Above: Steel strip undergoing initial forming on the 307HV4 CNC machine. After this step, the part is welded into a ring.

Manufacturer masters both the art and science of angle rolling

September 2016 - TMF Center in Williamsport, Indiana, can “pretty much do anything that customers need,” says Andy VanMeter, president. The company primarily fabricates heavy steel parts—from 8 mm to 125 mm thick—for the construction machinery and equipment industry. “We do CNC machining, we weld, we form, we saw, we grind, we paint and we assemble.” 

In business since 1979, TMF Center has “grown steadily, minus a few [economic] troughs we’ve faced over the years,” says VanMeter. “[The] part number count has increased regardless of the sales numbers, which go up and down with the business cycles.” TMF today makes more than 4,000 different parts and ships them to 47 facilities in seven countries.

A new skill

Three years ago, TMF expanded its capabilities to include roll forming. One customer sought to return production of a certain part to the United States and asked TMF to quote the job. The project required rolling round welded rings with a diameter and profile tolerance of 3 mm, which is “pretty tight” for a ring that’s approximately 650 mm in diameter, says VanMeter. 

To ensure the company had the appropriate equipment to complete the job, VanMeter and his team conducted some “research and visited a few tool shows, like Fabtech,” he says. “We then cut our list down to three, and from that, we interviewed, got quotes and did application studies.”

TMF chose to work with Carell Corp., Stapleton, Alabama, a manufacturer of bending equipment, including plate rolls, angle rolls, pipe benders and horizontal presses. TMF has three of Carell’s angle rolls, which it acquired one by one during the past three years: two 307HV4s (one operator controlled and one CNC) and a 308HV4. 

Carell’s 3000 Series hydraulic angle rolls are heavy-duty, rugged machines that have LED digital displays to monitor bending roll position. They are ideal for rolling standard and special sections, as well as steel, structural and stainless tube and pipe. The angle rolls also have the option of NC and CNC controls that have various automation levels for repetitive jobs and production of variable radius bends and parts with multiple bends.

Aaron Talbert is TMF Center's ringmaster. He can produce any part needed, according to Andy VanMeter, president.

The equipment is “durable, reliable and well built,” VanMeter says, adding that TMF’s partnership with Carell helped ensure the large rings could be produced to the customer’s specifications.

In this particular application, says Kevin Hannon, sales engineer at Carell,  TMF uses the CNC controlled unit to “initially roll the part, and then uses a standard push-button control to finalize the manufacturing process. We went through the entire process of the application, sizing the correct machine and then testing and delivering the equipment. Employees from TMF Center also came down to our facility, and we performed several run-offs here, which is typical on a complicated part.”

VanMeter confirms that Carell “hosted us for a week-long training session because we didn’t know how to operate their equipment. We sent down one of our employees who had some experience in CAD/CAM computer software, and he picked it up quickly.”

Developing a process

Achieving a perfectly round ring is “an art as much as it is a science,” says VanMeter, so TMF needed to ensure it had a consistent process. The angle benders include several tools that make the geometry possible, including the adjustable outrigger rolls, “which are great for achieving roundness.”  In addition, he says, “the non-CNC machines have a manual control station. Once we were able to fine-tune the process, we put a human machine interface from Mitsubishi Electronics on the manual machines. The HMI basically looks like an iPad, and you can program them to execute processes like work timers and switch closures.”

The approximately 30-in.-diameter part after final rolling. TMF Center holds the diameter to 0.020 in. and the roundness profile to 0.030 in.

Adding these devices makes the manual machines semi-automatic. An operator does all the preliminary work, and then the HMI will “execute the rest of our formula,” VanMeter explains. The ability to add this capability to the equipment allows the operation to be more consistent. “The flexibility to do that on their equipment was a really big asset,” not only for consistency but to “free up time for people to do other things while the machine is running,” he says.

After installing the equipment and perfecting the manufacturing process, TMF did not merely meet the project’s requirements, “[we] exceeded the target dramatically,” says VanMeter. “We’re using up one-quarter of the tolerance that we’d be allowed. We’re not having any trouble at all. Since we’ve had the equipment, we’ve produced nearly 20,000 rings in four sizes without a single issue and our scrap rate is less than one-tenth of one percent. We almost never scrap anything.”

The ability to tackle customers’ requests and exceed their expectations makes a company stand out and ensures it will earn repeat business. Behind this success is the collaborative relationship between manufacturer and equipment supplier. Customers come to Carell with an application, and then the work begins, Hannon says. “We know that the machine we have will do it, but then we have to develop the process and the path to accomplish it. In the case of TMF Center’s application, they actually made their own tooling as well, so it was a joint coordination. We work very closely, and it’s an ongoing relationship.”  FFJ