Hydroforming, laser cutting, robotic insertion, & high-tech fasteners.

The Volkswagen EuroVan MV TS, a commercial vehicle, unlike many other vehicles, has a hydroformed instrument panel crossbeam. Because this was a new application, VW had to determine an effective way to attach fasteners to the steel crossbeam, which is 1.6-m long and formed from 2-mm thick material. According to Matthias Jokisch, manager of application engineering in Europe for Textron Fastening Systems (TFS; in the U.S. headquartered in Troy, MI; www.textronfasteningsystems.com), "The tubular shape and closed geometry of the crossbeam prevented access to its blind side, so conventional fasteners could not be used." He adds, "As a structural support, the crossbeam needed high joint performance and pre-tensile force equal to weld nuts and clinch nuts." And one more thing: "It also had to be assembled with existing automated assembly tools."

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Engineers from VW and TFS spent about two years working on the program. Consideration had been given to such things as cage nuts and various types of blind inserts. But the determination was made through extensive testing that using high-strength Hexsert[R] inserts installed with the Autosert 2000[R] robotic assembly system would be the way to go. The inserts are inserted from one side. Their hexagonal shaft permits higher torquing without reciprocal rotation in the component. In the event of over torquing, the shank breaks away before there is damage to the nut winding.

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At the VW Braunschweig Metalforming Plant where the hydroformed beams are produced, holes are cut into the beams for the fasteners. Then the beams are transferred to a cell with four Kuka robots equipped with the Autosert 2000 system. The cycle time is 95 seconds, during which time 25 fasteners are installed: 7 inserts to the beam for attaching the steering column and other components; two custom-designed inserts for the gear stick attachment; 16 inserts for the air conditioner and other components. The finished beams are then shipped to the VW Hanover assembly plant, where the crossbeams are installed in the vans.