Materials with higher specific and buckling strength are increasingly used in order to reduce the weight of car bodies while maintaining or increasing passenger safety. Examples for such materials are ultra-high-strength aluminum alloys and press-hardened steels. A major challenge now is to combine the ultra-high-strength aluminum alloys with each other and, if necessary, with other metals without losing their outstanding strength properties.
High-strength aluminum alloys with virtually no loss of strength properties can be welded with the so-called friction stir welding process since the 1990s. In this process, a rotating tool is pressed into the joint gap of the joining partners and moved along the joint gap to produce the weld seam. An anvil adapted to the component is required on the opposite side of the weld seam in order to absorb the high process forces.
A joining process for the body-in-white assembly of aluminum and hybrid car bodies should have the following specifications: Joining high-strength aluminum alloys without hot cracks, high-strength joints, sufficient service life of the joining device, robot-supported execution, no complex and expensive component-adapted anvil and an accessibility similar to resistance spot welding guns.
Based on these requirements, a process concept for a new type of robot-guided friction stir welding gun for the production of short, merging weld seams was developed at the Materials Testing Institute (MPA, University of Stuttgart) and a patent application was filed. A first functional model of the welding gun was built and the underlying kinematics were successfully tested in initial tests. The concept differs from other known solutions because it compensates process forces through the weld gun completely. Moreover, the concept allows curved weld seams which are common in the automotive industry. These curved weld seams are realized as polygon courses in a robust manner and without component-specific anvils.
A New Concept for Producing High Strength Aluminum Line-Joints in Car Body Assembly by a Robot Guided Friction Stir Welding Gun
ARENA2036
Advances in Automotive Production Technology – Theory and Application ; Chapter : 42 ; 361-368
2021-06-02
8 pages
Article/Chapter (Book)
Electronic Resource
English
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