Dec 15 2005
Rapid prototyping makes it possible to quickly produce or modify tools and structural components, as one-off jobs or in small batches. A unique process allows 3D portraits and other patterns to be hammered into car bonnets or other sheet metal.
Rapid prototyping is more and more adopted as a method of manufacturing parts for the automobile and aerospace industries. Such processes work on the basis of a CAD model or the scanned image of a real object. Both can be easily modified and optimized on a computer. Once the virtual object has been designed, 3D prototypes may be created by different RP machines.
Incremental forming techniques are excellently suited to the production of sheet-metal parts, especially in small batches of typically up to 200 units. “Incremental” means hammering or pressing a part into shape in gradual stages. In the metal-hammering process developed at the Fraunhofer Institute for Manufacturing Engineering and Automation IPA, a robot guides an oscillating punching tool in circular movements over the fixed sheet of metal. It gradually creates a relief pattern corresponding to the computer template. It takes less than 15 minutes to convert a CAD model into a real object measuring 10 x 10 centimeters.
The limits of the process are dictated by the shape of the part: hammering is more suitable for curved shapes, whereas the traditional deep drawing is the better option for more sharply defined parts with sides exceeding an angle of 60 degrees. But the latter requires the additional investment of manufacturing a pair of new pressing tools.
The new process is also capable of customizing series-produced parts at little extra cost. For instance, it allows high-end customers to modify cars sporting their logo as a relief pattern incorporated in the bonnet, or as a permanent inscription in the fender. Car bodies can also be enhanced with ribbed styling to emphasize their aerodynamic performance. This would be a great asset for show cars, which are not destined for mass production.
“We are experiencing a trend toward shorter product life cycles, decreasing volumes, and ever more complex geometries,” points out IPA project manager Timo Schäfer. “‘Roboshaping’ is a clear response to this trend. Our unique forming process uses robots to manufacture components to the desired specifications, within short deadlines, to customized designs, and without major investment in plant.”