As Ford spends big, GM joins aluminum with simple welds
1. Welding aluminum requires only minor changes to GM's production equipment. Coolant lines (circled) are added to keep the copper tips at the proper temperature. An additional transformer handles the higher voltage needed to weld aluminum sheets.
2. Copper caps used on welding guns are the keys to GM's aluminum welding. The tips of the caps are scribed with concentric circles that disrupt the oxide on the surface of the aluminum, creating strong welds.
3. GM says its aluminum welds are strong and durable. Welded sheet aluminum parts in production include the doors on the Cadillac CTS and the liftgates on the Chevrolet Suburban, GMC Yukon and Cadillac Escalade.
