In-Situ Defect Detection in Electron Beam Powder Bed Fusion via Surface Height Reconstruction from Backscattered Electron Signals

In-situ defect detection during Electron Beam Powder Bed Fusion (EB-PBF) remains challenging, particularly with regard to surface height measurement. Traditional surface height measurement techniques are typically conducted post-process, limiting their potential for real-time quality control. Prior research has attempted to leverage backscattered electron (BSE) signals which are less affected by environmental factors signals to generate surface height maps in situ. Here, we present results applying this method to EB-PBF samples, examining measurement challenges and identifying sources of systematic error that stem from various process parameters. The goal is to establish a robust in-situ defect detection system for EB-PBF by developing a correlation between BSE signals and surface topography. This will advance the capability of the process to provide real-time feedback on surface quality, facilitating early detection and correction of defects.