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. 2025 Jul 26;15(1):27249.
doi: 10.1038/s41598-025-12573-8.

Continuous reuse of polyamide 12 in powder bed fusion

Aleksander Kubeczek  1 , Michał Olejarczyk  2 , Piotr Gruber  2 , Arkadiusz J Antończak  3
Affiliations

Continuous reuse of polyamide 12 in powder bed fusion

Aleksander Kubeczek et al. Sci Rep. .

Abstract

The thermal degradation of polymers in powder bed fusion (PBF) is one of the major issues preventing wider adoption of this technology at the production scale. Although standard PBF allows for elastic production of complex parts in a single-step manufacturing process, it is materially inefficient. This is because only approximately 10% of the material is used to develop parts, while the majority of semicrystalline polyamide 12 (PA12) remain unused. The recovered powder cannot be directly reused in subsequent processes because it remains at high temperatures, above the glass transition and below the melting point for a long time during printing. In this work, we present a novel way to process PA12 at room temperature without exposure to a thermal agent. Dual beam laser sintering (DBLS) uses a double laser system that effectively compensates for the temperature in the melting zone and prevents material shrinkage. To demonstrate the effectiveness of the DBLS method, the material was kept in a closed loop. Specimens from each iteration of the process (n = 4) were analyzed. No significant changes were observed in the chemical properties (molecular weight and melt viscosity, assessed via gel permeation chromatography (GPC) and melt flow index (MFI) analysis), rheological properties (flowability and size distribution) nor in the particle shape of the powder samples. Mechanical properties of the built specimens, when compared with the initial values, proved to be satisfactory.

Keywords: Additive manufacturing; Dual beam laser sintering; Polyamide 12; Polymer degradation; Powder bed fusion of polymers; Powder reuse.

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Conflict of interest statement

Declarations. Competing interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this manuscript.

Figures

Fig. 1
Fig. 1
Powder reuse and characterization scheme.
Fig. 2
Fig. 2
Manufacturing process: a) drawing of the build orientation with machine coordinates and b) image taken after the complete build process.
Fig. 3
Fig. 3
Example of the image processing method using the P0 sample: a) original image, b) image with binarized powder particles (yellow), c) image with binarized powder particles and filler (blue).
Fig. 4
Fig. 4
SEM images of postprocess PA12 powder samples: a) P0, b) P1, c) P2, d) P3, and e) a single powder particle of P0 with filler particles, which was used to identify the filler type by EDS, with f) EDS spectra of the indicated of the reference points (from 1 to 4 as marked in Fig. 4e).
Fig. 5
Fig. 5
Particle size cumulative distribution (CD) and density distribution (DD) curves of virgin and postprocess PA12 powder samples.
Fig. 6
Fig. 6
Cohesion index curves of virgin and postprocess PA12 powder samples collected while increasing (↑) and decreasing (↓) the rotation speed.
Fig. 7
Fig. 7
Differential curves of the function of molecular weight distribution (MWD) for virgin and postprocess PA12 powder samples.
Fig. 8
Fig. 8
Mechanical properties of PA12 tensile specimens.
See this image and copyright information in PMC

References

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