Electron-optical observation of smoke evolution during electron beam powder bed fusion

Abstract

Electron Beam Powder Bed Fusion (PBF-EB) is an additive manufacturing technique that produces customized components using an electron beam under vacuum conditions. A so-called smoke phenomenon might occur during the process, leading to an explosion-like powder spreading in the vacuum chamber, which is catastrophic for the build process. This phenomenon happens rapidly and it is hard to be observed from its initial stage. In this study, the powder smoke phenomenon and its development are investigated using an ELectron-Optical (ELO) monitoring system , which collects backscattered electrons during PBF-EB in similarity to scanning electron microscopy. In comparison to the optical process monitoring tool based on high-speed camera, the ELO system shows very promising results for real-time smoke detection and possibly prevention.