THE ESAB GROUP INC.

A method for piercing and cutting a workpiece that includes the use of a plasma torch having an electrode and a nozzle spaced from and surrounding a distal end portion of the electrode to form a process gas flow channel. A method includes delivering a plasma gas at a first pressure through the process gas flow channel of the torch while ionizing the plasma gas to produce a plasma arc. While the plasma gas is delivered at the first pressure, performing a piercing operation by producing a pierce hole in the workpiece using the plasma arc. Subsequent to the piercing operation, performing a cutting operation by delivering through the process gas flow channel the plasma gas at a second pressure lower than the first pressure, forming a cut in the workpiece that originates at and extends away from a boundary of the pierce hole.

A system to generate weld power for a welding process comprises: a power supply including a power inverter having multiple switches controlled by multiple switching signals such that each switch is alternately turned ON and OFF within each switching cycle of one of the multiple switching signals, to supply a current to an output circuit of the power supply that is configured to convert the current to the weld power, wherein the power inverter includes a capacitor and a capacitor switch connected in series with each other and across a switch of the multiple switches; and a controller to monitor a weld parameter and control the capacitor switch to either connect the capacitor across, or disconnect the capacitor from, the switch continuously across multiple cycles of a respective one of the multiple switching signals, depending on whether the weld parameter meets a predetermined operating condition of the welding process.

A method for using a plasma torch includes delivering a plasma gas through a plasma gas flow channel of a plasma torch while ionizing the plasma gas to produce a plasma arc that extends between the electrode and the workpiece. Additionally, shield fluid is delivered through a shield flow channel at a first pressure. A piercing operation to produce a pierce hole in the workpiece using the plasma arc is initiated while the shield fluid is delivered through the shield flow channel at the first pressure. After conducting the piercing operation for an amount of time, the shield fluid is delivered to the shield flow channel at a second pressure that is higher than the first pressure. Subsequent to the piercing operation, performing a cutting operation that forms a cut in the workpiece that originates at and extends away from a boundary of the pierce hole.

Systems and methods for operating a welding power supply are disclosed. A method may include operating the welding power supply during a short arc welding process having repetitive cycles each including a short circuit phase and an arc phase, during the short circuit phase, causing a fast ramp up of current from a background current level to a predetermined current level, and upon reaching the predetermined current level, slowing the fast ramp up of the current to a relatively slower ramp up of current until the arc phase begins, wherein the predetermined current level is set based on a percentage of a current level detected at a transition between the short circuit phase and the arc phase in at least one prior cycle.

A torch assembly includes a torch that has two torch body portions that can move relative to each other and also be locked in particular positions. When one of the torch body portions is moved relative to the other torch body portion, the overall configuration of the torch is changed. In some applications, it may be desirous to change the torch configuration to suit the applications, depending on the location of a workpiece or a seam to be welded, or the location of a cut to be made. In some instances, the torch body including a consumable stack can be moved to position the consumable stack in a desired position or location.

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 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 pulse 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 pulse 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.

A method is performed in a welding or cutting system, including a power supply to deliver a weld current through a weld circuit to a welding torch to create an arc. The method comprises: measuring the weld current to produce a measured current; measuring a weld voltage on a sense point of the power supply or the weld circuit that is spaced-apart from the welding torch, to produce a measured voltage that differs from an arc voltage by a voltage drop caused by the weld current and an inductance of the weld circuit; computing a derivative of the weld voltage based on the measured voltage; computing a second derivative of the weld current based on the measured current; and computing an inductance value representative of the inductance based on the derivative and the second derivative.

A method performed in a welding system that supplies a current and a voltage to a stickout of an electrode from a welding torch during a welding process comprises: sampling the current and the voltage to produce current values and voltage values; computing time derivatives of the current that coincide with the current values; determining first and second current values of the current values that differ from each other but that coincide with first and second time derivatives that match each other; computing a delta current between the first and second current values; computing a delta voltage based on first and second voltage values of the voltage values that correspond to the first and second current values; and computing a ratio of the delta voltage to the delta current to represent a resistance of the stickout.

A method, apparatus, and computer program product are provided for plasma piercing a workpiece using a plasma cutting torch. According to one implementation the method includes providing the plasma cutting torch at a first pierce height above a workpiece to initiate a piercing operation at the first pierce height for a first duration, during the piercing operation, lowering the plasma cutting torch to a second pierce height above the workpiece for a second duration, and lowering the plasma cutting torch to a cut height.