EP-4741090-A1 - METAL TRANSFER CONTROLLED PULSED WELDING PROCESS

Abstract

A method of controlling a pulsed welding process, in which an electrode tip of a consumable electrode is advanced toward a workpiece, comprises: generating a pulsed current waveform (300) having repetitive cycles (C1-C3); supplying the pulsed current waveform (300) to the electrode tip to strike an arc on the workpiece during each cycle, wherein a cycle (C2) of the repetitive cycles includes: a pulse forming period that includes a forming pulse (304) to form a droplet at the electrode tip, wherein the forming pulse includes a first peak (P1) that has a first peak duration (Δp1); and a pulse detachment period that includes a detachment pulse (308) separated from the forming pulse (304) and configured to transfer the droplet from the electrode tip to the workpiece, wherein the detachment pulse (308) includes a second peak (P2) that has a second peak duration (Δp2) that is less than the first peak duration (Δp1). A welding system which employs the aforementioned method is also provided.

Inventors

• KUBICEK, RASTISLAV
• LENNARTSSON, Karl
• LENNARTSSON, Bo
• JULIUSSON, Lars

Assignees

• The ESAB Group Inc.

Dates

Publication Date

20260513

Application Date

20251103

Claims (15)

1. A method of controlling a pulsed welding process in which an electrode tip of a consumable electrode is advanced toward a workpiece, comprising: generating a pulsed current waveform having repetitive cycles; and supplying the pulsed current waveform to the electrode tip to strike an arc on the workpiece during each cycle, wherein a cycle of the repetitive cycles includes: a forming period that includes a forming pulse to form a droplet at the electrode tip, wherein the forming pulse includes a first peak that has a first peak duration; and a detachment period that includes a detachment pulse separated from the forming pulse and configured to transfer the droplet from the electrode tip to the workpiece, wherein the detachment pulse includes a second peak that has a second peak duration that is less than the first peak duration.
2. The method of claim 1, wherein: the first peak has a first peak level and the second peak has a second peak level that is greater than the first peak level.
3. The method of claim 1, wherein the forming period further includes: a first inter-pulse segment between the forming pulse and the detachment pulse, wherein the first inter-pulse segment has a first inter-pulse level that is less than each of a first peak level of the forming pulse and a second peak level of the detachment pulse.
4. The method of claim 3, wherein: the first inter-pulse level is a background level; or the first inter-pulse level is greater than a background level.
5. The method of claim 3, wherein the detachment period includes: a second inter-pulse segment following the detachment pulse and that has a second inter-pulse level that is less than both the first peak level and the second peak level.
6. The method of claim 5, wherein: the first inter-pulse level and the second inter-pulse level differ from each other.
7. The method of claim 3, wherein: a next cycle following the cycle includes a next forming pulse that has a third peak; and a first peak-to-peak duration between the first peak and the second peak differs from a second peak-to-peak duration between the second peak and the third peak.
8. The method of claim 1, further comprising controlling the forming pulse and the detachment pulse to deliver equal energy levels to the electrode tip in the cycle; or wherein the first peak duration is greater than the second peak duration, and the first peak has a first peak level and the second peak has a second peak level that is greater than the first peak level; or wherein the pulsed welding process is performed without intentionally shorting the electrode tip to the workpiece during each cycle.
9. The method of claim 1, wherein the detachment pulse includes a first rising edge, the first peak, and a first falling edge during which the droplet detaches from the electrode tip; or wherein: the forming pulse includes a first rising edge, the first peak, and a first falling edge; and the detachment pulse includes a second rising edge, the second peak, and a second falling edge during which the droplet detaches from the electrode tip, wherein the first falling edge has a greater duration than each of the second rising edge and the second falling edge.
10. A welding system comprising: a power supply; and a controller to control the power supply during a pulsed welding process by causing the power supply to supply, to an electrode tip of a consumable electrode configured to advance toward a workpiece, a pulsed current waveform having repetitive cycles to strike an arc on the workpiece during each cycle, wherein a cycle of the repetitive cycles includes: a forming period that includes a forming pulse to form a droplet at the electrode tip, wherein the forming pulse includes a first peak that has a first peak duration; and a detachment period that includes a detachment pulse separated from the forming pulse and configured to transfer the droplet from the electrode tip to the workpiece, wherein the detachment pulse includes a second peak that has a second peak duration that is less than the first peak duration.
11. The welding system of claim 10, wherein: the first peak has a first peak level and the second peak has a second peak level that is greater than the first peak level.
12. The welding system of claim 10, wherein the forming period further includes: a first inter-pulse segment between the forming pulse and the detachment pulse, wherein the first inter-pulse segment has a first inter-pulse level that is less than each of a first peak level of the forming pulse and a second peak level of the detachment pulse.
13. The welding system of claim 12, wherein: the first inter-pulse level is a background level; or the first inter-pulse level is greater than a background level.
14. The welding system of claim 12, wherein the detachment period includes: a second inter-pulse segment following the detachment pulse and that has a second inter-pulse level that is less than both the first peak level and the second peak level.
15. The welding system of claim 14, wherein: the first inter-pulse level and the second inter-pulse level differ from each other.

Description

TECHNICAL FIELD The present disclosure relates to a pulsed welding process. BACKGROUND Pulsed Gas Metal Arc Welding (GMAW) including pulsed Metal Inert Gas (MIG) welding and Metal Active Gas (MAG) (MIG/MAG) welding involves supplying power in the form of current and voltage to a consumable wire electrode to form an electric arc between a tip of the wire electrode (i.e., the "electrode tip") and a workpiece on which melted welding material from the electrode tip is deposited, and which forms a weld when cooled. During the pulsed welding process, a welding power supply generates a pulsed current waveform and supplies the same to the electrode tip. Controlling melting characteristics of metal droplets at the electrode tip, and their transfer to the workpiece, to achieve consistent high-quality results across a wide range or welding conditions, presents a challenge. This is especially true given the indirect relationship between various parameters of the pulsed current waveform, droplet melt conditions, and the timing of droplet transfer. SUMMARY In some aspects, the techniques described herein relate to a method of controlling a pulsed welding process in which an electrode tip of a consumable electrode is advanced toward a workpiece, including: generating a pulsed current waveform having repetitive cycles; supplying the pulsed current waveform to the electrode tip to strike an arc on the workpiece during each cycle, wherein a cycle of the repetitive cycles includes: a forming period that includes a forming pulse to form a droplet at the electrode tip, wherein the forming pulse includes a first peak that has a first peak duration; and a detachment period that includes a detachment pulse separated from the forming pulse and configured to transfer the droplet from the electrode tip to the workpiece, wherein the detachment pulse includes a second peak that has a second peak duration that is less than the first peak duration. In some aspects, the techniques described herein relate to a method, wherein: the first peak has a first peak level and the second peak has a second peak level that is greater than the first peak level. In some aspects, the techniques described herein relate to a method, wherein the forming period further includes: a first inter-pulse segment between the forming pulse and the detachment pulse, wherein the first inter-pulse segment has a first inter-pulse level that is less than each of a first peak level of the forming pulse and a second peak level of the detachment pulse. In some aspects, the techniques described herein relate to a method, wherein: the first inter-pulse level is a background level. In some aspects, the techniques described herein relate to a method, wherein: the first inter-pulse level is greater than a background level. In some aspects, the techniques described herein relate to a method, wherein the detachment period includes: a second inter-pulse segment following the detachment pulse and that has a second inter-pulse level that is less than both the first peak level and the second peak level. In some aspects, the techniques described herein relate to a method, wherein: the first inter-pulse level and the second inter-pulse level differ from each other. In some aspects, the techniques described herein relate to a method, wherein: a next cycle following the cycle includes a next forming pulse that has a third peak; and a first peak-to-peak duration between the first peak and the second peak differs from a second peak-to-peak duration between the second peak and the third peak. In some aspects, the techniques described herein relate to a method, further including: controlling the forming pulse and the detachment pulse to deliver equal energy levels to the electrode tip in the cycle. In some aspects, the techniques described herein relate to a method, wherein: the first peak duration is greater than the second peak duration; and the first peak has a first peak level and the second peak has a second peak level that is greater than the first peak level. In some aspects, the techniques described herein relate to a method, wherein: the pulsed welding process is performed without intentionally shorting the electrode tip to the workpiece during each cycle. In some aspects, the techniques described herein relate to a method, wherein: the detachment pulse includes a first rising edge, the first peak, and a first falling edge during which the droplet detaches from the electrode tip. In some aspects, the techniques described herein relate to a method, wherein: the forming pulse includes a first rising edge, the first peak, and a first falling edge; and the detachment pulse includes a second rising edge, the second peak, and a second falling edge during which the droplet detaches from the electrode tip, wherein the first falling edge has a greater duration than each of the second rising edge and the second falling edge. In some aspects, the techniques described herein relate to a welding