# A Comparative Study and Introduction of a New Heat Source Model for the Macro-Scale Numerical Simulation of Selective Laser Melting Technology

## TL;DR

A new heat source model for laser melting simulations improves accuracy in predicting melt pool dimensions, helping optimize 3D printing processes.

## Contribution

A dynamic heat source model combining Gaussian surface and rotating body heat sources is introduced, offering higher prediction accuracy for melt pool dimensions.

## Key findings

- The dynamic heat source model achieves 1.0% and 5.5% relative errors in predicting melt pool width and depth compared to experiments.
- The model's melt pool depth is 17% greater than that of the combined heat source model.
- The model resolves overestimation of melt pool width and underestimation of depth by traditional models.

## Abstract

What are the main findings?
A three-dimensional transient heat transfer finite element model was constructed using APDL to investigate the temperature distribution and molten pool characteristics under four heat source models.A dynamic model combining Gaussian surface and rotating body heat sources was proposed, enabling dynamic allocation of laser energy absorption ratios between the powder surface layer and substrate depth.Predicted values from the dynamic heat source exhibit relative errors of only 1.0% (width) and 5.5% (depth) compared to experimental data, demonstrating high prediction accuracy.

A three-dimensional transient heat transfer finite element model was constructed using APDL to investigate the temperature distribution and molten pool characteristics under four heat source models.

A dynamic model combining Gaussian surface and rotating body heat sources was proposed, enabling dynamic allocation of laser energy absorption ratios between the powder surface layer and substrate depth.

Predicted values from the dynamic heat source exhibit relative errors of only 1.0% (width) and 5.5% (depth) compared to experimental data, demonstrating high prediction accuracy.

What are the implications of the main findings?
Resolves the issue of traditional surface/volume heat source models overestimating melt pool width and underestimating melt pool depth, enhancing the reliability of SLM numerical simulations.Provides an effective simulation method for temperature field and melt pool evolution under different laser parameters, enriching SLM heat source modeling theory.High-precision melt pool prediction offers critical theoretical support for SLM process parameter optimization and porosity defect suppression.

Resolves the issue of traditional surface/volume heat source models overestimating melt pool width and underestimating melt pool depth, enhancing the reliability of SLM numerical simulations.

Provides an effective simulation method for temperature field and melt pool evolution under different laser parameters, enriching SLM heat source modeling theory.

High-precision melt pool prediction offers critical theoretical support for SLM process parameter optimization and porosity defect suppression.

Selective Laser Melting (SLM), as a common metal additive manufacturing (AM) technology, achieves high-precision complex part formation by layer-by-layer melting of metal powder using a laser. However, the dynamic behavior of the melt pool during the SLM process is influenced by the heat source model, which is crucial for suppressing porosity defects and optimizing process parameters, directly determining the reliability of numerical simulations. To address the issue of traditional surface heat source models overestimating the melt pool width and volume heat source models underestimating the melt pool depth, this study constructs a three-dimensional transient heat conduction finite element model based on ANSYS Parametric Design Language (APDL) to simulate the evolution of the temperature field and melt pool geometry under different laser parameters. First, the temperature fields and melt pool morphology and dimensions of four heat source models—Gaussian surface heat source, volumetric heat source models (rotating Gaussian volumetric heat source, double ellipsoid heat source), and a combined heat source model—were investigated. Subsequently, a dynamic heat source model was proposed, combining a Gaussian surface heat source with a rotating volumetric heat source. By dynamically allocating the laser energy absorption ratio between the powder surface layer and the substrate depth, the influence of this heat source model on melt pool size was explored and compared with other heat source models. The results show that under the dynamic heat source, the melt pool width and depth are 128.6 μm and 63.13 μm, respectively. The melt pool width is significantly larger compared to other heat source models, and the melt pool depth is about 17% greater than that of the combined heat source model. At the same time, the predicted melt pool width and depth under this heat source model have relative errors of 1.0% and 5.5% compared to the experimental measurements, indicating that this heat source model has high accuracy in predicting the melt pool’s lateral dimensions and can effectively reflect the actual melt pool morphology during processing.