This tutorial demonstrates a multi-layer powder bed fusion workflow using AdditiveFOAM.

The purpose of this tutorial is to show how to run repeated layer simulations with a powder layer using a transient volumetric heat source and depth-dependent absorption.

This tutorial uses the IN625 material configuration from $ADDITIVEFOAM_ETC/materials/IN625.cfg.

Build AdditiveFOAM against OpenFOAM-14, source both environments, and run:

source /path/to/OpenFOAM-14/etc/bashrc
source /path/to/AdditiveFOAM/etc/bashrc
cd "$ADDITIVEFOAM_TUTORIALS/multiLayerPBF"
./Allrun

Use ./Allclean to remove generated layer and result files.

The heat source setup follows the dynamic volumetric heat source formulation cited in the tutorial dictionary:

J. Coleman, G.L. Knapp, B. Stump, M. Rolchigo, K. Kincaid, A. Plotkowski,
A dynamic volumetric heat source model for laser additive manufacturing,
Additive Manufacturing (2024), https://doi.org/10.1016/j.addma.2024.104531.

The important files for this tutorial are:

constant/heatSourceDict

Defines the moving heat source and absorption model.

constant/scanPath

Defines the laser path, laser power, and scan speed or dwell time for the current layer.

system/extrudeMeshDict

Defines the mesh extrusion behavior used by the multi-layer workflow.

The tutorial uses one heat source:

sources (beam);

The source uses the Kelly absorption model and a transient modifiedSuperGaussian heat source:

beam
{
    pathName            scanPath;

    absorptionModel     Kelly;

    KellyCoeffs
    {
        geometry        cone;
        eta0            0.28;
        etaMin          0.35;
    }

    heatSourceModel     modifiedSuperGaussian;

    modifiedSuperGaussianCoeffs
    {
        dimensions      (40.0e-6 40.0e-6 30e-6);
        m               2.72;
        k               7.95;
        transient       true;
        nPoints         (10 10 10);
    }
}

geometry

Absorption geometry used by the Kelly absorption model.

eta0

Fresnel absorption of the liquid metal.

etaMin

Effective absorption in the conduction regime, used when the melt-pool aspect ratio is less than aspectRatioSwitch.

aspectRatioSwitch

Optional aspect-ratio cutoff for switching between etaMin and the Kelly multiple-reflection model. If omitted, the cutoff is 1.0.

dimensions

Sets the heat source dimensions. The third component is the initial projected depth.

m and k

Shape parameters for the modifiedSuperGaussian heat source.

transient

When true, AdditiveFOAM updates the heat source depth using the material liquidus from constant/transportProperties.

nPoints

Controls sub-cell sampling resolution used when integrating the heat source over mesh cells.

Optional AdditiveFOAM function objects are listed in system/controlDict and are controlled by their enabled entries. To write additional data, set the selected function object entry to:

enabled true;

To disable a function object, set:

enabled false;

meltPoolDimensions writes melt-pool length, width, and depth data. solidificationData writes solidification events for CET analysis. ExaCA writes temperature history data for ExaCA input files.

The Allrun script calls the reconstruction helpers after all layers finish:

reconstructExaCAData

reconstructSolidificationData

These commands detect layer*/ directories and exit quietly when no matching function object data were written.

After reconstructing the temperature data, run ExaCA from the base case directory so that the layerwise relative paths in ExaCA/input.json resolve correctly:

mpirun -np <nProcs> <path-to-ExaCA> ExaCA/input.json

Plot absorbed power from the layer solver logs with:

plotPower layer0 layer1

Plot melt-pool dimensions:

plotDimensions layer0 layer1

Plot CET data:

plotCET layer0 layer1