Sheet metal is a plate produced by rolling semi-finished products, called slabs, obtained by casting liquid metal. It is usually supplied in coils of different thicknesses and lengths for easier transport. Depending on the intended use, sheets come in different thicknesses, sizes, grades and types. Special machinery and innovative methods allow sheet metal to be bent and shaped to specific requirements. The metal sheet, which may be steel, aluminium, brass or copper, is deformed into specific open-section shapes, which at the same time makes the semi-finished part stiffer.
Whatever the differences between sheets, each one is carefully worked by industry professionals using specific machinery. Sheets can respond very differently to bending, because semi-finished products may differ due to different casts, dimensional tolerances, laser or plasma cutting, making every piece unique.
The type of deformation the sheet undergoes depends on its width-to-thickness ratio. A low ratio produces “uniaxial” deformation, while a high ratio produces “plane” deformation.
During U, V or C bending, the sheet is loaded beyond its elastic limit. During processing, the natural phenomenon of elastic recovery (springback) must therefore be taken into account, as it can lead to a bend angle different from the one intended, requiring later corrections and wasting time and money.