Patent ID: 8759709

Claim:
An electrode for a plasma arc torch, the plasma arc torch including a plasma chamber defined by the electrode and a nozzle, the electrode comprising: an electrode body having a first end formed of high purity copper, containing at least 99.81% copper, a second end opposite the first end, and a front face located at the first end; a cavity in the front face of the electrode body; and an elongated insert formed of a high thermionic emissivity material disposed in the cavity, the insert having a first end and a second end, the first end oriented toward the front face of the electrode body, wherein a diameter of the first end is less than a diameter of the second end, such that the first end of the electrode body is configured to retain the first end of the insert, and wherein the exposure of higher temperatures creates thermal flexing in the insert which can allow the insert to advance towards the front face of the electrode body and the insert is configured to advance toward the front face during operation of the electrode such that the high thermionic emissivity material is replenished near the front face by the advancement of the insert.