Dabbing pulsed welding system and method

Patent metadata

Field	Value
Publication number	US-2016144444-A1
Application number	US-201414554508-A
Country	US
Kind code	A1
Filing date	Nov 26, 2014
Priority date	Nov 26, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A pulsed welding regime includes a peak phase in which energy is added to an electrode and a weld puddle, and a molten ball begins to detach from the electrode, followed by a dabbing phase in which current is significantly reduced to place the ball in the weld puddle with addition of little or no energy. The resulting short circuit clears and the system proceeds to a background phase. The current in the dabbing phase is lower than the current during the background phase. The process may be specifically adapted for particular welding wires, and may be particularly well suited for use with cored wires. The dabbing phase allows for lower energy to be transferred to the sheath of such wires, and resets the arc length after each pulse cycle.

First claim

1 . A welding method comprising:
generating a control waveform for welding power output, the waveform comprising at least one peak phase followed by at least one optional knee phase and then a required dabbing phase followed by at least one background phase; and converting incoming power to welding power based upon the control waveform.

2 . The method of claim 1 , comprising terminating the dabbing phase based upon expiration of a predetermined time.

3 . The method of claim 1 , comprising terminating the dabbing phase based upon determination of clearance of a short circuit between a welding electrode and a workpiece.

4 . The method of claim 1 , comprising terminating the dabbing phase based upon a prediction of clearance of a short circuit between a welding electrode and a workpiece.

5 . The method of claim 1 , comprising terminating the dabbing phase based upon occurrence of a short circuit between a welding electrode and a workpiece.

6 . The method of claim 1 , wherein during the background phase the welding power output has a current level of between approximately 25 amps and approximately 125 amps.

7 . The method of claim 6 , wherein during the dabbing phase the welding power output has a current level of less than approximately 25 amps.

8 . The method of claim 1 , wherein the dabbing phase has a duration of between approximately 1 millisecond and approximately 5 milliseconds.

9 . The method of claim 1 , wherein during the peak phase a ball of molten metal begins to detach from a welding electrode, and during the dabbing phase a short circuit is established between the ball and a workpiece.

10 . The method of claim 1 , wherein a short circuit clearing sequence is implemented only if a short circuit does not clear during the dabbing phase.

11 . The method of claim 1 , wherein the dabbing phase resets an arc length between an end of a welding electrode and a weld puddle into which a ball of molten metal is deposited.

12 . The method of claim 1 , wherein during the peak and background phases the welding output power is closed-loop controlled to maintain target voltages.

13 . A welding method comprising:
generating a cyclical control waveform for welding power output, the waveform comprising, in each cycle and in the following order, a peak phase, a knee phase, a dabbing phase, and a background phase; and converting incoming power to welding power based upon the control waveform.

14 . The method of claim 13 , comprising terminating the dabbing phase based upon expiration of a predetermined time.

15 . The method of claim 13 , comprising terminating the dabbing phase based upon determination of clearance of a short circuit between a welding electrode and a workpiece.

16 . The method of claim 13 , comprising terminating the dabbing phase based upon a prediction of clearance of a short circuit between a welding electrode and a workpiece.

17 . The method of claim 13 , comprising terminating the dabbing phase based upon occurrence of a short circuit between a welding electrode and a workpiece.

18 . A welding system comprising:
control circuitry configured to generate a control waveform for welding power output, the waveform comprising a peak phase followed by an optional knee phase and then a required dabbing phase followed by a background phase; and power conversion circuitry configured to convert incoming power to welding power based upon the control waveform.

19 . The system of claim 18 , wherein the control waveform comprises a cyclical waveform comprising, in each cycle and in the following order, a peak phase, a knee phase, a dabbing phase, and a background phase.

20 . The system of claim 18 , wherein the control circuitry is configured to terminate the dabbing phase based upon expiration of a predetermined time.

Assignees

• Illinois Tool Works

Inventors

• Davidson Robert R
• Mehn Peter Donald
• Schuh Richard J

Classifications

• B23K9/1062

  with computing means · CPC title

• B23K9/0956

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

• B23K9/173

  and of a consumable electrode · CPC title

• B23K9/092 Primary

  characterised by the shape of the pulses produced · CPC title

• B23K9/0953

  using computing means · CPC title