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Proceedings Paper

Beam shape optimization for laser powder beam fusion additive manufacturing (Conference Presentation)
Author(s): Alexander M. Rubenchik; S. Khairallah; S. Wu; G. Guss; T. Roehling; J. McKeown; M. Matthews

Paper Abstract

Laser Powder Beam Fusion (LPBF)processes use laser beams to selectively melt powder layers and build three dimensional parts layer by layer. Usually, the beam has a Gaussian profile and the melt temperature peaks near the beam center. For typical conditions this temperature is well over the boiling point and drives intensive evaporation. Evaporation-driven recoil momentum can produce detrimental material spattering and keyhole porosity. Evaporation itself consumes a significant amount of energy thus degrading the process efficiency. It can therefore be beneficial to alter the beam shape so as to have the temperature distribution in the melt pool close to that of a flat top. We determined with a simple thermal model the beam shape providing a relatively flat temperature distribution . The optimal is found to be doughnut mode-like, skewed in the scan direction. We did high fidelity simulations of the melt pool produced by the optimized beam and evaluated the possible benefits, including the efficiency increase. We started the experiments with doughnut shape beam far from the optimal but also far from the Gaussian one. The experimental data will be compared with simulation results. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Paper Details

Date Published: 4 March 2019
PDF
Proc. SPIE 10909, Laser 3D Manufacturing VI, 109090B (4 March 2019); doi: 10.1117/12.2511202
Show Author Affiliations
Alexander M. Rubenchik, Lawrence Livermore National Lab. (United States)
S. Khairallah, Lawrence Livermore National Lab. (United States)
S. Wu, Lawrence Livermore National Lab. (United States)
G. Guss, Lawrence Livermore National Lab. (United States)
T. Roehling, Lawrence Livermore National Lab. (United States)
J. McKeown, Lawrence Livermore National Lab. (United States)
M. Matthews, Lawrence Livermore National Lab. (United States)


Published in SPIE Proceedings Vol. 10909:
Laser 3D Manufacturing VI
Bo Gu; Henry Helvajian; Hongqiang Chen, Editor(s)

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