Turn solid wood into a continuous fiber
To make a monofilament from wood, we need very long pieces that are extremely small in diameter and highly flexible. Building on the knowledge of basketmakers, we are using split willow withes as our raw material. These are fine strips about 1.5 m long that are irregular in cross-section, measuring up to 7 mm wide and 1 mm thick. They are obtained from whole withes using a manual or mechanized cutting device that splits them off from the outer surface of the branch. This produces strips with a flat underside and curved upper side. The upper side is the peeled but otherwise undamaged surface of the withe. It is left intact, as it can withstand greater stresses than wood whose fibers have been opened up by processing.
The structure of willow wood, with its long cells and long fibers, contributes to this unusual flexibility, as does the fact that the wood in the fast-growing withes is naturally quite young. Whereas structural lumber must be laboriously steamed and compressed to increase its flexibility, simply being immersed in water is sufficient for willow. The traditional modification processes for wood can also be used on willow to further increase its flexibility. Willow withes are typically stripped of their bark before use, revealing a pleasing aesthetic of smooth, light-colored wood with fine pores. Willows grow in moist soils such as floodplains. Most willow grown commercially for wider distribution is cultivated in Spain, Poland, and France, but there are many smaller plantings throughout Europe for regional consumption. Increased use of willow for wood-based textiles could thus offer European farmers an opportunity to tap into new markets.
The qualities of a textile are greatly influenced by the cross-sectional shape of the fibers from which it is made. The more thoroughly uniform this shape is, the more precisely the characteristics of the fiber and the textile can be specified. To produce solid-wood monofilaments with specific cross-sectional shapes, we have adapted common processes for modifying the width and thickness of wood. The challenge here is that the split withes to be modified, like the monofilaments to be created, are very small in diameter. The smaller the piece is, the greater the impact of the material’s naturally occurring irregularities and the idiosyncrasies of its grain. This means that extremely precise tools and meticulously uniform handling of the workpiece are required to produce a cross-sectional shape that is consistent for the entire (effectively endless) length of the monofilament. However, with skillful technique, a piece that is exceedingly tiny in cross-section but also very long – unusual proportions for woodworking – can be reliably obtained from this pliable material.
Development is a process of iteration over artistic, artisanal, structural-engineering and mechanical-engineering approaches. We use DIY methods to build our own high-tech, low-budget machines and put them immediately to use. This allows us to arrive at a proof of concept via extremely short development cycles. Refining our processing methods and machines in tandem with the new material we are investigating is a great advantage to our development process, since tools and materials have a powerful influence on one another. By taking this duality into consideration at a very early stage of development, we can tightly control both the conditions under which our processes and methods are executed and the design possibilities of the material under development.
The research project FLIGNUM – A solid-wood monofilament is carried out by
Forschungsplattform BAU KUNST ERFINDEN | Prof. Heike Klussmann | Spokesperson|
Steffi Silbermann, Jan Juraschek, Frederik Ecke, Clarissa Rauch, Maria Vasenina, Lisa Schreiber, Julius Abromeit, Selsela Khorasani
FG Experimentelles und Digitales Konstruieren und Entwerfen | Prof. Philipp
Eversmann | Zuardin Akbar, Mohamed Dawod, Arjen Deetman, Christoph Schlopschnat
FG Trennende und Fügende Fertigungsverfahren | Prof. Dr.-Ing. Prof. h.c. Stefan Böhm|
Daniel Kohl, Jannis Heise
FLIGNUM is funded by the FNR - Förderagentur nachwachsende Rohstoffe e.V.