| May 22, 2012
Break the Rules to Solve Welding Automation Challenges
Robotics, load cells and advanced motion control combine with 100 year old welding technology to drive success for ARC Specialties, one of the Manufacturing Track presenters at the The Automation Conference.
Allford says his customers want a fully packaged solution, so his company does all the robotic programming as well as the machine engineering. “In Houston, we have a labor shortage. They can't find qualified operators to make welds, and they also can't find people to program robots. So we've pre-programmed all the parts in the robots. What we try to do is automate as much as possible, including material handling, so operators only have to know what part they are making. This is how robots will become more accepted in America,” he adds. “We have to take the programming part out of the equation.”
Dan Allford, president and owner of ARC Specialties in Houston (www.arcspecialties.com), kicked off the Manufacturing Track sessions of The Automation Conference with one of the challenges of his business, which is machine design for metal welding and cutting applications, among others. One challenge, he said, is the perception that the “biggest use of robotics in machine shops is dust collection. The first thing I usually have to do is overcome the idea that automation doesn't work."
Allford's collection of project examples showed attendees in his Automation Conference Manufacturing Track session that automation does work, and that innovation is not necessarily a linear process.
“I'll show you some projects that break some rules,” he promised, as he queued up videos in his presentation. “This video shows we're welding inside the part using hot wire technology. This is an old technology, and there are very few manufacturers of hot wire power supplies. So we're using advanced level motion control and old-style welding to solve a problem.”
That's common for Allford, who's projects seemed to excel in combining the best of old and new technology. An example of new technology is is the use of load cells on robots, which gives machines a sense of force and touch. “I think machines are going to get better because the use of force control,” said Allford. “With force control, we give our machines a sense of touch so we can clamp a part and rotate it at the same time. [For complex parts,] this is the only way we could cut the end square enough to facilitate the downstream automation of the weld.”
For the automated lapping of extreme service ball valves, use of load cells with robots is essential. “Lapping is very force dependent,” said Allford. “Now that we can put load cells in robots, we can work with force rather than position. Force sensing technology enables a robot to apply a programmable load. Forces and motion are more consistent using a robot, you end up with a process that is safer and faster manual methods.”
To create a Blow Out Preventer welder—a machine that could weld the large convoluted parts needed for the blow out preventers for subsea oil drilling—the “problem was keeping the part flat with regard to gravity, despite the the odd shapes of the parts. You should always weld in a flat position, but some of these parts weigh 40,000 pounds,” said Allford.
The solution Allford's team came up with was to use submerged arc welding, “something that's not even taught in schools anymore,” he said. “ The solution combines a 100 year old welding process with advanced motion control and some pretty intense math. We've done the reverse kinematics to control the motion of the parts and a welding robot simultaneously.”
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