Calculate bend allowance (BA), bend deduction (BD), and flat pattern length for sheet metal press brake work.
Enter your material thickness, inside bend radius, bend angle, and K-factor to calculate the exact bend allowance and flat blank size.
BA = π × (IR + K × T) × A / 180
OSSB = tan(A/2) × (IR + T)
BD = 2 × OSSB − BA
Flat Blank = Leg1 + Leg2 + BA (when legs are given)
| Material | Process | K |
|---|---|---|
| Aluminium | Air bend | 0.33–0.38 |
| Mild Steel | Air bend | 0.38–0.41 |
| Stainless 304 | Air bend | 0.41–0.44 |
| Any | Bottom bend | 0.44–0.50 |
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