A computationally efficient thermal model for selective laser melting

Abstract Predicting the part thermal history during the selective laser melting (SLM) process is critical to understand the influence of the process parameters to the part quality. Existing finite element based thermal analysis is mainly associated with simplifications in mesh configuration, heat source model, and domain size. The proposed work presents an efficient adaptive remeshing technique that enables part-scale SLM process simulations and helps reduce model size without sacrificing accuracy. The proposed work enables the part-scale simulation computationally efficient using existing commercial solvers. In this paper, the SLM process simulation for an entire part was developed considering different process parameters. The model predicts the influence of the process parameters on part thermal history, melt pool statistics, and lack-of-fusion porosity. The predicted results find an agreement with the experimental results in literature. Furthermore, the remeshing technique is demonstrated to be more computationally efficient than the existing element death and birth approach and also shows clear advantages compared with existing adaptive remeshing approaches.

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Computationally efficient thermal-mechanical modelling of selective laser melting

10.1063/1.5008031 ◽

2017 ◽

Cited By ~ 2

Author(s):

Yabin Yang ◽

Can Ayas

Keyword(s):

Selective Laser Melting ◽

Computationally Efficient ◽

Laser Melting ◽

Mechanical Modelling

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Feedback Control of Melt Pool Area in Selective Laser Melting Additive Manufacturing Process

Processes ◽

10.3390/pr9091547 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1547

Author(s):

Syed Zahid Hussain ◽

Zareena Kausar ◽

Zafar Ullah Koreshi ◽

Shakil R. Sheikh ◽

Hafiz Zia Ur Rehman ◽

...

Keyword(s):

Additive Manufacturing ◽

Feedback Control ◽

Selective Laser Melting ◽

Manufacturing Process ◽

Thermal Model ◽

Laser Melting ◽

Powder Bed ◽

Melt Pool ◽

Melt Pool Size ◽

Pool Area

Selective laser melting (SLM), a metal powder fusion additive manufacturing process, has the potential to manufacture complex components for aerospace and biomedical implants. Large-scale adaptation of these technologies is hampered due to the presence of defects such as porosity and part distortion. Nonuniform melt pool size is a major cause of these defects. The melt pool size changes due to heat from the previous powder bed tracks. In this work, the effect of heat sourced from neighbouring tracks was modelled and feedback control was designed. The objective of control is to regulate the melt pool cross-sectional area rejecting the effect of heat from neighbouring tracks within a layer of the powder bed. The SLM process’s thermal model was developed using the energy balance of lumped melt pool volume. The disturbing heat from neighbouring tracks was modelled as the initial temperature of the melt pool. Combining the thermal model with disturbance model resulted in a nonlinear model describing melt pool evolution. The PID, a classical feedback control approach, was used to minimize the effect of intertrack disturbance on the melt pool area. The controller was tuned for the desired melt pool area in a known environment. Simulation results revealed that the proposed controller regulated the desired melt pool area during the scan of multiple tracks of a powder layer within 16 milliseconds and within a length of 0.04 mm reducing laser power by 10% approximately in five tracks. This reduced the chance of pore formation. Hence, it enhances the quality of components manufactured using the SLM process, reducing defects.

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Optimization of Scan Strategies in Selective Laser Melting of Aluminum Parts With Downfacing Areas

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4028620 ◽

2014 ◽

Vol 136 (6) ◽

Cited By ~ 62

Author(s):

Raya Mertens ◽

Stijn Clijsters ◽

Karolien Kempen ◽

Jean-Pierre Kruth

Keyword(s):

Selective Laser Melting ◽

Thermal Model ◽

Layer By Layer ◽

Actual Process ◽

Laser Melting ◽

Melt Pool ◽

Scan Speed ◽

Process Behavior ◽

Metal Products ◽

Design Freedom

Selective laser melting (SLM) is an additive manufacturing technique in which metal products are manufactured in a layer-by-layer manner. One of the main advantages of SLM is the large geometrical design freedom. Because of the layered build, parts with inner cavities can be produced. However, complex structures, such as downfacing areas, influence the process behavior significantly. The downfacing areas can be either horizontal or inclined structures. The first part of this work describes the process parameter optimization for noncomplex, upfacing structures to obtain relative densities above 99%. In the second part of this research, parameters are optimized for downfacing areas, both horizontal and inclined. The experimental results are compared to simulations of a thermal model, which calculates the melt pool dimensions based on the material properties (such as thermal conductivity) and process parameters (such as laser power and scan speed). The simulations show a great similarity between the thermal model and the actual process.

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