A UK company that prints metal parts has collaborated with a British bicycle design and manufacturing company to create the world’s first 3D-printed metal bicycle frame.

Empire Cycles designed a mountain bike, based on their MX-6 model (see photo below), that could take advantage of Renishaw's additive manufacturing (another name for 3D printing) technology, allowing them to create a titanium alloy frame that was both strong and light.

The frame, manufactured in sections and then bonded together, is in fact a third lighter than the original.

Designing for 3D printing

The bike design used topological optimisation software programs that help to determine the "logical place" for material using iterative steps and finite element analysis.

With topological optimisation, material is removed from areas of low stress until a design is optimised for load bearing, resulting in a model that is light and strong.

In the case of this bike, the design was optimised for additive manufacturing by eliminating many of the downward-facing surfaces that would have otherwise needed support structures.

A very light bike

The bike is made of a titanium alloy, which is denser than aluminium alloys, so the only way to make the titanium alloy lighter was to pare back the design as described. The original bike frame weighs 2.100 grams, while through using 3D printing, the weight drops to 1.400 grams.

The makers admit there are lighter bikes available, made from carbon fibre, but say that the durability of carbon fibre can’t compare to metal.

"They [carbon fibre bikes] are great for road bikes, but when you start chucking yourself down a mountain, you risk damaging the frame. I over-engineer my bikes to ensure there are no warranty claims," said Empire Cycles Managing Director Chris Williams.
 

When processed using additive manufacturing, the titanium alloys achieved near perfect densities, which is better than casting, meaning the frames are also very strong.

Benefits of additive manufacturing

Another benefit of 3D printing is that the process gives the flexibility to make design improvements right up to production, as no tooling is required.

Of course, the most attractive benefit to prospective buyers of the bike the possibility of total customisation and tailoring, with one-offs as easy to make as batches. They are already including the rider’s name as one of the built-in features.

According to Renishaw, the project is not yet in commercial development, but they hope to continue to develop the project, with testing of the completed frame continuing in partnership with Swansea University.

Source: Renishaw