The requirements for uninterrupted production present many challenges to personnel operating the guns that power the furnaces. An expert system is used to help furnace operators diagnose and correct electron-beam gun problems.
Electron beam melting (EBM), invented nearly 100 years ago, is a two-mode process. The original drip-melting mode relies on selective vacuum purification, removing impurities with vapor pressures higher than the metal being processed. In cold-hearth refining, or EBCHR, inclusions are removed as the molten metal flows through the hearth by flotation and sedimentation in addition to the evaporative purification. Those floating on the surface break down on exposure to the beam and either evaporate or dissolve in the metal. The heavy inclusions sink to the bottom of the hearth and are removed with the skull. Any light inclusions that remain floating are prevented from flowing into the ingot by a dam.