Multi-scale simulation approach for identifying optimal parameters for fabrication ofhigh-density Inconel 718 parts using selective laser melting
ISSN: 1355-2546
Article publication date: 26 August 2021
Issue publication date: 3 January 2022
Abstract
Purpose
Depending on an experimental approach to find optimal parameters for producing fully dense (relative density > 99%) Inconel 718 (IN718) components in the selective laser melting (SLM) process is expensive and offers no guarantee of success. Accordingly, this study aims to propose a multi-scale simulation framework to guide the choice of processing parameters in a more pragmatic manner.
Design/methodology/approach
In the proposed approach, a powder layer, ray tracing and heat transfer simulation models are used to calculate the melt pool dimensions and evaporation volume corresponding to a small number of laser power and scanning speed conditions within the input design space. A layer-heating model is then used to determine the inter-layer idle time required to maximize the temperature convergence rate of the solidified layer beneath the power bed. The simulation results are used to train surrogate models to construct SLM process maps for 3,600 pairs of the laser power and scanning speed within the input design space given three different values of the underlying solidified layer temperature (i.e., 353 K, 673 K and 873 K). The ideal selection of laser power and scanning speed of each process map is chosen based on four quality-related criteria listed as follows: without the appearance of key-hole melting; an evaporation volume less than the volume of the d90 powder particles; ensuring the stability of single scan tracks; and avoiding a weak contact between the melt pool and substrate. Finally, the optimal laser power and scanning speed parameters for the SLM process are determined by superimposing the optimal regions of the individual process maps.
Findings
The feasibility of the proposed approach is demonstrated by fabricating IN718 test specimens using the optimal processing conditions identified by the simulation framework. It is shown that the maximum density of the fabricated parts is 99.94%, while the average density is 99.88% and the standard deviation is less than 0.05%.
Originality/value
The present study proposed a multi-scale simulation model which can efficiently predict the optimal processing conditions for producing fully dense components in the SLM process. If the geometry of the three-dimensional printed part is changed or the machine and powder material is altered, users can use the proposed method for predicting the processing conditions that can produce the high-density part.
Keywords
Acknowledgements
The authors gratefully acknowledge the financial support provided to this study by the Ministry of Science and Technology of Taiwan under Grant Nos MOST 107–2218-E-006–051 and MOST 110–2222-E-218–002-MY2. The study was also supported in part by the funding provided to the Intelligent Manufacturing Research Center (iMRC) at National Cheng Kung University (NCKU) by the Ministry of Education, Taiwan, Headquarters of University Advancement. In addition, the financial support from the Higher Education Sprout Project of the Ministry of Education at Southern Taiwan University of Science and Technology is greatly appreciated.
Citation
Tran, H.-C., Lo, Y.-L., Le, T.-N., Lau, A.K.-T. and Lin, H.-Y. (2022), "Multi-scale simulation approach for identifying optimal parameters for fabrication ofhigh-density Inconel 718 parts using selective laser melting", Rapid Prototyping Journal, Vol. 28 No. 1, pp. 109-125. https://doi.org/10.1108/RPJ-11-2020-0278
Publisher
:Emerald Publishing Limited
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