Frequently Asked Questions

Air bending is the preferred bending method for most press brake applications. With just a limited set of tools you can make a wide variety of bends. Less tonnage is required compared to other bending methods. Air bending allows for a slim tool design, giving you more bending freedom. Additionally, it’s easier to compensate for springback.

The general rule of thumb for air bending steel is to select a V-opening of 6-8 times the sheet thickness. By deviating from this you can influence the product radius, the required bending force, degree of marking and minimum leg length. But be aware that a modified V-opening will also affect the flat pattern of the sheet. Learn more about the V-opening.

Using air bending, you can bend different angles with a limited set of tools and need to change them less often. Choose a tool combination with a sharp tip and groove angle for the greatest flexibility. Learn more about the tool angle.

Oddly enough, when air bending, it is not the tip radius of the punch that you use to influence the product radius, but the V-opening of the die. Choose the punch tip radius as close to the natural radius as possible without exceeding it. Learn more about the tip radius of the top tool.

Yes, with WILA standard tools, the shoulder radius is linked to the working height. By bending in a die with larger shoulder radii, less marking is visible on the product, or it is even possible to bend mark-free. Learn more about the shoulder radius of the bottom tool.

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. Learn more about tool height.

Choose a punch with a gooseneck for the most flexibility. The larger the gooseneck, the more bending freedom. This does come at the expense of maximum load capacity. Do you want to be able to set different angles with the same punch? Then choose a 28° point angle and a small gooseneck. A straight shape has the least bending freedom, but the highest load capacity. Learn more about tool shapes.

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.

Check out our ‘Bending near holes and cut-outs’ applications page, to learn how to prevent deformation of holes and cut-outs.

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.

WILA recommends a flange length that is at least 6 times the material thickness using regular press brake tools. The minimum flange length also depends on the V-opening and shoulder radius of the tool. Check out the WILA Smart Tooling app for bend advice and the minimum flange length that can be bent.

If you use bottom tools with a smaller V-opening, you will be able to bend a shorter flange. However, the material might crack, larger tonnages are required and there might be excessive tool wear. Note that the inside radius will also change, as will the flat pattern, when you change the width of the V-opening. If you want to bend shorter flanges, check out WILA RotaBend tooling.

RotaBend tools provide the highest accuracy when bending parts up to approximately 1 m in length. Contact WILA if you are looking for a solution for bending a short flange longer than 1 m.

Your holes will deform if they are too close to the bend line. Check out our download “Minimum distance to holes” to learn how to calculate the minimum safe distance.

In general, try to bend your parts using air bending as your bending method. However, bottom bending or bottoming will result in less deformation and more bending consistency.

Check out our download “Minimum distance to holes” to learn how to calculate the minimum safe distance.

Using abrasive pads like Scotch Brite can be an effective means for removing zinc deposits on your bottom tools. However, excessive cleaning may cause wear.

You can use Scotch Brite or similar abrasive pads to effectively remove zinc deposits on your bottom tools. However, excessive cleaning may cause wear.

There is a reasonable chance that your tools suffer from galling. The zinc deposits on the shoulders of the bottom tools will look similar to scratches. Using abrasive pads like Scotch Brite is an effective means for removing zinc deposits on your tools. However, excessive cleaning may cause wear. Also check out our guide on how to prevent galling.

That depends on the amount of springback that occurs and the dimensions of your Top Tool Holder. Use offline bend simulation software or contact WILA.

For an accurate calculation, you will want to consider both the springback and the width of your Tool Holder. Use offline bend simulation software or contact WILA.

For an accurate calculation, you will want to consider both the springback and the width of your Tool Holder. Use offline bend simulation software or contact WILA.

WILA offers tool extenders of different heights. Check out our tool extenders in the web shop. Make sure that the open height and stroke of your press brake are suitable for the combined height of tools and extenders. Use offline bend simulation software or contact WILA for determining the required height.

As a rough guideline, at WILA we talk about Heavy Duty bending when bending 6mm mild steel or thicker. These thicknesses require V-openings starting at 60 mm (V = 10 x sheet thickness or more).

When bending thicker, higher tensile strength plate, you will need bottom tools with a V-opening that is more than 8 times the sheet thickness to prevent cracking. Make sure your press brake can supply the required bending force for the bend operation. Allow for springback of the plate when selecting the V-angle of the bottom tool. Make sure your tip radius matches the natural inside radius as close as possible but does not exceed it. This will give the best and most consistent results and prevent excessive wear of your top tools.

Depending on the material and your tool set-up, you can hem sheet metal up to 4mm thick. Check out our product specifications or contact WILA for advice.

The first step when creating a hem is to make a 30° bend. The shortest hem you can make depends on the minimum flange length you can bend in this step. You can look up the minimum flange length for WILA bottom tools in the WILA Smart Tooling app.

Unfortunately, creating a hem will always leave marking on the sheet.

Alas, a hemming operation will always damage the foil and will leave marking on the product.

Yes, you can! The end result depends on the radius that is created when making the 30° pre-bend and also on the depth of the hemming stroke.

Check out the tonnage chart for flattening in the WILA catalog for required tonnages.

Check out the tonnage chart for flattening in the WILA catalog for required tonnages.

Yes, you can! But because the sheet thickness is doubled, you should adjust your tool set-up accordingly.

Provide WILA with the material thickness and hemming frequency and receive our hemming flyer and expert advice on the best solution for your needs.

Our hydraulic Dutch bending tables can be used for automating the hemming process. Contact WILA to explore your options.

Try to make the pre-bend as sharp as you can. Also check if the material and thickness are suitable for the hemming tool you are using.

Not if you use your hemming tools correctly. When hemming thicker materials, side forces can be eliminated by using our hammer tools in combination with a rolling table.

Apart from aesthetic or functional reasons, a larger bend radius might be required to prevent the material from cracking during bending. Large radius bending is also ideal for creating U-profiles in two or three bends.

Check out our radius tools in the web shop with radii of up to 50 mm. The thinner the sheet and the larger the radius, the more springback. Note that this could result in a radius that is larger than the radius of your tool.

The maximum size of the top tool radius (R_max) for bending up to approx. 90° is R_max = 0.7 x V-opening (V) - 2 x material thickness (s)

A safe minimum V-opening for your bottom tool is V = 2.5 x (radius of used bar (R) + material thickness (S)). The V-angle depends on the springback of the part.

The required bending force is also larger and can be determined by calculating a correction factor (C) and multiplying it with the required force for air bending C ≅ (0.6∙V-s) / (0.7∙V-(s+R)). Please contact WILA for further assistance.

If the tip radius of your top tool exceeds the natural inside radius of the material, Multi-Breakage will occur, resulting in a non-circular bend that has a smaller radius in the center of the bend.

Multi-Breakage is a common phenomenon that occurs when bending a large radius. As the punch engages the working material, the center of the working material separates from the punch and forms a radius smaller than the punch tip radius. This can be reduced by opting for a larger die opening.

Springback will always occur but forming larger radii in thinner materials with higher yield strengths will result in a lot of springback. When bending large radii, springback could easily be up to 30°.

With a radius tool you can bend any angle between 0° and 180° in one or more steps, depending on the bending freedom you have.

Larger radii can be bent in steps using regular tooling. This is often referred to as step bending. A larger number of bend steps will result in a smoother angle, but there will also be a larger build-up of tolerances. The distance between bends has to be greater than the minimum flange length that can be bent on the bottom tool.

Our knowledge article on “How to reduce part marking at the press brake” will put you right on track. Are you bending galvanized material? Then check out our guide on how to prevent galling.

There is a difference in lifespan and thickness. WILA protective foil is available in thicknesses of 0.8 mm and 2 mm. WILA protective cloth is made of a densely woven nylon cloth that is 0.3 mm thick. Protective cloth has a life cycle of as much as 8-10 times that of protective foil and is more flexible. Our advice is to use non-marking cloth.

Non-marking sheet or foil can be clamped onto the Bottom Tool Holder using our clamping system for K-003/4/5.

A non-marking synthetic insert is an insert that can be used inside bottom tools, type OZU-016, enabling you to bend without marking. Contact WILA for tailored advice.

Try to minimize friction. You can do this by using bottom tools with a larger shoulder radius. You can also opt for a larger V-opening, which will reduce the required tonnage. Note that this will also result in a larger bend radius and will require changing the flat pattern of the product. Lubrication will reduce friction but often requires more cleaning of both tools and products.

Check out our guide on how to prevent galling.

Rotabend will significantly reduce part marking, but it will not enable you to bend completely mark-free.

Our knowledge article on “How to reduce part marking at the press brake” will provide you with tips and tricks. Are you bending galvanized material? Then check out our guide on how to prevent galling.

Offset bending can be used to form two equal and opposite bends that are too close together for regular bending. Offset bends can be used to create a flat surface when connecting two panels, or to strengthen the sheet metal.

There are tools that use the up-sweep principle where the metal sheet sweeps up and horizontal offset tools. WILA tools use the up-sweep principle for air forming and bottoming offset bends.

This depends on your material, press brake and tools. The largest standard offset tool that WILA offers has a Z-dimension of 15 mm. This corresponds to a V-opening of about 20 mm and allows you to bend up to 3 mm thick mild steel with a tonnage less than the maximum load of the offset tool. Contact WILA for more information on what is possible in your situation.

This is not possible. The reason for this is that a V-opening of 6 to 8 times the sheet thickness is required. This corresponds to a Z-value which is about 4 times the sheet thickness. If you want your offset to be the sheet thickness, bend at more open angles. Contact WILA for advice.

Lateral forces can be an issue if the offset tool is asymmetric and it is a heavier bending operation. WILA offset tools are not asymmetric.

Please contact WILA if you are looking for options other than the standard WILA offset inserts.