GM Touts Lower Cost of Its Aluminum Spot-Welding System

General Motors Co. tells Automotive News its patented spot-welding system for aluminum allows it to add aluminum components to its vehicles without the downtime and expense of adopting more conventional rivet-and-bond systems.

The technology also enables GM to join steel and aluminum panels simply by adjusting voltage.

GM revealed the system two years ago and began using it to make aluminum hoods for Cadillac CTS-V sport sedans and liftgates for hybrid versions of its Chevrolet Tahoe and GMC Yukon SUV. Since then the technology has been adopted at more plants for higher-volume components.

The GM system requires higher power and frequently resurfaced liquid-cooled copper welding tips. The multi-ring domed electrodes "disrupt" the oxide coating that forms on aluminum that otherwise would interfere with the welding process.

GM says it can easily add its welding system to existing lines, keeping retooling costs low. AN notes that Ford Motor Co. spent $359 million to retool its truck factory in Dearborn, Mich., to make the aluminum-intensive F-150 pickup truck.