Evaluation of the Ultra-High Vacuum Suitability of Laser Powder Bed Fusion Manufactured Stainless Steel 316L

Additive manufacturing has been adopted across various industries to benefit from its unique capabilities. However, there is currently no significant use of the technology in the ultra-high vacuum industry. One challenge is the limited data available on the vacuum-specific performance of laser powder bed fusion manufactured parts. In this paper, the leak rate, outgassing, and residual gas analysis of stainless steel 316L samples is evaluated, considering the as-built surface and post-processing by glass bead blasting, Hirtisation, and machining. Two of three machined samples showed a leak rate at the detection limit of the test stand of 10 \(^{-9}\) mbar L s \(^{-1}\) . All samples showed a pump-down behavior very similar to conventional stainless steel with all chamber pressures within \(1.4 \times 10 ^{-8}\) after 20 h of pumping. All surface post-processed samples showed low levels of surface contamination, with the ion currents above 50 amu more than three decades below the ion current of H \(_2\) O. The as-built samples with a machined surface were the only samples to exceed this limit. Overall, while application-specific standards must be evaluated for each use case, the results show the process to generally be ultra-high vacuum compatible.