Design and Experimental Validation of a Pressurized Laser Powder Bed Fusion Platform for Continuous Multilayer Processing

Investigating pressure-dependent laser powder bed fusion (LPBF) requires equipment capable of performing repeated layer cycles in a sealed pressurized environment. This study describes a pressurized LPBF platform integrating internal powder feeding and recoating, external laser delivery, synchronized motion control, and recirculating gas flow. The platform has a nominal design-pressure limit of 20 bar absolute, which was not experimentally demonstrated as a multilayer operating condition. Ar builds comprising 200 programmed layers with a nominal height of 6 mm were completed at 1 and 3 bar in approximately 2 h per build. One block was characterized at each Ar pressure; repeated Archimedes measurements yielded relative densities of 99.58 ± 0.19% and 94.08 ± 0.50%, respectively, without establishing between-build variability. Separate experiments demonstrated multilayer LPBF processing in N2 up to 9 bar and stationary laser melting up to 15 bar. The mean final nitrogen content increased from 0.05985 to 0.09270 wt.% between 1 and 9 bar for multilayer specimens and from 0.1415 to 0.3505 wt.% between 1 and 15 bar for stationary-melted specimens. Pressure retention was assessed through mechanical-gauge observation rather than continuous time-resolved acquisition. The results document the machine’s initial multilayer processing capability and its potential for investigating pressure-dependent processing behavior; they do not establish full-range performance or pressure-induced densification enhancement.