Spatter transport by inert gas flow in selective laser melting : a simulation study
Spattering is an unavoidable phenomenon during Selective Laser Melting (SLM). The distinctively large and dark solidified molten particles have always been observed on the powder bed, leading to the potential deterioration of the final printed parts. In commercial SLM machines, inert gas flow is pum...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
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2020
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| Online Access: | https://hdl.handle.net/10356/141001 |
| _version_ | 1824455568316694528 |
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| author | Ahmad Bin Anwar Ibrahim, Imran Halimi Pham, Quang-Cuong |
| author2 | School of Mechanical and Aerospace Engineering |
| author_facet | School of Mechanical and Aerospace Engineering Ahmad Bin Anwar Ibrahim, Imran Halimi Pham, Quang-Cuong |
| author_sort | Ahmad Bin Anwar |
| collection | NTU |
| description | Spattering is an unavoidable phenomenon during Selective Laser Melting (SLM). The distinctively large and dark solidified molten particles have always been observed on the powder bed, leading to the potential deterioration of the final printed parts. In commercial SLM machines, inert gas flow is pumped into the chamber over the powder bed to remove spatter and other unwanted by-products such as metal vapour and plasma plumes. However, traces of spatter still remain on the powder bed and the regions close to the chamber outlet. In this work, the trajectories of spatter particles were tracked using the Discrete Phase Model (DPM). The continuous fluid domain was solved using three-dimensional Computational Fluid Dynamics (CFD) simulations. The entrainment effects on the hot ejections as well as the recoil pressure driven ejections were considered. In other words, it was assumed that the latter were also entrained by the metal vapour and laser plume. The final distribution characteristics downstream of the cross-flow (-x direction) were validated by an earlier experimental study. The results show that a gradually decreasing trend in terms of the spatter size and mass distributions were obtained from the simulations which showed good agreement with the earlier experiments. It was also shown that the trajectories of the spatter particles were governed mainly by their initial momentum when the inert gas flow velocity was increased. While complete removal of the spatter particles from the powder bed was not achieved, the presence of the inert gas flow aided in the transport of a majority of the particles further downstream giving a more even mass distribution. Also, in spite of not accounting for the complete multi-physics of the SLM process and the associated recoil pressure driven ejections, the proposed spatter transport simulations can be applied in future gas cross-flow optimisation designs for the effective removal of spatter over the powder bed in commercial SLM machines. |
| first_indexed | 2025-02-19T03:40:16Z |
| format | Journal Article |
| id | ntu-10356/141001 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2025-02-19T03:40:16Z |
| publishDate | 2020 |
| record_format | dspace |
| spelling | ntu-10356/1410012023-03-04T17:22:24Z Spatter transport by inert gas flow in selective laser melting : a simulation study Ahmad Bin Anwar Ibrahim, Imran Halimi Pham, Quang-Cuong School of Mechanical and Aerospace Engineering Singapore Centre for 3D Printing Engineering::Mechanical engineering Additive Manufacturing Selective Laser Melting Spattering is an unavoidable phenomenon during Selective Laser Melting (SLM). The distinctively large and dark solidified molten particles have always been observed on the powder bed, leading to the potential deterioration of the final printed parts. In commercial SLM machines, inert gas flow is pumped into the chamber over the powder bed to remove spatter and other unwanted by-products such as metal vapour and plasma plumes. However, traces of spatter still remain on the powder bed and the regions close to the chamber outlet. In this work, the trajectories of spatter particles were tracked using the Discrete Phase Model (DPM). The continuous fluid domain was solved using three-dimensional Computational Fluid Dynamics (CFD) simulations. The entrainment effects on the hot ejections as well as the recoil pressure driven ejections were considered. In other words, it was assumed that the latter were also entrained by the metal vapour and laser plume. The final distribution characteristics downstream of the cross-flow (-x direction) were validated by an earlier experimental study. The results show that a gradually decreasing trend in terms of the spatter size and mass distributions were obtained from the simulations which showed good agreement with the earlier experiments. It was also shown that the trajectories of the spatter particles were governed mainly by their initial momentum when the inert gas flow velocity was increased. While complete removal of the spatter particles from the powder bed was not achieved, the presence of the inert gas flow aided in the transport of a majority of the particles further downstream giving a more even mass distribution. Also, in spite of not accounting for the complete multi-physics of the SLM process and the associated recoil pressure driven ejections, the proposed spatter transport simulations can be applied in future gas cross-flow optimisation designs for the effective removal of spatter over the powder bed in commercial SLM machines. Accepted version 2020-06-03T06:30:32Z 2020-06-03T06:30:32Z 2019 Journal Article Ahmad Bin Anwar, Ibrahim, I. H., & Pham, Q.-C. (2019). Spatter transport by inert gas flow in selective laser melting : a simulation study. Powder Technology, 352, 103-116. doi:10.1016/j.powtec.2019.04.044 0032-5910 https://hdl.handle.net/10356/141001 10.1016/j.powtec.2019.04.044 2-s2.0-85064931375 352 103 116 en Powder Technology © 2019 Elsevier B.V. All rights reserved. This paper was published in Powder Technology and is made available with permission of Elsevier B.V. application/pdf |
| spellingShingle | Engineering::Mechanical engineering Additive Manufacturing Selective Laser Melting Ahmad Bin Anwar Ibrahim, Imran Halimi Pham, Quang-Cuong Spatter transport by inert gas flow in selective laser melting : a simulation study |
| title | Spatter transport by inert gas flow in selective laser melting : a simulation study |
| title_full | Spatter transport by inert gas flow in selective laser melting : a simulation study |
| title_fullStr | Spatter transport by inert gas flow in selective laser melting : a simulation study |
| title_full_unstemmed | Spatter transport by inert gas flow in selective laser melting : a simulation study |
| title_short | Spatter transport by inert gas flow in selective laser melting : a simulation study |
| title_sort | spatter transport by inert gas flow in selective laser melting a simulation study |
| topic | Engineering::Mechanical engineering Additive Manufacturing Selective Laser Melting |
| url | https://hdl.handle.net/10356/141001 |
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