For Robot Bike Company (RBC), the goal is to “create the best bike frames possible.” The challenge will be to build and tailor the bike to an individual’s weight, height, and riding style, all within acceptable delivery timescales and manufacturing costs. How do the founders plan to do this? They are turning to additive manufacturing (AM) technologies to create these high-end mountain bikes.

Although the team at RBC had considerable experience in additive manufacturing and developing products and systems for the aerospace industry, it required multiple partnerships with industry experts to turn its ambition into a workable business. The team approached:

• HiETA Technologies, a specialist in design and engineering solutions for additive manufacturing technologies
• Renishaw, a leading developer of additive manufacturing machinery,
• and Altair ProductDesign. The engineers here were given the role of ensuring that the bike took full advantage of the flexibility that additive manufacturing offers.

In recent years, there have been several interesting examples where 3D printing or additive manufacturing was used in the bike industry, but to date the manufacturing method has been limited to technology demonstrations or short-run manufacturing rather than a practical way of delivering commercial products to market.

RBC’s goal for the project was to design and manufacture a fully customizable product that could be sold online to the public.

To deliver a lightweight, high stiffness bike, the RBC frame was to be created from carbon fiber. The carbon fiber tubes, as well as the bike’s other components and systems were to be joined with additively manufactured titanium ‘nodes’ made based on the specifications of individual riders (height, weight, riding style, and so on.).

Altair ProductDesign’s engineering team designed these joints, which included the head tube, seat post, and chain stay lugs. The goal for these parts was to ensure they were as lightweight as possible, yet still able to withstand the forces of downhill mountain bike riding. Plus, they had to be produced with additive manufacturing.

Maximizing material layout

The first task for the engineers at Altair ProductDesign was to perform optimization studies on each of the nodes to find a material efficient design that met the required performance characteristics and could be sized for different riders’ specifications. The engineers used solidThinking Inspire. The technology allowed the team to quickly take the existing designs into the virtual environment and apply a variety of loading data that the bike frame would be required to withstand during use.

The data were then used to develop a new geometry layout that maximized material layout efficiency while still achieving all performance targets.

Throughout this process, the design iterations were optimized for the additive manufacturing (AM) process, which included determining the ideal print angle and placement of the supporting structure to avoid the component collapsing during manufacturing. This process was conducted in conjunction with HiETA Technologies.

In addition to designing weight efficient components, Altair engineers also looked for opportunities to simplify the frame design to lower the cost of production. One such example was the chain stay lug, which was originally a three-piece assembly of two symmetric titanium components and an interlinking carbon fiber tube.

Using solidThinking’s Inspire for optimization, and Evolve for final part refinement, the team built in the additive manufacturing requirements from HiETA Technologies. The lug was designed as a single component, optimized for mass, performance, and manufacturing cost.

This optimization work delivered designs engineered for mass for the additively manufactured titanium frame nodes. The new material layout created innovative, organic looking designs targeted for AM. Weight was reduced where possible and part count was cut to minimize manufacturing complexity and cost.

RBC’s customizable mountain bike is a ground-breaking entry to the market. Altair ProductDesign’s involvement and usage of solidThinking Inspire and Evolve contributed to an extremely lightweight and stiff frame which, with HiETA Technologies and Renishaw, can be taken into production.

“Working with Altair ProductDesign has helped us create a minimum weight, maximum performance bike that really takes advantage of additive manufacturing,” said Ed Haythornthwaite, Founder, RBC. “Altair’s experience in designing for AM optimization technologies, have been extremely valuable. We would not have such a lightweight and stiff bike frame without their involvement.”