Calculate bend force

The formula

For air bending (the usual bending method), the rule-of-thumb formula is:

Fb = 1.42 × bend length × tensile strength × thickness² / V-die width

Without a value of your own, this tool assumes the common V-die width of 8× the material thickness (see also the bend deduction calculator, which uses the same rule of thumb for the corresponding inside bend radius).

Another rule of thumb as a sanity check: for S235 steel, air bending needs roughly 8 tonnes per metre of bend length for every millimetre of thickness (so 3 mm plate ≈ 24 tonnes/metre). The exact formula above gives a similar but slightly different value — both are approximations. If in doubt about feasibility, send the drawing and we'll verify it against the actual press and tooling.

Tensile strength per material

Nominal values — the exact tensile strength is stated on the material certificate and may vary by a few percent.

Not sure if your part is feasible on our press?Send your drawing