With a precise four-roll plate bender, job shop shows it can turn a contract into cashflow

February 2014 - When it comes to bending and folding in job shops, the common three-roll sheet rolling machine is king. It satisfies most shapes, as it does for Fab-All Manufacturing. But when the prospect of a contract for a high-tolerance, perfectly round product came up, the company knew it needed a four-roll solution. Based in Port Coquitlam, British Columbia, near Vancouver, Fab-All is a diversified job shop, doing everything from machining and forming to metal finishing and coating for industries such as electronics, marine and trucking.

Recently, Fab-All landed a production contract for an unnamed lighting company to fabricate impeccably rolled components—a specification for which a standard roller wouldn’t do, says Ronald Adolf, president of Fab-All.

“They have to be perfectly straight,” he says. Specifically, Fab-All needed a four-roll machine that would eliminate crown, the difference in thickness between the center and edge of a sheet, and bow across the sheet for 22-gauge cold-rolled steel.

In searching online for a set of rolls that would meet Fab-All’s tolerance needs, Adolf came across Carell Corp., a manufacturer of bending, rolling and forming equipment based in Stapleton, Ala. Working through local distributor Ecco Machinery, Fab-All bought a Hi-Tech series model HT 13/106 four-roll plate bender. It’s a double-initial-pinch, pneumatic actuated machine and is designed for efficient manufacturing, using an automated work cycle for making cylindrical and radius segmental parts. Fab-All also had Carell modify the rollers to guarantee there would be no crown or bow on material. 

“The attraction was the ability to customize the rollers to solve challenges we had in tolerances,” Adolf says.

Rolling workflow

Fab-All operates from a 30,000 sq. ft. facility, the third one it has operated in since the company was founded in 1984 by Ron Adolf and his dad, Sigfried Adolf.

When Fab-All brought on the HT 13/106, operators easily set it up, turned it on and began rolling sheet within a day—demonstrating the minimal learning curve Carell’s design presents new users. The reason Fab-All bought the machine is to roll one specific customer part that’s in the pre-production phase; however, the company already anticipates using it for others.

Bill Robinson, technical sales at Carell Corp., says the machine is ideal for applications that have high volume requirements with minimal setup changes, making it versatile for new jobs later on. At Fab-All, before parts are rolled, they are laser cut. They get fed through the HT 13/106 plate bender, creating the roll and form, and then they’re integrated into an assembly. Lastly, the parts are powder coated and finished.

The HT 13/106’s production velocity is 32 fpm, driven by 1.8 hp. The pinch roll and upper roll diameters are 4.17 in., while the lateral rolls are 3.35 in. in diameter. Those rolls can handle up to 50-in.-long sheet. It’s not a giant machine, either: It weighs 1,452 lbs. 

In considering the HT 13/106, Adolf says he had two choices regarding the issue of correcting roll tolerances. First was to build custom-formed tooling.

“We’d build these long, 4-ft. sections that’d go into a brake press and they’d come down and press the radius into this part,” he says. “That was costly. Once the tooling is built it only has one purpose for this project. We invest this money and the tooling would be only good for one thing.” 

That presented a couple of scenarios. First, if the contract didn’t end up going through, Fab-All would have useless tooling on its hands.

“We had to make a decision—are we going to make custom-rolled tooling? Or do we get a roller, which takes longer to do each part, but then we have ability to use it for other parts and customers? It ended up being a no-brainer in my mind,” Adolf adds.

The result has been parts without crown and bow, which were the biggest challenges Fab-All faced for this particular contract. To put the results in perspective, Adolf says operators did a preproduction run of the parts with the existing three-roll roller. They had to run the parts through the roller six to eight times to achieve a remotely acceptable product.

“Even then, the parts were questionable,” he says. “With the Carell roller, we ran it once and it was perfect. That’s the big difference.”

Automation advantage

For the last 40 years, Carell Corp. has offered the HT 13/106—a four-roll workhorse and one of 18 models in the pneumatic line. For heavier gauges, there are beefier hydraulic versions. Its induction-hardened 54-60 HRC and polish rolls easily ply up to 16-gauge material, although Fab-All’s current focus is on thinner metal. The rolls are mounted in spherical roller bearings, and the top material support can be adjusted to part diameters of 19 in. (with larger options available).

Among the biggest benefits of the machine is its automation. Because Fab-All only needs to roll parts once, the customer is getting consistent parts. Plus, it’s a lot faster than rolling parts half a dozen times. The machine can be automated further by adding a CNC control, as well as custom material handling fixtures. A CNC control would enable operators to change the radius during forming for a desired shape like an ellipse.

To optimize and fully harness not only the machine but its operators, Fab-All is planning to move the HT 13/106 into a work cell. Because the machine only requires one operator, the idea is to have the operator feed the blank from the laser into the roller. While it’s rolling, he will take the previously rolled part and finish the forming and other processes. 

The HT 13/106 has yet to move into full-throttle production, but it’s already displaying results. Yes, had Fab-All gone with the dedicated tooling, it would’ve taken a third of the time to produce these curved parts. But in this case, Adolf says, the Carell roller offsets any time loss because the operator can do other tasks while it’s rolling sheet.

“We get all that time back again, so that’s how it will be used,” Adolf says. FFJ