Written by: David Prokop Metalforming LLC
April, 2025- It’s often said that an operator is responsible for producing quality parts but has little control over the outcome. This is especially true when working with large, heavy profiles. Despite advances in traditional bending methods, most fabricators agree that the forming process remains their biggest challenge. An estimated 70 percent to 90 percent of sheet metal parts undergo some type of bending. The process demands skilled operators and is one of the more hazardous tasks in a job shop. The difficulty in finding and retaining qualified employees also drives labor costs up, creating a ripple effect throughout the entire process, as downstream operations grapple with similar challenges.
By embracing fundamental lean principles simplifying processes, reducing inefficiencies and eliminating unnecessary steps folding technology is reshaping the bending process for large part applications. Its performance advantages make it an attractive choice over other forming methods.
Modern servo-electric press brakes can quickly bend small intricate profiles with a single operator while panel benders are ideal for larger, thin-gauge parts and high production volumes.
Mid- to large-scale parts, on the other hand, often represent the biggest forming difficulty. Their size consumes labor, cripples production speed and destroys part accuracy. Modern folding technology can deliver unmatched accuracy, efficiency and labor savings, regardless of part size.
Only the flange moves during the bend while the part lies flat.
HEAVY LIFTING
The biggest problem with bending large parts is handling where 90 percent of a part is controlled by the operator. As part size increases, productivity drops, labor demands rise, safety risks grow, and accuracy suffers. Large parts often require two operators, doubling labor costs while reducing efficiency. Larger parts demand lifting equipment like jib cranes or forklifts, further increasing costs and slowing output. While sheet lifters support the part, they don’t assist with flipping or lifting for reverse bends. These inefficiencies disrupt downstream workflow, creating inconsistencies and reducing overall efficiency as well as part quality.
Operator easily manages a 145 lb. part.
Poor fitment leads to extra assembly time, higher welding and grinding costs, and difficulty in adopting robotic welding. With 50 to 80 percent of sheet metal parts requiring welding, precision in forming is critical to boosting efficiency and reducing overall production costs.
Folding eliminates size-related challenges while ensuring consistent processing times. Unlike press brakes, over 90 percent of the part is secured in the machine, moving only the flange during bends. No flipping, supporting or wrestling is required. A single operator can easily handle even the largest parts on the folder’s ball transfer table. The semiautomated gauge holds and advances the part, while the folder transitions between up and down bends without manual intervention.
The ease of part manipulation on a folder contributes to high, consistent accuracy, eliminating fitment and cost issues downstream.
Beyond ergonomics, it also tackles another major challenge in bending: material thickness variation.
Part being robotically unloaded and moved to the finished stack.
Both surfaces of the material come into play when bending with a punch and die, making thickness variation a major source of bend error about 70 percent. A folder avoids this issue by bending like a protractor, using only the outside surface to form the angle.
The remaining 30 percent of angular error stems from tensile and grain variation. A punch tip creates a compressed zone at the bend center, splitting the radius into two halves. In contrast, folders form a single air-formed radius outside the tooltip, cutting tensile variation error by roughly half.
PRODUCTION GAINS
Maintaining angular accuracy is also essential for dimensional precision since each bend relies on the previous one. A ½-degree bend error can lead to a 0.008 in. flange deviation at a 1-in. gauge point, compounding to a 0.024-in. error over three bends and nearly 0.050 in. when both sides are bent. These inaccuracies disrupt robotic welding and reduce manual welding efficiency, with larger parts magnifying the issue as handling errors contribute to the problem.
Folding method compared to measuring with a protractor.
Flat is pre-staged while part is being folded in machine.
Folders solve this problem by using a single datum point per part side, ensuring all bends are gauged from a single precise reference point. The gauge firmly holds the part, automatically advancing it through each bend to prevent cumulative errors that affect fitment.
With the part resting on a ball transfer table, handling difficulties associated with large components are completely eliminated. Significant production benefits are also gained by a folder’s ability to use a single toolset for bending the full range of material thicknesses and types within the machine’s capacity. This capability reduces setup time, lowers tooling expenses and enhances overall efficiency. Different part radii, material thickness offsets and hems can be easily programmed with the same set of tools.
Automatic Tool Change enhances production efficiency further by cutting setup times to under a minute on average. During this brief window, the operator can remove the finished part and position the next flat, ensuring seamless workflow. This rapid transition between parts is ideal for kit production, directly feeding assembly or welding stations while maintaining high production speed, regardless of batch size.
AUTOMATION
Folding technology is also ideal for automating large-part production. Automated part handling in a folder is designed for simplicity and efficiency. Throughout the bending cycle, the part remains in a horizontal plane, eliminating the need for flipping or regripping. The robot serves only as a pick-and-place device, with no direct involvement in the bending process. It retrieves a blank from a stack or conveyor, sets it on the alignment table, and transfers it to the folder’s gauge table, where it is positioned against gauge pins. The Advanced Handling System (AHS) then takes control, gripping the part, executing the entire bending sequence, and returning the finished piece to the robot for stacking. Meanwhile, the next part is pre-staged, ensuring continuous workflow.
Capable of handling parts up to 159 in. by 72 in. by 0.196 in., the AHS maintains consistent production rates regardless of size or weight. The folder retains full control over the bending process, preserving accuracy and production speed.
Whether forming a 500 lb. part or a 50 lb. part, differences in handling time are measured in seconds rather than minutes. Additionally, robotic part handling takes place outside the bending cycle, unlike other automated bending systems where material handling is part of the bending process. This separation ensures that part size or weight never slows the process, maintaining optimal production efficiency.
Advanced folding technology provides significant advantages over traditional bending methods, particularly for large profiles. Fabricators who adopt this technology can gain a competitive edge in an increasingly demanding industry.
DAVID PROKOP is executive vice president of precision sales for Metalforming LLC
