Experimental and numerical investigations on the thermoforming of 3D-printed polylactic acid parts
ISSN: 1355-2546
Article publication date: 2 May 2024
Issue publication date: 17 May 2024
Abstract
Purpose
The purpose of this study is to investigate the thermoforming process of 3D-printed parts made from polylactic acid (PLA) and explore its application in producing wrist-hand orthoses. These orthoses were 3D printed flat, heated and molded to fit the patient’s hand. The advantages of such an approach include reduced production time and cost.
Design/methodology/approach
The study used both experimental and numerical methods to analyze the thermoforming process of PLA parts. Thermal and mechanical characteristics were determined at different temperatures and infill densities. An equivalent material model that considers infill within a print is proposed. Its practical use was proven using a coupled finite-element analysis model. The simulation strategy enabled a comparative analysis of the thermoforming behavior of orthoses with two designs by considering the combined impact of natural convection cooling and imposed structural loads.
Findings
The experimental results indicated that at 27°C and 35°C, the tensile specimens exhibited brittle failure irrespective of the infill density, whereas ductile behavior was observed at 45°C, 50°C and 55°C. The thermal conductivity of the material was found to be linearly related to the temperature of the specimen. Orthoses with circular open pockets required more time to complete the thermoforming process than those with hexagonal pockets. Hexagonal cutouts have a lower peak stress owing to the reduced reaction forces, resulting in a smoother thermoforming process.
Originality/value
This study contributes to the existing literature by specifically focusing on the thermoforming process of 3D-printed parts made from PLA. Experimental tests were conducted to gather thermal and mechanical data on specimens with two infill densities, and a finite-element model was developed to address the thermoforming process. These findings were applied to a comparative analysis of 3D-printed thermoformed wrist-hand orthoses that included open pockets with different designs, demonstrating the practical implications of this study’s outcomes.
Keywords
Acknowledgements
Funding: This work was supported by a grant from the Ministry of Research, Innovation and Digitization, CNCS–UEFISCDI, project number PN-III-P4-PCE-2021–0070, within PNCDI III.
Ethical compliance: The research did not include studies involving human participants.
Author contributions: Conceptualization: TGA and DP; methodology: DP, TGA, CS; investigation: TGA, DP, FB, CS; data interpretation: TGA, DP, CS; validation: TGA, FB, DP; writing – original draft preparation: DP, TGA, FB; writing – review and editing: TGA, DP, CS; and funding acquisition, DP. All the authors have read and agreed to the published version of the manuscript.
Data availability: not applicable.
Conflicts of interest: The authors declare no conflicts of interest.
Citation
Alexandru, T.G., Popescu, D., Constantin, S. and Baciu, F. (2024), "Experimental and numerical investigations on the thermoforming of 3D-printed polylactic acid parts", Rapid Prototyping Journal, Vol. 30 No. 5, pp. 928-946. https://doi.org/10.1108/RPJ-09-2023-0338
Publisher
:Emerald Publishing Limited
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