3D printing technology has become science fact, and new engineering techniques are making printing larger, more complex objects – bicycle frames, for instance – a reality.
The Arc Bicycle is just such an example. It’s the product of a engineering student design project by five students based at the Delft University of Technology (TU Delft) in the Netherlands. Their aim was to create a ‘proof of concept’, to demonstrate that a new method of 3D printing was capable of making a functional medium-sized complex object – and they succeeded.
The Arc consists of a 3D printed stainless steel frame, formed of a spidery web of struts and looking both organic and futuristic. The team behind it claim it weighs in at ‘under 20kg’ – so we’d leave those Alpine ascents alone for now – and when fitted with bars, forks, wheels and gears is fully functional. In fact, it survived a ride around the lumpy cobbled streets of Amsterdam.
“We didn’t know how the material would behave, so we chose to make it extra strong and sacrifice a bit of weight.” the design team said. “Our frame proves it’s possible to produce a bicycle frame in this way that was our goal.
“We tested the bicycle on the streets of Delft and it performed well. It offers quite a smooth ride. The wheelbase and the low centre of gravity of the bicycle make it easy to take fast turns. It has a fixed-gear configuration which was the most elegant solution for us as it’s primarily a concept bicycle.”
Drawn-out printing process
The process was not a quick one – the team report that total time taken to print the frame was in the region of 100 hours. This was however split over several weeks, with frame sections being assembled and welded together by members.
So where do the robots come into it? The students worked at R&D startup company MX3D, which is based in Amsterdam. It specialises in a new method of 3D printing, which uses multi-axis robotic arms and can ‘print’ using an extrusive process.
This essentially means that the robots can construct 3D shapes into mid-air, building in any direction without using supportive structures. The company is able to build using resin and metal, and offers its services to projects covering everything from art to civil engineering.
The process used to make the Arc bike is called wire and arc additive manufacturing, or WAAM. This process builds up the metal layer by layer to create the intended shape.
Lest you think this is simply concept-model pie in the sky, MX3D is in the process of designing a bridge that will be 3D printed using its robots – and which will be sited in Amsterdam.
While 3D printing is now being used more and more to produce smaller objects and parts, this technology helps open up the way to constructing larger and more complex designs. Charge produced titanium parts for its special edition Freezer Ti custom cyclocross bike using a more traditional 3D-printing method, and Bastion Cycles has created a titanium and carbon bike that incorporates 3D-printed features.