Printable wood flour forms complex shapes as it dries
A lot of work goes into creating wooden objects like furniture, with the timber needing to be harvested, treated, cut into shape and finished. Some scientists are rethinking this process with some interesting results, and researchers from the Hebrew University of Jerusalem have put forward a particularly creative example. The team's technology sees a wood-based ink 3D printed into flat shapes, which then morph into more complex 3D forms as they dry out.
The technology hinges on the way water content can influence the shape of wood, such as a tree deforming after it is cut down and begins to dry out. This is due to the configuration of fibers within the material, which vary in their orientation and cause the wood to shrink in a non-uniform manner as moisture evaporates. By leveraging this characteristic, the scientists were able to come up with a way of carefully manipulating this morphing process to produce desired three-dimensional shapes.
“Warping can be an obstacle,” says Doron Kam, a graduate student who is presenting the work at a meeting of the American Chemical Society this week. “But we thought we could try to understand this phenomenon and harness it into a desirable morphing.”
Wood waste microparticles described as "wood flour" were taken and mixed with cellulose nanocrystals and xyloglucan, which are natural binders found in plants, to form a water-based ink. This ink can be extruded by a 3D printer into flat shape, with the direction of lines and speed of the printing dictating the alignment of the fibers, and ultimately the 3D form that the dried wood will take.
The print speed and print pathways could be programmed to create flat discs that morphed into saddle-shaped objects similar to a Pringle, or create rectangular layers that morph into a helix after drying, twisting in both clockwise and anti-clockwise directions. The team believes more complicated shapes can be created with further refinement of the technique.
One day, the scientists imagine creating objects as complex as chairs or other furniture items, which could be shipped as flat-packed structures and morphed into the finished product, no hex key required. The team is also exploring how the process might be reversed.
“We hope to show that under some conditions we can make these elements responsive – to humidity, for example – when we want to change the shape of an object again," said one of the project's principal investigators, Eran Sharon.
The video below shows some of the wood-morphing in action.
Source: American Chemical Society