Patent ID: 8525069
Filing Date: 2013-09-03
Classification: B23K,H05H,Y10T

Abstract:
1. An electrode for a plasma arc torch having a prolonged service life, the plasma arc torch including a plasma chamber defined by the electrode and a nozzle, the electrode comprising: an electrode body having a front face at a first end of the electrode body; an orifice in the front face of the electrode body; and an elongated emissive insert made of a high thermionic emissivity material and located within the orifice, the insert having a forward end and a rearward end, wherein the forward end of the insert is oriented toward the front face of the electrode body, wherein the insert has an initial configuration and an operational configuration, the operational configuration being formed after a plurality of operations of the torch, the initial configuration of the insert having the rearward end of the insert located at a first distance (D1) from the front face, and the operational configuration of the insert having the rearward end located at a second distance (D2), wherein D1 is at least 0.6 mm greater than D2 based upon at least two of the following: (i) the electrode is formed of a high purity copper containing at least 99.81% copper; (ii) radial compression is applied at the first end of the electrode body to retain the insert; or (iii) the insert is tapered, such that a diameter of the forward end of the insert is less than a diameter of the rearward end of the insert.