Comparative study of autoclave thermoforming and hot-press moulding for manufacturing green composite parts
G. Parodo, L. Sorrentino, S. Turchetta
Abstract. The demand for sustainable and efficient manufacturing of lightweight polymer composite parts is driving the adoption of thermoplastic-based composites reinforced with natural fibres. This study explores two distinct manufacturing processes (autoclave thermoforming and hot-press moulding) to produce green composites from flax fibre woven fabric and polypropylene prepregs. The thermoforming process in autoclave offers precise pressure and temperature control, ensuring high-quality consolidation and fibre impregnation. Conversely, hot-press moulding allows for faster cycle times and increased production efficiency due to its direct compression approach. A comparative analysis of the two methods highlights differences in fibre-matrix adhesion, mechanical properties, and process repeatability. The results demonstrate that while both methods achieve high-performance eco-friendly composites, the choice of process can be optimized based on production rate and sustainability goals.
Keywords
Composites, Press Moulding, Thermoforming, Thermoplastics, Eco-Design
Published online 9/10/2025, 8 pages
Copyright © 2025 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: G. Parodo, L. Sorrentino, S. Turchetta, Comparative study of autoclave thermoforming and hot-press moulding for manufacturing green composite parts, Materials Research Proceedings, Vol. 57, pp 278-285, 2025
DOI: https://doi.org/10.21741/9781644903735-32
The article was published as article 32 of the book Italian Manufacturing Association Conference
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
References
[1] S.D.S. Kopparthy, A.N. Netravali, Review: Green composites for structural applications, Compos. Part C Open Access. 6 (2021) 100169. https://doi.org/10.1016/j.jcomc.2021.100169
[2] G. Parodo, L. Sorrentino, S. Turchetta, G. Moffa, Manufacturing of Sustainable Composite Materials: The Challenge of Flax Fiber and Polypropylene, Materials (Basel). 17 (2024) 4768. https://doi.org/10.3390/ma17194768
[3] O. El Hawary, L. Boccarusso, M.P. Ansell, M. Durante, F. Pinto, An Overview of Natural Fiber Composites for Marine Applications, J. Mar. Sci. Eng. 11 (2023) 1076. https://doi.org/10.3390/jmse11051076
[4] E. Pourahmadi, F. Shadmehri, R. Ganesan, Interlaminar shear strength of Carbon/PEEK thermoplastic composite laminate: Effects of in-situ consolidation by automated fiber placement and autoclave re-consolidation, Compos. Part B Eng. 269 (2024) 111104. https://doi.org/10.1016/j.compositesb.2023.111104
[5] C. Bellini, L. Sorrentino, Analysis of cure induced deformation of CFRP U-shaped laminates, Compos. Struct. 197 (2018) 1–9. https://doi.org/10.1016/j.compstruct.2018.05.038
[6] Y. Li, A. Yang, Y. Liu, Y. Gao, J. Zhou, Y. Dong, S. Zhu, Analysis of warping defect formation mechanisms in hot molding of CF/PEEK thin-wall structures and their influence on mechanical properties, Thin-Walled Struct. 207 (2025) 112740. https://doi.org/10.1016/j.tws.2024.112740
[7] C.J. Ogugua, S. V. Anton, A.P. Tripathi, M.D. Larrabeiti, S.O. van Hees, J. Sinke, C.A. Dransfeld, Energy analysis of autoclave CFRP manufacturing using thermodynamics based models, Compos. Part A Appl. Sci. Manuf. 166 (2023) 107365. https://doi.org/10.1016/j.compositesa.2022.107365
[8] O.A. Ekuase, N. Anjum, V.O. Eze, O.I. Okoli, A Review on the Out-of-Autoclave Process for Composite Manufacturing, J. Compos. Sci. 6 (2022). https://doi.org/10.3390/jcs6060172
[9] D. Tatsuno, T. Yoneyama, K. Kawamoto, M. Okamoto, Hot press forming of thermoplastic CFRP sheets, Procedia Manuf. 15 (2018) 1730–1737. https://doi.org/10.1016/j.promfg.2018.07.254
[10] K.R. Ramakrishnan, N. Le Moigne, O. De Almeida, A. Regazzi, S. Corn, Optimized manufacturing of thermoplastic biocomposites by fast induction-heated compression moulding: Influence of processing parameters on microstructure development and mechanical behaviour, Compos. Part A Appl. Sci. Manuf. 124 (2019) 105493. https://doi.org/10.1016/j.compositesa.2019.105493
[11] J. Bachmann, C. Hidalgo, S. Bricout, Environmental analysis of innovative sustainable composites with potential use in aviation sector—A life cycle assessment review, Sci. China Technol. Sci. 60 (2017) 1301–1317. https://doi.org/10.1007/s11431-016-9094-y
[12] M. Mehdikhani, L. Gorbatikh, I. Verpoest, S. V. Lomov, Voids in fiber-reinforced polymer composites: A review on their formation, characteristics, and effects on mechanical performance, J. Compos. Mater. 53 (2019) 1579–1669. https://doi.org/10.1177/0021998318772152
[13] E. Kobler, J. Birtha, C. Marschik, K. Straka, G. Steinbichler, S. Schlecht, Modeling the anisotropic squeeze flow during hot press consolidation of thermoplastic unidirectional fiber-reinforced tapes, J. Thermoplast. Compos. Mater. 37 (2024) 2775–2801. https://doi.org/10.1177/08927057231214458
[14] G. Parodo, L. Sorrentino, S. Turchetta, Study of autoclave process to manufacture thermoplastic composites constituted by PP/flax fibers, in: Mater. Res. Proc., 2023: pp. 385–392. https://doi.org/10.21741/9781644902714-46
[15] J. George, E.T.J. Klompen, T. Peijs, Thermal degradation of green and upgraded flax fibres, Adv. Compos. Lett. 10 (2001) 81–88. https://doi.org/10.1177/096369350101000205.
[16] J. Gassan, A.K. Bledzki, Thermal degradation of flax and jute fibers, J. Appl. Polym. Sci. 82 (2001) 1417–1422. https://doi.org/10.1002/app.1979
