To reduce weight yet still maintain integrity, the design of the Vauxhall Astra called for the introduction of an alloy bar joined to a steel bracket, coupled with a 16kN shear strength, to serve as a weight saving side impact bar.
Joining steel to extruded aluminium demanded an alternative to welding for these dissimilar metals. In addition the solution had to meet an assembly speed of 18 components/min, SPC capabilities with process monitoring, require only limited manual intervention, and ensure a consistent quality product.
The answer was the self-pierce rivet Fastriv from Aylesbury Automation, together with a machine specially designed and built by Paro in Switzerland to fully automate the process – and insert the 72 rivets/min. required.
The technique includes the ability to automate the assembly process by joining alloys as well as precoated steels – which are unsuitable for spot welding – resulting in a joint that typically offers a higher fatigue strength than a traditional spot welded joint.
Aylesbury Automation Tel: 01296 314300