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Keyhole pores reduction in laser powder bed fusion additive manufacturing of nickel alloy 625

Published

Author(s)

Ho Yeung, Felix Kim, Alkan Donmez, Jorge Neira

Abstract

The effect of the scan strategy on internal porosity is investigated on a custom-built laser powder bed fusion additive manufacturing testbed. Two different scan strategies are compared: constant laser power and constant laser power density. The constant laser power density is achieved by continuously proportioning the laser power to the scanning speed. Two nickel alloy 625 (IN625) cubic parts of identical geometry were built. The parts were examined with X-ray computed tomography (XCT) for porosity, and a 67 % drop was found for the part built with a constant power density scan strategy. Digital twins of process monitoring were created from laser position measurements and coaxial meltpool imaging. Techniques were developed to analyze the digital twins and correlate them to the XCT measurements. The overall porosity reduction in the part created using the constant power density scan strategy is explained as the reduction in keyhole pore formation often caused by high laser power density.
Citation
International Journal of Machine Tools & Manufacture

Keywords

Additive manufacturing, scan strategies, meltpool image registration, X-ray computed tomography, digital twin

Citation

Yeung, H. , Kim, F. , Donmez, A. and Neira, J. (2022), Keyhole pores reduction in laser powder bed fusion additive manufacturing of nickel alloy 625, International Journal of Machine Tools & Manufacture, [online], https://doi.org/10.1016/j.ijmachtools.2022.103957, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932372 (Accessed April 14, 2024)
Created October 26, 2022, Updated December 9, 2022