How many tonnes to bend 2 mm mild steel 1 metre long?

In a 16 mm (0.630 inch) V-die: 1.42 × 450 × 4 × 1000 ÷ 16,000 ≈ 160 kN, about 16 tonnes per metre.

Why does a narrower V-die need more force?

The force goes up as the die opening goes down: halving the opening roughly doubles the tonnage, and gives a tighter radius.

Is bottoming or coining the same force?

No. Bottoming takes about 3 to 5 times the air bending force, and coining much more. This calculator is for air bending.

Press brake bending force calculator (tonnage)

Sheet thickness T (mm)(0.0787 inch)Bend length (mm)(39.37 inch)V-die opening (mm)Leave empty for 8 × thickness, the usual choice.Material

Bending force: 16.3 tonnes
In kN: 160 kN
Per metre of bend: 16.3 t/m
V-die used: 16 mm
Inside radius (about): 2.6 mm

Air bending. Bottoming needs about 3 to 5 times more; coining far more. Keep within 80% of the press rating.

How it is worked out

Force (kN) = 1.42 × tensile strength (N/mm²) × T² × bend length (mm) ÷ (1000 × V).
The usual V-die opening is about 8 × the thickness.
The inside radius in air bending comes out near 0.16 × the die opening (mild steel).

Questions

How many tonnes to bend 2 mm mild steel 1 metre long?: In a 16 mm (0.630 inch) V-die: 1.42 × 450 × 4 × 1000 ÷ 16,000 ≈ 160 kN, about 16 tonnes per metre.
Why does a narrower V-die need more force?: The force goes up as the die opening goes down: halving the opening roughly doubles the tonnage, and gives a tighter radius.
Is bottoming or coining the same force?: No. Bottoming takes about 3 to 5 times the air bending force, and coining much more. This calculator is for air bending.

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Results use standard formulas and typical values. Use them for estimating and planning; check critical figures against the drawing, the material certificate or the maker's data.