Tube bending, the lean way
Wisconsin tube shop bends on demand
A Wisconsin tube bending shop takes an untraditional approach to the traditional job schedule--and thrives because of it.
Jim Grunewald remembers the phone conversation. It was his friend, Steve Donovan. Grunewald hung up feeling exhilarated and terrified, typical for an aspiring entrepreneur. To have time to launch a new business, Donovan quit his perfectly good job, and Grunewald had just done the same.
For years the two had talked about launching a midtier tube bending company, bigger than a mom-and-pop but smaller than a production bending facility. Small shops require less revenue to make a good profit; large tube bending companies benefit from few changeovers and long production runs. The midtier operation, though, can be a challenge. They have more overhead than garage shops and certainly don’t have the capacity of larger operations. So why launch such an organization from the get-go?
To answer, Donovan explained a bit of his employment history. Years ago he worked as a purchasing agent for an equipment manufacturer that outsourced tube bending work. He recalled how he once had to call each of the company’s four tube bending suppliers to see if they could turn around an order in a few days. The equipment that needed these tubes sold for more than a half million dollars, so delaying the shipment would cost his employer big-time. He told the tube bending suppliers that his employer would pay triple just to have the job done by the end of the week. The tube shops wouldn’t budge. Their rationale: If they fit the rush tube bending job in, they would irritate the rest of their customers.
After dealing with this, Donovan’s eyes opened to some obvious opportunity. After all, he knew tube bending. In the 1990s he worked at a major exhaust tubing supplier, managing its Neillsville, Wis., bending plant. There Donovan met Grunewald as well as dozens of other talented managers, quality assurance personnel, and machine operators. That facility was eventually shut down several years later, leaving Neillsville without a major employer. It also, however, left what any metal fabrication manager would kill for these days: a highly experienced, available workforce.
The day of Donovan’s fateful phone call, the aspiring entrepreneurs knew that if they could set up a Neillsville tube shop, they could find the right people to work there. As Grunewald put it, “What better way to start a company than to have experienced folks who can step right in and do the job?”
A Little Serendipity
Still, they couldn’t find a suitable building to lease in town. So they ventured elsewhere, ensuring that wherever they looked wasn’t too far from available talent. Between 1989 and 1995 Grunewald had managed a Wautoma, Wis., tube facility, and so knew that area had knowledgeable workers. The town of Berlin, about a half hour away, had a 10,000-square-foot building available. The building didn’t suit, but thanks to a little serendipity, visiting that shop space changed everything.
Driving through a Berlin industrial park on his way to tour the potential facility, Grunewald turned his head. “Out of the corner of my eye I noticed the Phoenix Coaters facility. And, of course, one of the things Steve and I needed to make this thing successful was to have some paint capabilities.”
Phoenix is a subsidiary of Mayville Engineering Co. (MEC), a large contract fabricator with plants across Wisconsin. The two visited Phoenix intending to present their business plan for future subcontracting partnerships. But when they were directed to meet with Bob Kamphuis, CEO of the entire MEC group, they soon realized that MEC’s managers had something else in mind.
Donovan recalled the meeting. “We went through our [business plan] presentation with the intent of getting them interested in doing some painting work for us down the road. Whenever we’d make these presentations, obviously we wanted people to understand that we had bank financing, we had investors, and we showed what investment levels the new business would take. At that point Bob stepped into the conversation. ‘Well, what if we make all of that go away?’ Jim and I were a little dumbfounded; we didn’t know what he was getting at. ‘What if we make that go away,’ he said, ‘and have you guys come onboard and become part of the MEC family of companies?’”
Unbeknownst to Donovan and Grunewald, MEC’s leaders had wanted to get into tube bending for some time. Managers at Mayville did their homework, so when they met Donovan and Grunewald, they offered to bring both of them—each with years of tube bending experience—onboard then and there.
After deliberating several days, they ultimately agreed. The plan just made sense. Employees could be part of MEC’s ESOP (employee stock ownership plan), and the new tube shop could tap into MEC’s general fabrication, machining, painting resources, and strong balance sheet.
Still, all this wouldn’t count for much if they couldn’t find a building. Eventually Grunewald and Donovan learned of a building in Neillsville owned by another manufacturer that had previously used the 50,000 sq. ft. of floor space for machining. They contacted the owner, paid a visit, and all seemed perfect—except for one important detail: Instead of leasing the space, the manufacturer wanted to sell it to them. That was a deal breaker. Even if the new company would be launching under the MEC umbrella, they still wanted to put most of the upfront investment into good tube bending machinery and people—not a building.
At this point they appealed to Neillsville City Hall and community members, and many listened. Neillsville is a tube bending town. Citizens wanted local businesses to thrive, and they knew how vital the town’s manufacturing base had been. So, quietly, some stepped up. The city government worked with several groups of anonymous investors who bought the facility and leased it back to the new tube bending operation. To this day Donovan and Grunewald don’t know most of the people who fronted them the money.
“We talk about this all the time,” Donovan said. “When you think about it, they took an enormous leap of faith.”
At long last, a new MEC subsidiary called Fabricating Specialists opened its doors, with Donovan as sales manager and Grunewald as general manager. The launch happened in 2008, just in time for the economy to crash.
Grunewald laughed. “We’ve always joked among ourselves; when your revenue is zero, the only way you can go is up!”
Despite bad timing, sales grew extremely quickly. Late last year the still-young enterprise bought the leased facility and another adjacent building, giving the company a total of 100,000 sq. ft. of space. The 3-year-old company now employs 85 people, and managers expect to hire many more. Within three years, they said, the head count could be as high as 275.
How has the company grown so quickly during challenging times? One ingredient has been the shop’s quick turnaround. When company operations began in late 2008 and early 2009, businesses were holding on to cash like lifeboats. It was a time when no one wanted inventory, and everyone waited until the ninth hour to place an order. As it turned out, Fabricating Specialists’ quick turnaround was just what the market wanted.
The tube shop has a range of CNC and NC equipment (see Figure 1). Its rotary draw machines, most of which are all-electric, can bend round tube with diameters between 0.625 in. and 6 in. (0.250-in. maximum wall thickness at 6 in. diameter), and 0.625 through 4.00 in. diameters for square and rectangular tube (0.250-in. maximum wall thickness at 4 in. diameter).
The company performs interpolation (or push) bending, generally used when the bend’s centerline radius is at least six to eight times the tube diameter. “It’s for larger, sweeping bends,” Donovan explained. The CNC bender’s collet holds and feeds the tube into a series of rollers, which replace the traditional pressure die used in the rotary draw process. The bend die rotates on a series of bearings. The tube is fed through the rollers and across the bend die, which forms the tube to the desired shape.
The company also offers air-gap, or tube-in-a-tube, bending. The process bends sections having one tube inserted into another, slightly larger-diameter tube. “You typically put some kind of shotblast media between the two tube walls so they don’t touch each other while you’re bending,” Donovan said, adding that ice or other media also can be used. “But we have a proprietary process that allows us to bend [the joined] tubes without having to use media in between.”
Responsive Job Schedule
Such proprietary processes wouldn’t be that valuable if customers still had to wait weeks for a slot in the schedule, the very thing that frustrated Donovan as a purchasing manager years ago. This is why Fabricating Specialists doesn’t adhere to the kind of job schedule that avoids machine setups like the plague. Instead, tool changes can occur many times a day. This means the shop can process a job in a few days or weeks, depending on the order size, complexity, and engineering involved.
Myriad jobs hit the floor during a typical day. Workers must respond not only to customer orders, which run the gamut from prototype work to runs of a few thousand, but also to work from other MEC divisions. The operation abides by several principles to make this all work.
First, an order isn’t a “Fabricating Specialists job,” a “Phoenix Coaters job,” or a “Mayville Engineering fabrication job.” Everything is just “an order” for the entire MEC operation, which is coordinated through a software scheduling system MEC developed in-house. The system is flexible enough so that Donovan can call someone at another division to ensure a hot job makes it through production by a certain date. But the software keeps everyone on the same page so that people don’t compete with each other for shop floor resources.
A second element includes efficient, careful quoting. Shop software simulates the bend process, taking into account the machine model; tube material, radius, and diameter; and other variables. This helps prevent unexpected manufacturing challenges such as improper or unavailable tooling, or tool or workpiece interference problems during bending. The simulation isn’t perfect, but it does offer a good prediction of what the job will require.
Perhaps most important, the software helps the shop’s quoting engineers suggest minor design alternatives that could save time and money. Engineers plug the alternative into the simulator, which shows how the design alternative would make tube bending simpler.
After bending, operators can take the first part in a run to a coordinate measuring machine (CMM) that has a direct connection to a bending machine’s controller. If the CMM measures an out-of-tolerance bend radius, it sends that information back to the bending machine control, which then adjusts the program accordingly. It does not overwrite the original program but instead labels the new program as a revision. After all, the original program usually is correct; the out-of-tolerance bends often occur because tube material properties vary between heats.
Lean Tube Bending
About 90 percent of the company’s machines are on wheels, so workers can move them into cells dedicated to part families requiring a range of tube diameters and radii (see Figure 2). Tooling is labeled clearly and organized at the point of use.
Quick changeover is Fabricating Specialists’ linchpin. If machine operators couldn’t change over quickly between jobs, the shop’s entire business model would fall apart. To that end, the company machines its own tooling and uses specialized tools for high-mix part runs, including rotary draw stacked tooling (one bend die stacked on top of another). The repeatability of all-electric benders also helps reduce tryout times, and such precision makes traditionally difficult downstream operations, like robotic welding of tube, much easier.
These methods aren’t unique, but according to sources, some tool-change procedures are. Workers take advantage of certain proprietary techniques that greatly reduce changeover times between runs.
New Space, New Possibilities
Donovan and Grunewald recalled the opening of Fabricating Specialists as a kind of homecoming. Donovan’s manufacturing manager at the previous Neillsville tube bending plant now is Fabricating Specialists’ plant manager; his welding supervisor at the previous plant is his welding supervisor now. When the managers met again after several years apart, all of them sat down at a conference table and asked, “What would we have done differently?” That meeting led to the company’s current lean culture.
The shop floor designed in 2008 isn’t perfect, either. For instance, monuments like large part-washing equipment sometimes cause part flow problems. Now, after acquiring an additional building last year, the company again has a clean slate, and managers are asking the same question: “What would we have done differently?”
And, thus, improvement continues.
The FABRICATOR is North America's leading magazine for the metal forming and fabricating industry. The magazine delivers the news, technical articles, and case histories that enable fabricators to do their jobs more efficiently. The FABRICATOR has served the industry since 1971.