to the workpiece from the detected electrical potential before ignition of the arc.

16. The welding device according to claim 15 , wherein:
the feed controller is configured to determine a short circuit between the welding wire and the workpiece via the detected electrical potential;
when the short circuit is detected, the feed controller is configured:
to stop the supply of welding wire at a first welding wire feed speed by the welding wire feed; or
to change the supply of welding wire to a second welding wire feed speed;

the feed controller is configured to determine, via a tapped electrical potential and a specified limit value of the electrical potential, that the stopped welding wire has melted to a certain extent causing elimination of the short circuit, whereby the feed controller restarts the supply of the welding wire into the region of the electrode.

17. The welding device according to claim 16 , wherein:
the feed controller is configured to repeat stopping and restarting and stopping of the supply of the welding wire according to the detected electrical potential cyclically during welding.

18. The welding device according to claim 17 , wherein:
the welding device sets a distance between the electrode and the workpiece according to a cycle frequency of a cyclical repetition.

19. The welding device according to claim 15 , wherein:
the welding device sets a desired distance between the elec

Assignees

• Fronius Int Gmbh

Inventors

• Willinger Martin
• Artelsmair Josef
• Lattner Peter
• Kruglhuber Wolfgang

Classifications

• B23K9/125 Primary

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

• B23K9/0956

  using sensing means, e.g. optical · CPC title

• B23K9/126

  Controlling the spatial relationship between the work and the gas torch (between wire tip and piece B23K9/073) · CPC title

• B23K9/167 Primary

  and of a non-consumable electrode · CPC title

• B23K9/124 Primary

  Circuits or methods for feeding welding wire · CPC title