# US 11,992,905 B2 · Method for ascertaining the wear of a contact tube during a robot-supported welding method

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,992,905 B2
- Document ID: US11992905B2
- Status: Granted
- Kind: B2
- Application number: 17/767,754
- Filed: 2021-05-18
- Published: 2023-08-31
- Granted: 2024-05-28
- Earliest claimed: 2020-05-19
- Assignees: Fronius International GmbH
- Applicants: Fronius International GmbH
- Inventors: Josef Artelsmair
- Web page: https://patentgrep.com/patent/US11992905B2

## CPC

- B23K 9/123: {Serving also as contacting devices supplying welding current to an electrode}
- B23K 9/09: Arrangements or circuits for arc welding with pulsed current or voltage
- B23K 9/095: Monitoring or automatic control of welding parameters
- B23K 9/0953: {using computing means}
- B23K 9/173: and of a consumable electrode
- B23K 9/295: {using consumable wire electrodes}
- G01N 27/041: {of a solid body}
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A method for ascertaining the wear of a contact tube during a robot-assisted welding method on a workpiece using a welding torch with a consumable welding wire includes the steps of measuring a welding current, measuring a welding voltage, dividing the welding current so measured by the welding voltage so measured to calculate a conductance value and comparing the conductance value with at least one defined conductance threshold value or dividing the welding voltage so measured by the welding current so measured to calculate a resistance value and comparing the resistance value with at least one defined resistance threshold value, and issuing a warning when at least one of the conductance value equals the at least one defined conductance threshold value and the resistance value equals the at least one defined resistance threshold value.

## Claims

### Claim 1

A method for determining a wear of a contact tube during a robot-assisted welding method on a workpiece using a welding torch with a consumable welding wire, the method comprising the steps of:
measuring a welding current,
measuring a welding voltage,
dividing the welding current so measured by the welding voltage so measured to calculate a conductance value and comparing the conductance value with at least one defined conductance threshold value,
or
dividing the welding voltage so measured by the welding current so measured to calculate a resistance value and comparing the resistance value with at least one defined resistance threshold value, and
issuing a warning when the conductance value equals the at least one defined conductance threshold value or the resistance value equals the at least one defined resistance threshold value.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the steps of measuring the welding current and measuring the welding voltage comprise measuring the welding current and the welding voltage at a time at which the welding current has a maximum value, the time corresponding to an end of a pulse phase of a pulsed process or an end of a short-circuit phase during an arcing phase of a short-circuit-based arc welding process.

### Claim 3 (depends on 1)

The method according to claim 1, further comprising the step of averaging the conductance value or the resistance value over time.

### Claim 4 (depends on 1)

The method according to claim 1, further comprising a step of setting at least one of the at least one defined conductance threshold value and the at least one defined resistance threshold value.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the step of issuing the warning comprises issuing the warning acoustically, optically, and/or in tactile form.

### Claim 6 (depends on 1)

The method according to claim 1, further comprising a step of reducing a distance from the welding torch or an end of the contact tube to the workpiece, in an event of the warning being issued, thereby compensating for the wear of the contact tube.

### Claim 7 (depends on 1)

The method according to claim 1, further comprising a step of determining a distance from the welding torch or an end of the contact tube to the workpiece.

### Claim 8 (depends on 1)

The method according to claim 1, further comprising a step of carrying out a weld on a reference metal plate in an event of the warning being issued.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the steps of measuring the welding current and measuring the welding voltage comprise measuring the welding current and the welding voltage at a sampling frequency of 10 KHz to 100 KHz.

### Claim 10 (depends on 1)

The method according to claim 1, further comprising a step of averaging the welding current and the welding voltage over a time interval of 1 ms to 300 ms.

### Claim 11 (depends on 1)

The method according to claim 1, further comprising a step of recording the conductance value or the resistance value as a function of a time of welding.