A better mouse trap

By Lynn Stanley

Above: The iRoll-Camera allows manufacturers to compare the radius of a drawing or model with the part—without having to remove material from the machine.

New technology eliminates the need for manual radius sweeps, introduces auto learning and smart hydraulics

May 2018 - Novelist and entrepreneur Mark Twain believed there was no such thing as a new idea. “We simply take old ideas, put them in a sort of mental kaleidoscope, give them a turn and make new and curious combinations,” he wrote. Looking to improve its angle rolls, Davi Inc. took “old” methods, added a mix of customer input, field experience and engineering know-how and made something new. The technology could be considered a once-in-a-generation development for an industry that has seen little change over the last 75 years, says Steven Bonnay, Davi regional sales manager special projects.

“We asked angle roll operators what changes they would make to their machines if they could—what capabilities they wished their equipment had but didn’t,” Bonnay says. “Their immediate response was, ‘We wish we didn’t have to take a part on and off the angle roller multiple times to check its radius.’’

Headquartered in Italy, Davi claims to be the largest plate and angle roll manufacturer in the world. Its intimate knowledge of the market and its willingness to invest in research and development has given the company an eye for opportunities.

“Market conditions were favorable,” says Bonnay, “The timing was right to expand our angle roll product line, but [we] wanted to go beyond what already existed. Once we collected customer feedback, Davi turned its engineers loose. We spun off a new division and went to work.”

The company introduced the iRoll-Camera, a radius checking system, last year. “We are the only company to have this technology,” asserts Bonnay.

FFJ 0518 bending image1

Davi's new angle rolls have been built with a compact footprint yet retain the strength of larger angle rolls.

“Eye rolls”

The iRoll-Camera allows manufacturers to compare the radius of a drawing or model with the actual part in real time without having to remove material from the machine. The camera is located above the operation to give benders a bird’s-eye view of the entire part. Once a bender imports a blueprint, DXF file or CAD file into the CNC, it appears as an overlay. Benders can also draw shapes and radii directly on the screen to create a template.

The ability to match a specified radius with a part, inch by inch via a camera, is game changing when one considers the method employed for decades, Bonnay notes.

Take a square bar bent into a U-shape, for example. The two ends of the U-shape represent a wider radius then the part’s mid-section. Until now, achieving part accuracy was considered a black art. An operator had to rely on touch and feel and his or her skill and experience. Templates consisted of a blank cut by a waterjet or a piece of cardboard. Once the part was bent, it was removed from the machine and laid on the floor where the operator would draw a chalk line to mark where the part matched the required radius and where it didn’t. Then the part was put back on the machine to adjust it to a perfect match. A bender might have to repeat this process multiple times before turning out a good part.

Meeting specs

“Invariably a part would be out of spec with this method,” says Bonnay. “Anyone that gets it right the first time is just lucky. Material that weighs 80 lbs. takes two operators to lift the part in and out of the machine. If you have a part weighing 1,800 lbs. to 5,000 lbs., you have to have a crane to do the heavy lifting.

“Skilled operators get good parts. An inexperienced operator might get one in three good parts,” he says. With the iRoll-Camera, an operator can simply draw a calibrated line on the screen, pick up the virtual template, move it around, rotate it and place it directly on the part to check radii without ever taking the part off the bending machine.

“What took a skilled operator one to two hours to do, a less experienced individual can now do in about 20 minutes,” Bonnay says.

Because the iRoll-Camera eliminates the need to perform manual radius sweeps, the technology is a no brainer. But the feature shines for high-volume suppliers handling big parts.

“The ROI is not there for low-volume suppliers or applications that don’t require a very precise result,” Bonnay concedes. “Right now [camera] buyers are fabricators that need to add or replace a machine with a focus on quality.”

Davi redesigned its angle rolls to accommodate the iRoll-Camera system because the camera, the machine’s CNC control and its hydraulics have to interface and communicate with each other.

FFJ 0518 bending image2

Davi’s new CNC mandrel bending capability helps fabricators minimize buckling.

Lessons learned

Enter Auto Learning, another Davi concept that helps a bending machine operator to “teach” the iRoll-Camera what he or she wants it to do for a particular part. Digital signals send real-time data to the CNC control so it can monitor the angle roll’s electronic, mechanical and hydraulic components. In addition to different size parts, these features also help accommodate material inconsistencies due to hard spots and other variables. An operator can input the steps he or she needs to take for a specific part. “From there, it is just a matter of hitting go,” Bonnay says.

But the CNC can also act as an aid to inexperienced operators by analyzing radii and dimensions before presenting scenarios for possible modifications. The CNC can source historical data as well.

Once a part is prepped, smart hydraulics adjust torque for optimal rolling. This is made possible with the use of independent hydraulic motors and pumps and high-torque planetary drives tied directly to each roll. A conventional approach would dictate putting a single motor on one shaft and using chains to drive the other two rolls.

Working smarter

“This is problematic if you are bending a square piece,” says Bonnay. “If you are bending a 4-in. square, the outside rolls need to move faster because they have to travel further than the top roll. The problem with a single motor is that unless you hit that sweet spot, one of the rolls will rotate too slowly and skid along the part.

“We’ve given the operator an auto button that allows the hydraulic system and CNC control to determine what percentage of torque the top roll and the other rolls require,” he explains.

The operator may also manually override the system and adjust torque on the fly. “The majority of the shops might not need this option,” explains Bonnay, “but it’s a benefit for shops that bend all day, every day, and that are handling very large parts with extreme tolerances.”

Davi isn’t leaving out manufacturers that roll lighter weight material. Its new CNC mandrel bending capability helps fabricators minimize buckling. The feature is especially attractive for shops making cosmetic parts.

“If you are rolling 3-in. square material, the material inside the centerline or neutral axis is being compressed while the material outside the centerline is being stretched or expanded,” says Bonnay. “Yield strength is always lower than compressive strength. If you haven’t developed enough tonnage to compress the inner half of the piece, it will buckle in on itself. Our CNC-driven mandrel minimizes buckling. We are one of a very few companies that have successfully created a mandrel system for rolling.”

In addition to technology advances, Davi built its new angle rolls with a compact footprint. The machines retain the strength of larger angle rolls but ancillary costs like pit installation are lower. Since introducing the feature-smart machines, Davi has sold several of the angle rolls equipped with the iRoll-Camera system in North America.

“The best way to partner with customers is to build a better mouse trap,” Bonnay says. FFJ



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