Installation and Thermal Feedback from a Multi-wavelength Pyrometer in Electron Beam Melting

Mijares, Jonathan
Mireles, Jorge
Gaytan, Sara M.
Espalin, David
Carter, William T.
Wicker, Ryan B.
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University of Texas at Austin

The purpose of this paper is to outline and discuss the installation and use of a multi-wavelength pyrometer for process temperature monitoring in Electron Beam Melting (EBM). A multi-wavelength pyrometer was externally mounted atop an EBM system to observe and record surface temperatures during the fabrication process. The multi-wavelength pyrometer is a non-contact device capable of measuring the temperature of an object without the need of knowing the object’s emissivity. Temperature data from the EBM system thermocouple and the multi-wavelength pyrometer were compared, and it was determined that the pyrometer measurements were reasonable. During fabrication, the multi-wavelength pyrometer allowed the characterization of the EBM process that consisted of various steps during fabrication (e.g. heating of the build platform, powder deposition, and melting). Measurement of surface temperatures during fabrication can be useful for parameter development of novel materials, prediction of resulting microstructural architectures, and ultimately as feedback used in a closed-loop control system, allowing full spatial and temporal control of melting and microstructure.