Bending without back pains — what to choose? Part III.

We keep on looking into modern sheet metal forming and bending technologies, evaluating their benefits and pitfalls and clarifying what is specific about the manufacturing, to which each of those technologies looks like the best solutions.

You can look back and read the previous chapters - about the press brakes and folding machines.

Today, let us explore the panel benders.

In panel bending, the sheet is positioned below blank-holder tools, which descend and clamp the workpiece in place, with material protruding on the other side. The farther the metal protrudes beyond the tooling—an area of the machine called the throat — the higher the resulting flange will be. The deeper the throat, the higher the flange.

With the sheet metal in place, the machine’s bending blades from above and below move to fold the metal. For most operations, the motion of the bending blade, not the shape of the tools, determines the final bend angle and radius. The segmented blank-holder tools automatically change out to match the required bend lengths. And like the folding machine, panel benders can form special shapes like hems, with the bending blades forming material past 90 degrees and the hold-down tools descending to form the final hem.

Panel bending has evolved from being one type of machine to a technology incorporated into a variety of systems, from the manually fed to the completely automated.

Traditional panel benders use part manipulators that manipulate a part throughout the bending cycle. In this case, an operator inserts the sheet against locating devices, initiates a cycle, and the manipulator completes the entire part. Still other panel benders are integrated into fully automated cutting and forming systems. Sheet metal is cut, punched, and then formed on a panel bender, all on one extensive system.

In some systems, an operator places a blank against locating pins, and the machine makes all the bends on that side of the workpiece. Once those bends are complete, the operator rotates the workpiece, again places it against locating pins, and the panel bender takes it from there for all the bends on that edge of the panel. Alternatively, an operator can manipulate the piece between each bend if needed.

Because it doesn’t have a manipulator to move the part in and out, it allows the machine to bend certain geometries that couldn’t be made using the manipulator. All these systems excel at high-product-mix production, considering that changeover times are minimal or nonexistent. Some have sheet size limits, depending on the machine model and how the sheet is manipulated during the bending cycle. Some offer features that allow for the machine to remove parts with a downward final flange. Some models have features that allow the systems to handle small parts, such as an integrated shear that can cut off a narrow part from a larger sheet. Others use a separate set of smaller hold-down clamping tools.

Consider a door and frame of an electrical cabinet. They always consist of large panels and small channels. If you can do both, you have an ideal application for a panel bender. An adjustable-height backgauge table on a folding machine allows operators to form complex part geometries. Here, the table allows the operator to gauge off of a negative bend.

The panel bender’s upside: Once a blank is introduced into the machine, either automatically or manually, all bends are performed automatically with no operator handling required. Between bending cycles, universal blank-holder tooling moves to accommodate different bend lengths, but that’s about it. No die width changes, no switching from a straight to gooseneck punch, or any of the other complications that come with press brake tooling.

And the panel bender, like the folder and horizontal bending tooling on the brake, allows the worksheet to stay flat as the edge flange is bent.

As with any horizontal bending technology, a panel bender doesn’t work for every part. Depending on the system, interior windows and cutouts can prevent the manipulator from having enough surface to grip and move the work into position. And the part itself needs a flat or near-flat surface. Some panel bending tables have vacuums or brushes to accommodate a few downward-facing shallow forms, like a louver or emboss. But in general, the machine needs the part to have a flat surface to move the part from bend to bend.

To handle an even greater variety of parts, some panel benders are integrated as part of a system that incorporates both automatic-tool-change press brakes and panel bending. Parts labeled with bar codes arrive at the bending station that has one operator running both a press brake and a panel bender. The operator scans the bar code, which spurs either the panel bender or press brake into action.

By the time the operator delivers the part to the bending machine, the program has been downloaded and the tooling arranged. The machine forms the part, uses automatic angle correction as needed, then completes the job as the operator sends the formed part and retrieves the next, entirely different part. In this situation, the operator could form a small bracket on the brake, then retrieve a panel (or utilize conveyor automation) and position it on the panel bender, no heaving required.

IMA Information:

  • To summarize the above said, let us once again assume, that today there are a big variety of modern technologies present on the market, and all of them are able to increase the production efficiency, cutting down costs in the same time. That's why it's essential to investigate each option's specifics and its compatibility with the parts you produce. Italian Machinery Association is ready to handle this analysis together with the customer and offer the best variant from Italy, whether it will be something from the Association members of other Italian company.

This article consists of three parts. Please read the other two:

Part I

Part II

  • If the time has come to upgrade or enhance your production capabilities, you can also get a new press brake from a reliable Italian manufacturer. Our catalog's range of press brakes from our members can satisfy needs of any manufacturing, from a small job shop to an automated multi-tasking plant.
  • In some cases, the existing machines boost their productivity when setup with new tooling of some of the most popular styles. Please go here to see what Italian Machinery Association can offer.
  • You also might need some repair, installation, re-launch or training services for your existing machines. IMA's maintenance team has enough skills and experience to solve any problem you might have.
  • Any other questions or inquiries? Don't hesitate to contact us via phone/e-mail or visit us in any of our offices.
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Which press brake is best?
This question is asked a lot, and even with plenty of experience answering it, it remains subjective by its nature. There is no “absolute best” press brake. There is, however, an absolute best press brake for you, and that really is the heart of your question.

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