System and method of controlling heat input in tandem hot-wire applications

Patent metadata

Field	Value
Publication number	US-9498838-B2
Application number	US-201313949932-A
Country	US
Kind code	B2
Filing date	Jul 24, 2013
Priority date	Jul 24, 2013
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A system and method is provided. The system includes a high intensity energy source to create a molten puddle on a surface of a workpiece and a wire feeder that feeds a wire to the molten puddle via a contact tube. The system also includes a power supply that outputs a first heating current during a first mode of operation and a second heating current during a second mode of operation. The system further includes a controller that initiates the first mode of operation in the power supply to heat the wire to a desired temperature and switches the power supply from the first mode of operation to the second mode of operation to create a micro-arc. The second mode of operation provides at least one of an increased heat input to the molten puddle and an increased agitation of the molten puddle relative to the first mode of operation.

First claim

What is claimed is:

1. A welding system, said system comprising:
a high intensity energy source to create a molten puddle on a surface of a workpiece;
a wire feeder that feeds a wire to said molten puddle via a contact tube;
a power supply that outputs a first heating current during a first mode of operation and a second heating current during a second mode of operation, said power supply providing said first heating current or said second heating current to said wire via said contact tube;
a controller that initiates said first mode of operation in said power supply to heat said wire to a desired temperature and switches said power supply from said first mode of operation to said second mode of operation to create a micro-arc, said micro-arc created between said wire and said workpiece; and
a ramp down circuit to suppress at least one of an induced current and said micro-arc when said output of said power supply is off or reduced in power to extinguish said micro-arc;
wherein said second mode of operation provides at least one of an increased heat input to said molten puddle and an increased agitation of said molten puddle relative to said first mode of operation.

2. The welding system of claim 1 , wherein said ramp down circuit introduces a resistance in a current path of said induced current to suppress said induced current.

3. The welding system of claim 2 , wherein said resistance is such that a flow of current can be reduced below 50 amps in 50 microsecond from a current of 400 amps.

4. The welding system of claim 2 , wherein said ramp down circuit ramps down said induced current three to ten times faster than a welding system with no ramp down circuit.

5. The welding system of claim 1 , wherein said ramp down circuit comprises a switch that shorts said contact tube to said workpiece such that said induced current bypasses said wire in order to suppress said micro-arc.

6. The welding system of claim 4 , wherein said ramp down circuit comprises a resistor that suppresses said induced current.

7. The welding system of claim 1 , wherein at least one of a duration, amplitude, and frequency of said micro-arc is controlled to control said increased heat input and/or said increased agitation.

8. The welding system of claim 7 , wherein at least said duration is controlled and said duration is in a range from 50 microseconds to 2 milliseconds.

9. The welding system of claim 1 , wherein said second heating current is one of a steady-state current, a pulsed DC current, and variable polarity current.

10. The welding system of claim 9 , wherein said second heating current is said pulsed DC current,
wherein said pulsed DC current comprises a series of pulses with each said pulse having a pulse current value, and
wherein said pulses of said series of pulses are separated by background current segments with each background current segment having a background current value that is lower than said pulse current values of adjacent pulses of said series of pulses.

11. A method of welding, said method comprising:
creating a molten puddle on a surface of a workpiece;
feeding a wire to said molten puddle via a contact tube;
outputting a first heating current during a first mode of operation and a second heating current during a second mode of operation to said contact tube;
initiating said first mode of operation to heat said wire to a desired temperature;
switching from said first mode of operation to said second mode of operation to create a micro-arc, said micro-arc created between said wire and said workpiece;
extinguishing said micro-arc after a desired duration by stopping said second heating current; and
suppressing at least one of an induced current and said micro-arc when said second heating current is stopped,
wherein said second mode of operation provides at least one of an increased heat input to said molten puddle and an increased agitation of said molten puddle relative to said first mode of operation.

12. The method of claim 11 , wherein said suppressing comprises introducing a resistance in a current path of said induced current to suppress said induced current.

13. The method of claim 12 , wherein said resistance is such that a flow of current can be reduced below 50 amps in 50 microsecond from a current of 400 amps.

14. The method of claim 12 , wherein said suppressing of said induced current ramps down said induced current three to ten times faster than if no external suppression is applied.

15. The method of claim 11 , wherein said suppressing comprises shorting said contact tube to said workpiece such that said induced current bypasses said wire in order to suppress said micro-arc.

16. The welding system of claim 15 , wherein said suppressing further comprises introducing a resistance in a current path of said induced current to suppress said induced current.

17. The method of claim 11 , further comprising:
controlling at least one of a duration, amplitude, and frequency of said micro-arc to control said increased heat input and/or said increased agitation.

18. The method of claim 17 , wherein said controlling includes controlling said duration in a range from 50 microseconds to 2 milliseconds.

19. The method of claim 11 , wherein said second heating current is one of a steady-state current, a pulsed DC current, and variable polarity current.

20. The method of claim 19 , wherein said second heating current is said pulsed DC current,
wherein said pulsed DC current comprises a series of pulses with each said pulse having a pulse current value, and
wherein said pulses of said series of pulses are separated by background current segments with each background current segment having a background current value that is lower than said pulse current values of adjacent pulses of said series of pulses.

Assignees

• Lincoln Global Inc

Inventors

• Peters Steven R

Classifications

• B23K9/091

  characterised by the circuits · CPC title

• B23K9/125

  Feeding of electrodes (for stabilising arc B23K9/073) · CPC title

• B23K9/1043 Primary

  characterised by the electric circuit (B23K9/1012 takes precedence) · CPC title

• B23K9/1735

  making use of several electrodes · CPC title

• B23K9/092 Primary

  characterised by the shape of the pulses produced · CPC title