Story | 10/26/2018 06:38:23 | 3 min Read time

Steps on a 3D-printed bridge

“The purpose of the Leaf Bridge is to demonstrate the properties of the material, from usability to durability,” explains Eve Saarikoski, applications manager, and the developer of the UPM Formi 3D material.

The bridge made of a wood composite material was introduced to the public for the first time at Pori Housing Fair las summer.

“Visitors were intrigued by the Leaf Bridge, although they were hesitant to walk on it, especially on the first days. But it was made to be strong; the bridge was printed hollow, weighs 93 kilograms and can support around 500–1000 kilograms of weight,” says Eve Saarikoski.

In addition to being able to support great weight, the material was also designed to withstand challenging weather conditions. “The material imitates the properties of wood, and can be processed like wood materials.”

According to Saarikoski, housing and construction fairs are ideal events to showcase the material, as potential customers for UPM Formi 3D are primarily in the construction and furniture industries.

Field of the future

The Leaf Bridge project was initiated at the end of 2017 when 3DStep, a 3D printing company from Ylöjärvi, Finland contacted application manager Eve Saarikoski, the developer of the material.

“We had a wonderful group of experts from various fields working on the project. Their expertise, willingness to experiment and forward-thinking attitude made this possible. The Leaf Bridge would not be here without that co-operation, and especially not this quickly. The success behind this project was co-creation together with a shared vision and goal.,” says Pekka Ketola, CEO of 3DStep.

3D printing is still quite an unknown technique of manufacturing products in Finland but, according to Ketola, UPM Formi 3D will be able to cater for even private individuals’ printing needs in the near future.

“You could, for example, print a cradle for your baby. The material imitates wood and can be used to print a unique product with production costs comparable to mass-produced ones.”

Ketola describes UPM Formi 3D and 3D technology as a new and upcoming industry branch in Finland. “Material bends to many, and the material can be used in wall elements, three-dimensional advertisements, and interior decorations. The material is very versatile. It is up to 100 times faster to print than metal, for instance.”

Printed in Tampere

One of the six partners involved in the Leaf Bridge project was TAMK, Tampere University of Applied Sciences. Principal lecturer Mika Ijas says that in the project TAMK was involved in the role of the hardware developer and the bridge itself was also printed on TAMK. "The project was interesting because we were able to develop large-scale printing devices.”

The Leaf Bridge was printed with two separate printers. One was modified from a welding robot and the other was a 3D printer on an assembly line. They were both designed for this project, but they can also be utilised in the future. According to Ijas, In the project, teaching and ICT activities were able to combine, because students was involved at the equipment development and the printing process.

Read more about upm formi 3d material

Read more about the leaf bridge


The leaf bridge in brief

  • The printing material is a wood composite and the bridge was printed using two 3D printers at
  • Tampere University of Applied Sciences (TAMK).
  • The frame of the bridge was printed in 10 parts, and the railings in 17 parts.
  • The bridge is designed to support 500–1000 kilograms of weight.
  • The bridge was assembled using weatherproof wood glue. The railings were attached to the frame using glue and slot joints.
  • The railings were printed hollow and then filled with polyurethane.
  • The bridge was first painted with two layers of primer coating and then with an anti-slip agent and spray paint.


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