Variation of Emittivity with Powder Bed Fusion Build Parameters
Jarred C. Heigel, Brandon M. Lane, Shawn P. Moylan
Common approaches to process monitoring of powder bed fusion rely heavily on optical measurements. These measurements can be used to verify powder spreading, assess the quality of each layer, and to measure process temperatures. In regards to the latter, radiometric detectors such as cameras or pyrometers only measure radiant emissions from the surface, and do not directly measure its temperature. Calculating the temperature from these measurements relies on the calibration of the camera or pyrometer with a blackbody and on knowledge of the emittivity of the surface being measured. Emittivity depends on multiple factors including surface texture and viewing angle, among others. An apparatus and method for measuring emittivity using an infrared camera is detailed. Measured emittivity values from metal surfaces produced using a commercial powder bed fusion process are presented and related to temperature, viewing angle, and oxidation state.
Proceedings of the Solid Freeform Fabrication Symposium
, Lane, B.
and Moylan, S.
Variation of Emittivity with Powder Bed Fusion Build Parameters, Proceedings of the Solid Freeform Fabrication Symposium, Austin, TX, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921671
(Accessed February 24, 2024)