Fused filament fabrication of thermoplastics in high vacuum without convective heat transfer

Abstract In-space additive manufacturing (AM) offers significant potential to expand human space exploration beyond low Earth orbit and the moon. Although extrusion-based AM has proven feasible in zero gravity, the functionality of such a process in orbit-like vacuum conditions with practically no c...

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Main Authors: Marina Kühn-Kauffeldt, Marvin Kühn, Noé Perrin, Wolfgang Saur
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
Subjects:
Online Access:https://doi.org/10.1038/s41598-025-13181-2
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author Marina Kühn-Kauffeldt
Marvin Kühn
Noé Perrin
Wolfgang Saur
author_facet Marina Kühn-Kauffeldt
Marvin Kühn
Noé Perrin
Wolfgang Saur
author_sort Marina Kühn-Kauffeldt
collection DOAJ
description Abstract In-space additive manufacturing (AM) offers significant potential to expand human space exploration beyond low Earth orbit and the moon. Although extrusion-based AM has proven feasible in zero gravity, the functionality of such a process in orbit-like vacuum conditions with practically no convective heat loss remains barely explored. To this end, a Fused Filament Fabrication (FFF) system was designed that successfully operated in high vacuum at 10− 4 mbar where convective heat transfer is negligible. Polylactic acid (PLA) tensile specimens were fabricated in three orthogonal print orientations under high vacuum conditions. Tensile testing, scanning electron microscopy, and micro-computed tomography were employed to assess tensile strength, elongation at break, void content, and the effects of vacuum on thermal dissipation. The objective was to evaluate how the vacuum environment influences the anisotropy of mechanical properties in printed parts. The absence of convective losses improved the layer bonding strength of specimens printed in the vertical (z) direction with load applied perpendicular to the filament strand orientation (V90), compared to specimens printed in horizontal (x or y) direction with load applied perpendicular to filament strand orientation (H90). This was attributed to the considerably slower cooling process in the case of V90 specimens. Moreover, thermal insulation provided by the vacuum environment had a beneficial influence on heat break and hot end. In vacuum, the set extrusion temperature was closer to the temperature measured at the tip of the nozzle. This study also identifies a temperature undershoot during decrease in hot end temperature in the printing process, which adversely affected interlayer adhesion. The findings indicate that the current PID-based hot-end control requires optimization to enhance the temperature control rate and minimize thermal deviations. These insights contribute to a deeper understanding of thermoplastic processing under convection-free conditions using fused filament fabrication (FFF).
format Article
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institution Kabale University
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spelling doaj-art-07efe6201eff4e5ab894962dc3eda2282025-08-20T04:02:46ZengNature PortfolioScientific Reports2045-23222025-07-0115111310.1038/s41598-025-13181-2Fused filament fabrication of thermoplastics in high vacuum without convective heat transferMarina Kühn-Kauffeldt0Marvin Kühn1Noé Perrin2Wolfgang Saur3Institute for Electrical Energy Systems, University of the Bundeswehr MunichInstitute for Electrical Energy Systems, University of the Bundeswehr MunichInstitute for Electrical Energy Systems, University of the Bundeswehr MunichChair of Construction Materials, University of the Bundeswehr MunichAbstract In-space additive manufacturing (AM) offers significant potential to expand human space exploration beyond low Earth orbit and the moon. Although extrusion-based AM has proven feasible in zero gravity, the functionality of such a process in orbit-like vacuum conditions with practically no convective heat loss remains barely explored. To this end, a Fused Filament Fabrication (FFF) system was designed that successfully operated in high vacuum at 10− 4 mbar where convective heat transfer is negligible. Polylactic acid (PLA) tensile specimens were fabricated in three orthogonal print orientations under high vacuum conditions. Tensile testing, scanning electron microscopy, and micro-computed tomography were employed to assess tensile strength, elongation at break, void content, and the effects of vacuum on thermal dissipation. The objective was to evaluate how the vacuum environment influences the anisotropy of mechanical properties in printed parts. The absence of convective losses improved the layer bonding strength of specimens printed in the vertical (z) direction with load applied perpendicular to the filament strand orientation (V90), compared to specimens printed in horizontal (x or y) direction with load applied perpendicular to filament strand orientation (H90). This was attributed to the considerably slower cooling process in the case of V90 specimens. Moreover, thermal insulation provided by the vacuum environment had a beneficial influence on heat break and hot end. In vacuum, the set extrusion temperature was closer to the temperature measured at the tip of the nozzle. This study also identifies a temperature undershoot during decrease in hot end temperature in the printing process, which adversely affected interlayer adhesion. The findings indicate that the current PID-based hot-end control requires optimization to enhance the temperature control rate and minimize thermal deviations. These insights contribute to a deeper understanding of thermoplastic processing under convection-free conditions using fused filament fabrication (FFF).https://doi.org/10.1038/s41598-025-13181-2High vacuumFused filament fabricationConvective heat transferMechanical propertiesPLA
spellingShingle Marina Kühn-Kauffeldt
Marvin Kühn
Noé Perrin
Wolfgang Saur
Fused filament fabrication of thermoplastics in high vacuum without convective heat transfer
Scientific Reports
High vacuum
Fused filament fabrication
Convective heat transfer
Mechanical properties
PLA
title Fused filament fabrication of thermoplastics in high vacuum without convective heat transfer
title_full Fused filament fabrication of thermoplastics in high vacuum without convective heat transfer
title_fullStr Fused filament fabrication of thermoplastics in high vacuum without convective heat transfer
title_full_unstemmed Fused filament fabrication of thermoplastics in high vacuum without convective heat transfer
title_short Fused filament fabrication of thermoplastics in high vacuum without convective heat transfer
title_sort fused filament fabrication of thermoplastics in high vacuum without convective heat transfer
topic High vacuum
Fused filament fabrication
Convective heat transfer
Mechanical properties
PLA
url https://doi.org/10.1038/s41598-025-13181-2
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