Diagnostics of powder particle parameters under laser radiation in direct material deposition

Sergachev, D. V.; Ковалев, О. Б.; Grachev, G. N.; Смирнов, А. Л.; Pinaev, P. A.

doi:10.1016/j.optlastec.2019.105842

Cited by 9 publications

(1 citation statement)

References 13 publications

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“…This effect is even more pronounced with nozzle A and B, for which the mean particle velocities never exceed 2.5 m/s, while the gas velocity field was, respectively, 10 and 3 times faster. Finally, similar to the results published by Kovaleva et al [28] or Sergachev et al [29], a limited number of particles were shown to accelerate under laser irradiation, due to severe heating, vaporization and corresponding recoil pressure. However, this effect was shown to be negligible in our case, with only a few detected particles enlightening, and subsequent high velocities.…”

Section: Vpsupporting

confidence: 86%

Experimental and Numerical Analysis of Gas/Powder Flow for Different LMD Nozzles

Ferreira

Dal

Colin

et al. 2020

Metals

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The Laser Metal Deposition (LMD) process is an additive manufacturing method, which generates 3D structures through the interaction of a laser beam and a gas/powder stream. The stream diameter, surface density and focal plan position affect the size, efficiency and regularity of the deposit tracks. Therefore, a precise knowledge of the gas/powder streams characteristics is essential to control the process and improve its reliability and reproducibly for industrial applications. This paper proposes multiple experimental techniques, such as gas pressure measurement, optical and weighting methods, to analyze the gas and particle velocity, the powder stream diameter, its focal plan position and density. This was carried out for three nozzle designs and multiple gas and powder flow rates conditions. The results reveal that (1) the particle stream follows a Gaussian distribution while the gas velocity field is closer to a top hat one; (2) axial, carrier and shaping gas flow significantly impact the powder stream’s focal plan position; (3) only shaping gas, powder flow rates and nozzle design impact the powder stream diameter. 2D axisymmetric models of the gas and powder streams with RANS turbulent model are then performed on each of the three nozzles and highlight good agreements with experimental results but an over-estimation of the gas velocity by pressure measurements.

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Section: Vpsupporting

confidence: 86%