Do you operate in one of the various industries that frequently use pre-coated aluminium sheets? We hear stories of the headaches caused when using a sheet metal folding machine to bend these, but it is avoidable.

perfect aluminium sheet bending example

Is the colour stretched when bending on the outside of the flashings? When this happens the bend does not give an optically flawless profile. To achieve this the paint should not thin out at the edges and should certainly not flake off.

But how can you achieve this?

The problem

If you work with aluminium sheets that are between two and four millimetres thick, the material manufacturers will usually recommend you use a specific inner radius when bending. This is to prevent unsightly cracks from forming at the bending edges.

In many cases, like in sheets that are used for metal facades, water can penetrate the cracks left which will cause the aluminium sheets to break in the event of frost.

If you’re producing for use in the UK then these weather conditions are all too common. It’s going to be an issue and cost your business. Is your folding machine set up to avoid this common issue?

aluminium bending sheet metal

The solution

When it comes to working with such sheet metals, machine quality can make all the difference. RAS has years of experience in bending such sheets. They have developed techniques to ensure a quality bend every time from their sheet metal folding machines.

With sheet steel and stainless steel, you usually want to bend with sharp edges. As such you would use an upper beam tool with a tooltip. With aluminium and titanium zinc, however, it is advisable to use tools with a radius of 1.5 to 2 mm. Together with the deflection of the material, this achieves the required radius.

In the past, radius tools that ended with the bending line were often used. However, if you want to achieve a cleanly formed radius, the tool radius must protrude beyond the bending line. Most commonly with thicker sheets, this procedure can also be used to calculate the sheet development exactly.

RAS aluminium bending tools

When bending sheet steel and stainless steel with sharp edges, there is almost no movement between the surface of the bending beam tool and the material during the bending process.

This is different when using radius tools. In these instances, the bending beam tool slides on the surface of the sheet during the bending process. This can lead to clearly visible scratch marks and damage to the material surface.

RAS folding machines avoid this problem by using folding beam tools with a plastic insert. These bending beam tools are available for the FLEXI2bend and the XLTbend (since thicker aluminium is also often bent on this machine).

example of damage aluminium when bending compared to a clean bend

Plastic inserts also solve another problem

After the bending beam has reached the programmed angle, it swivels back to the starting position. Due to the spring back of the material, a normal bending beam tool can leave scratches on painted or coated material when the bending beam is swivelled back.

This can go so far that a normal bending beam tool bites into the sheet metal and unintentionally deforms the material during the backward movement. It can even jam it between the bending beam and the lower beam.

All of these effects can be avoided by using the bending beam tools with plastic inserts. Just see the difference below!

clean vs damaged aluminium bend

Built to last?

Long-term tests have dispelled concerns that the plastic insert is subject to high wear and tear. These tools can even be used when bending sheet steel or stainless steel.

It is understandable that a small amount of wear cannot be avoided. However, the plastic insert can be replaced quickly and inexpensively. We see this as a small price to pay for a clean bend with no damaged done to your sheet metal.

RAS Bending inserts

Ready to find out more about damage-free bending?

Our team of experts are on hand to help advise you on how you can ensure a clean bend every time. We take the time to understand the type of materials you are bending, the thickness and where they will be used. This means we can ensure you make the correct investment in a folding machine fit for your purpose.

Ready to find out more?