New from Böllhoff Systemtechnik : Innovative rivet for high-strength sheet metal

Böllhoff Systemtechnik (Bielefeld/ Germany), specialists in mechanical joining technologies, has developed a new generation of self-pierce rivets.
The innovation is specifically tailored to provide fastening of high-strength sheet metal, as is becoming increasingly used in car body construction. Developed at our Sonnewalde (Brandenburg) location, this new product emphasizes the well established expertise in self-pierce rivet technology of the Böllhoff Group and close partnership close partnership which has developed with the automotive industry.

Extensive know-how and trend-setting innovations are the cornerstones of the leading position adopted by Böllhoff in regards to self-pierce riveting. A technology which looks to the future. Light-weight construction, innovative material mixes and the use of new materials combine to create challenges in joining technology that make the self-pierce rivet appear very attractive.

At an early stage, Böllhoff prepared itself for the coming challenges. This is because as an answer to the trend towards lighter and yet safer car bodies, the steel industry developed respective innovative products that have one important thing in common: the material is very strong and the sheet metals are considerably thinner than before. The consequence is that conventional rivets are reaching their limits due to the high tensile strength of the materials. Rivets are either destroyed during the punching process or they don’t even penetrate into the material.

This is different with self-pierce rivets from the Böllhoff Company. They now make it possible to fasten high-strength sheet metal with a tensile strength of 600 to 1,200 Nmm2. In shearing force tests with single point probes in sheet metal at 800 N/mm2, a tensile force of 11 to 12 kN is reached.

This is essentially possible due to three innovations in the rivet itself. Firstly, this is due to improved material where the choice of sheet materials guarantees an optimum combination of hardness and flexibility. Secondly, the geometry of the conventional rivet was changed considerably to increase its stability when it is subjected to greater forces. Thirdly, Böllhoff optimized the cold forming production process and modified it to meet the new requirements for the production of the new generation of rivets.

The Böllhoff development team worked on the new rivet for approximately one and a half years and it is now ready for volume production. Böllhoff combined the expertise of the family-run company with rivet technology through close collaboration of development and production at locations in Bielefeld and Sonnewalde. The automotive industry and its subcontractors in particular are considered to be potential applications for the new generation of rivet, but above and beyond this, there are many other industry sectors that use high-strength sheet metal.

Currently, the fasteners are available in two styles and additional dimensions for new requirements are under development. As usual at Böllhoff, customer-specific specifications can be implemented in suitable surface shapes and solutions for the new rivet as well.