At first glance, the industrial production of car body components or even complete vehicles in a batch size of one appears impossible, particularly for economic reasons. However, the Fraunhofer Institute for Machine Tools and Forming Technology has developed a process mix that now makes automotive production in single-unit quantities economically viable.

Fraunhofer researchers demonstrate how their approach works in practice using the exhibit “Silberhummel” – a streamlined concept vehicle based on the plans of a racing car that was never produced. Fraunhofer IWU reconstructed the vehicle and manufactured the model’s exterior parts. The body consists of benchmark components produced using various forming, joining and additive manufacturing technologies developed at the institute.

Its shape is created by means of incremental sheet metal forming.

Incremental sheet metal forming is a forming process used to manufacture complex components in small quantities. The final shape is generated through multiple successive movements of a CNC-controlled forming tool. Compared with conventional deep-drawing processes, elaborate tooling can be dispensed with. This significantly reduces tooling costs and shortens the time to the first finished part.

• Production of sheet metal components with complex geometries in the shortest possible time
• Minimal tooling costs and therefore cost efficiency from a batch size of one
• Greater degrees of forming compared with deep drawing

Simple geometries such as truncated pyramids can be produced entirely without counter-tools using this method, while more complex component shapes require simple counter-tools. In the case of the Silberhummel, these are not made of solid metal as is usually the case, but of cost-effective and easy-to-machine wood-based materials. To create the shape, a sheet of metal is clamped in a frame over the tool on the AXA VPC 2800 U machining centre. The hemispherical forming tool is then brought into action. Pass by pass, it moves across the sheet until the semi-finished product has assumed its final shape – in this case, the curved wings of the Silberhummel.

Find out more about incremental sheet metal forming on the website of the Fraunhofer Institute.