Die opening follows sheet thickness: about 6 × t up to 2.6 mm, and 8 × t from 3 to 8 mm. Send the material and we confirm the tool.
A starting point, not a rule for every part
For air bending, the V opening is the first number we check. A smaller V needs more tonnage and leaves a tighter inside radius. A wider V bends with less force and a larger radius. The figures below are the openings we start from for mild steel.
- Up to 2.6 mm: V ≈ 6 × thickness
- 3 mm to 8 mm: V ≈ 8 × thickness
- Above 8 mm: we size the V from the drawing and the available tonnage
What else changes the die
Stainless and high-strength steel need more force than mild steel of the same thickness, so the V is often one step wider. A short flange, a mark-free face, or a hemming step will also move the choice away from a standard single-V die.
Send the press brake model, the material, the thickness and the bend length. We confirm the V, the punch angle and the tool length before quoting.
