Blue-laser powder bed fusion system for in situ optical and synchrotron characterization.

Laser powder bed fusion (LPBF) of highly reflective metals, such as copper, is challenging under near-infrared lasers because of low absorptivity and unstable energy coupling. While short-wavelength lasers improve copper absorption, experimental platforms that combine controlled powder-bed processing with in situ diagnostic access remain limited. This work presents a laboratory-scale blue-LPBF system based on a 250 W diode laser (443 ± 15 nm). The platform integrates automated powder recoating, controlled argon atmosphere and circulation, and multiple optical access ports within a compact sealed chamber, supporting in situ characterization techniques, such as high-speed optical imaging, schlieren imaging, and transmission-mode synchrotron x-ray experiments. Baseline experiments demonstrate coordinated layer-wise fabrication of pure copper. Schlieren and high-speed visible-light imaging capture plume and spatter behavior under controlled gas flow, and synchrotron x-ray imaging reveals subsurface melt pool geometry during blue-laser scanning. The system provides a controlled platform for time-resolved investigation of blue-laser-matter interaction during LPBF.