Tube & Pipe
By Lynn Stanley, senior editor
CML’s CNC mandrel bending machines, like the Erco 65 CNC 3V1, can process ferrous and nonferrous material including high tensile strength Grade B carbon steel.
Affordable efficiency
CNC bending technology helps fabricators bridge skills gap, opens vistas for new applications

hen it comes to tube bending, the process is “still a bit of a mystery to a lot of fabricators,” CML USA Inc. General Manager Scott Tunis says. Bending tube is necessary for a broad range of applications from automotive, aerospace and shipbuilding to handrails, wheelchairs and amusement rides. Yet despite its expansive reach, Tunis says manufacturers tend to see the technology as a niche market.

“When people hear the phrase tube bender, they typically think in terms of round tubing,” Tunis adds. “But the uses for equipment like our Erco 65 CNC 3V1 Mandrel Bender are so diverse that we are still discovering new applications.”

CML International S.p.A. has engineered and produced tube, pipe, mandrel and rotary draw benders, angle rolls, pipe notchers and ornamental metal working equipment for more than 45 years. The Italian company built its reputation under the Ercolina brand. The parent company established CML USA in 1990 to serve metalworkers in the Western hemisphere. In 2018, CML International acquired Pedrazzoli IBP.

“The Ercolina and Pedrazzoli brands each have a long history, which started in the garages of our fathers’ homes,” said CML International CEO Alessandro Primo Caporusso. The acquisition expanded CML International’s tube and metal profile processing capabilities and provided a line of equipment with the capacity to handle high-volume bending projects.

Smart solution
CML’s line of numerically controlled (NC) and computer numerically controlled (CNC) mandrel bending machines will handle raw stock in diameters of ½ in. to 6½ in. According to Tunis, the company developed its CNC controls to support two major trends. Medium to large-sized contract job shops have embraced automated machines in response to a shrinking pool of skilled laborers. Senior personnel with the experience to position parts and bend material are retiring at a rapid rate.
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The Erco 65 CNC 3V1 Mandrel Bender performs part simulations, then calculates and accommodates each variable needed to bend parts efficiently.
“A lot of fabricating equipment has transitioned to CNC controls,” he says. “Customers now want machines that are plug-and-play. Manufacturers want to eliminate secondary operations in lieu of more finished parts and they want to reduce part handling. We’re seeing this across the board, not just with bending equipment.”

Companies are also evaluating how they will hire and train new metalforming equipment operators. “Computers are like second nature for young people who have grown up knowing how to use them,” Tunis says. “In terms of trying to replace the hands-on know-how of workers who are retiring, an individual with fabrication experience becomes less critical because the CNC bender is doing the thinking, and it’s a more efficient way to produce bends.

I think CNC is proving to be a gateway to bending.
Scott Tunis, CML USA Inc.
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“Take a handrail that requires three to four bends,” he continues. “The customer doesn’t know the length of the part or where to position it between bends. With the Erco 65 CNC 3V1 Mandrel Bender, you can import a DXF file or drawing from CAD to the control. It performs a simulation to show you what the part will look like. Once you approve the design, you can proceed to automatic cycle mode. The machine calculates and accommodates the length, direction and other aspects of the bending process. In short, it does the thinking for the operator.”
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The design process begins with a complete understanding of a customer’s part requirements. Material selection and size depends on application, formability, weldability, corrosion resistance, strength and weight. Modeling a component takes into account variables like wall thickness, bend radii, hole locations, notch and slot orientation, springback and bend allowance.

“We are seeing a number of people who have been afraid of bending technology in the past, start to understand that it is really not a black art,” Tunis says. “If I take a drawing from my design department, put it in a CNC-controlled mandrel bender, it shows me the part on my machine. If I need to make a change, I can do that right on the spot. If I need that part anytime during a shift or if I need it a month later, I can recall the data and quickly repeat the program. I think CNC is proving to be a gateway to bending.”

Versatile machines like the Erco 65 CNC 3V1 Mandrel Bender can do much more than manipulate and modify data. Depending on the application, the unit can process ferrous and nonferrous material—carbon and stainless steels, aluminum, titanium and brass. The sturdy equipment can handle high-tensile strength grade B carbon steel. It can perform bends on square or round tubes and extrusions or follow a die with a unique shape.
CML’s mandrel bending machines can perform bends on square or round tubes and extrusions or follow a die with a unique shape.
“More suppliers are stocking grade B carbon steel over grade A for its high tensile strength,” Tunis says. “Pricing for grade B has equalized, and engineering designs are calling for it as state and county specifications for construction and infrastructure are upgraded.”

Features on the Erco 65 CNC 3V1 Mandrel Bender include programmable carriage movement for tight radii, independent pressure and clamp die adjustment, programmable material springback settings for each bend angle and unlimited program memory storage.

Tunis cautions companies to perform due diligence when they source tubing. “Very often when we ask a customer what material type they are bending, they can name the alloy but don’t know the grade,” he says. “It’s important to have a certified mill test report (MTR) because it makes a difference in terms of bend quality, springback and potential issues like cracking.”

CML has a variety of machine models on hand. “We can visit a customer’s facility and analyze their work,” Tunis says. “If our bending equipment is a good fit, we’ll tell you. If it’s not, we’ll tell you that, too. I’ve been in this business a long time and we still hear, ‘I didn’t know a bender could do that.’”

Davenport, Iowa, 563/391-7700,