Study of the spatter distribution on the powder bed during selective laser melting

In Selective Laser Melting (SLM), inert gas is pumped into the chamber to eliminate the deleterious by-products, which includes spatter. Despite this, traces of spatter on the powder bed have always been observed. Earlier research mainly focussed on the formation and characterization of spatter par...

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Main Authors: Ahmad Bin Anwar, Pham, Quang-Cuong
Other Authors: School of Mechanical and Aerospace Engineering
Format: Article
Language:English
Published: 2019
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Online Access:https://hdl.handle.net/10356/106099
http://hdl.handle.net/10220/47926
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1060992020-09-26T22:06:24Z Study of the spatter distribution on the powder bed during selective laser melting Ahmad Bin Anwar Pham, Quang-Cuong School of Mechanical and Aerospace Engineering Singapore Centre for 3D Printing DRNTU::Engineering::Mechanical engineering Selective Laser Melting Additive Manufacturing In Selective Laser Melting (SLM), inert gas is pumped into the chamber to eliminate the deleterious by-products, which includes spatter. Despite this, traces of spatter on the powder bed have always been observed. Earlier research mainly focussed on the formation and characterization of spatter particles that were freshly ejected from the melt pool. However, in this study, the quantification of the spatter distribution on the powder bed was performed, following their transport by the inert gas flow which was varied at two gas pump settings (60 and 67%). Image processing for spatter detection based on contrast was first conducted. The sieved out spatter particles were quantified by precision weighing of mass. Optical microscopy was then utilised for size determination. The majority of spatter particles were originally distributed along the −x direction, as observed from the top down images taken. It was found that spatter was generally transported in the −x direction with the mass and size gradually decreasing with distance from the scanned regions. However, increasing the gas flow velocity did not correspond to a lesser mass distribution. Computations on the Stk number revealed that at the gas pump setting of 67%, spatter particles of greater size were deposited earlier on the powder bed, suggesting that increasing the gas flow velocity to a large extent would increase the likelihood of powder bed contamination. The forward extrapolation of the exponential Stk number trendlines also elucidated the reason for the limitations on the width of the powder bed in machines designed by SLM Solutions. Accepted version 2019-03-28T07:57:09Z 2019-12-06T22:04:33Z 2019-03-28T07:57:09Z 2019-12-06T22:04:33Z 2018 Journal Article Anwar, A. B., & Pham, Q. C. (2018). Study of the spatter distribution on the powder bed during selective laser melting. Additive Manufacturing, 22, 86-97.doi:10.1016/j.addma.2018.04.036 2214-7810 https://hdl.handle.net/10356/106099 http://hdl.handle.net/10220/47926 10.1016/j.addma.2018.04.036 en Additive Manufacturing © 2018 Elsevier B.V. All rights reserved. This paper was published in Additive Manufacturing and is made available with permission of Elsevier B.V. 28 P. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic DRNTU::Engineering::Mechanical engineering
Selective Laser Melting
Additive Manufacturing
spellingShingle DRNTU::Engineering::Mechanical engineering
Selective Laser Melting
Additive Manufacturing
Ahmad Bin Anwar
Pham, Quang-Cuong
Study of the spatter distribution on the powder bed during selective laser melting
description In Selective Laser Melting (SLM), inert gas is pumped into the chamber to eliminate the deleterious by-products, which includes spatter. Despite this, traces of spatter on the powder bed have always been observed. Earlier research mainly focussed on the formation and characterization of spatter particles that were freshly ejected from the melt pool. However, in this study, the quantification of the spatter distribution on the powder bed was performed, following their transport by the inert gas flow which was varied at two gas pump settings (60 and 67%). Image processing for spatter detection based on contrast was first conducted. The sieved out spatter particles were quantified by precision weighing of mass. Optical microscopy was then utilised for size determination. The majority of spatter particles were originally distributed along the −x direction, as observed from the top down images taken. It was found that spatter was generally transported in the −x direction with the mass and size gradually decreasing with distance from the scanned regions. However, increasing the gas flow velocity did not correspond to a lesser mass distribution. Computations on the Stk number revealed that at the gas pump setting of 67%, spatter particles of greater size were deposited earlier on the powder bed, suggesting that increasing the gas flow velocity to a large extent would increase the likelihood of powder bed contamination. The forward extrapolation of the exponential Stk number trendlines also elucidated the reason for the limitations on the width of the powder bed in machines designed by SLM Solutions.
author2 School of Mechanical and Aerospace Engineering
author_facet School of Mechanical and Aerospace Engineering
Ahmad Bin Anwar
Pham, Quang-Cuong
format Article
author Ahmad Bin Anwar
Pham, Quang-Cuong
author_sort Ahmad Bin Anwar
title Study of the spatter distribution on the powder bed during selective laser melting
title_short Study of the spatter distribution on the powder bed during selective laser melting
title_full Study of the spatter distribution on the powder bed during selective laser melting
title_fullStr Study of the spatter distribution on the powder bed during selective laser melting
title_full_unstemmed Study of the spatter distribution on the powder bed during selective laser melting
title_sort study of the spatter distribution on the powder bed during selective laser melting
publishDate 2019
url https://hdl.handle.net/10356/106099
http://hdl.handle.net/10220/47926
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