KEVOS® MAKEOS · Fabrication
Press Brake Set-up: Die, Radius, Flange and Tonnage
Which V-die should I use for this bend, what inside radius and minimum flange will it give, and is the press brake big enough?
Air-bending set-up for a press brake: the die opening from a chosen multiple of thickness (rounded up to a common die opening), the inside radius that air bending produces (a share of the die opening), the shortest flange that still spans the die, the bending force by the handbook-style formula (as the press brake force tool), force per metre and the press capacity check.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Thickness | mm | Sheet thickness. |
| Tensile strength | MPa | Tensile strength of the sheet. |
| Bend length | mm | Length of the bend. |
| Die opening as a multiple of thickness | Die opening as a multiple of thickness (about 6–8 for thin sheet, 8–12 for plate). | |
| Inside radius ÷ die opening (air bending) | Inside radius produced by air bending as a share of die opening (about 0.15–0.16 mild steel, 0.2 or more for stainless and aluminium). | |
| Minimum flange ÷ die opening | Shortest flange as a share of die opening (so the flange still bridges the die). | |
| Bending factor | Air-bending factor in the force formula. | |
| Press capacity | kN | Press brake rated force. |
| Die rating (force per metre) | kN/m | Load rating of the die per metre of length. |
Method and formulas
- Die opening = multiple × t, rounded up to a common opening (6, 8, 10, 12, 16, 20, 24, 30, 35, 40, 50, 60, 80, 100, 120, 160, 200, 250 mm).
- Inside radius ≈ share × die opening; minimum flange ≈ share × die opening.
- Force F = k L t² UTS ÷ V (as the press brake force tool); force per metre = F ÷ L.
- Example: 3 mm sheet on a 24 mm die bends to about 3.84 mm inside radius with 224.44 kN.
Limitations
- Air bending rules of thumb; bottoming and coining need several times more force.
- Radius and flange shares vary with material and tooling.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Choose a die for a new sheet-metal part
- Check the minimum flange a die allows
- Confirm press brake tonnage before bending
Who it is for
- Press brake operators
- Fabrication supervisors
- Sheet-metal designers
What you get
- Die opening chosen
- Inside radius and minimum flange
- Bending force, force per metre and checks
Interpreting the result
- A wider die lowers force and raises the inside radius; a narrower die does the reverse.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1346–1353, 1383–1386. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Press Brake Set-up: Die, Radius, Flange and Tonnage calculator
