The phrase “six of one, half a dozen of the other” gets a lot of mileage. It’s perfect to interject when presented with two choices that are basically the same. Think phone carrier A versus phone carrier B. Sure, they might have a different deal du jour, but in the end, it doesn’t really matter which one you choose.
Despite their assumed similarities, the phrase doesn’t apply when comparing panel benders with press brakes. They can both produce accurate bends in sheet metal parts, but they solve very different manufacturing challenges.
Most fabricators have or are familiar with press brakes – they’re known as the workhorses of the bending department. They can process a broad range of materials, thicknesses, bend lengths, profiles and production quantities, and they can do it all in high-mix, low-volume environments.
Conversely, panel benders are all about repeatable, automated production. While speed is a major selling point, fabricators lean on their unmatched ability to automatically position, rotate and manipulate blanks throughout the entire bending cycle. For fabricators with large, thin or difficult-to-handle panels, the panel bender’s material handling prowess is a gamechanger.
Rationalizing ROI
According to Ethan Hundley, bending applications engineer at Prima Power’s Chicago Training and Technology Center, about 95 percent of sheet metal fabricators already have press brakes. When they come to Prima with their bending needs, they’re fully aware of the capabilities of press brakes and are typically looking to expand their operations with a panel bender.
“Fabricators come to us because they’ve heard about our deep experience producing panel benders and want to learn more about their possibilities and how they operate,” he says. “Nine times out of 10, they’re trying to justify an ROI on a panel bender because they want to further automate their operations.
“A panel bender has multiple axes compared to the simple up-and-down functionality of a press brake,” he adds. “It’s unbelievable. There are motors all over it to make it work. While it’s a complicated machine, you can do a lot of really neat and productive stuff with it. When we show customers its capabilities and how much faster it can run with so much accuracy and repeatability, they’re pretty excited.”
Thanks to its ability for sustained production as well as to handle large parts, a panel bender is well-suited for fabricators involved with the production of electrical cabinets and enclosures, including the type found in data centers; HVAC and commercial kitchen components; steel furniture; storage systems; doors, covers, trays and architectural panels; and elevator components. Additional parts could include those with the following characteristics:
- Large, thin sheet metal panels
- Multiple bends along the perimeter
- Repeated positive and negative bends
- Families of similar parts
- Awkward for an operator to support
- Operations facing skilled-labor constraints
- Production requiring consistent bend quality across shifts
Bend and repeat
Press brakes can handle a lot, and when augmented with modern offline programming, automatic tool changing, angle-control systems, robotic handling and servo-electric technology, they can do even more for the bending department. However, the fact is repeatability of a press brake isn’t always as high as it can be with a panel bender. And some of that comes down to the human factor.
“Operators grow tired as the day wears on,” Hundley says. “An operator’s accuracy can dip from the beginning of the shift to the end. It’s a factor that has to be taken into consideration.”
Repeatability also comes from a panel bender’s ability to fully support blanks as they’re being bent. Large panels don’t have to be lifted and turned by an operator or two as each flange is produced. Regardless of the model, Prima’s panel benders ensure accuracy and repeatability. The company makes machines with varying levels of automation, ranging from entry-level semi-automatic systems to fully automatic industrial lines.
“All machines have a centering phase where the machine finds its programmed position,” Hundley says. “This is where you get your repeatability from a panel bender.”
Another factor to consider in regard to the repeatability of press brakes is the viscosity of the oil, which for fabricators using hydraulic press brakes can change throughout the day. For anyone keeping score, the lion’s share of press brakes in use are hydraulic.
“If you have a hydraulic machine, the oil is cold when you start it up in the morning,” Hundley explains. After a press brake has been running for eight or 10 hours, the machine becomes looser, so it can actually go into different positions. Not everyone wants to disclose that, but it’s a known issue with hydraulic machines. Prima has a servo-electric brake, so we don’t have to worry about this issue. Our machine motors use a belt to drive the ram to a specific position with even, consistent pressure.”
Despite the many wow factors behind panel bender technology, Hundley stresses that a fabricator’s part can fall outside of the limitations of a panel bender and, therefore, must be made with a press brake. Common characteristics include:
- Small parts
- Narrow parts
- Thicker materials
- Deep boxes exceeding 10 in.
- Parts requiring specialized tooling
- Geometries that make it difficult to center the part
- Large forms near bend lines
Take the time
When potential customers come to Prima for guidance on switching to a panel bender or perhaps upgrading their current press brake, Hundley recommends they bring in a sample part or part file. The company is happy to conduct time studies to learn more about the production of the part and what machine would best handle the job.
“Typically, we ask customers to provide us with a 3-D file, if they have it, especially a native file because it carries all of the metadata attached to that particular part,” he explains. “The more data we have access to, such as tolerances and material thickness, the better our recommendation can be. Obviously, we can still use legacy files, but sometimes information like material type and thickness or inner radii can be lost. That information can make a big difference in how we approach a part. We also like to get a PDF from the customer that shows the tolerances.”
For customers looking to add a panel bender to their operations, one of the biggest questions Hundley is asked is if they can run their existing flat blanks without modifying them. If the part allows for a slightly looser tolerance, a panel bender can typically use pre-existing blanks.
“A panel bender can absolutely clean up a part to make it work – if it’s within your specs, of course,” he says. “But, if you need something to be within five thousandths of an inch all around, it isn’t recommended to use old blanks.”
For those parts, it’s best to create a dedicated, newly unfolded blank designed specifically for the panel bender rather than forcing a press brake blank onto it. In those situations, the team at Prima is happy to help with the unfolding.
“We consider the relationships we have with our customers as a partnership,” Hundley adds. “We’re basically like family where their problems are our problems, so we like to help out as much as possible. It isn’t uncommon for customers to reach out to us if they need help with a redesign or if they’re struggling with a part.”
Automation options
Whether a customer’s part mix dictates a press brake or panel bender, the level of automation needed is an additional part of the conversation. Typically, machine automation centers on the same three issues: replacing or easing manual labor, increasing repeatability and integration into an otherwise fully automated production line.
Inherently, panel benders are an automated technology, in part because of how material is positioned and centered on the machine. Using internal centering pins, manipulators and pushers, panel benders square blanks into position without deviation. By eliminating the need for human intervention during the bending sequence, fabricators can be sure their parts are exact and to spec every time.
Prima offers a full range of panel benders from semi-automatic to fully automatic, depending on a fabricator’s needs. For those pursuing a fully automated production line, Prima delivers machines that require zero human intervention. The machines receive parts from a connected blanking system, orient them into the correct position and then robotically rotate them for each part of the bending sequence.
For a more entry-level model, the semi-automated BC Smart, for example, is manually loaded by an operator, but features ergonomic loading zones, GUI displays and LED positioning guides to minimize human error.
“The BC Smart offers a graphic display on the user interface to help the operator see where and how to load a blank,” Hundley says. “A red LED bar lights up so they know where to put the corner to ensure it’s in the proper position. We do as much as we can from the user interface standpoint to walk operators through the entire process, but, of course, anytime a human is introduced, there’s a little bit more room for error.”
In terms of automating a traditional press brake, there are several options. Fabricators can invest in a fully automated robotic cell where loading, holding, manipulating and unloading are all automated operations. In these instances, the press brake runs lights out and with additional material handling automation, these cells can be streamlined into a fully automated production line.
Additional automation can also come in the form of offline programming, which reduces cycle times and streamlines the robot’s motion path. Thanks to offline programming, a robot cell has higher uptime and is easier to integrate into an automation production line.
Based on the ease in which both technologies can be automated, it again comes down to letting the part mix dictate whether a panel bender or press brake is the right choice. However, it’s important to remember that some fabricators might actually need both technologies. For a fabricator with regular repetitive panel work and large components that also works with thicker, smaller, lower volume or geometrically complex parts, a panel bender and a press brake may very well be the way to go.
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