Patent ID: 6114650
Filing Date: 2000-09-05
Classification: H05H

Abstract:
An electrode for supporting an electric arc in a plasma arc torch, the electrode being made by a process comprising the steps of:forming a metallic holder by forming a receptacle in a generally planar front face of a metallic blank, the receptacle extending along an axis generally normal to the front face and including an end wall within the blank;forming a relatively non-emissive separator from a relatively non-emissive metallic material such that the separator has an outer surface extending between first and second end faces, the outer surface being configured to fit closely within the receptacle in the metallic holder;forming a cavity in the first end face of the separator and extending thereinto;forming an emissive element from a solid body of material having a work function lower than that of the separator, such that the emissive element is slidably insertable into the cavity in the separator;inserting the separator into the receptacle of the metallic holder such that the second end face of the separator abuts the end wall of the receptacle and the first end face of the separator is adjacent the front face of the metallic holder;inserting an end of the emissive element into the cavity of the separator until the end of the emissive element is seated within the separator; andapplying force to the emissive element and the first end face of the separator generally parallel to the axis of the metallic holder to axially compress the emissive element and the separator so as to cause the emissive element and the separator to plastically deform radially outwardly until the emissive element is gripped and retained by the separator and the separator is gripped and retained by the metallic holder.