An in-situ monitoring system for electron beam wire-feed additive manufacturing

•An in-situ monitoring system for AM process was proposed with a special designed hollow electromagnetic acoustic transducer.•Triple typical wire-plate contact situations were distinguished.•It is applicable to high temperature and vacuum environment. Wire-feed additive manufacturing (AM) is a promising method for fabricating large metal components with complex geometry. Plenty of studies proved that wire transition status has critical influence on the forming quality in wire-feed AM process. It is important to develop a high adaptive system for in-situ monitoring wire transition status, due to common methods such as CCD monitoring fail in smoky, high temperature and vacuum environment. In this paper, in order to overcome this problem, an in-situ monitoring system based on the electromagnetic principle was firstly designed and fabricated. The experiments indicated that triple common states of wire transition can be distinguished with the system. The results showed that 0.5–mm spatial resolution and 0.4-s response time satisfy the demand for monitoring in AM process. In addition, the system adaptability for complex situation was validated and enhances performance with the lifting voltage. In practical, the monitoring system successfully worked over a long period in the high temperature, vacuum environment during the electron beam AM process. This study provided a new design for process monitoring, which is feasible and valuable for developing AM technology.