5. Automotive

5.1 Benefits and history of bonding

The first metal bonding operations in the automotive industry were the bonding of stiffeners to the inside of hoods, starting in 1954.

• In the past, these stiffeners were spot-welded, but this had three disadvantages:

  • multiple spot welding (dozens for a hood) required highly complex and expensive machines with dozens of electrodes to weld a hood on a chain in a single operation;

  • the weld marks on the outer sheets meant that they had to be coated before painting to achieve a perfect surface finish;

  • the welding points, more or less spaced out, didn't provide perfect stiffening, and the sheets...