A bicycle built for … you!

Caren B. Les, caren.les@photonics.com

If yours won’t be a stylish marriage, and you can’t afford a carriage, you could possibly commission a bicycle built for two – just for you – thanks to a new laser-sintering-based manufacturing process.

A prototype bicycle dubbed “Airbike” was created using additive layer manufacturing, a 3-D printing process that begins with a design on a computer. A press of the button transforms the design into a physical object through laser sintering, or melting, of the selected structural material into successive 2-D layers. Images courtesy of EADS.

In Bristol, UK, the European aerospace and defense group EADS has unveiled a demonstrator model that was “grown” from nylon powder in a process that allows complete sections of the bicycle – such as the wheels, bearings and axle – to be built in one piece and to precise user specifications.

The additive layer manufacturing (ALM) process, similar in concept to 3-D printing, enables a computer design to be transformed into a physical object at the press of a button. A laser melts successive thin layers of nylon until a solid, fully formed bicycle emerges. The computer, connected to a machine containing the powdered structural material, splits the 3-D design of a component into many 2-D layers, and the laser melts the powder into the layers to form the object.

An engineer prepares the control system for laser sintering nylon powder material, part of a process that can “grow” a physical object from a computer design.

“The beauty is that complex designs do not cost any extra to produce,” said Andy Hawkins, the lead engineer. “The laser can draw any shape you like, and many unique design features have been incorporated into the Airbike, such as the auxetic structure to provide saddle cushioning or the integrated bearings encased within the hubs.” Auxetic structures, which when stretched become thicker perpendicular to the applied force, offer high energy absorption and fracture resistance.

The ALM technology can manipulate metals, nylon and carbon-reinforced plastics at the molecular level, which means it can be used in high-stress, safety-critical aviation applications. Compared with traditional machined parts, those produced by ALM are up to 65 percent lighter but just as strong, according to EADS.

Manufactured using a laser-based process, this bicycle is constructed entirely of nylon, except for the tires and drive train.

The demonstrator model features a strong, lightweight integrated truss structure, a spoke design that mimics the A400M eight-bladed scimitar propeller, a Kevlar belt for a clean drive system, and embossed text for personalization.

But your own Airbike could be made to your specs – so as you plan your dream wedding, how would you like your bike?