Bottom bending (bottoming)

For applications that require a higher accuracy than air bending

Bottom bending is well suited for applications that require a higher accuracy than air bending, for dealing with springback and for bending near cuts and holes. Material tension caused by cutting or punching is less critical in bottom bending. Bottom bending requires more bend force and each bend radius requires a different set of tools.

Tools for bottom bending

With our range of 90° New Standard tools for bottom bending, modular and available in several standard lengths, we make it possible to quickly achieve virtually any bending length.

View products

Ask the experts

Need help choosing tools? Our sales staff are happy to develop a custom tool kit so you can bend anything you need without paying for tools you don't use.

Tool Holders

WILA’s clamping and crowning systems offer the ultimate solution when it comes to efficiently changing tools, whether hydraulic, mechanical or pneumatic.

View products

Benefits

High accuracy

Bottom bending with WILA’s high quality and multi-faceted New Standard tooling results in higher accuracy compared to air bending. Under optimal circumstances an angle accuracy of ± 0.25° can be achieved.

Less influenced by material stress

With bottom bending the bend result is less dependent on material stress caused by cutting or punching. It also reduces the amount of springback.

Bend near cut-outs and holes

If holes, notches, or diagonal edges are located close to the bend, the sheet surface will remain flat, as long as the punch and die have matching surfaces that engage and compress the material.

Small inside bend radius

Compared to air bending, bottom bending allows for a smaller inside bend radius, determined by the shape of the punch and the die.

Frequently Asked Questions

With bottom bending smaller bend radii can be formed and bending is more accurate. There will be less deformation of holes near the bend line. Material tension in the edge of the sheet metal has less influence on the end result.

Compared to air bending, tooling costs are higher and set-ups take longer. You will need a different set of top and bottom tools for each angle and bend radius. Bottom bending typically requires a tonnage that is 3-5 times higher than that required for air bending.

The general rule of thumb for bottom bending mild steel is to select a V-opening of 8 times the sheet thickness.

When bottom bending, the tip of the top tool determines the internal radius in the sheet. It depends on the properties of the sheet material how small you can choose the tip radius.

A larger tool height offers more bending freedom and also gives you the most flexibility in the future. When choosing the height, do take into account the stroke and installation height of the press brake.

The shortest flange you can bend will depend on the V-opening and shoulder radius of your bottom tool and the angle of your bend. Check out the WILA Smart Tooling App for advice on the minimum flange length.

Check out our ‘Mark-free bending’ applications page, to learn how to minimize part marking while bending sheet metal.

Talk to an expert

Any questions on bottom-bending or any other type of sheet metal bending on a press brake? We're happy to share our expertise.

Find a dealer close to you

WILA dealers have the knowledge and expertise to support your press brake tooling needs. There is always a WILA dealer near you.

Find your local dealer