Welding arc termination method and system

• US 8,642,924 B2
• Filed: 02/09/2011
• Issued: 02/04/2014
• Est. Priority Date: 04/09/2010
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Knoener, Craig Steven
• Primary Examiner(s): Hoang, Tu B
• Assistant Examiner(s): LAFLAME JR, MICHAEL A
• Application Number:
  US13/023,928
• Publication Number:
  US 20110248010A1
• Time in Patent Office: 1,091 Days
• Field of Search: 219/133, 219/130.1, 219/130.5, 219/617, 219 54- 57, 219/61.5, 219/86.7, 219/91.1, 219/111, 219/136
• US Class Current: 219/137.7
• CPC Class Codes: B23K 9/1012 characterised by parts of the process

Abstract

A system and method for welding arc termination are provided. In an exemplary embodiment, a method for controlling a welding process includes receiving a signal indicating an operator intention to terminate a welding arc and stopping advance of a welding wire in response to the signal. The method also includes reducing a conduction angle for switching of solid state switches that generate welding power in response to the signal.

Claims

1. A method for controlling a welding process, comprising:

receiving a signal indicating an operator intention to terminate a welding arc;

stopping advance of a welding wire in response to the signal; and

progressively reducing a conduction angle through multiple successive half cycles of an input AC waveform in response to the signal, wherein the conduction angle is used to switch solid state switches that generate welding power, and progressively reducing the conduction angle reduces the welding power generated by the solid state switches.

2. The method of claim 1, comprising reducing the conduction angle for switching of the solid state switches from a conduction angle utilized when the signal is received to a predetermined minimum conduction angle.

3. The method of claim 2, comprising reducing the conduction angle for switching the solid state switches from the conduction angle utilized when the signal is received to the predetermined minimum conduction angle within a predetermined time.

4. The method of claim 3, wherein the predetermined time corresponds to between 3 and 6 half cycles of the input AC waveform.

5. The method of claim 4, wherein the predetermined time is between approximately 20 and 50 milliseconds.

6. The method of claim 3, wherein the predetermined minimum conduction angle is approximately 20 degrees.

7. The method of claim 1, comprising dissipating energy stored in a capacitive circuit coupled to welding power by continuation of the welding arc during the reduction of the conduction angle.

8. The method of claim 7, comprising dissipating residual energy stored in the capacitive circuit through a resistor coupled in parallel with the capacitive circuit.

9. The method of claim 1, wherein the solid state switches are coupled on a primary side of a welding power supply transformer.

10. The method of claim 1, wherein the solid state switches are coupled on a secondary side of a welding power supply transformer.

11. A welding system, comprising:

a welding power supply configured to generate welding power for an arc welding application, the welding power supply comprising solid state switches that generate welding power, and a capacitive circuit coupled to the welding power;

a welding torch for initiating feed of a welding wire for the arc welding application; and

control circuitry configured to receive a signal from the torch indicating an operator intention to terminate a welding arc, to stop advance of a welding wire in response to the signal, and to progressively reduce a conduction angle through multiple successive half cycles of an input AC waveform in response to the signal, wherein the conduction angle is used to switch solid state switches that generate welding power to dissipate energy stored in the capacitive circuit through the welding arc, and progressively reducing the conduction angle reduces the welding power generated by the solid state switches.

12. The system of claim 11, comprising a resistor in parallel with the capacitive circuit and configured to dissipate residual energy stored in the capacitive circuit.

13. The system of claim 11, wherein the control circuitry is configured to reduce the conduction angle for switching of solid state switches from a conduction angle utilized when the signal is received to a predetermined minimum conduction angle.

14. The system of claim 13, wherein the control circuitry is configured to reduce the conduction angle for switching of solid state switches from the conduction angle utilized when the signal is received to the predetermined minimum conduction angle within a predetermined time.

15. The system of claim 14, wherein the predetermined time is between approximately 20 and 50 milliseconds.

16. A computer implemented method for controlling a welding process, comprising:

receiving a signal indicating an operator intention to terminate a welding arc;

stopping advance of a welding wire in response to the signal; and

progressively reducing a conduction angle through multiple successive half cycles of an input AC waveform in response to the signal.

17. The method of claim 16, wherein progressively reducing the conduction angle comprises reducing the conduction angle for switching of solid state switches from the conduction angle utilized when the signal is received to a predetermined minimum conduction angle within a predetermined time.

18. The method of claim 17, wherein progressively reducing the conduction angle for switching of solid state switches comprises adjusting a potentiometer setting.

19. The method of claim 16, comprising dissipating energy stored in a capacitive circuit coupled to welding power by continuation of the welding arc during the reduction of the conduction angle.

20. The method of claim 19, comprising dissipating residual energy stored in the capacitive circuit through a resistor coupled in parallel with the capacitive circuit.