Bending heavy parts – Here’s what you need to know

247TailorSteel can bend heavy parts for you. You should however bear in mind certain guidelines in your design, plus a few limitations. This blog tells you everything you need to you.

We will cover the following questions:

1. When is a part ‘heavy’?
2. Guidelines
   
   1. Enough room for suction cups
   2. Proper suction cup distribution
   3. Preventing collisions
3. Points for attention

1. When is a part ‘heavy’?

We divide parts into two groups:

• Parts under 45 kg
• Parts from 45 kg to 75 kg (= heavy)

For bending work, we define parts from 45 kg to 75 kg as heavy. To lift these, we use lifting devices. These devices use suction cups to grip the part and bear all of its weight. This way, all our operators need to do is position the part properly in the bending machine.

We lift parts weighing up to 45 kg by hand (if necessary with two people and/or the accordion bending device). The weight of a part does not limit the possible operations, as long as you draw your 3D design according to our bending guidelines.

2. Guidelines

The lifting device is an ideal tool, and enables quite a lot, but also requires additional guidelines. In brief:

1. Make sure your bending piece has enough room for four suction cups.
2. Make sure the suction cups can be distributed properly over the part.
3. Make sure flanges will not collide with the lifting device or bending machine (tools).

2.1 Enough room for suction cups

It must be possible to attach all four of the lifting device suction cups, each with a diameter of 200 mm, onto the surface of your part. If that is not possible, we cannot lift, or bend, your heavy part.

Below you can see the two most common situations where a part lacks room for the suction cups.

First, parts with a lot of holes on their surface pose a problem. Suction cups cannot create a vacuum with holes underneath.

Second, parts with small surface areas have limitations. A complete blank, or even a single flange or body may be too small. Let’s look at a U-shaped part as an example: The middle section must be wide enough for one or two suction cups. After all, they must be able to grip the piece to perform the final bending operation on the U-shape.

This brings us to the following specific guidelines:

• Always be sure to leave enough room between holes for four suction cups with a diameter of 200 mm each.
• Make sure your part has minimum dimensions of 520 x 420 mm.
• Make sure all bodies or flanges on your U-shaped product are at least 270 mm wide.
• Make sure all flanges on an L-shaped product are always 260 mm wide.

2.2 Good suction cup distribution

We must be able to position your part straight in the bending machine. This only works if the lifting device can hold your part straight. And that only works if we can distribute the suction cups properly and evenly over the surface. 

If not, your part will be held crooked, and our operators will have to lift it again to get it straight in the bending machine. We want to avoid this at all costs, as it is not ergonomically sound. 

Tip: Draw an imaginary cross over your product to ‘divide’ it into four quadrants. We must be able to attach a suction cup to each quadrant.

2.3 Avoid collisions with lifting devices and bending machines(tools)

If the edges of your heavy product are raised up too far, they will contact the lifting device, the bending machine and/or the tools. This is known as ‘collision’, and must be avoided. Therefore, ensure the following maximum flange heights in your dimensions.

(Only bold) Small products (520 x 420 mm > 620 x 620 mm)

With small products, the flanges can touch the two beams (suction cup holders). So for this dimension, the flange should never be higher than 50 mm.

(Only bold) Medium-sized products (620 x 620 mm > 1,220 x 620 mm)

With medium-sized products, the flanges can touch the top support beam of the overall lifting device. So for this dimension, the flange should never be higher than 180 mm.

(Only bold) Large products (1,220 x 620 mm > …)

With large products, the flanges can touch the opening of the bending machine. So for this dimension, the flange should never be higher than 230 mm.

3. Points for attention

Our online software, Sophia®, will typically warn you if your heavy part cannot be bent. It will offer any available solutions, which you can also read about here.

Finally, please also bear the following points in mind:

• Edge finishing is not possible for products heavier than 40 kg.
• Thread tapping is not possible for products heavier than 40 kg.
• Tolerances may come out 1.5 degrees higher (normally we can correct a deviating angle somewhat, but not with heavy parts).
• Certain shapes, such as closed U-channels and corrugated sheet, are not possible in products weighing over 45 kg. With closed U-channels, the suction cups often cannot get through the opening, and with corrugate sheet, they cannot achieve a vacuum.

Half-closed U-channel

Corrugated sheet

Questions about bending heavy parts?

If you have further questions on this topic, please feel free to contact us.