Abstract
Metal additive manufacturing is moving from rapid prototyping to on-demand manufacturing and even to serial production. Consistent part quality and development of a wider range of available materials are key for wider adoption. This requires control and optimization of various laser and scanning parameters. Therefore, process modeling has been extensively pursued to reduce experimental runs in the search for parameters that produce dense, high-quality parts for the given alloy. However, these optimal parameters remain machine-specific if conditions defined by the machine architecture are not considered. Previous studies have shown that shielding gas flow is one such parameter that affects porosity and mechanical properties of parts produced with laser powder bed fusion. However, a lack of consensus remains regarding which phenomena are responsible for the observed decrease in quality. In this study, the effect of shielding gas flow velocity on porosity and melt pool geometry in laser powder bed fusion additive manufacturing is studied. It is shown that decreasing the gas flow velocity leads to a drastic loss of penetration of single scan tracks, leading to increased lack-of-fusion porosity at the part level. This is attributed to the obstruction of the laser beam by the process-induced vapor plume emissions of the individual tracks being scanned. As the vapor plume, and how effectively it is removed by the shielding gas flow, have a significant effect on the melt pool geometry in laser powder bed fusion, models aiming at predicting the melt pool geometry and attempts to transfer process parameters from one machine to another should consider the effect of the shielding gas flow.
| Original language | English |
|---|---|
| Article number | 101030 |
| Journal | Additive Manufacturing |
| Volume | 32 |
| Early online date | 3 Jan 2020 |
| DOIs | |
| Publication status | E-pub ahead of print - 3 Jan 2020 |
| MoE publication type | A1 Journal article-refereed |
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Keywords
- Gas flow
- Melt pool geometry
- Porosity
- Powder bed fusion
- Vapor plume
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On the effect of shielding gas flow on porosity and melt pool geometry in laser powder bed fusion additive manufacturing. / Reijonen, Joni (Corresponding Author); Revuelta, Alejandro; Riipinen, Tuomas; Ruusuvuori, Kimmo; Puukko, Pasi.
In: Additive Manufacturing, Vol. 32, 101030, 03.2020.Research output: Contribution to journal › Article › Scientific › peer-review
TY - JOUR
T1 - On the effect of shielding gas flow on porosity and melt pool geometry in laser powder bed fusion additive manufacturing
AU - Reijonen, Joni
AU - Revuelta, Alejandro
AU - Riipinen, Tuomas
AU - Ruusuvuori, Kimmo
AU - Puukko, Pasi
N1 - project 125784
PY - 2020/1/3
Y1 - 2020/1/3
N2 - Metal additive manufacturing is moving from rapid prototyping to on-demand manufacturing and even to serial production. Consistent part quality and development of a wider range of available materials are key for wider adoption. This requires control and optimization of various laser and scanning parameters. Therefore, process modeling has been extensively pursued to reduce experimental runs in the search for parameters that produce dense, high-quality parts for the given alloy. However, these optimal parameters remain machine-specific if conditions defined by the machine architecture are not considered. Previous studies have shown that shielding gas flow is one such parameter that affects porosity and mechanical properties of parts produced with laser powder bed fusion. However, a lack of consensus remains regarding which phenomena are responsible for the observed decrease in quality. In this study, the effect of shielding gas flow velocity on porosity and melt pool geometry in laser powder bed fusion additive manufacturing is studied. It is shown that decreasing the gas flow velocity leads to a drastic loss of penetration of single scan tracks, leading to increased lack-of-fusion porosity at the part level. This is attributed to the obstruction of the laser beam by the process-induced vapor plume emissions of the individual tracks being scanned. As the vapor plume, and how effectively it is removed by the shielding gas flow, have a significant effect on the melt pool geometry in laser powder bed fusion, models aiming at predicting the melt pool geometry and attempts to transfer process parameters from one machine to another should consider the effect of the shielding gas flow.
AB - Metal additive manufacturing is moving from rapid prototyping to on-demand manufacturing and even to serial production. Consistent part quality and development of a wider range of available materials are key for wider adoption. This requires control and optimization of various laser and scanning parameters. Therefore, process modeling has been extensively pursued to reduce experimental runs in the search for parameters that produce dense, high-quality parts for the given alloy. However, these optimal parameters remain machine-specific if conditions defined by the machine architecture are not considered. Previous studies have shown that shielding gas flow is one such parameter that affects porosity and mechanical properties of parts produced with laser powder bed fusion. However, a lack of consensus remains regarding which phenomena are responsible for the observed decrease in quality. In this study, the effect of shielding gas flow velocity on porosity and melt pool geometry in laser powder bed fusion additive manufacturing is studied. It is shown that decreasing the gas flow velocity leads to a drastic loss of penetration of single scan tracks, leading to increased lack-of-fusion porosity at the part level. This is attributed to the obstruction of the laser beam by the process-induced vapor plume emissions of the individual tracks being scanned. As the vapor plume, and how effectively it is removed by the shielding gas flow, have a significant effect on the melt pool geometry in laser powder bed fusion, models aiming at predicting the melt pool geometry and attempts to transfer process parameters from one machine to another should consider the effect of the shielding gas flow.
KW - Gas flow
KW - Melt pool geometry
KW - Porosity
KW - Powder bed fusion
KW - Vapor plume
UR - http://www.scopus.com/inward/record.url?scp=85077782592&partnerID=8YFLogxK
U2 - 10.1016/j.addma.2019.101030
DO - 10.1016/j.addma.2019.101030
M3 - Article
AN - SCOPUS:85077782592
VL - 32
JO - Additive Manufacturing
JF - Additive Manufacturing
SN - 2214-8604
M1 - 101030
ER -