Among the various metalworking processes, sheet metal bending allows to shape surfaces giving standard or customized shapes.

Sheet metal bending: tools and technical knowledge for deforming metal materials

As part of metal carpentry, sheet metal shaping can refer to relatively small or even large objects. Obviously, depending on the type of procedure, it will be necessary to use special instruments. The metal bending is performed not only to give a certain shape to the object, but sometimes also to accentuate some characteristics of resistance.

Machinery


The shaping of the sheets is carried out by a bending machine, managed by a numerical control which, depending on the prism opposite the blade, the thickness and the hardness/quality of the material used, defines the pressure values of the blade descent in order to obtain the right degrees of bending.

The blades and prisms are interchangeable with each other and of different shapes to obtain cutting and bending of sheet metal of different shape and inclination. By means of stoppers or supports generally behind the machine, each piece is positioned so that the upper blade lies and bends the material to be processed exactly on a pre-established line.

In this way it is possible to obtain boxes formed by folds at different angles according to the desired result, thus avoiding unnecessary and expensive welding.

Stamping is another methodology in pressure sheet metal deformation.

It is used especially in the automotive sector and on very low thicknesses. It consists in funneling/deforming at high pressure a very soft soft soft iron sheet between two male/female moulds that give in a single moulding all the necessary folds, bends and edgings to give extraordinary rigidity and non-deformability to the piece.


Materials


In order to successfully carry out sheet metal bending work you need not only a powerful machine but also a deep knowledge of the metal you are working with.

The materials used in sheet metal bending are all those where it is possible to obtain deformations without compromising the structure and homogeneity of the final product.

Therefore it is important to know well the reaction of the metal that is subjected to the bending deformation process, as it is fundamental to know the direction of rolling of the fibres on the piece, as a parallel bending to this direction would cause cracks and splits at the bending point.

Another factor to be taken into consideration is the springback: after bending, although for minimum values, the metal will tend to return to the original stage.


Methods


  • Moulding: by means of a male/female mould inserted in a hydraulic or mechanical press depending on the size and the force to be transmitted, a sheet metal strip, generally coils, is passed through it at predetermined intervals and steps and is moulded with the result of obtaining a particular three-dimensional shape that acquires rigidity and non-deformability.
  • Bending: it is the most used in the iron and steel industry and consists in bending in correspondence of a certain line the piece that is between blade and prism (male female) obtaining a box from the simple angular to structures with different angles and shapes. Through this method it is possible to obtain a bending of sheets with a large thickness, up to 20mm.