Sweden: Researchers 3D Printing with Wood-Based Ink for Greener Manufacturing

Wood materials would normally be impossible to process without a range of sharp tools to manipulate them into the desired form; however, as researchers often are famous for (within the 3D printing industry especially), thinking outside the normal range of conventional processes has allowed the team at Chalmers University of Technology to come up with a way to make new products with what is, essentially, wood pulp. They also added hemicellulose, a natural component derived from plants, that acts like a gluing agent.

Creating such a material works against the actual genetic code that wood contains, making it hard—offering durability, toughness, and porosity and torsional strength. In most construction projects, wood must be handled with a saw or other basic tools. Unlike many other materials, options such as melting or reshaping wood are normally not available.

3D printing with sustainable Swedish forest materials. The microscopy images of real wood tissue and the 3D printed version show how the researchers mimicked the real wood’s cellular architecture. The printed version is at a larger scale for ease of handling and display, but the researchers are able to print at any scale.

“Processes which do involve conversion, to make products such as paper, card and textiles, destroy the underlying ultrastructure, or architecture of the wood cells. But the new technology now presented allows wood to be, in effect, grown into exactly the shape desired for the final product, through the medium of 3D printing,” states a recent press release regarding the research from Chalmers.

As researchers, developers, and manufacturers around the world continue to study materials and the science of how they work with various technologies—especially 3D printing today—it is astounding how many different types of plastics, metals, fibers, ink, and more can be used to create complex geometries. Even a material as unique as wood has already been used for innovations like digital wood and complex textures, to tire technology, and wood as a better alternative to plastics.

With this new ultrastructure, the researchers see the potential for making a wide range of items with their wood composite ink, to include:

• Packaging
• Clothes
• Furniture
• Healthcare and personal care products

Professor Paul Gatenholm

Once they had the material in place, Chalmers researchers were ready to take their project to the next level as they began using the ink to ‘instruct a 3D printer’ and create a structure showing off the benefits of wood cellulose.

“This is a breakthrough in manufacturing technology. It allows us to move beyond the limits of nature, to create new sustainable, green products. It means that those products which today are already forest-based can now be 3D printed, in a much shorter time. And the metals and plastics currently used in 3D printing can be replaced with a renewable, sustainable alternative,” says Professor Paul Gatenholm, who has led this research within the Wallenberg Wood Science Centre at Chalmers University of Technology.

The ramifications go far beyond just the typical benefits of 3D printing as products manufactured with the wood ink could be created and then ‘grown to order’ – and quickly so.

“Manufacturing products in this way could lead to huge savings in terms of resources and harmful emissions,” said Gatenholm. “Imagine, for example, if we could start printing packaging locally. It would mean an alternative to today’s industries, with heavy reliance on plastics and C02-generating transport. Packaging could be designed and manufactured to order without any waste.

“The source material of plants is fantastically renewable so that the raw materials can be produced on site during longer space travel, or the moon or on Mars. If you are growing food, there will probably be access to both cellulose and hemicellulose.”

A honeycomb structure with solid particles encapsulated in the air gaps between the printed walls. Cellulose has excellent oxygen barrier properties, meaning this could be a promising method for creating airtight packaging, for foodstuffs or pharmaceuticals for example.

Taking the manufacturing innovation full circle, Gatenholm’s group has even created a new packaging concept with honeycomb structures that could serve as airtight packaging—even for food or medication. They have also designed prototypes for clothing, healthcare products, and more. Gatenholm also envisions the potential for the use of their materials and products in space, with the technology recently presented at a European Space Agency (ESA) workshop. Other projects are also in the works with Florida Tech and NASA.

“Traveling in space has always acted as a catalyst for material development on earth,” he says.

Find out more about this recent Chalmers University of Technology research in their recently published article, ‘Materials from trees assembled by 3D printing – Wood tissue beyond nature limits.’

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The microscope images show how the researchers are able to precisely control the orientation of the cellulose nanofibrils, printing in different directions in the same way that natural wood grows.