Abstract: An electrode for supporting an arc in a plasma arc torch. The electrode includes a metallic holder having a front end and a rear end. An emissive insert cavity is formed in the front end. An emissive insert is mounted in the cavity and is a metallic material having a relatively low work function. The front end is a casting made of a metal which is selected from silver, gold, platinum, rhodium, indium, palladium, nickel and alloys thereof. The rear end is a metal selected from copper and copper alloys. A cylindrical post extends inwardly from the front end of the metallic holder. The cylindrical post has an inner-rear tip portion which is a metal selected from copper and copper alloys.

Abstract: An electrode for supporting an arc in a plasma arc torch. The electrode includes a metallic holder having a cavity formed in a front end portion. An insert assembly is mounted in the cavity. The insert assembly includes an emissive insert composed of a metallic material having a relatively low work function. The emissive insert has a bore formed therein for securing a non-emissive core. The core has a base portion, which provides an interface between the emissive insert and the holder. The core and base portion act to thermally conduct heat out of the emissive insert so that the service life of the emissive insert is increased by the lowering of the emissive insert's operating temperature.

Abstract: A nozzle assembly, for laser cutting heads, which includes a connection which easily, inexpensively, and removably connects a conductive insert to an insulating receptacle. A conductive nozzle can then be threaded into the conductive insert. The insulating receptacle includes holes through an annular cross section thereof. One hole receives a conductor pin having a head at one end and threads at the other. The other holes each have a larger diameter portion and a smaller diameter portion that receive a screw head, and a screw shaft, respectively. The screws and the threaded end of the conductor pin are then screw threaded into holes, which have complementary threads, in the conductive insert to connect the conductive insert to the insulating body. Such a connection thus allows damaged or worn parts to be easily replaced which thereby reduces cost of the nozzle assembly.

Abstract: An electrode for supporting an arc in a plasma arc torch. The electrode includes a metallic holder having a front end, and a cavity in the front end, the cavity having an enlarged outer end portion. An insert assembly is mounted in the cavity and includes an emissive insert composed of a metallic material having a relatively low work function, a sleeve which substantially surrounds the emissive insert so as to separate the emissive insert from contact with the holder at least at the front end. The sleeve is composed of a metal which is selected from the group consisting of silver, gold, platinum, rhodium, iridium, palladium, nickel, and alloys thereof. The insert assembly further includes an aluminum face plate disposed in the enlarged outer end portion of the cavity and which is exposed at the front end of the metallic holder so as to surround a front portion of the sleeve. Alternatively, the aluminum face plate is eliminated and the front end of the metallic holder directly contacts the emissive insert.

Abstract: A method of repairing a spent electrode for a plasma arc torch. The method includes removing an end piece of the spent electrode thereby leaving an electrode base. A blind bore is drilled into the end face of the electrode base. Internal female threads are then formed in the blind bore. A bevelled angle is machined at the entrance of the blind bore. Finally, a replacement end piece having a matching bevelled angle and threaded male portion is mated with the bevelled angle and internal threads, respectively, of the blind bore in the electrode base, thereby forming a rebuilt electrode.

Abstract: An electrode for supporting an arc in a plasma arc torch. The electrode includes a metallic holder having a front end, and a cavity in the front end, the cavity having an enlarged outer end portion. An insert assembly is mounted in the cavity and includes an emissive insert composed of a metallic material having a relatively low work function, a sleeve which substantially surrounds the emissive insert so as to separate the emissive insert from contact with the holder at least at the front end. The sleeve is composed of a metal which is selected from the group consisting of silver, gold, platinum, rhodium, iridium, palladium, nickel, and alloys thereof. The insert assembly further includes an aluminum face plate disposed in the enlarged outer end portion of the cavity and which is exposed at the front end of the metallic holder so as to surround a front portion of the sleeve.