Spot pattern welding scanning strategy for sensor embedding and residual stress reduction in laser-foil-printing additive manufacturing
Abstract
Purpose
This paper aims to present spot pattern welding (SPW) as a scanning strategy for laser-foil-printing (LFP) additive manufacturing (AM) in place of the previously used continuous pattern welding (CPW) (line-raster scanning). The SPW strategy involves generating a sequence of overlapping spot welds on the metal foil, allowing the laser to form dense and uniform weld beads. This in turn reduces thermal gradients, promotes material consolidation and helps mitigate process-related risks such as thermal cracking, porosity, keyholing and Marangoni effects.
Design/methodology/approach
304L stainless steel (SS) feedstock is used to fabricate test specimens using the LFP system. Imaging techniques are used to examine the melt pool dimensions and layer bonding. In addition, the parts are evaluated for residual stresses, mechanical strength and grain size.
Findings
Compared to CPW, SPW provides a more reliable heating/cooling relationship that is less dependent on part geometry. The overlapping spot welds distribute heat more evenly, minimizing the risk of elevated temperatures during the AM process. In addition, the resulting dense and uniform weld beads contribute to lower residual stresses in the printed part.
Originality/value
To the best of the authors’ knowledge, this is the first study to thoroughly investigate SPW as a scanning strategy using the LFP process. In general, SPW presents a promising strategy for securing embedded sensors into LFP parts while minimizing residual stresses.
Keywords
Acknowledgements
This work was supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001). This work is approved for unlimited release under LA-UR-24–20427.
Statements and declarations.
Conflicts of interest/competing interests: The authors declare that they have no conflict of interest.
Author contributions: Conceptualization, design, material preparation, experimental work, data collection and analysis were performed by Tunay Turk. All the authors contributed to the investigation. The first draft of the manuscript was written by Tunay Turk, and all the authors contributed to review and editing of the manuscript. Jonghyun Park and Ming C. Leu were supervisors for this study. Ming C. Leu is responsible for funding acquisition. All the authors read and approved the final manuscript.
Availability of data and material: The raw/processed data required to reproduce these findings will be available on email request.
Code availability: Not applicable.
Ethics approval: The manuscript contains original ideas which have never been published before in other journals.
Consent to participation: This study is not a human transplantation study. No consent needed for this paper.
Consent for publication: The authors declare their consent for publication.
Citation
Turk, T., Dominguez, C.E., Sutton, A.T., Bernardin, J.D., Park, J. and Leu, M.C. (2024), "Spot pattern welding scanning strategy for sensor embedding and residual stress reduction in laser-foil-printing additive manufacturing", Rapid Prototyping Journal, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/RPJ-01-2024-0042
Publisher
:Emerald Publishing Limited
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