Bending without back pains — what to choose? Part II

Last week we have started our journey into exploring modern technologies of bending, trying to choose a technology which would be the best suited for manufacturing and help to get rid from back pains and strains of the operators. Let us get on today and see, what benefits the folding machines can bring.

Folding Machines

To form a workpiece on a folding machine, an operator (or automation) places a workpiece on a backgauge table, which has recessed rails with pop-up fingers, each individually controlled. The piece slides forward and is positioned under clamping beam tools that clamp the workpiece in place. In recent years folding machines have been able to form in both positive and negative directions with a single beam.

Backgauge tables are sometimes L-shaped, with the horizontal leg of the L behind the folding tools. When working with large panels, many folding machine operators prefer to work from behind the machine, and an L-shaped backgauge table allows them to support the work throughout the folding cycle.

The height of the clamping beam tools generally determines the height limit for a 90-degree flange in a four-sided box. If the workpiece has flanges on only one or two sides, folders have no limit on flange heights. The clamping beam tools are changed and rearranged to accommodate different bend lengths while avoiding collisions with previously formed flanges.

Once the machine has material clamped, a tool on a swinging beam contacts and folds the workpiece. The beam can swing to a position within 0.1 degree, resulting in an angle tolerance of plus or minus half a degree. Standard tooling is very flexible, and there are no tool changes required to accommodate different material thicknesses.

Some machines offer a height-adjustable backgauging table, which can help operators run more kinds of parts—say, to support a negative bend. You can drop down your backgauge table to gauge off of a negative bend. Folding machines also can form hems and other edge geometries. The operator slides the part onto the backgauge table, and the clamping beam tool descends to form the hem, be it flat, teardrop, or another shape.

Modern folding systems can create both positive and negative bends. The folding beam does this by swinging upward and downward. To swing downward, it must pivot outward by the width of the folding tool. Say the beam tool is 0.6 in. wide. For the first upward bend, the top edge of the tool contacts the sheet to make the bend. To bend downward, the tool’s bottom edge must fold the material surface. This requires the beam’s pivot point to move 0.6 in.

Thicker tools on the folding beam can accommodate thicker materials. Thinner tools can fold material only so thick, but these narrow tools also can access certain areas that thicker folding tools can’t, like the back-to-back bends required for narrow offsets.

Automatic tool change on press brakes has been growing in popularity, and in recent years tool change automation has hit the folding machine market too. In these machines, robotic manipulators change and rearrange clamping beam tools for the job at hand.

Alternatively, some folding systems change tooling automatically by rotating the upper beam. One side of the beam can have a conventional clamping beam solid tool, while the other side of the beam can have segmented clamping beam tooling. An operator can do as many bends with the solid tool, and on the segmented side, he can have tools set up for panels of different widths and other parts.

Like press brakes, folding machines now have automatic tool change options, only here the clamping beam tools are changed and manipulated to accommodate different bend lengths and avoid collisions with previously formed flanges.

A lot has changed with folding technology to relieve the bottleneck in the forming department. Fully automated folding systems with auto tool change and part manipulation have hit the stage.

As we already said, every option, from special brake tooling to automated systems incorporating several machines, has a business case to be made for it. Which to choose depends on a fabricator’s current and potential part and customer mix. Please feel free to address Italian Machinery Association to choose the best technology for you and your operators.

IMA Information:

Bending is a broad subject with many issues and challenges. Italian Machinery Association is here to assist you with bending processes and press brakes in many different ways.

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