You might think there’s only one way for something to be straight, but many ways it can be bent. In engineering, however, bends must be precise, so there is only one way they can be bent, after all.
Selecting appropriate bending machines and procedures depends on the shape, size, cross-section and material of the manipulated items. However, there are always practical considerations too.
For example, when laying pipelines, sections must often be adjusted to accommodate the topography and geology of the land. Each section’s bend may be unique and access to electricity is often limited. Being able to perform operations in the field (which are often in remote locations) can be critical. In contrast, a manufacturer has easy access to power, but often needs to repeat identical manipulations at high speed on a large quantity of product.
General machine types
A common use for a manual bending machine is in the manufacture of ornate balconies, railings or gridwork from round or squared steel bars. These tools are economical, but their power and precision is limited.
Hydraulic machines can be used for angles within 180 degrees. They are durable, easy to maintain, and easy to operate for less skilled personnel. They can tackle a wide range of diameters and are the type most used in pipe laying operations. The steps in both manual and hydraulic bending are described here: https://www.ehow.com/how_7572574_use-bending-machine.html.
Good quality electrically powered benders use hydraulics and spring-back compensation to achieve high precision. An important advantage of electric machines is that they can be linked to software or remotely controlled. Many electrics are also “universal”, that is, able to perform a wide range of bends, such as u-bending, offset bending, edgewise bending, torsion bending, vector bending, straightening and so on.
The best electric machines are equipped with CNC computer control. Cotswold Machinery Sales distribute bending machines of this type. By delegating complex operations to a computer, you ensure bends are performed precisely every time.
Cold versus hot bending
Another consideration is whether you need heating equipment. Temperature affects the yield stresses and leads to different profiles in the bend. For example, a flattened pipeline bend will have a reduced cross-section and provide more pumping resistance.
In factories, induction heating is often used, simultaneously with the bending operation. An induction ring can guarantee uniform heating much better than other heating methods.