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EP-4735199-A1 - START OF WELD PROCEDURE

EP4735199A1EP 4735199 A1EP4735199 A1EP 4735199A1EP-4735199-A1

Abstract

In an embodiment, a method performed by a welding or cutting system having a power supply to supply weld power to an electrode tip extending from a welding torch, comprises: upon detecting a weld start condition, performing a start of weld procedure that includes sequential phases of controlling the weld power to strike an arc on a workpiece, grow a length of the arc to a target length, and heat the electrode tip and the workpiece until a weld energy supplied to the electrode tip across the sequential phases reaches a weld energy threshold indicative of a desired heat-related condition of the electrode tip and the workpiece for welding; and when the weld energy reaches the weld energy threshold, performing a welding operation on the workpiece.

Inventors

  • JULIUSSON, LARS DAVID LEIF
  • LENNARTSSON, KARL JAKOB ERIK
  • KUBICEK, RASTISLAV
  • WADSTRÖM, Patrik
  • KARLSSON, DANIEL
  • LENNARTSSON, BO DANIEL

Assignees

  • The ESAB Group Inc.

Dates

Publication Date
20260506
Application Date
20240627

Claims (20)

  1. 1. A method performed by a welding or cutting system having a power supply to supply weld power to an electrode tip extending from a welding torch, comprising: upon detecting a weld start condition, performing a start of weld procedure that includes sequential phases of controlling the weld power to strike an arc on a workpiece, grow a length of the arc to a target length, and heat the electrode tip and the workpiece until a weld energy supplied to the electrode tip across the sequential phases reaches a weld energy threshold indicative of a desired heat-related condition of the electrode tip and the workpiece for welding; and when the weld energy reaches the weld energy threshold, performing a welding operation on the workpiece.
  2. 2. The method of claim 1, wherein the desired heat-related condition includes a desired temperature or a desired melt condition of the electrode tip and the workpiece.
  3. 3. The method of claim 1, wherein the sequential phases include: upon detecting the weld start condition, controlling the weld power in an ignition phase to strike the arc on the workpiece; upon detecting the arc, controlling the weld power in an arc-length phase to grow the length of the arc to the target length; and upon detecting the target length, continuing to supply the weld power to the electrode tip in a heat phase.
  4. 4. The method of claim 3, wherein: controlling the weld power in the ignition phase includes rapidly increasing a current of the weld power to strike the arc on the workpiece; controlling the weld power in the arc-length phase includes increasing a voltage of the weld power; and continuing to supply the weld power to the electrode tip in the heat phase including supplying the weld power at a substantially constant voltage.
  5. 5. The method of claim 3, further comprising: measuring a voltage indicative of a weld voltage of the weld power; and wherein detecting the arc includes detecting that the voltage exceeds a first threshold indicative of the arc; wherein detecting the target length includes detecting that the voltage exceeds a second threshold indicative of the target length and that is greater than the first threshold.
  6. 6. The method of claim 3, further comprising: upon detecting that the weld energy supplied across the ignition phase, the arc-length phase, and the heat phase reaches the weld energy threshold, controlling the weld power for the welding operation.
  7. 7. The method of claim 6, wherein detecting that the weld energy reaches the weld energy threshold includes: integrating the weld energy across the ignition phase, the arc -length phase, and the heat phase to produce an integrated weld energy; and comparing the integrated weld energy against the weld energy threshold.
  8. 8. The method of claim 1, further comprising: measuring a voltage indicative of a weld voltage; wherein detecting the weld start condition includes detecting the weld start condition based on the voltage.
  9. 9. The method of claim 8, further comprising: computing a time derivative of the voltage to produce a voltage derivative, wherein detecting the weld start condition includes detecting that the voltage derivative falls below a voltage derivative threshold indicative of contact between the workpiece and the welding torch or the electrode tip.
  10. 10. The method of claim 1, wherein: controlling the weld power for the welding operation includes generating the weld power for a metal inert gas (MIG) or a metal active gas (MAG) (MIG/MAG) welding operation.
  11. 11. The method of claim 1, wherein: performing the welding operation includes controlling voltage and current waveforms of the weld power for one of short-arc, spray-arc, or pulsed welding.
  12. 12. The method of claim 1, further comprising, during the sequential phases: upon detecting that undesired molten droplets have formed on the electrode tip, pulsing a weld current of the weld power to release the undesired molten droplets from the electrode tip.
  13. 13. The method of claim 1, further comprising, during the sequential phases: upon detecting an undesired short-circuit between the electrode tip and the workpiece, increasing a weld current of the weld power rapidly to melt the electrode tip and clear the undesired short-circuit.
  14. 14. A welding or cutting system comprising: a power supply to supply weld power to an electrode tip of a welding torch; and a controller to control the weld power supplied by the power supply, wherein the controller is configured to perform: upon detecting a weld start condition, performing a start of weld procedure that includes sequential phases of controlling the weld power to strike an arc on a workpiece, grow a length of the arc to a target length, and heat the electrode tip and the workpiece until a weld energy supplied to the electrode tip across the sequential phases reaches a weld energy threshold indicative of a desired heat-related condition of the electrode tip and the workpiece for welding; and when the weld energy reaches the weld energy threshold, performing a welding operation on the workpiece.
  15. 15. The welding or cutting system of claim 14, wherein the desired heat-related condition includes a desired temperature or a desired melt condition of the electrode tip and the workpiece.
  16. 16. The welding or cutting system of claim 14, wherein the controller is configured to perform, for the sequential phases of controlling the weld power: upon detecting the weld start condition, controlling the weld power in an ignition phase to strike the arc on the workpiece; upon detecting the arc, controlling the weld power in an arc-length phase to grow the length of the arc to the target length; and upon detecting the target length, continuing to supply the weld power to the electrode tip in a heat phase.
  17. 17. The welding or cutting system of claim 16, wherein the controller is configured to perform: controlling the weld power in the ignition phase by rapidly increasing a current of the weld power to strike the arc on the workpiece; controlling the weld power in the arc -length phase by increasing a voltage of the weld power; and continuing to supply the weld power to the electrode tip in the heat phase by supplying the weld power at a substantially constant voltage.
  18. 18. The welding or cutting system of claim 16, wherein the controller is further configured to perform measuring a voltage indicative of a weld voltage of the weld power, and the controller is configured to perform: detecting the arc by detecting that the voltage exceeds a first threshold indicative of the arc, and detecting the target length by detecting that the voltage exceeds a second threshold indicative of the target length and that is greater than the first threshold.
  19. 19. The welding or cutting system of claim 16, wherein the controller is further configured to perform: upon detecting that the weld energy supplied across the ignition phase, the arc-length phase, and the heat phase reaches the weld energy threshold, controlling the weld power for the welding operation.
  20. 20. The welding or cutting system of claim 19, wherein the controller is configured to perform detecting that the weld energy reaches the weld energy threshold by: integrating the weld energy across the ignition phase, the arc-length phase, and the heat phase to produce an integrated weld energy; and comparing the integrated weld energy against the weld energy threshold.

Description

START OF WELD PROCEDURE CLAIM TO PRIORITY [0001] This application claims priority to and the benefit of U.S. Patent Application No. 18/595,862, filed March 5, 2024, entitled “START OF A WELD PROCEDURE,” which claims priority to U.S. Provisional Application No. 63/510,901, filed June 29, 2023, entitled “START OF A WELD PROCEDURE,” the entirety of which are incorporated herein by reference. TECHNICAL FIELD [0002] The present disclosure relates to starting a welding operation. BACKGROUND [0003] Gas Metal Arc Welding (GMAW) including Metal Inert Gas (MIG) welding and Metal Active Gas (MAG) (MIG/MAC) 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. At the start of a welding operation, a number of electrical and physical conditions (referred to as “initial conditions”) exist, including the current and the voltage supplied to the electrode tip, a length of an arc (i.e., an “arc length”) extending from the electrode tip to the workpiece, temperatures of the electrode tip and the workpiece, and melt conditions at the electrode tip. The initial conditions affect the characteristics and quality of the weld produced by the welding operation. The initial conditions can vary substantially from one welding operation to the next. Therefore, the characteristics and quality of the welds produced from one welding operation to the next can vary substantially, which leads to unreliable and non- uniform or inconsistent weld results. BRIEF DESCRIPTION OF THE DRAWINGS [0004] FIG. 1 is an illustration of an example welding system in which embodiments directed to a start of weld procedure may be implemented. [0005] FIG. 2 is a block diagram of a power supply and a power supply controller (PSC) of the welding system, according to an example embodiment. [0006] FIG. 3 is a high-level flowchart of an example method of performing the start of weld procedure. [0007] FIG. 4 shows weld power waveforms (i.e., current and voltage waveforms) for an example start of weld procedure for short-arc welding. [0008] FIG. 5 shows weld power waveforms for an example start of weld procedure for pulsed or spray arc welding. [0009] FIG. 6 shows weld power waveforms for an example short-circuit clearing technique. [0010] FIG. 7A shows weld power waveforms for an example droplet clearing technique. [0011] FIG. 7B is a flowchart of an example method of performing a start of weld procedure in a welding or cutting system. [0012] FIG. 8 is a diagram of the PSC accordance to an embodiment. DETAILED DESCRIPTION Overview [0013] In an embodiment, a method performed by a welding or cutting system having a power supply to supply weld power to an electrode tip extending from a welding torch, comprises: upon detecting a weld start condition, performing a start of weld procedure that includes sequential phases of controlling the weld power to strike an arc on a workpiece, grow a length of the arc to a target length, and heat the electrode tip and the workpiece until a weld energy supplied to the electrode tip across the sequential phases reaches a weld energy threshold indicative of a desired heat-related condition of the electrode tip and the workpiece for welding; and when the weld energy reaches the weld energy threshold, performing a welding operation on the workpiece. Example Embodiments [0014] With reference to FIG. 1, there is an illustration of an example metal inert gas (MIG)/metal active gas (MAG) welding system 100, in which a start of weld procedure may be implemented. The embodiments are presented in the context of MIG/MAG welding by way of example only. It is understood that the embodiments may be employed generally in any known or hereafter developed welding environments, such as, but not limited to, tungsten inert gas (TIG) welding, flux cored arc welding (FCAW), shielded metal arc welding (SMAW) or stick welding, submerged arc welding (SAW), and so on. Additionally, the embodiments may be employed equally in an arc cutting apparatus. Welding system 100 includes: a power supply 102; a power supply controller (PSC) 104 coupled to and configured to control the power supply; an electrode feeder 106 coupled to the power supply; a cable assembly 108 coupled to the electrode feeder; a welding torch 110 (also referred to as a “welding gun”) coupled to the cable assembly and having a sturdy metal contact tip 111 that extends from an end of the welding gun or torch; a gas container 112 coupled to the cable assembly; and a workpiece 114 coupled to the power supply through at least a return path/cable 115. In the ensuing description, the terms “weld” and “welding” are synonymous and interchangeable. Also, the terms “weld” and “welding” refer broadly to both welding and plasma cutting systems and operations.