In-situ, Parallel Monitoring of Relative Temperature, Material Emission, and Laser Reflection in Powder-blown Directed Energy Deposition

Published

September 10, 2024

Author(s)

Samantha Webster, Jihoon Jeong, Rujing Zha, Shuheng Liao, Alberto Castro, Lars Jacquemetton, Darren Beckett, Kornel Ehmann, Jian Cao

Abstract

In-situ monitoring is critical for developing new control methods, advanced materials, and toolpath planning strategies in laser beam Directed Energy Deposition (DED-LB). Coaxial melt pool monitoring has typically been performed with cameras (e.g., infrared (IR), two-color pyrometer, charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS)) which have focused on melt pool morphology and temperature distribution. While these techniques capture critical deposition information, they do not capture other important phenomena such as the unique coupling between the laser and melt pool, which limits the design and generality of open-loop and closed-loop process control. We establish in-situ, parallel signals by monitoring multiple process phenomena at the same time through different wavelength bands and thermal correlation. Increased laser coupling was observed using in-situ, parallel monitoring, where lower reflectivity/higher absorption of the laser light within a vapor depression led to an increase in thermal emission in the visible region. Ultimately, a relationship between each change in process parameter and the relative absorption of the laser was established. In-situ monitoring of the laser coupling phenomena not only provides insight on material processing conditions but will also enable more complex control in DED-LB processes.

Citation

JOM Journal of the Minerals Metals and Materials Society

Pub Type

Journals

Download Paper

https://doi.org/10.1007/s11837-024-06837-3

Local Download

Keywords

additive manufacturing, melt pool, photodiode

Citation

Webster, S. , Jeong, J. , Zha, R. , Liao, S. , Castro, A. , Jacquemetton, L. , Beckett, D. , Ehmann, K. and Cao, J. (2024), In-situ, Parallel Monitoring of Relative Temperature, Material Emission, and Laser Reflection in Powder-blown Directed Energy Deposition, JOM Journal of the Minerals Metals and Materials Society, [online], https://doi.org/10.1007/s11837-024-06837-3, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=957543 (Accessed October 14, 2025)