Method and device for marking a workpiece surface (2A) of a metal workpiece (2), in which a welding torch (3) comprising a welding wire electrode (4) is guided along the workpiece surface (2A) to be marked and meanwhile a wire end (4A) of the welding wire electrode (4) is moved towards and away from the work-piece surface (2A) to be marked, wherein an electric voltage (U) present at the welding wire electrode (4) and/or an electric current (I) flowing through the welding wire electrode (4) bring about electric sparks, which bring about material removal and/or material alteration at the workpiece surface (2A) of the metal workpiece (2) to mark the workpiece surface (2A).

An apparatus and method for cleaning an oxide film using a direct current reverse polarity are provided. The apparatus for cleaning an oxide film formed on a workpiece may include a power supply configured to apply direct current power and to include a positive electrode terminal and a negative electrode terminal, the workpiece configured to be electrically connected to the negative electrode terminal to act as a negative electrode to which a current is applied, and a torch having a positive electrode, which is spaced apart from the oxide film by a predetermined distance and is electrically connected to the positive electrode terminal, the torch being installed to be movable relative to the workpiece. The oxide film formed on the workpiece may be removed by applying a reverse polarity direct current between the workpiece, serving as the negative electrode, and the positive electrode to generate an arc.

In some aspects, contact members to connect plasma torch leads to plasma cutting systems can include: a base portion; a set of ports within the base portion that include: a coolant supply port to convey a liquid coolant from the cutting system to a plasma arc torch connected to the contact member by the torch lead, a coolant return port: i) to convey return liquid coolant from the torch to the cutting system, and ii) to convey an operational current from the cutting system to the torch, at least one gas supply port to convey processing gases to the torch, and an ohmic contact connector; and a connector to couple the base portion to the cutting system and connect each of the ports and electrical connectors to respective complementary connections of the cutting system upon coupling to the cutting system.

In some aspects, contact members to connect plasma torch leads to plasma cutting systems can include: a base portion; a set of ports within the base portion that include: a coolant supply port to convey a liquid coolant from the cutting system to a plasma arc torch connected to the contact member by the torch lead, a coolant return port: i) to convey return liquid coolant from the torch to the cutting system, and ii) to convey an operational current from the cutting system to the torch, at least one gas supply port to convey processing gases to the torch, and an ohmic contact connector; and a connector to couple the base portion to the cutting system and connect each of the ports and electrical connectors to respective complementary connections of the cutting system upon coupling to the cutting system.

Methods for forming pierce holes in a metal workpiece are disclosed. According to one implementation, upon a plasma torch be energized, the cutting axis of the torch is rotated repeatedly between first and second angular positions to produce successively deeper pierces in a workpiece until a pierce hole is produced through a thickness of the workpiece. According to other implementations pierce holes are produced by rotating the cutting axis of the plasma torch tip around a designated central axis of the pierce hole in a diametrically reducing manner so that the produced pierce hole has a tapered profile with a cross-sectional area of the pierce hole at a top surface of the workpiece being greater than a cross-sectional area of the pierced hole at a bottom surface of the workpiece.

Methods for forming pierce holes in a metal workpiece are disclosed. According to one implementation, upon a plasma torch be energized, the cutting axis of the torch is rotated repeatedly between first and second angular positions to produce successively deeper pierces in a workpiece until a pierce hole is produced through a thickness of the workpiece. According to other implementations pierce holes are produced by rotating the cutting axis of the plasma torch tip around a designated central axis of the pierce hole in a diametrically reducing manner so that the produced pierce hole has a tapered profile with a cross-sectional area of the pierce hole at a top surface of the workpiece being greater than a cross-sectional area of the pierced hole at a bottom surface of the workpiece.

A cooling component suitable for cooling an electrical component disposed in a power source of a welding or cutting system includes a heat transfer surface, an inlet, an outlet, and a closed flow area. The heat transfer surface transfers heat away from the electrical component. The inlet receives process gas from a gas source and the outlet directs the process gas downstream towards a torch assembly. The closed flow area extends between the inlet and the outlet and is in thermal communication with the heat transfer surface so that the process gas enhances cooling of the electrical component as the process gas travels through the closed flow area, from the inlet to the outlet.

Approaches herein provide a torch handle including a pneumatically controlled jaw operable to engage an electrode. In one approach, a system is provided for distributing gas within the torch handle, the system including a pneumatic cylinder within a main housing of the torch handle. The pneumatic cylinder is coupled to a shaft for actuating a first member of a jaw relative to a second member of the jaw. The system further includes a gas passageway through the main housing, the gas passageway extending to an exit orifice disposed within the second member. A flow controller is operable to direct a flow of a gas to either the pneumatic cylinder or the gas passageway. In one approach, the first member is actuated towards the second member when the gas is directed through the gas passageway, and actuated away from the second member when the gas is directed to the pneumatic cylinder.

Approaches herein provide a torch handle including a pneumatically controlled jaw operable to engage an electrode. In one approach, a system is provided for distributing gas within the torch handle, the system including a pneumatic cylinder within a main housing of the torch handle. The pneumatic cylinder is coupled to a shaft for actuating a first member of a jaw relative to a second member of the jaw. The system further includes a gas passageway through the main housing, the gas passageway extending to an exit orifice disposed within the second member. A flow controller is operable to direct a flow of a gas to either the pneumatic cylinder or the gas passageway. In one approach, the first member is actuated towards the second member when the gas is directed through the gas passageway, and actuated away from the second member when the gas is directed to the pneumatic cylinder.

An example welding or cutting circuit includes: an input leg comprising a capacitor coupled between a high bus and a low bus; a buck converter coupled in parallel with the input leg, wherein the buck converter comprises a first transistor, a first diode, and an output electrically coupled to a node between the first transistor and the first diode, and wherein the buck converter is configured to convert input voltage to current in an inductor coupled to the output of the buck converter; and a steering leg coupled in parallel with the input leg, wherein the steering leg is configured to control a rate at which the current in the inductor decreases, and wherein a current detector is positioned at the output to monitor the current, the current detector providing current level indications to a hysteretic controller, the hysteretic controller providing signals to the first transistor that control the transistor to an on state or an off state to control the voltage applied to the inductor