Talking about ‘blowing up metal objects’ often brings explosions to mind. But a technique developed over the last decade is rather more subtle, and looks set to make a mark in the manufacturing industry.

Called FiDU, the technique involves welding thin metal plates together at their edges and then inflating them to create any number of shapes and objects.

One example, a gleaming metal stool, has received much attention. Now, its developers have turned their attention to other applications, from skateboards to wind turbines.

FiDU, which stands for the German ‘Freie Innen Druck Umformung’, or free inner-pressure deformation, is a technique that takes advantage of the stability and strength of metal sheets, along with low weight and little material waste.

In short, the FiDU process turns flat, 1 mm thick metal sheets into supremely stable three-dimensional elements. Watertight welded double metal sheet elements are deformed with the aid of water and air pressure respectively, which are applied from the inside. At 0,4 bar, the pressure used is relatively low.

This ‘blow-up’ method is still being developed. It’s an alternative to similar, recently developed processes in terms of very low applied pressures as well as involving widely-used technologies and equipment.

FiDU requires just one thousandth of the pressure needed for internal high-pressure forming. The main advantages of this process is that the material production is very fast, easy and precise. Two dimensional elements are cut from the steel sheets and welded one to another using lasers. Inflation transforms them into a stable 3 dimensional object, such as the chair, skateboard and other objects seen in the pictures.

Recent developments in the technology have led to the FiDU footbridge, an extremely low-weight metal bridge, with a 1:10 weight to load-bearing ratio. On a different tack, a non-symmetrical profile is being developed for rotor blades. Three aerodynamic profiles were created and successfully tested for a low-cost wind turbine.

More information can be found on the developer’s site.