Detection of temporary capillary stability in EB beam-deflection techniques using X-ray self-illumination

A deeper understanding of the temporal behaviour of capillaries enables the improvement of modern beam welding processes, e.g. the application of the multi-bath or multi-process technique in electron beam welding. The temporal capillary behaviour in an Electron Beam (EB) multi-bath welding process can be analysed at different beam deflection frequencies by means of secondary X-ray. This is visualised by X-rays which are generated during beam-material interaction in the capillary and can be visualised as an upside-down image on a scintillator screen via a pinhole camera. The analysis of the high-speed images allows conclusions regarding the inertia of a temporarily unheated EB capillary. This paper shows that with increasing deflection rate the collapse of capillary decreases while at a deflection rate of 1000 Hz no collapse in capillary depth can be detected.