Orbitrec 3D prints a bike in the smartest way

CES 2016: Titanium and carbon fiber used effectively

Orbitrec titanium 3D printed crank assemblyCerevo’s Orbitrec is claimed to be the world’s first 3D printed bike, and the tech is impressive. SemiAccurate thinks 3D printing things like the Orbitrec is the way of the future.

On the surface the Orbitrec looks like any other high-end carbon bike, only with a little twist, the connected part. The cloud connectivity is via a device called the Ride-1, an ANT+ sensor device that does all the usual biking tricks plus a few more. The only down side is it only connects to an iPhone at the moment, but the Ride-1 is otherwise a slick bike computer. All together it looks like this.

Cerevo Orbitrec 3D printed bike

Orbitrec 3D printed connected bike

The thing that SemiAccruate found interesting is not the printing part but how different materials, both 3D printed and normally constructed, were used. Orbitrec is carbon fiber and titanium, what goes where and why is the smart bit. The tubes are all carbon fiber, the places where they meet like the head tube, the crank assembly, and others are titanium, 3D printed titanium. Very complex 3D printed titanium shapes at that, see?

Orbitrec titanium 3D printed crank assembly

Try machining this

The piece above is the heart of a bike, the point where almost all the major load bearing tubes connect, and the pass through for the cranks. There is a lot of torque at this point because of the cranks, plus various and continually changing forces from the tubes. It is a mess to model and very hard to manufacture in a light but just strong enough way.

As you are probably aware carbon fiber is very light and strong but only strong in a single plane, sometimes two. This means you have to model the forces on a part very carefully and align the carbon cloth layers in such a way as to be strong where needed. Anything more adds weight, anything less will shatter in very short order.

You can make a part out of carbon fiber that will support a car but can be crushed with one hand from another angle. Making a part like the head tube or crank assembly out of carbon fiber is extremely hard to do and takes up more weight than you might expect because of the way the forces interact. Ideally you want to make these parts out of metal but as you can see above, the part is a royal pain to machine from billet if it is possible at all. The end result is you make it from several sub-assemblies and weld or bond them together. This again adds weight, cost, and usually isn’t optimal for the forces involved.

If only there were another way, and there is, 3D printing. With the titanium part above it was 3D printed in one pass, and printed in a way that is optimal for size and weight. Assuming they did the FEA analysis right but that isn’t a major trick nowadays. There was probably some minor machining that needed to be done on the tube fitting surfaces, but otherwise it is a case of print, polish up a few bits, and glue the tubes on.

If you don’t need to adhere to minimum weight standards, the Orbitrec or similarly constructed bikes could be made to weigh less than a full carbon bike and far less than a fully printed titanium bike. Add in a Ride-1 and you would still be under the weight limit, plus you are connected. I really want one of these bikes, and not just for the geek factor either.S|A

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Charlie Demerjian

Roving engine of chaos and snide remarks at SemiAccurate
Charlie Demerjian is the founder of Stone Arch Networking Services and SemiAccurate.com. SemiAccurate.com is a technology news site; addressing hardware design, software selection, customization, securing and maintenance, with over one million views per month. He is a technologist and analyst specializing in semiconductors, system and network architecture. As head writer of SemiAccurate.com, he regularly advises writers, analysts, and industry executives on technical matters and long lead industry trends. Charlie is also a council member with Gerson Lehman Group. FullyAccurate