Southwest Manufacturing News • May 2017 • Metal 3-D Printing Pushes The Boundaries In Moto2

In the high-octane world of MotoGP motorcycle racing, technical enhancements can have a big impact. Moto2 team TransFIORmers is using cutting edge metal additive manufacturing (3-D printing) technology in an unconventional front suspension system to gain a competitive advantage.

Motorcycles ridden in the MotoGP World Championships are special; the general public cannot buy them and they cannot be used on a public road. As prototype racing bikes they are custom-built to outdo their rivals and maximize performance on the track. Moto2, the second of the three MotoGP classes, was created in 2010, and its official engine is a 600cc four-stroke production engine, currently supplied by Honda.

The French Moto2 team TransFIORmers, based in Perigueux, South West France, is revolutionizing front suspension design in order to stay ahead of the pack. Christian Boudinout, a former 250cc World Championship rider, lead’s the team, and the unconventional suspension system was inspired by the seminal work of the legendary French motorbike designer Claude Fior. Boudinot’s former friend and mentor, Fior, recognized the gains to be made from isolating the front suspension from steering forces. Resolving issues of ‘brake dive,’ the design enables later braking into a corner and faster acceleration out.

Instead of the more traditional telescopic front fork suspension, the Trans- FIORmers motorcycle employs a rigid front fork suspension system separated from the chassis using two wishbones. “To further advance the development of its new design, TransFIORmers approached I3D Concept, a world-class expert in metal additive design and manufacturing techniques,” said a Renishaw spokesperson.

Using Renishaw’s AM 250 additive manufacturing system, I3D Concept worked in partnership with the Trans- FIORmers team to optimize the design of its upper wishbone component, one of two attaching the front fork to the chassis and critical to the bike’s steering.

In the development of new components in the Moto2 bike design, achieving a weight reduction is a priority. In particular, reducing the unsprung mass of the bike is a key consideration. The lower the unsprung mass, the better the suspension is in terms of vibration management and responsiveness to both braking and acceleration. Of equal importance is the speed with which the design of a new component can be modified, and how long it takes to remanufacture. “Achieving perfection in a highly competitive environment demands fast and accurate component iteration,” said a spokesperson.

In a high reliability environment, mechanical strength is a further prime consideration. The TransFIORmers’ wishbone component needs to assure best possible rigidity, while handling significant levels of dynamic steering force. “To improve overall motorcycle performance, reducing the weight of all components located behind the shock absorbers is absolutely vital. Failure to optimize component weights can have an adverse effect on vibration, braking and acceleration, so weight reduction is a really high priority,” said Jérôme Aldeguer, Mechanical Engineer, Trans- FIORmers.

TransFIORmers’ original wishbone component was hand-fabricated in steel; with the assembly comprising twelve separately machined and welded parts. I3D Concept consolidated the design into a single-piece component, greatly reducing assembly time. The company produced the metal 3-D printed wishbone using a Renishaw AM 250 additive manufacturing system, initially prototyping in stainless steel (inox) and finally manufacturing a lighter weight part in titanium.

Key to the new 3-D component design was an iterative process of topological optimization, whereby the wishbone layout was successively rationalized in software within tight space constraints to withstand a set of predefined front fork loading conditions. Once the final component design was validated using digital CAD software, the build preparation file was prepared offline prior to export to the additive manufacturing system.

Within the CAD software, I3D Concept was able to assess whether the parameters were effectively predetermined or whether they required tweaking to match the specific metal powder characteristics and the complex target geometries of the TransFIORmers wishbone.

Importantly, using the AM 250’s dedicated Optical Control System (OCS) software , I 3D Concept was able to very accurately control laser steering which helped to enhance precision, definition of features and surface finish. By taking an additive manufacturing approach to Moto2 bike design, TransFIORmers succeeded in dramatically reducing the weight of its critical wishbone front suspension component by 40%. Comparing the one-piece titanium component with the original welded steel component, a weight savings of 600 g was achieved.

Metal 3-D printing has also provided TransFIORmers with much finer control over component tolerances and the flexibility to very quickly iterate wish bone geometries to match specific chassis and kinematic requirements.

“The weight reduction that metal 3-D printing has achieved for us in our wishbone component has enabled us to bypass traditional weight transfer phenomenon and the problems associated with brake dive. More than that, it has allowed us to design a part that is not only lighter, but far more rigid at the same time,” said Jérôme Aldeguer, Mechanical Engineer, TransFIORmers.

“With an ultimate tensile strength in excess of 1,100 MPa when processed using additive manufacturing, and near perfect 99.7% densities, the titanium Ti6AI4V alloy used has delivered a radical new wishbone offering far greater rigidity than the original multi-part, hand-assembled steel component.”

“Due to additive manufacturing, TransFIORmers’ prototype wishbone development has become a highly efficient and cost effective process. Extensive part machining and assembly time overheads have been removed and design iterations and manufacturing have been made many times faster. In June 2016 the team won its first ever Moto2 GP race at the FIM CEV event in Barcelona,” said the spokesperson.