Inspirational ideas: Cork for 3D printing

High value 3D printed products from low quality cork

Cork oak forests have to be managed about for 60 years before they produce high-quality cork. A lot of low quality cork is produced during this time, and there is little demand for it as a product. In Catalonia, lack of economic incentive means forests are left unmanaged and this has led to large forest fires. The Catalan Cork Institute has found a use for low quality cork (including the burnt cork) - 3D printing.

The raw material

Over the years, Catalan forests have been ravaged by large forest fires. These fires left behind huge amounts of burnt cork oak groves. Research had shown that the burnt cork can be used in new applications, such as 3D printing, as so this brought about an opportunity for the forest managers to still make a profit from these areas and to manage them again in following years.

Another source of this raw material is from the cork stopper industry. Cork oak is a typical product of the Mediterranean forest. However, it takes many years for the trees to be mature enough to provide cork of a quality which is suitable for the cork stopper industry. When the oak tree is 35-40 years old, the first harvesting of cork (removal of the bark) can be done. Then, after a further 9-14 years the bark will be harvested again. But it is not until the third harvesting another 9-14 years later that the bark harvested can be used in its entirety for the cork stopper industry. So, tons of low quality cork are generated every year.

“One of the main problems of cork forests is the lack of productivity of good quality cork, and therefore, a big quantity of cork is not useful for cork-stoppers fabrication. For this reason, many forest owners don’t manage their forests, this can lead to abandonment and forest fires or just a reduction in cork production. If we are able to create a new use for this low-quality cork, forest owners would have an economic incentive to manage their forest.” Says Albert Hereu, Director of Catalan Cork Institute.

3D printing

3D printing is a new technology for making objects by building up layers of a given material, usually plastic or metal. The material is fed into 3D printers in the form of a filament, which is heated so that it liquefies and then solidifies one layer at a time.

Some studies had already been looking into combining a plastic base with wood or coconut fibre to obtain a filament for 3D printing using a natural base.

But in 2016, Catalan Cork Institute began a circular economy project, called 3DCork to create a new filament made up of granulated cork, using even the cork from the burnt forests, and a plant-based plastic. The new material consists of more than 20% of cork mass, and it will be biodegradable and therefore environmentally sustainable.

In this new study, Catalan Cork Institute has shown that a cork-based filament is natural, renewable and biodegradable. Cork has a combination of properties that make it unique and versatile, low in density and high in elasticity, it has high mechanical strength, low thermal and electrical conductivity and a good thermal and acoustic insulation. This material can be used to manufacture any prototypes from cork before a mass production.

“These properties can provide a lot of versatility in terms of 3D printing and they reduce the percentage of other plastic components, and therefore lower the environmental impact.” Says Maria Verdum, technician of R&D Department of Catalan Cork Institute.

Catalan Cork Institute is a semi-public partnership. They promote and develop Catalan Cork sector. Their main aim is raising the value of cork territories, they work on providing services and investigation on cork-stoppers companies and developing new applications of cork and giving value to it.

More information

This case study was presented at the EIP-AGRI workshop ‘New value chains from multifunctional forests’ in Vienna in November 2016. See page 16 of this document

Contact: María Verdum, mverdum@icsuro.com, Albert Hereu, ahereu@icsuro.com

Photos: Catalan Cork Institute (ICSURO)