Numerical Simulations - A Versatile Approach for Better Understanding Dynamics in Laser Material Processing

Otto, Andreas; Koch, Holger; Leitz, Karl-Heinz; Schmidt, Michael

doi:10.1016/j.phpro.2011.03.003

Cited by 112 publications

(34 citation statements)

References 10 publications

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“…Over the last two decades, literature has been reported on sophisticated modeling approaches [7][8][9][10][11][12] and experimental techniques [13][14][15][16][17][18] to study the dynamics of the keyhole phenomena during high power density fusion welding technologies, such as laser welding. From a modeling perspective, the interface deformation that leads to keyhole formation during the laser welding has been studied intensively using various numerical techniques, including a volume-of-fluid approach [13,14] and a level set method. [9] Recently, Courtois et al [9] have proposed a level set approach and included the influence of the electromagnetic field to accurately capture the energy reflection inside the keyhole.…”

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confidence: 99%

An Integrated Modeling Approach for Predicting Process Maps of Residual Stress and Distortion in a Laser Weld: A Combined CFD–FE Methodology

Turner

Panwisawas

Sovani

et al. 2016

Metall Mater Trans B

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Laser welding has become an important joining methodology within a number of industries for the structural joining of metallic parts. It offers a high power density welding capability which is desirable for deep weld sections, but is equally suited to performing thinner welded joints with sensible amendments to key process variables. However, as with any welding process, the introduction of severe thermal gradients at the weld line will inevitably lead to process-induced residual stress formation and distortions. Finite element (FE) predictions for weld simulation have been made within academia and industrial research for a number of years, although given the fluid nature of the molten weld pool, FE methodologies have limited capabilities. An improvement upon this established method would be to incorporate a computational fluid dynamics (CFD) model formulation prior to the FE model, to predict the weld pool shape and fluid flow, such that details can be fed into FE from CFD as a starting condition. The key outputs of residual stress and distortions predicted by the FE model can then be monitored against the process variables input to the model. Further, a link between the thermal results and the microstructural properties is of interest. Therefore, an empirical relationship between lamellar spacing and the cooling rate was developed and used to make predictions about the lamellar spacing for welds of different process parameters. Processing parameter combinations that lead to regions of high residual stress formation and high distortion have been determined, and the impact of processing parameters upon the predicted lamellar spacing has been presented.

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mentioning

confidence: 99%

An Integrated Modeling Approach for Predicting Process Maps of Residual Stress and Distortion in a Laser Weld: A Combined CFD–FE Methodology

Turner

Panwisawas

Sovani

et al. 2016

Metall Mater Trans B

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“…Apparently, the hole diameter reveals the same dependence on focus position as the beam diameter and both range similarly by size. Numerical deviations between the hole diameter and the beam diameter are attributed to melt ejection (Otto et al, 2011). Nonetheless, based on the observed correlation between hole diameter and beam diameter it is possible to adjust the hole diameter easily by the focus position.…”

Section: Minimum Drilling Timementioning

confidence: 99%

“…This effect is based on plasma with a temperature gradient which keeps the beam diameter constant. According to Otto et al (2011) reflections inside the hole can result in a reduced beam spread for materials with a high reflection at larger angles of incidence. A further effect is the decreasing power density with increasing laser beam diameter.…”

Section: Minimum Drilling Timementioning

confidence: 99%

Rapid micro hole laser drilling in ceramic substrates using single mode fiber laser

Adelmann

Hellmann

2015

Journal of Materials Processing Technology

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“…Several simulation approaches for laser material processing consider fluid-dynamic effects occurring in the heat affected zone [12][13][14]. In this sense, electron beam melting and laser beam melting are specifically investigated in [15][16][17].…”

Section: Microscale Simulationmentioning

confidence: 99%

Investigations on Temperature Fields during Laser Beam Melting by Means of Process Monitoring and Multiscale Process Modelling

Schilp

Seidel

Krauss

et al. 2014

Advances in Mechanical Engineering

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Process monitoring and modelling can contribute to fostering the industrial relevance of additive manufacturing. Process related temperature gradients and thermal inhomogeneities cause residual stresses, and distortions and influence the microstructure. Variations in wall thickness can cause heat accumulations. These occur predominantly in filigree part areas and can be detected by utilizing off-axis thermographic monitoring during the manufacturing process. In addition, numerical simulation models on the scale of whole parts can enable an analysis of temperature fields upstream to the build process. In a microscale domain, modelling of several exposed single hatches allows temperature investigations at a high spatial and temporal resolution. Within this paper, FEMbased micro-and macroscale modelling approaches as well as an experimental setup for thermographic monitoring are introduced. By discussing and comparing experimental data with simulation results in terms of temperature distributions both the potential of numerical approaches and the complexity of determining suitable computation time efficient process models are demonstrated. This paper contributes to the vision of adjusting the transient temperature field during manufacturing in order to improve the resulting part's quality by simulation based process design upstream to the build process and the inline process monitoring.

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Numerical Simulations - A Versatile Approach for Better Understanding Dynamics in Laser Material Processing

Cited by 112 publications

References 10 publications

An Integrated Modeling Approach for Predicting Process Maps of Residual Stress and Distortion in a Laser Weld: A Combined CFD–FE Methodology

An Integrated Modeling Approach for Predicting Process Maps of Residual Stress and Distortion in a Laser Weld: A Combined CFD–FE Methodology

Rapid micro hole laser drilling in ceramic substrates using single mode fiber laser

Investigations on Temperature Fields during Laser Beam Melting by Means of Process Monitoring and Multiscale Process Modelling

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