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Characterizing light engine uniformity and its influence on LCD-based vat photopolymerization printing

Published

Author(s)

Benjamin Caplins, Callie Higgins, Thomas Kolibaba, Uwe Arp, C Cameron Miller, Dianne L. Poster, Clarence Zarobila, Yuqin Zong, Jason Killgore

Abstract

Vat photopolymerization (VP) is a rapidly growing category of additive manufacturing. As VP methods mature the expectation is that the quality of printed parts will be highly reproducible. At present, detailed characterization of the light engines used in LCD-based VP systems is lacking and so it is unclear if they are built to sufficiently tight tolerances to meet the current and/or future needs of additive manufacturing. Herein, we map the irradiance, spectral characteristics, and optical divergence of a nominally 405 nm LCD-based VP light engine. We find that there is notable variation in all of these properties as a function of position on the light engine that cause changes in extent of polymerization and surface texture. We further demonstrate through a derived photon absorption figure of merit and through printed test parts that the spatial heterogeneity observed in the light engine is significant enough to affect part fidelity. These findings help to explain several possible causes of variable part quality and also highlight the need for improved optical performance on LCD-based VP printers.
Citation
Additive Manufacturing
Issue
62

Keywords

Vat Photopolymerization, Masked Stereolithography (MSLA), Liquid Crystal Display (LCD), 3D Printing, Additive Manufacturing

Citation

Caplins, B. , Higgins, C. , Kolibaba, T. , Arp, U. , Miller, C. , Poster, D. , Zarobila, C. , Zong, Y. and Killgore, J. (2022), Characterizing light engine uniformity and its influence on LCD-based vat photopolymerization printing, Additive Manufacturing, [online], https://doi.org/10.1016/j.addma.2022.103381, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935474 (Accessed May 20, 2024)

Issues

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Created December 27, 2022, Updated January 3, 2023