Ultrasonic welding has been widely used by automotive suppliers to weld plastics, but so far, the applications for bonding metals have been limited. Ford believes that Aston Martin is the first company to use metal ultrasonic welding for body assembly.
Aston Martin engineers used ultrasonic welding to create aluminum alloy C-pillars on DB9 and V8 Vantage, which will be launched next year. This component plays a vital role in helping the body structure meet crash requirements.
"We want to use ultrasonic welding on the DB9 because it has a lower temperature, so the deformation of the key joints is also less," said Jeremy Main, Aston's product development director. "It turns out that this is an excellent quality improvement."
Conventional resistance welding, which is widely used in steel body assembly, has strict restrictions on aluminum, including high energy costs, weakened heating areas, and deformed or warped panels.
Ultrasonic welding is 90% stronger than conventional spot welding and requires 95% less energy than conventional resistance welding. It is important that there is no contamination or changes in the material properties or dimensions of the components.
The key part of the ultrasonic welding process is the Sonotrode ultrasonic probe, which oscillates at 20,000 cycles per second (20 kHz) to form a molecular-level weld without melting the aluminum plate being welded.