WELDING WIRE PREHEATING SYSTEM AND METHOD

• US 20140217077A1
• Filed: 12/06/2013
• Published: 08/07/2014
• Est. Priority Date: 02/05/2013
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Davidson, Robert R., Schuh, Richard J.
• Granted Patent: US 9,950,383 B2
• Time in Patent Office: Days
• US Class Current: 219/130.33
• CPC Class Codes: B23K 20/22 taking account of the properties of the materials to be welded
• CPC Class Codes: B23K 2103/54 Glass
• CPC Class Codes: B23K 9/0956 using sensing means, e.g. optical
• CPC Class Codes: B23K 9/1043 characterised by the electric circuit B23K9/1012 takes precedence
• CPC Class Codes: B23K 9/1093 Consumable electrode or filler wire preheat circuits
• CPC Class Codes: B23K 9/173 and of a consumable electrode
• CPC Class Codes: B23K 9/235 Preliminary treatment

Abstract

In a welding system, a preheating process is carried out prior to initiation of a welding arc, such as upon depression of a trigger or switch on a welding torch. The preheating process involves generation and application of desired currents and voltages to a welding electrode from a power supply. Preheating is continued until the welding electrode reaches a desired temperature or resistance, which may be determined by reference to an increasing voltage, a decreasing current, a peaked and declining voltage, resistance and/or power measurements, and so forth. Following preheating, a desired welding process may begin with initiation of the welding arc.

Claims

1. A welding method, comprising:

receiving a signal indicative of initiation of welding process;

prior to initiating a welding arc, controlling voltage or current applied to a welding electrode to preheat the electrode;

monitoring feedback voltage and current to determine a termination of preheating; and

terminating preheating and initiating the welding arc in accordance with a desired welding protocol.

2. The method of claim 1, wherein the signal is received from a welding torch as a result of an operator depressing a trigger of the torch.

3. The method of claim 1, wherein during preheating, current applied to the welding electrode is maintained generally constant and voltage feedback from the electrode is monitored for an increase.

4. The method of claim 3, wherein preheating is terminated when the voltage feedback from the electrode reaches a predetermined threshold value.

5. The method of claim 3, wherein preheating is terminated when the voltage feedback reaches a peak and declines.

6. The method of claim 1, wherein during preheating, voltage applied to the welding electrode is maintained generally constant and current feedback from the electrode is monitored for a decrease.

7. The method of claim 1, wherein the applied voltage and current are monitored to determine when the welding electrode has reached a desired resistance, and preheating is then terminated.

8. The method of claim 1, wherein the applied voltage and current are monitored to determine when the welding electrode has reached a desired power level, and preheating is then terminated.

9. The method of claim 1, wherein at least one of the applied current, the applied voltage and the termination of preheating is based upon a type and size of the electrode.

10. A welding method, comprising:

receiving a signal indicative of initiation of welding process;

prior to initiating a welding arc, automatically controlling voltage or current applied to a welding electrode to preheat the electrode;

terminating preheating when the electrode reaches a desired resistance or a desired power level as determined based upon monitored current and voltage applied to the welding electrode; and

initiating the welding arc in accordance with a desired welding protocol.

11. The method of claim 10, wherein termination of preheating is based upon a feedback voltage reaching a desired threshold.

12. The method of claim 10, wherein termination of preheating is based upon a feedback current reaching a desired threshold.

13. The method of claim 10, wherein termination of preheating is based upon a feedback voltage reaching maximum level and declining.

14. The method of claim 10, wherein at least one of the applied current, the applied voltage and the termination of preheating is based upon a type and size of the electrode.

15. A welding system, comprising:

a power supply comprising power conversion circuitry and control circuitry configured to cooperate to provide welding current and voltage to a welding electrode;

a signal source configured to provide a signal for initiation of a welding process; and

current and voltage monitoring sensors;

wherein the control circuitry is configured to, prior to initiating a welding arc, control voltage and current applied to a welding electrode to preheat the electrode, to monitor the applied voltage and current to determine a termination of preheating, and to terminate preheating and initiate the welding arc in accordance with a desired welding protocol.

16. The system of claim 15, wherein the signal source comprises a welding torch.

17. The system of claim 15, wherein during preheating, current applied to the welding electrode is maintained generally constant and voltage feedback is monitored for an increase.

18. The system of claim 17, wherein preheating is terminated when the voltage applied to the electrode reaches a predetermined threshold value.

19. The system of claim 17, wherein preheating is terminated when the applied voltage reaches a peak and declines.

20. The system of claim 15, wherein during preheating, voltage applied to the welding electrode is maintained generally constant and current is monitored for a decrease.

21. The system of claim 15, wherein the applied voltage and current are monitored to determine when the welding electrode has reached a desired resistance, and preheating is then terminated.

22. The system of claim 15, wherein the applied voltage and current are monitored to determine when the welding electrode has reached a desired power level, and preheating is then terminated.

23. A welding method, comprising:

receiving a signal indicative of initiation of welding process;

prior to initiating a welding arc, determining an amount of time that a welding wire has not been under an arc condition;

determining at least one of a preheating time, current, or voltage based on the determined amount of time;

terminating a preheat cycle based on a timer; and

initiating the welding arc in accordance with a desired welding protocol.