GM Launches Flexible Tooling for Robotic Welding

C-Flex is a servo-driven, programmable body shop tooling system that can adjust to varying product sizes, increasing GM’s ability to build different vehicles on the same assembly line.

As part of its drive to boost manufacturing flexibility and performance, General Motors Corp. is phasing in a new flexible tooling system for robotic automotive production lines. The system, known as C-Flex, was developed originally by GM over a period of several years, and is now being provided to the automaker by Fanuc Robotics, Rochester Hills, Mich., under terms of an exclusive, multi-year agreement.

GM sees the C-Flex system as an important part of its future manufacturing strategy, says James W. Wells, a senior staff research engineer, manufacturing systems, at the General Motors R&D Center, in Warren, Mich. Wells provided a glimpse of the technology during a presentation at the Robots 2004 conference, June 9-10, in Ypsilanti, Mich. “We think this is strategic, so we’ve been very quiet about it over the past four years. We’re just now starting to talk it up a little bit,” Wells told attendees at the conference, sponsored by the Robotic Industries Association, Ann Arbor, Mich.

C-Flex is a servo-driven, programmable tooling system that can adjust to the contours and size of various automotive models and body components moving down a production line. As such, it can eliminate the need for model-specific tooling traditionally used for automotive applications such as robotic welding. “Instead of fixed tooling, you have servo tooling do your fixturing, so that within a certain envelope, you can allow that tooling to move around to accommodate different products,” Wells explained.

Big savings

The C-Flex system enables multiple body panels—such as floor pans, deck lids, hoods, doors and engine compartments—to be welded with the same set of programmable tools and robots. By improving GM’s ability to build different vehicles on the same assembly line, the C-Flex technology can save both money and manufacturing floor space. Indeed, according to a recent GM press release, C-Flex, along with other manufacturing improvements, will reduce GM’s cost of introducing new products into a body shop by about $100 million, while saving up to 150,000 square feet in body shop floor space.

The C-Flex technology has been deployed in pilot applications in various locations, said Wells. But at GM’s Lansing Grand River plant, the technology is now being used in production on three models of GM’s Cadillac—the high horsepower CTS-V, the SRX sport wagon and the STS, a 2005 model year replacement for the Cadillac Seville. All three vehicles have slightly differing sizes and dimensions. “The goal was to use our flexible tooling systems to run all three of these products down the same line,” Wells explained, so that depending on market acceptance, production volumes on each vehicle can be more easily adjusted. “If one model is hot and one’s not, then we can run more of one and less of the other.”

During a question and answer session following the Robots conference presentation, Wells confirmed that the C-Flex tooling systems are more expensive than traditional fixed tooling. But the savings due to the C-Flex system’s flexibility should make up that difference relatively quickly, he said. GM developed the C-Flex system internally in a “skunkworks” facility, Wells said, and it is not commercially available to others. GM currently has an exclusive agreement with Fanuc Robotics to supply C-Flex technology, he said.

Permission needed

Rick Frohock, director of sales, body structures group, at Fanuc Robotics, confirmed the exclusive nature of the deal during a recent interview with Automation World. “We can’t sell it outside GM unless they give us permission,” he said.

Fanuc Robotics signed the contract to provide the C-Flex product in early 2002, after winning a competitive quote process, Frohock said. GM had been working with another vendor during earlier development work, he noted. “Basically, what GM asked us to do was to take its proven design and to manufacture it using Fanuc servo technology.”

The first year of the contract was spent proving out the Fanuc design, as well as making enhancements and expanding the number of units in the C-Flex product family, Frohock said. GM “started purchasing production units in 2003. We delivered quite a few through 2003, and the quantity is growing this year, and will probably grow more next year” as GM installs the technology in more plants, he said.

The five-axis C-Flex units are used in multiples, Frohock noted. “A cell may have two, or it may have 10 of these things, depending on what the cell is doing, and they all work together.” Fanuc Robotics provides the mechanical units and the motion controllers for each unit, while GM produces other pieces of the control system that marries the total C-Flex system together, Frohock said.

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