Welding wire preheating system and method

• US 9,950,383 B2
• Filed: 12/06/2013
• Issued: 04/24/2018
• 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.
• Primary Examiner(s): Antonucci, Anne M
• Assistant Examiner(s): LAROSE, RENEE MARIE
• Application Number:
  US14/099,513
• Publication Number:
  US 20140217077A1
• Time in Patent Office: 1,600 Days
• 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 based on the received signal, controlling voltage or current applied to a welding electrode to preheat the electrode to a temperature above an ambient temperature but below a melting point of the welding electrode;

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

terminating preheating prior to initiating the welding arc in accordance with a 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 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 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 based on the received signal, automatically controlling voltage or current applied to a welding electrode to preheat the electrode to a temperature above an ambient temperature but below a melting point of the welding electrode;

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

initiating the welding arc in accordance with a welding protocol after terminating preheating of the electrode.

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

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

and

current and voltage monitoring sensors configured to sense current and voltage applied to the welding electrode by the power supply;

wherein the control circuitry is configured to receive a signal for initiation of a welding process and to, prior to initiating a welding arc based on the received signal, control the voltage and current applied to the welding electrode to preheat the welding electrode to a temperature above an ambient temperature but below a melting point of the welding electrode, to monitor the sensed current and voltage to determine a termination of preheating, and to terminate preheating prior to initiating the welding arc in accordance with a welding protocol.

16. The welding system of claim 15, comprising a welding torch configured provide a signal to the control circuitry to initiate the welding process.

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

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

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

22. The welding system of claim 15, wherein the applied voltage and current are monitored to determine when the welding electrode has reached a 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 based on the received signal, 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 welding protocol after the preheat cycle has terminated.