KEVOS® MAKEOS · Fabrication
Press Brake Bending Force
What tonnage does this V-die bend need, and is the press brake big enough?
Bending force for air bending in a V-die from length, thickness, tensile strength and die opening, with force per metre and comparison with the press brake capacity.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Bend length | mm | Length of the bend line. |
| Material thickness | mm | Sheet or plate thickness. |
| Tensile strength | MPa | Ultimate tensile strength of the material. |
| V-die opening | mm | Width of the V-die opening (often about 8 × thickness for air bending). |
| Die factor | 1.0 gives the handbook approximation F = L T² UTS ÷ W; many press brake makers use about 1.33 for air bending. Bottoming and coining need several times more. | |
| Press brake capacity | kN | Rated tonnage of the press brake (1 t ≈ 9.81 kN). |
Method and formulas
- F = k × L × t² × UTS ÷ V.
- Force per metre = F ÷ L × 1000.
- Example: 2000 mm of 3 mm, 450 MPa sheet in a 24 mm die needs 448.88 kN.
Limitations
- Air bending in a V-die; bottoming and coining forces are much higher.
- Long bends near full capacity can deflect the beam and bed; check the maker’s load-per-length limit.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check press brake tonnage before quoting a bend
- Choose a V-die opening
- Compare materials and thicknesses
Who it is for
- Fabrication supervisors
- Manufacturing engineers
- Estimators
What you get
- Bending force
- Force per metre
- Utilisation of the press capacity
- Die opening to thickness ratio
Interpreting the result
- Do not concentrate full tonnage on a short length; follow the maker’s maximum force per metre.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1346–1353. Topic reference; no source tables or recommended settings are reproduced.
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