3D printing could hold the key to glue- and adhesive-free timbers, driving the future of low-carbon car, aircraft and furniture manufacturing.
That is according to researchers at the Graz University of Technology—the home of the earliest research into cross-laminated timber—who have tested a new ultra-strong joining process, dubbed “AddJoining,” which uses metal and polymer composite to bind timber pieces together.
Led by Sergio Amancio from the university’s Institute of Materials Science, Joining, and Forming, the breakthrough could lead to more mass timbers replacing carbon-intensive materials (like steel and aluminium) in the multi-trillion-dollar automotive and aircraft manufacturing industries.
“Our motivation is environmental protection,” said Professor Amancio, a global expert in aerospace engineering, who used beech, oak, carbon fibre-reinforced polyamide and polyphenylene sulphide, stainless steel 316L, and Ti-64 alloys as test materials. “This process could see renewable raw material (like) wood replacing components made from energy-intensive or difficult-to-recycle materials.”
Role of AddJoining in manufacturing adhesive-free and screwless joints
According to Dr Gean Marcatto, ‘AddJoining’ is a polymer composite affixed to and printed directly onto a surface—in this case, wood, as part of a 3D printing process—which penetrates the wood pores and causes a chemical reaction similar to the reaction of glue with timber.
“After the joint fractured, we were able to find polymer in the (untreated) wood pores and broken wood fibres in the polymer, which suggests that the fracture occurred in the wood and polymer but not at the joint,” Dr Marcatto said, adding that better results could be possible if treated with a nanostructure via laser engraving.
However, “we wanted to work with as few steps as possible and, above all, without chemicals. We can use this technology particularly well with complicated 3D geometries because the components are printed directly onto the surface – in whatever geometry is required.”
In addition to ‘Adjoining’, researchers are also using ‘Ultrasonic Joining’ – a new manufacturing technique that involves joining two pieces of materials together through the production of ultrasound and heat to develop extremely strong joints without using adhesives or screws.
“This technique is suitable for large components and 2D structures since we achieve a precisely localized spot joint,” said Awais Awan, who was also involved in the work and said joints could be strengthened using pre-treatment of the wood surface via laser texturing.
Why Auto Giants are betting on Timber for Next-Gen EVs!
In December, Wood Central reported that the automotive industry is investing in new technologies, which could see timber panels replace steel in car chassis, seats, and body parts to make cars greener and lighter to reduce range anxiety.
At the same time, BMW is backing a new product known as “Woodflow,” with the car manufacturer exploring whether mass timber could offer a low-carbon alternative to steel in future electronic and hybrid vehicles.
The partnership saw “Strong by Form”—the start-up behind the new timber technology—visit BMW Group’s Dingolfing factory in June as part of the “Ready Go” advanced leadership program.
According to Andrés Mintik, Strong by Form’s founder, BMW has been “instrumental in helping the start-up secure global opportunities”, leading to Strong by Form oversubscribing its IPO, thanks to swell in demand for timber to be used lightweight construction, freeform formwork and furniture.
- To learn more about the role of timbers in building the next generation of batteries, windows, chassis and motor bodies, click here for Wood Central’s special feature.
