How flax-linen and hemp are being used for biocomposite 3D printing
When we talk about composite 3D printing materials, we are often referring to thermoplastics embedded with carbon fibers or glass fibers. However, there are many alternative reinforcing agents that can be used in composite materials, including organic fibers like flax-linen and hemp. Thanks to work highlighted by the Alliance for European Flax-Linen & Hemp, there is big potential for using these organic materials in the production of advanced composite materials for processes like additive manufacturing.
The advancement of flax-linen and hemp biocomposites in the additive manufacturing sector has been driven by a few key technologies. Among them is coreless filament winding, a robotic manufacturing process that essentially winds resin-impregrated flax fibers into 3D structures. This approach, which bears similarities to robotic extrusion, enables the creation of large-scale, complex, and structurally optimized geometries without the need for molds or formwork.
In research being done at the Eindhoven University of Technology—through the framework of the FIBRAS project—coreless filament winding is being explored using materials reinforced with flax roving, a short-length commercially processed form of flax fiber. Through their work, the FIBRAS team is developing large-scale architectural lattice structures that are both strong, lightweight, and resource efficiency.
Another key process innovation that is unlocking potential for the use of flax and hemp in the construction sector is a technology called “Con[knit]uous Rubble”. While not strictly additive manufacturing, this process relies on continuous circular knitting to “encase unprocessed demolition waste in seamless flax fibre structures”. Developed by the University of Stuttgart’s ICD/ITKE with support from linen and hemp spinner Safilin, this technology is enabling the creation of self-supporting architectural structures like arches and columns without the need for traditional cement binders or mortar.
Looking more narrowly at how additive manufacturing can use biocomposites, the Alliance for European Flax-Linen & Hemp points to continuous flax-fiber-reinforced printing. This process, which co-extrudes flax yarns with thermoplastics like PLA, is reportedly already resulting in composite parts with properties comparable to conventional composite components. Other 3D printing materials, like compounded flax fiber filaments, are also enabling the production of biocomposite parts using conventional extrusion platforms.
French designer Alyssa Cartaut is among the innovators using these types of 3D printing composites in her work. Specifically, she designed footwear as part of her recent The Cushion Issue collection that was made using 3D printing and a PLA filament reinforced with European flax-linen fibers. Several shoe components, including the heels and insoles were 3D printed from the flax-linen composite, providing a bio-based alternative to more traditional materials like resin or plastic. As the designer said: “PLA filament infused with linen has enabled me to design precise, flexible shapes while limiting the environmental impact of production.”
Research is also being done on the 4D printing front. For instance, Professor Antoine le Duigou from the Institut de Recherche Dupuy de Lôme is investigating how these natural-fiber composites can be used to create structures that respond to stimuli like heat or moisture.
“European Flax-linen and hemp are redefining what’s possible in biocomposite manufacturing, moving far beyond traditional lay-up into highly automated processes like filament winding, prepreg systems and additive manufacturing,” said Bruno Pech of the Alliance for European Flax-Linen & Hemp. “These innovations are unlocking new levels of precision, design freedom and performance, proving natural fibres are ready for the most advanced industrial applications.”
