Abstract: A method of starting a multi-gas plasma arc torch for cutting a workpiece is provided that includes directing a pre-flow gas within the plasma arc torch and switching the pre-flow gas to a plasma gas before a pilot arc is transferred to the workpiece. The plasma gas is supplied initially at a first gas pressure when the pre-flow gas is switched to the plasma gas. The gas pressure is switched to a second gas pressure that is different than the first gas pressure after the pilot arc is transferred. The method provides a smooth transition from the pre-flow gas to the plasma gas and reduces the time delay in replacing the pre-flow gas with the plasma gas in the plasma arc torch, thereby improving cut or marking quality.

Abstract: An electrode for a plasma arc torch is provided by the teachings of the present disclosure. In one form, the electrode includes a conductive body, a plurality of deformed emissive inserts, and a dimple. In one form, the plurality of emissive inserts are concentrically nested about the centerline of the conductive body, and the dimple is positioned concentrically about a centerline of the conductive body. The plurality of emissive inserts and the dimple increase the life of the electrode.

Abstract: A method of manufacturing an electrode for use in a plasma arc torch is provided that includes forming a conductive body to define a proximal end portion, a distal end portion, a distal end face disposed at the distal end portion, a central cavity, and a central protrusion disposed within the central cavity near the distal end portion. A plurality of emissive inserts are inserted through the distal end face and into the central protrusion. The plurality of emissive inserts are pressed into the central protrusion and both a proximal end portion of the central protrusion and the plurality of emissive inserts are deformed such that the plurality of emissive inserts extend radially and outwardly from the distal end portion at an angle relative to the distal end portion.

Abstract: A plasma arc torch is provided that includes a tip having an improved life. The tip defines a first set of fluid passageways, a second set of fluid passageways and an internal cavity in fluid communication with the first and second fluid passageways. The internal cavity includes a base portion disposed proximate and surrounding a central orifice of the tip. A first set of fluid passageways allow for entry of a cooling fluid into the tip and a second set of fluid passageways allow for exit of the cooling fluid from the tip.

Abstract: A method of operating a plasma arc torch is provided that includes directing a first portion of gas into a plasma chamber, directing a second portion of the gas to initiate a pilot arc in the plasma chamber, and redirecting the second portion of the gas to form a shield gas flow rather than venting the second portion to atmosphere. A plasma arc torch for this method includes a start cartridge disposed between an electrode and a tip for initiating the pilot arc. The start cartridge defines at least one redirect gas passageway in fluid communication with a shield gas passageway. The second portion of gas is redirected through the at least one redirect gas passageway and into the shield gas passageway.

Abstract: A drag tip for use in a plasma cutting torch is provided that includes an inner tip portion defining a distal end face, an inner cavity through which a plasma gas flows, and an orifice disposed between the distal end face and the inner cavity. An outer tip portion surrounds the inner tip portion and defines an inner chamber to accommodate a flow of secondary gas and also a distal end portion. The distal end face of the inner tip portion is adapted for contact with a workpiece and extends distally beyond the distal end portion of the outer tip portion, and the flow of secondary gas exits the outer tip portion proximate the distal end portion. Variations of the drag tip and methods of operation are also provided.

Abstract: In general, the present invention provides a method of piercing a workpiece with a plasma arc torch of the type having a plasma gas flow path for directing a plasma gas through the torch and a secondary gas flow path for directing a secondary gas through the torch. The method comprises directing a flow of shield gas along a distal end portion of the plasma arc torch to deflect metal spatter generated from the piercing, and ramping a current provided to the plasma arc torch along a profile during piercing and controlling current ramp parameters as a function of a thickness of the workpiece and an operating current level, wherein the current ramp parameters comprise a length of time, a ramp rate, a shape factor, and a modulation.

Abstract: A shield device for a plasma arc torch includes an inner shield member defining an inner auxiliary gas chamber and an outer shield member surrounding the inner shield member. An outer auxiliary gas chamber is defined between the inner shield member and outer shield member. The shield device allows an auxiliary gas flow to be split into a first flow of auxiliary gas through the inner auxiliary gas chamber and a second flow of auxiliary gas through the outer auxiliary gas chamber. The inner shield member and the outer shield member are configured to be mounted to the plasma arc torch as an integral unit.

Abstract: Methods and devices for controlling the flow of gases through a plasma arc torch are provided. A flow of plasma gas is directed to a plasma chamber, a first flow of auxiliary gas is directed around a plasma stream that exits a tip in one of a swirling manner and a radial manner, and a second flow of auxiliary gas is directed around the first flow of auxiliary gas and the plasma stream in one of a coaxial manner, an angled manner, and a radial manner. The first flow of auxiliary gas functions to constrict and shape the plasma stream to improve cut quality and cut speed, and the second flow of auxiliary gas functions to protect the plasma arc torch during piercing and cutting and to cool components of the plasma arc torch such that thicker workpieces may be processed with a highly shaped plasma stream.

Abstract: A tube support bracket that comprises an aluminum-coated steel support bracket formed having a circular tube-receiving aperture and an annular, castellated collar abutting the aperture. The aperture and collar are sized for receiving therethrough in close-fitting relationship an aluminum alloy heat exchanger tube. The collar, formed by a draw-punching process, has a plurality of spaced-apart, axial tabs sized for swaging against in hoop stress and bite the received tube. An inner surface of each of the collar tabs being has at least one axial groove therein, the groove being configured for receiving exterior regions of the received tube when the collar is swaged tightly against the tube to thereby lock the tube in the collar and thus in the support bracket. A corresponding method for making a tube support is disclosed.

Abstract: A dual mode plasma arc torch and methods of operation thereof are provided, wherein the plasma arc torch is operable with both a high frequency power supply and a contact start power supply.

Abstract: A component for use in a plasma arc torch is provided that includes an orifice that defines a continuously changing cross-sectional size along the length of a surface of the orifice from an inlet portion to an outlet portion. The surface extends along the component and directs a flow of shield gas at a predetermined angle to result in a specific pierce or cut location on a workpiece. In one form, the component is a shield cap. The continuously changing surface may be convergent, divergent, or a combination of convergent and divergent according to the principles of the present disclosure. Additionally, the shield cap may comprise a single, unitary piece or alternately a plurality of pieces or components.

Abstract: A component for use in a plasma arc torch is provided that includes a continuously contoured surface extending along the component that directs a flow of shield gas at a predetermined angle to result in a specific pierce or cut location on a workpiece. In one form, the component is a shield cap that includes an exit orifice extending through a central portion of the shield cap, the exit orifice defining an inlet portion and an outlet portion, and a continuously contoured surface extending between the inlet portion and the outlet portion. The continuously contoured surfaces may be convergent, divergent, or a combination of convergent and divergent according to the principles of the present disclosure. Additionally, the shield cap may comprise a single, unitary piece or alternately a plurality of pieces or components.

Abstract: In general, the present invention provides a method of piercing a workpiece with a plasma arc torch of the type having a plasma gas flow path for directing a plasma gas through the torch and a secondary gas flow path for directing a secondary gas through the torch. The method comprises directing a flow of shield gas along a distal end portion of the plasma arc torch to deflect metal spatter generated from the piercing, and ramping a current provided to the plasma arc torch along a profile during piercing and controlling current ramp parameters as a function of a thickness of the workpiece and an operating current level, wherein the current ramp parameters comprise a length of time, a ramp rate, a shape factor, and a modulation.

Abstract: Devices and methods are provided that control gas flow to a plasma arc torch local to a torch handle. Generally, a plasma arc torch is provided that comprises a gas control device operable with a torch lead and a torch head, and an activation member operable with the gas control device. Accordingly, the activation member activates the gas control device such that gas flow is supplied from the torch lead to the torch head, and the activation member deactivates the gas control device such that the gas flow is terminated. Further, the activation member may comprise a trigger system, a button, or a safety member, among others. Moreover, the gas control device may comprise a gas control valve or a switch that activates a gas control device disposed within a power supply, among others.

Abstract: A drag tip for use in a plasma cutting torch is provided that includes an inner tip portion defining a distal end face, an inner cavity through which a plasma gas flows, and an orifice disposed between the distal end face and the inner cavity. An outer tip portion surrounds the inner tip portion and defines an inner chamber to accommodate a flow of secondary gas and also a distal end portion. The distal end face of the inner tip portion is adapted for contact with a workpiece and extends distally beyond the distal end portion of the outer tip portion, and the flow of secondary gas exits the outer tip portion proximate the distal end portion. Variations of the drag tip and methods of operation are also provided.

Abstract: Methods and devices for controlling the flow of gases through a plasma arc torch are provided. A flow of plasma gas is directed to a plasma chamber, a first flow of auxiliary gas is directed around a plasma stream that exits a tip in one of a swirling manner and a radial manner, and a second flow of auxiliary gas is directed around the first flow of auxiliary gas and the plasma stream in one of a coaxial manner, an angled manner, and a radial manner. The first flow of auxiliary gas functions to constrict and shape the plasma stream to improve cut quality and cut speed, and the second flow of auxiliary gas functions to protect the plasma arc torch during piercing and cutting and to cool components of the plasma arc torch such that thicker workpieces may be processed with a highly shaped plasma stream.

Abstract: A modular plasma arc torch is provided that comprises a torch head and a torch lead, and a quick disconnect that is operatively engaged between the torch head and the torch lead. Accordingly, the torch head and torch lead may be quickly assembled and disassembled through the use of the quick disconnect. Further, the modular plasma arc torch also comprises a gas control device disposed within the plasma arc torch, which is operatively engaged between the torch head and the torch lead through the use of the quick disconnect according to the present invention. In addition, the quick disconnect may be used to connect a wide range of torch components within a plasma arc torch, thereby providing a reconfigurable plasma arc torch. Moreover, the quick disconnect according to the present invention conducts both gas and electric power from a power supply to the torch head for operation of the plasma arc torch.

Abstract: A component for use in a plasma arc torch is provided that includes a continuously contoured surface extending along the component that directs a flow of shield gas at a predetermined angle to result in a specific pierce or cut location on a workpiece. In one form, the component is a shield cap that includes an exit orifice extending through a central portion of the shield cap, the exit orifice defining an inlet portion and an outlet portion, and a continuously contoured surface extending between the inlet portion and the outlet portion. The continuously contoured surfaces may be convergent, divergent, or a combination of convergent and divergent according to the principles of the present disclosure. Additionally, the shield cap may comprise a single, unitary piece or alternately a plurality of pieces or components.