Dual wire welding or additive manufacturing system and method

Patent metadata

Field	Value
Publication number	US-11498146-B2
Application number	US-201916585628-A
Country	US
Kind code	B2
Filing date	Sep 27, 2019
Priority date	Sep 27, 2019
Publication date	Nov 15, 2022
Grant date	Nov 15, 2022

Abstract

A welding or additive manufacturing system includes a contact tip assembly having first and second exit orifices. A wire feeder is configured to deliver a first and second wire electrodes through the exit orifices. An arc generation power supply is configured to output a current waveform to the wire electrodes simultaneously, through the contact tip assembly. The current waveform includes a bridging current portion, and a background current portion having a lower current level than the bridging current portion. The bridging current portion has a current level sufficient to form a bridge droplet between the wire electrodes before the bridge droplet is transferred to a molten puddle during a deposition operation. Solid portions of the wire electrodes do not contact each other during the deposition operation. The bridge droplet is transferred to the molten puddle during a short circuit event between the molten puddle and the wire electrodes.

First claim

What is claimed is:

1. A welding or additive manufacturing system, comprising:
a contact tip assembly having a first exit orifice and a second exit orifice;
a wire feeder configured to simultaneously deliver a first wire electrode through the first exit orifice of the contact tip assembly and a second wire electrode through the second exit orifice of the contact tip assembly; and
an arc generation power supply configured to output a current waveform to the first wire electrode and the second wire electrode simultaneously through the contact tip assembly, wherein:
the current waveform includes a bridging current portion, and a background current portion having a lower current level than the bridging current portion,
the bridging current portion has a current level sufficient to form a bridge droplet between the first wire electrode and the second wire electrode before the bridge droplet is transferred to a molten puddle during a deposition operation, wherein solid portions of the first wire electrode delivered through the first exit orifice are spaced apart from solid portions of the second wire electrode delivered through the second exit orifice during the deposition operation, and
the bridge droplet is transferred to the molten puddle during a short circuit event between the molten puddle and the first and second wire electrodes.

2. The welding or additive manufacturing system of claim 1 , wherein the current waveform includes a short circuit wire heating portion that occurs during the short circuit event, wherein the short circuit wire heating portion has a higher current level than the background current portion and a lower current level than the bridging current portion.

3. The welding or additive manufacturing system of claim 1 , wherein, during the short circuit event, a feeding direction of the wire feeder is reversed such that the first wire electrode and the second wire electrode are initially driven into the molten puddle and subsequently pulled away from the molten puddle by the wire feeder during the short circuit event.

4. The welding or additive manufacturing system of claim 3 , wherein arcs are reestablished between the molten puddle and the first and second wire electrodes while the feeding direction is away from the molten puddle.

5. The welding or additive manufacturing system of claim 1 , wherein, during the short circuit event, a wire feed speed of the wire feeder is reduced.

6. The welding or additive manufacturing system of claim 5 , wherein the wire feeder stops feeding the first wire electrode and the second wire electrode toward the molten puddle during the short circuit event, and resumes feeding the first wire electrode and the second wire electrode toward the molten puddle when the short circuit event is cleared.

7. The welding or additive manufacturing system of claim 5 , wherein one or both of the wire feeder and the arc generation power supply is configured to monitor a rate of change of voltage (dV/dt) of the deposition operation and determine clearance of the short circuit event from said rate of change of voltage (dV/dt).

8. The welding or additive manufacturing system of claim 7 , wherein the arc generation power supply is configured to output the bridging current portion of the welding waveform based on the clearance of the short circuit event.

9. The welding or additive manufacturing system of claim 1 , wherein the wire feeder delivers the first wire electrode and the second wire electrode toward the molten puddle at a first wire feed speed during the bridging current portion of the current waveform, and delivers the first wire electrode and the second wire electrode toward the molten puddle at a second wire feed speed during the background current portion of the current waveform, wherein the second wire feed speed is less than the first wire feed speed.

10. The welding or additive manufacturing system of claim 1 , wherein the first and second exit orifices are separated from each other by a distance configured to facilitate formation of the bridge droplet between the first wire electrode and the second wire electrode.

11. A welding or additive manufacturing method, comprising the steps of:
providing a current waveform to a contact tip assembly having a first exit orifice and a second exit orifice, wherein the current waveform includes a bridging current portion, and a background current portion having a lower current level than the bridging current portion;
feeding a first wire electrode through the first exit orifice of the contact tip assembly and simultaneously feeding a second wire electrode thorough the second exit orifice of the contact tip assembly;
forming, during the bridging current portion of the current waveform, a bridge droplet coupling the first wire electrode to the second wire electrode before the bridge droplet is transferred to a molten puddle during a deposition operation, wherein solid portions of the first wire electrode delivered through the first exit orifice are spaced apart from solid portions of the second wire electrode delivered through the second exit orifice during the deposition operation; and
transferring the bridge droplet to the molten puddle during a short circuit event between the molten puddle and the first and second wire electrodes.

12. The welding or additive manufacturing method of claim 11 , wherein the current waveform includes a short circuit wire heating portion that occurs during the short circuit event, wherein the short circuit wire heating portion has a higher current level than the background current portion and a lower current level than the bridging current portion.

13. The welding or additive manufacturing method of claim 11 , further comprising the step of reversing a feeding direction of the first and second wire electrodes during the short circuit event such that the first and second wire electrodes are initially driven into the molten puddle and subsequently pulled away from the molten puddle during the short circuit event.

14. The welding or additive manufacturing method of claim 13 , further comprising the step of reestablishing arcs between the molten puddle and the first and second wire electrodes while the feeding direction of the first and second wire electrodes is away from the molten puddle.

15. The welding or additive manufacturing method of claim 11 , further comprising the step of reducing a wire feed speed of the first and second wire electrodes during the short circuit event.

16. The welding or additive manufacturing method of claim 15 , further comprising the steps of stopping the feeding of the first and second wire electrodes during the short circuit event, and resuming the feeding of the first and second wire electrodes when the short circuit event is cleared.

17. The welding or additive manufacturing method of claim 15 , further comprising the step of monitoring a rate of change of voltage (dV/dt) of the deposition operation and determining clearance of the short circuit event from said rate of change of voltage (dV/dt).

18. The welding or additive manufacturing method of claim 17 , wherein a timing of the bridging current portion of the welding waveform is based on determining the clearance of the short circuit event.

19. The welding or additive manufacturing method of claim 11 , wherein the step of feeding includes feeding the first wire electrode and the second wire electrode toward the molten puddle at a first wire feed speed during the bridging current portion of the current waveform, and feeding the first wire electrode and t

Assignees

• Lincoln Global Inc

Inventors

• Henry Judah B
• Fleming Daniel P
• Peters Steven R

Classifications

• B23K9/042 Primary

  Built-up welding on planar surfaces · CPC title

• B23K9/04 Primary

  Welding for other purposes than joining, e.g. built-up welding · CPC title

• B22F12/53

  Nozzles · CPC title

• B22F12/50

  Means for feeding of material, e.g. heads · CPC title

• B22F12/41

  characterised by the type, e.g. laser or electron beam · CPC title