Robotic Technology

Easier impellers

By Gretchen Salois

From restaurants to coal mines, the right tools create the means for fresh air

October 2012 - Whether keeping manufacturing workers’ lungs clear in less than pristine conditions or ensuring restaurant patrons can enjoy their food without sitting in a cloud of cooking smoke, Twin City Fan and Blower products are on the job all across the U.S. Founded in the early 1970s, the company is headquartered in Minneapolis and manufactures an extensive line of high-quality industrial and commercial fans in its four South Dakota facilities. Guided from its earliest days by a commitment to quality, Twin City Fan is always on the lookout for new technology, seeking to add the right tools to meet growing demand. Lately that has meant increasing the firm’s robotic welding capabilities.

Fans are used for everything, from ventilation as mushroom tops on restaurants—a stamp blade that’s riveted together—to complex ventilation systems for coal mines. “Something as simple as keeping the air pressure constant to hold up the roof of the Metrodome in Minneapolis, or grain drying for the farming industry—these are some of the things we do,” says Craig Vostad, robotics technician at Twin City Fan.

The company welds mild steel, stainless steel and aluminum to produce fans of various sizes, including 12 in. diameter through 100 in. diameter wheels. The mild steel wheels use 14 gauge and heavier material; aluminum wheel material thickness is 0.1 in. and greater. Among its large offering of products, some of the company’s fans can serve as material handling tools. For example, a 60-in. double wide aluminum fan by Twin City Fan can transport materials as part of the manufacturing process. The company’s fans also have been used to transport cereal without damaging the delicate corn flakes.

On the other end of the spectrum, the company also provides fans for the oil and gas industry. Those heavy duty fans require metal housings as thick as 3⁄8 in.

“We weld more than impellers—things like the pedestals of the fans and the housings—and we needed to reduce the heat of welding near our operators,” Vostad adds, noting the company needed a customized solution. 

Forgoing fatigue

In addition to meeting growing demand, Twin City Fan wanted to reduce production costs and improve efficiency. To do so, the company turned to Reis Robotics USA Inc., Elgin, Ill., in 2001. Working with the research staff at Reis Robotics’ U.S. and German facilities, Twin City Fan determined which robots and positioners would be the best fit. As a result, Twin City Fan has purchased a series of robots, most recently a Reis RV20-16 in 2011.  

The RV20-16 is set up to work with two RDS 11 positioners. While the robot is welding in one station, the operator can set up the other to prepare for the next part. The positioners are programmable swiveling and rotary modules and therefore put two additional axes under robotic control. They also make it easier for operators to manually mount the heavy and cumbersome impellers and pedestals for welding. The additional maneuverability also provides the best welding access and angle for the robot. 

“This positioner does a fantastic job at allowing that to happen,” says Christopher Clark, vice general manager at Reis Robotics. The RV20-16’s capabilities also include path welding, thermo-cutting, die casting automation, gravity die casting automation, handling and palletizing, interlinking and loading, sealing, coating and gluing, mounting and joining, as well as injection molding automation features. 

The robot arm is mounted on a rotating pedestal that moves between the two positioning stations. Because it operates based on programming rather than a hard-wired setup, the robot easily handles fabrication of two different assemblies on the two positioners. “Some competitors might try to gear it toward one type of part,” Clark says, “but Reis gears it toward a wider spectrum. Flexibility is key.”

Critical angles

Because Twin City Fan is creating and welding spinning parts, it’s critical that the weld size is correct. That requires precise accuracy, and careful attention to precision requires welder experience and expertise, says Twin City’s Vostad. However, exposure to the welding-generated heat for long periods of time, coupled with fatigue, can magnify a welder’s exhaustion and take a toll on consistency.

“It can be really hot and uncomfortable for a welder to really get into the space they need in order to weld in these hard-to-reach spaces,” Vostad says.

“All those vanes have varying pitches, different contours, making it very difficult for an operator to reach inside and get a consistent weld every time,” says Clark at Reis Robotics. “You’re trying to move your gun and maintain a constant speed. Too much variance can get you into trouble easily—especially after an eight- or 10-hour work day,” he adds, noting the seam tracker is especially useful in these cases.

The lack of skilled workers has also driven Twin City Fan toward using more robotics. “We’re finding it difficult to find qualified welders out there today,” Vostad says. “The natural progression is to automate welding processes.” 

Reis Robotics’ robots are sold as modular products. “We use most of [the] standard components to custom build for our customers and deliver state-of-the-art turnkey systems,” Clark says. “We also manufacture our robots, as opposed to buying robots from other companies, so we’re 100 percent self-contained and retain full responsibility for the system.”

Another feature Twin City Fan values is the automated neck changer. It allows operators to use several different angles of torches to complete various applications. “Operators can call out for a different neck at the beginning of an application and program the needed tool center point, which is a great feature that projects the weld path and weld speed at any angle—and the machine always maintains the proper weld speed,” Vostad says. “It doesn’t matter how fast the wheel is turning or how the robot is moving, all you need to care about is that the seam remains in position.” FFJ

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  • Reis Robotics USA Inc.
    Elgin, Ill.
    phone: 847/741-9500
    fax: 847/888-2762
  • Twin City Fan and Blower
    phone: 763/551-7600
    fax: 763/551-7601


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