Multiscale Modeling of Powder Bed–Based Additive Manufacturing

Markl, Matthias; Körner, Carolin

doi:10.1146/annurev-matsci-070115-032158

Cited by 329 publications

(152 citation statements)

References 102 publications

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“…It is straight forward to extend the scheme to three dimensions. The VOF in combination with the lattice Boltzmann method has been proven to be very effective when it comes to simulating complex geometries like a powder bed in additive manufacturing [9][10][11]. To represent a given geometry, the space in the simulation domain is discretized into cells.…”

Section: Methodsmentioning

confidence: 99%

Modeling of Laser Beam Absorption in a Polymer Powder Bed

et al. 2018

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Abstract:In order to understand the absorption characteristic, a ray trace model is developed by taking into account the reflection, absorption and refraction. The ray paths are resolved on a sub-powder grid. For validation, the simulation results are compared to analytic solutions of the irradiation of the laser beam onto a plain surface. In addition, the absorptance, reflectance and transmittance of PA12 powder layers measured by an integration sphere setup are compared with the numerical results of our model. It is shown that the effective penetration depth can be lower than the penetration depth in bulk material for polymer powders and, therefore, can increase the energy density at the powder bed surface. The implications for modeling of the selective laser sintering (SLS) process and the processability of fine powder distributions and high powder bed densities are discussed.

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Section: Methodsmentioning

confidence: 99%

Modeling of Laser Beam Absorption in a Polymer Powder Bed

et al. 2018

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“…The change in volume during melting of the powder [42,46,47] and layer built-up were modeled in some studies [37,41,48,49]. We refer the interested readers to review papers on numerical modeling and simulation of AM for more information [50][51][52].…”

Section: Melt Pool Modeling Through Fem Based Thermal Modelingmentioning

confidence: 99%

Multivariate Calibration and Experimental Validation of a 3D Finite Element Thermal Model for Laser Powder Bed Fusion Metal Additive Manufacturing

Mahmoudi

Tapia

Karayagiz

et al. 2018

Integr Mater Manuf Innov

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Metal additive manufacturing (AM) typically suffers from high degree of variability in the properties/performance of the fabricated parts, particularly due to the lack of understanding and control over the physical mechanisms that govern microstructure formation during fabrication. This paper directly addresses an important problem in AM: the determination of the thermal history of the deposited material. Any attempts to link process to microstructure in AM would need to consider the thermal history of the material. In-situ monitoring only provides partial information and simulations may be necessary to have a comprehensive understanding of the thermo-physical conditions to which the deposited material is subjected. We address this in the present work through linking thermal models to experiments via a computationally efficient surrogate modeling approach based on multivariate Gaussian processes (MVGPs). The MVGPs are then used to calibrate the free parameters of the multi-physics models against experiments, sidestepping the use of prohibitively expensive Monte Carlo-based calibration. This framework thus makes it possible to efficiently evaluate the impact of varying process parameter inputs on the characteristics of the melt pool during AM. We demonstrate the framework on the calibration of a thermal model for Laser-Powder Bed Fusion AM of Ti-6Al-4V against experiments carried out over a wide window in the process parameter space. While this work deals with problems related to AM, its applicability is wider as the proposed framework could potentially be used in many other ICME-based problems where it is essential to link expensive computational materials science models to available experimental data.

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“…These state-of-the-art models can become very cumbersome to use for more general problems, so Markl and Korner [44] developed a numerical model on multiple length and time scales to model and describe various aspects of the process across numerous applications and parameter sets. Carefully-designed experiments were used to tune and verify the numerical model in real time in order to provide a more comprehensive understanding of the underlying physics of the process.…”

Section: General Slm/dmls Process Modelsmentioning

confidence: 99%

Overhanging Features and the SLM/DMLS Residual Stresses Problem: Review and Future Research Need

2017

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Abstract:A useful and increasingly common additive manufacturing (AM) process is the selective laser melting (SLM) or direct metal laser sintering (DMLS) process. SLM/DMLS can produce full-density metal parts from difficult materials, but it tends to suffer from severe residual stresses introduced during processing. This limits the usefulness and applicability of the process, particularly in the fabrication of parts with delicate overhanging and protruding features. The purpose of this study was to examine the current insight and progress made toward understanding and eliminating the problem in overhanging and protruding structures. To accomplish this, a survey of the literature was undertaken, focusing on process modeling (general, heat transfer, stress and distortion and material models), direct process control (input and environmental control, hardware-in-the-loop monitoring, parameter optimization and post-processing), experiment development (methods for evaluation, optical and mechanical process monitoring, imaging and design-of-experiments), support structure optimization and overhang feature design; approximately 143 published works were examined. The major findings of this study were that a small minority of the literature on SLM/DMLS deals explicitly with the overhanging stress problem, but some fundamental work has been done on the problem. Implications, needs and potential future research directions are discussed in-depth in light of the present review.

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Multiscale Modeling of Powder Bed–Based Additive Manufacturing

Cited by 329 publications

References 102 publications

Modeling of Laser Beam Absorption in a Polymer Powder Bed

Modeling of Laser Beam Absorption in a Polymer Powder Bed

Multivariate Calibration and Experimental Validation of a 3D Finite Element Thermal Model for Laser Powder Bed Fusion Metal Additive Manufacturing

Overhanging Features and the SLM/DMLS Residual Stresses Problem: Review and Future Research Need

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