FAQ How Electron Beam Welding Works

When fast moving electrons hit a metal surface they are decelerated which transofrms the kinteic energy of each individual electron in the beam into thermal energy in the component. This transformation is table in the high 90% range for all metals regardless of whether the electrons hit the surface at a perpendicular or a shallow angle. As a practical matter, this physical behavior makes the process very robust and reliable! When electrons in a focused beam hit a metal surface, the high energy density instantly vaporizes the material, generating a so-called key hole. A characteristic of this phenomenon is that it allows the unique capability for deep, narrow welds with very small heat affected zones (HAZ) and minimized thermal distortions of welded assemblies. Depth-to-width ratios of up to 40:1 have been achieved in production for many years. Special circumstances may require conduction mode welding (as opposed to key-hole welding) that typically produces wide and shallow welds. Conduction type welds can be used e.g. for cosmetic paths to smoothen the top bead of key hole welds in a subsequent operation. How is this done? By lowering the beam power and either defocusing the beam and/or widening the beam by using a deflection pattern.