By CLARE GOLDSBERRY, associate editor

Resistance welding involves primarily automated systems in the automotive industry, where the 4,000 to 5,000 spot welds it takes to assemble a car are done by robotics. Resistance welding is also the most cost effective way to perform high-volume spot welding, with the only consumables being the copper tips, "Which is why it's so popular in the automotive industry," said David Bacon, a teacher and consultant for resistance welding technology.

Then came the next step in resistance welding: Deformation Resistance Welding. Developed by Delphi Corp. (www.delphi.com), deformation resistance welding came in response to a desire for increased efficiency, productivity and quality, while at the same time reducing costs. The process forms a near instantaneous, full strength, weak-tight weld by heating metal surfaces only to the point of softening, followed by rapid, engineered compression of the joint. The heating and deformation of mating surfaces automatically bonds metals and creates solid-state joints. The result is a full thickness, solid-state weld that gives designers the freedom to create lean structural assemblies using tubular components.

Conventional technologies such as brazing or MIG welding, while good for many applications, have drawbacks in high-volume applications, said Jayson Pankin, New Venture Creation Specialist at Delphi.

For example, brazing is a "batch" technology that takes approximately 45 minutes, and while it's functionally effective, is not a cost effective technology. "Brazing's been made obsolete by rapid technology," said Pankin. "For a number of years Delphi looked for ways to weld tubular structures onto sheets or two tubular structures together without brazing. We came up with deformation resistance welding. You can now push together two tubes and within 2-3 seconds, you have your weld, with better quality and reduced cost over brazed welding. Brazing or MIG appears to be ready to replaced by this process."

The initial group of companies that are interested in this technology include users of heat exchangers. Deformation resistance welding technology is being marketed and licensed in the heat exchanger field, including chemical plants, oil refineries, those companies that require a lot of tube welding, and are currently using a manual process and looking to automate, Pankin said. Other interested markets are companies that make structural products such as wheel chairs, motorcycles, and companies in the recreational vehicle market. "As people validate deformation resistance weldingin a real production setting, we'll see it grow in markets as advantages are proven," he said.

In December, after receiving encouraging results with the technology, the National Aeronautics and Space Administration (NASA) and the Michigan Research Institute (MRI) will grant Delphi an additional $950,000 to help fund the continuing development of deformation resistance welding. The first two grants, totaling $2.17 million, were used to perfect existing welding technologies, to create new ones, and to find new innovative ways to use deformation resistance welding on suspension sub-frames.

The new grant will fund work done by Delphi in cooperation with the Edison Welding Institute (www.ewi.org) and SpaceForm Inc.(www.spaceformtech.com), a company formed in 2005 based on deformation resistance welding technology. Planned projects will develop the technology in the area of ferrous and non-ferrous materials, dissimilar joints, lean tubular structures and concepts for future manufacturing cells.

NASA plans to use what is learned from Delphi's work with deformation resistance welding as part of its Space Power Development Programs. Of specific interest is advanced welding of dissimilar materials and shapes that could be used for manned space vehicles in Man-on-the-Moon and Man-toMars projects. Deformation resistance welding can work with similar and dissimilar materials and shapes at significantly lower cost than conventional welding solutions.

While Pankin believes that there will "absolutely be many applications for all the existing welding technologies," competition between brazing, MIG and deformation resistance welding will be fueled by people always looking at ways to improve a welded part. "Deformation resistance welding will be used both for novel applications, heretofore not being done because current weld technology can't do an efficient and qualitative job, or with metals like aluminum to offer something unique," Pankin said. "Deformation resistance welding will compete on a quality and total cost basis to become the preferred technology for certain high-volume products that potentially will include suspension links, instrument panel cross-car beams and engine cradles, while creating savings in tooling, masks, the number of work stations required, and foot-printing."

Deformation resistance welding might also become key to lighter-weight vehicles made with different metals that typically are difficult to weld. "With this deformation resistance welding process, that will no longer be an obstacle," said Pankin.