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Title: Characterization of temperature-dependent optical material properties of polymer powders

In former works, the optical material properties of different polymer powders used for Laser Beam Melting (LBM) at room temperature have been analyzed. With a measurement setup using two integration spheres, it was shown that the optical material properties of polymer powders differ significantly due to multiple reflections within the powder compared to solid bodies of the same material. Additionally, the absorption behavior of the single particles shows an important influence on the overall optical material properties, especially the reflectance of the powder bed. Now the setup is modified to allow measurements at higher temperatures. Because crystalline areas of semi-crystalline thermoplastics are mainly responsible for the absorption of the laser radiation, the influence of the temperature increase on the overall optical material properties is analyzed. As material, conventional polyamide 12 and polypropylene as new polymer powder material, is used. By comparing results at room temperature and at higher temperatures towards the melting point, the temperature-dependent optical material properties and their influence on the beam-matter interaction during the process are discussed. It is shown that the phase transition during melting leads to significant changes of the optical material properties of the analyzed powders.
Authors:
 [1] ;  [2] ;  [2] ; ; ;  [1] ;  [2] ;  [1] ;  [2] ;  [2] ;  [2]
  1. Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany)
  2. (Germany)
Publication Date:
OSTI Identifier:
22391882
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1664; Journal Issue: 1; Conference: PPS-30: 30. International Conference of the Polymer Processing Society, Cleveland, OH (United States), 6-12 Jun 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; COMPARATIVE EVALUATIONS; LASER RADIATION; MELTING; MELTING POINTS; POLYAMIDES; POLYPROPYLENE; POWDERS; REFLECTION; SOLIDS; TEMPERATURE DEPENDENCE; THERMOPLASTICS