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Experimental Determination of the Emissivity of Powder Layers and Bulk Material in Laser Powder Bed Fusion Using Infrared Thermography and Thermocouples
- Recording the temperature distribution of the layer under construction during laser powder bed fusion (L-PBF) is of utmost interest for a deep process understanding as well as for quality assurance and in situ monitoring means. While having a notable number of thermal monitoring approaches in additive manufacturing (AM), attempts at temperature calibration and emissivity determination are relatively rare. This study aims for the experimental temperature adjustment of an off-axis infrared (IR) thermography setup used for in situ thermal data acquisition in L-PBF processes. The temperature adjustment was conducted by means of the so-called contact method using thermocouples at two different surface conditions and two different materials: AISI 316L L-PBF bulk surface, AISI 316L powder surface, and IN718 powder surface. The apparent emissivity values for the particular setup were determined. For the first time, also corrected, closer to real emissivity values of the bulk or powder surface condition are published. In the temperature region from approximately 150 °C to 580 °C, the corrected emissivity was determined in a range from 0.2 to 0.25 for a 316L L-PBF bulk surface, in a range from 0.37 to 0.45 for 316L powder layer, and in a range from 0.37 to 0.4 for IN718 powder layer.
Author: | Gunther Mohr, Susanna Nowakowski, Simon J. Altenburg, Christiane Maierhofer, Kai Hilgenberg |
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URN: | urn:nbn:de:kobv:526-opus4-13564 |
DOI: | https://doi.org/10.3390/met10111546 |
ISSN: | 2075-4701 |
Parent Title (English): | Metals |
Publisher: | MDPI |
Document Type: | Article |
Language: | English |
Year of Publication: | 2020 |
Date of first Publication: | 2020/11/20 |
Publishing Institution: | Technische Hochschule Wildau |
Release Date: | 2021/01/08 |
Tag: | 316L; IN718; calibration; emissivity; laser beam melting (LBM); laser powder bed fusion (L-PBF); process monitoring; selective laser melting (SLM); thermocouples; thermography |
Volume: | 10 |
Issue: | 11 |
Source: | Mohr, G., Nowakowski, S., Altenburg, S., Maierhofer, C., & Hilgenberg, K. (2020). Experimental Determination of the Emissivity of Powder Layers and Bulk Material in Laser Powder Bed Fusion Using Infrared Thermography and Thermocouples Metals. 10 (11), 1546. |
Faculties an central facilities: | Fachbereich Ingenieur- und Naturwissenschaften |
Dewey Decimal Classification: | 6 Technik, Medizin, angewandte Wissenschaften / 62 Ingenieurwissenschaften / 620 Ingenieurwissenschaften und zugeordnete Tätigkeiten |
Licence (German): | Creative Commons - CC BY - Namensnennung 4.0 International |