TY - JOUR

T1 - PBF-LB/M process under a silane-doped argon atmosphere

T2 - Preliminary studies and development of an innovative machine concept

AU - Emminghaus, Nicole

AU - Fritsch, Sebastian

AU - Büttner, Hannes

AU - August, Jannes

AU - Tegtmeier, Marijan

AU - Huse, Michael

AU - Lammers, Marius

AU - Hoff, Christian

AU - Hermsdorf, Jörg

AU - Kaierle, Stefan

N1 - Funding Information: Funded by the Deutsche Forschungsgemeinschaft (DFG , German Research Foundation) – Project-ID 394563137 – SFB 1368 .

PY - 2021/5

Y1 - 2021/5

N2 - In laser-based powder bed fusion of metals (PBF-LB/M) the presence of oxygen is known to encourage embrittlement and impair the wetting properties of the substrate and solidified material. Conventionally, inert gases like argon are used to reduce the residual oxygen content within the processing atmosphere. However, especially in terms of reactive materials like titanium the remaining oxygen still causes critical oxidations. In this publication, a new approach for obtaining an oxygen-free processing atmosphere is presented. Thereby the argon shielding gas is doped with reactive monosilane to reduce the residual oxygen content to a range comparable to XHV (Extreme High Vacuum, thermodynamic oxygen activity <10−15). The handling of this new silane-containing atmosphere requires the development of a special manufacturing system. Therefore, this work elucidates the development of an innovative machine system in accordance with the VDI (German Association of Engineers) Guideline 2221. For determination and specification of the underlying requirements, the interaction of the gas mixture with various construction materials and Ti–6Al–4V powder material was investigated in a test chamber. It could be shown that metallic materials and smooth surfaces are favorable for the design while polymers are likely to degrade in silane-containing atmosphere. Further, the design of the gas flow in the build chamber was optimized using flow simulation. In order to avoid the deposition of reaction products in the process zone, a laminar flow should be established, which can be achieved by baffles and honeycomb structures.

AB - In laser-based powder bed fusion of metals (PBF-LB/M) the presence of oxygen is known to encourage embrittlement and impair the wetting properties of the substrate and solidified material. Conventionally, inert gases like argon are used to reduce the residual oxygen content within the processing atmosphere. However, especially in terms of reactive materials like titanium the remaining oxygen still causes critical oxidations. In this publication, a new approach for obtaining an oxygen-free processing atmosphere is presented. Thereby the argon shielding gas is doped with reactive monosilane to reduce the residual oxygen content to a range comparable to XHV (Extreme High Vacuum, thermodynamic oxygen activity <10−15). The handling of this new silane-containing atmosphere requires the development of a special manufacturing system. Therefore, this work elucidates the development of an innovative machine system in accordance with the VDI (German Association of Engineers) Guideline 2221. For determination and specification of the underlying requirements, the interaction of the gas mixture with various construction materials and Ti–6Al–4V powder material was investigated in a test chamber. It could be shown that metallic materials and smooth surfaces are favorable for the design while polymers are likely to degrade in silane-containing atmosphere. Further, the design of the gas flow in the build chamber was optimized using flow simulation. In order to avoid the deposition of reaction products in the process zone, a laminar flow should be established, which can be achieved by baffles and honeycomb structures.

KW - Additive manufacturing

KW - Design methodology

KW - Flow simulation

KW - Gas flow

KW - Laser-based powder bed fusion

KW - Monosilane

UR - http://www.scopus.com/inward/record.url?scp=85107649792&partnerID=8YFLogxK

U2 - 10.1016/j.aime.2021.100040

DO - 10.1016/j.aime.2021.100040

M3 - Article

AN - SCOPUS:85107649792

VL - 2

JO - Advances in Industrial and Manufacturing Engineering

JF - Advances in Industrial and Manufacturing Engineering

M1 - 100040

ER -