In-situ Three-dimensional Monitoring of LPBF Processing Reliability by Laser Line Scanning System

During laser powder bed fusion (LPBF), surface height data of the powder bed and part contain valuable information about potential defects and process reliability. However, traditional off-axis powder-spreading monitoring camera lacks accuracy and cannot measure out-of-plane deformation online. This paper presents the development of a high-precision laser line scanning system for in-situ layer-wise 3D powder bed monitoring. Specifically, an image processing method based on thresholding is proposed to preprocess the monitored 3D data, extracting morphological and height features. Furthermore, layer-wise roughness during component fabrication was analyzed based on these features to establish correlations between process parameters and roughness quality, providing a basis for diagnosing abnormal conditions. Finally, high-throughput experimental validation of the process parameters confirmed the effectiveness of both the developed monitoring system and the proposed methodology.