A method for identification and quantification of thermal lensing in powder bed fusion

S. A. Andersen*, E. H. Valente, V. K. Nadimpalli, H. N. Hansen, D. B. Pedersen

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsResearchpeer-review

    259 Downloads (Pure)

    Abstract

    With the increase in use of L-PBF for functional components, an increase in productivity demands higher laser power and continuous operation. However, both these factors can affect the optics involved. The principal components of a Laser Powder Bed Fusion system are the galvanometer mirrors and the focusing lens.
    In the present work a method for identification and quantification of thermal lensing is proposed. Laser powder bed fusion experiments of stainless steel 316L powder was carried out at varying scan speeds and scan strategies in order to study the effects, of long exposure times, on the quality of single layer scans.
    It was observed that the heating of silver-coated mirrors under continuous exposure led to a significant decrease in the beam quality as evidenced by weld track widening and loss in depth of melt pool penetration. Power measurements conducted at various locations along the beam path indicated that the mirrors were absorbing up to 42 % of the total power coming from the laser while also defocusing the beam.
    Thus demonstrating the importance of including identification and quantification of thermal influence and possible instability of the optical elements as cause for irregular weld tracks.
    Original languageEnglish
    Title of host publicationProceedings of the 19th International Conference and Exhibition (EUSPEN 2019)
    EditorsC. Nisbet, R. K. Leach, D. Billington, D. Phillips
    PublisherThe European Society for Precision Engineering and Nanotechnology
    Publication date2019
    Pages230-233
    ISBN (Electronic)978-099577514-5
    Publication statusPublished - 2019
    Event19th International Conference of the european Society for Precision Engineering and Nanotechnology (euspen 19) - Bilbao, Spain
    Duration: 3 Jun 20197 Jun 2019

    Conference

    Conference19th International Conference of the european Society for Precision Engineering and Nanotechnology (euspen 19)
    Country/TerritorySpain
    CityBilbao
    Period03/06/201907/06/2019

    Fingerprint

    Dive into the research topics of 'A method for identification and quantification of thermal lensing in powder bed fusion'. Together they form a unique fingerprint.

    Cite this