An ABB robotic welding system was, no doubt, the last thing a blacksmith named W.R. Nichols would have expected to find in his shop back in 1930s Simla, Colorado, a small town near Colorado Springs. Decades later, though, that blacksmith's grandson, Rob Nichols, has put an ABB system to work manufacturing replacement farm tool parts at the Sterling, Colorado headquarters of what is now called Nichols Tillage Tools, Inc. The company relocated to Sterling, in the northeast part of the state, in the early eighties in search of a bigger labor pool and a better transportation system for its raw materials and products.
Today, most of the company's manufacturing operations remain in Sterling. About 120 people are employed in the plant, as well as in sales and distribution centers throughout the United States. Nichols' products are sold by these centers, as well as by independent distributors, to customers throughout the U.S., Canada, Mexico, and Australia as well as Europe, Asia, and the Middle East.
Rob Nichols, who remembers helping his grandfather in the shop as a child in Simla, started working at the Sterling location right out of college, where he studied mechanical engineering. Over the years, the company's manufacturing techniques have become increasingly sophisticated in order to keep pace with an ever more diverse product line. Nichols recalls that he purchased the company's first robot about five years ago to weld parts that did not require complex positioning and could be placed on a stationary table. Several months ago, he purchased a second robot. This time, he selected ABB's FlexArc® R-250 robotic welding system, citing two reasons for his choice.
"We needed additional capacity," he explains, "and we also needed the extra capabilities of the FlexArc." Those capabilities include the six axis IRB 1400 robot, an automated table that indexes 180 degrees, plus the Orbit 250R rotary positioner. "The 250R allows us to optimize the welding conditions for some of our products," Nichols explains. The Orbit 250R is a dual head and tailstock configuration that interchanges with the robot when signaled by the operator. Its turning assembly can rotate 360 degrees and present both sides of the workpiece to the robot, or tilt up at any desired angle to present the optimum weld position. "This multipositioning capability enables us to weld the products that previously needed to be done by hand," he points out.
ABB's reputation also influenced Nichols' decision. In fact, he was already familiar with the company before he purchased the FlexArc system. "I had been to Fort Collins [ABB headquarters] and toured their facility and was very impressed with its degree of sophistication. I think they build an outstanding piece of equipment, very robust, and I expect it to have a long life cycle," he says. In addition, ABB's proximity, only an hour and a half away, was "definitely a factor."
Another feature that appealed to Nichols was that "ABB's FlexArc systems are prebuilt packages. It wasn't that many years ago that a configuration like this would have to have its components put together by a third party engineering company. This configuration, already assembled and on a skid like this, just makes it so much more convenient and less expensive."
In fact, the FlexArc 250 cell is ABB's most popular configuration. All of the components, including robot, controller, positioner, welding power supply, torch service, and supply station and perimeter fencing, are mounted to a common base for easy shipment and quick set-up on the factory floor. Nichols recalls that his FlexArc system arrived several months ago at closing time on a Friday afternoon. The following Monday, "basically we just set it in place, unfolded a few parts, and attached the wire, gases and power to it. On Tuesday, Vernon Deucore, ABB's installer, came out, made sure everything was working correctly, and gave us a bit of a jump start as far as the programming and the operation. It was operational the same day."
To maintain cross training between the different robots and other operations in the plant, three different operators take turns operating the ABB system. These operators also handle all of the programming, and required very little training to do so. While the company's proximity to ABB's Fort Collins headquarters would make it relatively inexpensive to bring someone on site for training, "we didn't rely on that much because it was something we could teach ourselves," he notes, adding that the robot also comes with "pretty sophisticated" offline programming software that installs on a Windows NT station, and "we used that to do a lot of offline programming." Since they have only had the robot for a short time, they are still learning how to take advantage of its capabilities. "As time goes on, though we still use the same programs, we can optimize it to improve its efficiency and productivity. And the ability to edit offline makes that relatively painless."
The robot welds a wide variety of parts, although most of those fall within "just a handful of families," according to Nichols. Each family may contain 40 different items. While fairly similar, each requires different fixturing. Therefore the company has built modular fixtures so that while the fundamental mount is the same, the components can be swapped, decreasing setup time. Currently, they are using the new system to weld about 50 or 60 different parts, a number Nichols says "will grow over time." Right now the system is operating one shift per day, although for four or five months of the year it runs for two shifts daily.
Many of the parts are high carbon alloy steels, and the robot must often weld high chromium castings to those parts. Because of the dissimilar metals, "it's kind of a tricky weld procedurally," Nichols asserts. "Everything has to be right or the weld will fail. There are some precautions that have to be taken" because of the high carbon content. Fortunately, the ABB system "does the job well," and the quality of the welding is "far superior" to manual welding. In addition to welding, they are also using the robot for hard-facing many of the parts. A layer of chromium alloy between l/16 to l/8 of an inch thick is applied by the torch in wire form, covering the surface in a reciprocating kind of weave pattern.
Nichols estimates that the new robot is "between two and five times more productive than manual welding. "That is, an individual can produce between two and five times as much production on the robot than he would manually." As for quality: "There is no person alive who is as stable as a robot," says Nichols. He points out that "automation tends to be very intolerant of variation, but as long as quality control issues are dealt with, the robot's repeatability presents a great opportunity for some fantastic welds."
