Much like baseball and apple pie holds an iconic place in U.S. history, so too does bicycle riding in The Netherlands. From the simple working man and woman to the Dutch prime minister, residents ride bikes. In fact, according to the BBC, there are more bicycles in The Netherlands than people, and in major cities up to 70 percent of all journeys are made by bike.
So, they ride bikes, a lot. What they don’t do is make many of them. Dating back to the 1800s, bicycle manufacturing in this northern European country was a burgeoning industry, but over time this changed. The labor intensive, costly process of hand brazing or welding multiple tubes together at the ends to build the frames has driven major Dutch brands to move to cheaper labor markets.
A new startup, however, is looking to bring bicycle manufacturing back home. The company is Mokumono and it was formed by twin brothers Bob and Tom Schiller. A graduate of the Design Academy Eindhoven, Bob Schiller conceived of a monocoquedesign bicycle as his graduate project. According to Schiller, the name Mokumono is an abbreviation of the words ‘mokum’ which refers to Amsterdam, and ‘mono’ as a reference to the frame’s monocoque construction. Monocoque design is a structural approach in which loads are supported through an object’s external skin, much like an egg shell. The term itself is French for “single shell,” and the technique has been used in the manufacture of cars, planes, motor bikes, and myriad other products.
In Mokumono’s case, the monocoque design is achieved by joining two aluminum sheets, formed into a mirror of each other, into one single shell. This shell makes up the frame of the bike onto which components are assembled and through which break and gear cabling is routed. By adopting automated manufacturing techniques, which Schiller said was inspired by the automotive industry, the Amsterdam-based, Kickstarter-funded company is scheduled to begin filling orders by the end of this year.
The laser welding process leaves a raised seam, which has been incorporated into the design of the bicycle.
The laser welding process leaves a raised seam, which has been incorporated into the design of the bicycle. | “By borrowing these techniques,” he said, “we are able to almost fully automate our production process, significantly lowering labor requirements and thus making it possible to build bicycles in The Netherlands again.”
To this point, only prototypes have been built; tooling still needs to be produced. The process to develop the bike involved producing three prototypes. The first two were lifesize, 3D printed bikes that looked like the real thing, but were not strong enough on which to ride. The third and final prototype is a functional bike. Instead of 3D printing, this prototype was handformed out of 7000 grade aluminum, the same material that will be used in the final product. This allowed them to test them in a truly Dutch way, by extensively riding them. Additional testing is projected to occur after production fully begins
The company has contracted with Witte van Moort, a local sheet-metal fabricator that has been in business for more than 60 years to do the actual manufacturing. The production process of the bicycle frame starts with deep drawing aluminum sheets. At Witte van Moort, automated material handling equipment uploads flat sheets of steel into the deep drawing, hydroforming machines that press the material into desired shapes with between 65 and 110 tons of pressure. For the bike’s frame, after the two halves of the frame are pressed, the handling system offloads the formed sheets and transfers them to a robotic, 3D laser processing system.
As seen in a production video, a Trumpf 7040 laser processing system will use a laser cutter to trim excess material from the two frame halves. In the final step, a rotating table will transfer the components to the laser welder on the 7040 model, and the two pieces will then be joined to form a strong and lightweight aluminum frame. “The 7000 alloy is the strongest aluminum and therefore very suitable for bicycle frame building,” Schiller said. “Another benefit is that it is self hardening after the welding process. This means that it does not need heat treatment after welding.” The technique leaves a raised seam running along the middle of the frame, and this stripe is incorporated into the design. The head tube, bottom bracket shell, and dropouts aren’t part of the monocoque, allowing them to be changed out for future design iterations without having to alter the rest of the frame. Other components such as the carbon-fiber belt drive and flat mount hydraulic disk brakes are assembled at the factory.
Schiller said some testing still needs to be done such as strength testing and various production inspections. “The hand-formed prototype we have now, does not have the same properties as the production version, that is why we have not been able to test the frame to give exact figures.” Still, “the prototype does give a good idea of the strength of the frame.” he said. “We are therefore certain that the frame is strong and stiff enough. To be certain, we will simulate the frame testing in the computer before the dies (are) produced.”
While there are many reasons for wanting his bikes manufactured in The Netherlands, Schiller said that the main advantage of producing bicycles in his home country is that it “allows us to closely monitor every step of the production process. This means that we can discover and fix potential flaws fast and adequately, making sure that every Mokumono bike is of the highest possible quality.”
