Press brake tonnage and V-die calculator
Enter material, thickness, bend length and V-die to calculate reference tonnage. A result is always calculated; NKAM machines below are optional references.
No technical details required. Leave a phone number and our team will help select the machine and configuration.
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Bending force depends on four things: sheet thickness, bending length, material strength and the V-opening of the lower die. The V-opening is the one most often overlooked — with the same sheet, changing the V die noticeably changes the force required. Enter the four values below for an estimate, then compare it against the NKAM models in stock.
Developed / cut lengthExpand to enter values and calculate ▾461.94 mm
Bend allowance and deductionExpand to enter values and calculate ▾BA 5.969 mm · OSSB 5 mm · BD 4.031 mm
Minimum flange heightExpand to enter values and calculate ▾≈ 8 mm
Sheet weightExpand to enter values and calculate ▾Per piece: 7.85 kg · Total: 78.5 kg
How to choose the V-opening
In air bending, the V-opening is normally chosen as a multiple of the sheet thickness. A wider V needs less force, but produces a larger inside radius and requires a longer minimum flange.
Three consequences worth remembering:
- Narrow V → more force, smaller inside radius, shorter flanges possible
- Wide V → less force, larger inside radius, longer flanges required
- Choose the V first, then calculate the force. Calculating force first and then picking a V is the wrong order.
How far can this result be trusted?
The figure from the tool is an estimate for sizing the machine, not an acceptance value. Actual force varies with the material batch, rolling direction, tooling condition and wear. When selecting a machine, leave headroom rather than choosing exactly at the calculated number.
For long, thin sheet the deciding factor is usually not force but table deflection — this is where a crowning table matters.
Example
CT3 sheet 3 mm thick, bending length 2500 mm, using a 24 mm V die. The estimate falls in the range a 110T/2500 handles with headroom. The same part at a bending length of 3200 mm requires a longer machine class — because of table length, not because of force.
Not sure? Send us the drawing and we will calculate it and propose a configuration.