In-situ monitoring of interlayer surface with electron beam luminescence in wire-based additive manufacturing

Electron beam freeform fabrication (EBF3) technology is primarily known for its vacuum environment, high deposition efficiency, and versatile electron beam capabilities. However, this technology suffers the challenges of poor stability, repeatability, and forming quality for its complex deposition process. Timely interlayer surface inspection can effectively reflect the actual deposition state, thereby providing valuable guidance for the operators. Therefore, this study proposes an interlayer surface reconstruction technique based on the electron beam scanning luminescence. Specifically, a reconstruction system was first developed based on the electron beam AM equipment. Subsequently, the system was calibrated, and an appropriate image processing algorithm was developed to extract the electron beam central line. Finally, several surfaces were reconstructed to verify its practicality. Results indicate that the representative samples can be successfully rebuilt with a maximum reconstruction error within 0.15 mm. This research is of great significance in enhancing the deposition success rate, stability, and part quality.