Analytical modeling and experimental validation of powder stream distribution during direct energy deposition

Liu, Zhichao; Zhang, Hongchao; Peng, Shitong; Kim, Hoyeol; Du, Dong; Cong, Weilong

doi:10.1016/j.addma.2019.100848

Cited by 26 publications

(11 citation statements)

References 31 publications

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Section: Resultssupporting

confidence: 81%

“…Hence, the powder flow can be divided into three different regimes: (a) Gaussian stream, (b) Transition stream, and (c) Annular stream. This study displays a good correlation with the experimental findings given in [37]. Figure 7 shows a comparison between the current analytical modelling with the numerical simulations of Emamian et al [34] and Duan et al [35], and experimental results of Peyre et al [36], with the emphasis on average peak temperature value, in case of LMD deposition process.…”

Section: Resultssupporting

confidence: 78%

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Three-Jet Powder Flow and Laser–Powder Interaction in Laser Melting Deposition: Modelling Versus Experimental Correlations

Mahmood

Popescu

Oane

et al. 2020

Metals

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Powder flow and temperature distribution are recognized as essential factors in the laser melting deposition (LMD) process, which affect not only the layer formation but also its characteristics. In this study, two mathematical models were developed. Initially, the three-jet powder flow in the Gaussian shape was simulated for the LMD process. Next, the Gaussian powder flow was coaxially added along with the moving laser beam to investigate the effect of powder flow on temperature distribution at the substrate. The powder particles’ inflight and within melt-pool heating times were controlled to avoid vapors or plasma formation due to excessive heat. Computations were carried out via MATLAB software. A high-speed imaging camera was used to monitor the powder stream distribution, experimentally, while temperature distribution results were compared with finite element simulations and experimental analyses. A close correlation was observed among analytical computation, numerical simulations, and experimental results. An investigation was conducted to investigate the effect of the focal point position on powder stream distribution. It was found that the focal point position plays a key role in determining the shape of the powder stream, such that an increment in the distance from the focus point will gradually transform the powder stream from the Gaussian to Transition, and from the Transition to Annular streams. By raising the powder flow rate, the attenuation ratio prevails in the LMD process, hence, decreasing the laser energy density arriving at the substrate. The computations indicate that, if the particle’s heating temperature surpasses the boiling point, a strong possibility exists for vapors and plasma formation. Consequently, an excessive amount of laser energy is absorbed by the produced vapors and plasma, thus impeding the deposition process.

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Section: Resultssupporting

confidence: 81%

Section: Resultssupporting

confidence: 78%

Three-Jet Powder Flow and Laser–Powder Interaction in Laser Melting Deposition: Modelling Versus Experimental Correlations

Mahmood

Popescu

Oane

et al. 2020

Metals

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“…In their work, the powder flow density was found to follow an annular distribution above and below the focal plan, which differs from the nozzle's size. Liu et al [13] placed the processing head statically above cylindrical containers with specific concentric holes of different diameters [14] and showed that the powder flow keeps pitot ian distribution within a +/− 2 mm distance to the focal plan. All these experimental studies allow a more or less accurate description of the powder jet structure and density, without clearly establishing a dependency on process parameters or on the nozzle design.…”

Section: Experimental Conditionsmentioning

confidence: 99%

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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“…where c p denotes the specific heat capacity of a particle, v p denotes the particle velocity, denotes the powder spatial mass concentration, T m denotes the melting temperature, and T 0 denotes the room temperature. For the heated powder flux with a 2D Gaussian distribution, previous literature suggests that an exponential distribution can describe the powder stream Gauss concentration under a coaxial nozzle [18]. The powder concentration x ′ , y ′ caused by powder feed rate F within a circular area with radius r is given by the following equation [18]:…”

Section: Temperature Fieldmentioning

confidence: 99%

Analytical solutions for rapid prediction of transient temperature field in powder-fed laser directed energy deposition based on different heat source models

et al. 2021

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The present paper aims to develop an effective analytical solution for laser directed energy deposition through powder feeding (LDED-PF). Three heat source models are introduced and compared to analytically describe the transient temperature field in the process. These models are known as point (1D) heat source, circular (2D) heat source, and semi-spherical (3D) heat source. For the validation tests, single-track deposition of Ti-5Al-5 V-5Mo-3Cr powder on Ti-6Al-4 V substrate is conducted at different laser powers, scanning speeds, and powder feed rates. The temperature field is validated using the measurement of melt-pool/deposit geometry. In order to improve the model fidelity, the enhanced thermal diffusivity and heat source radius are calibrated in terms of linear functions. It is found that the 2D Gaussian heat source model, which is in agreement with the underlying physics of the process, establishes a better match between the predicted and experimental data. The developed model only needs the basic information from the LDED-PF setup and material thermal properties to predict the thermal history and melt-pool geometry at different processing parameters.

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Analytical modeling and experimental validation of powder stream distribution during direct energy deposition

Cited by 26 publications

References 31 publications

Three-Jet Powder Flow and Laser–Powder Interaction in Laser Melting Deposition: Modelling Versus Experimental Correlations

Three-Jet Powder Flow and Laser–Powder Interaction in Laser Melting Deposition: Modelling Versus Experimental Correlations

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

Analytical solutions for rapid prediction of transient temperature field in powder-fed laser directed energy deposition based on different heat source models

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