Sheet Metal Unfold
Material
Method
Material
Steel (carbon)— Common structural steel S235–S355
Default K-factor: 0.38
Bend parameters
Result
9.05mmBend Allowance
Outer R: 7.00 mmK-factor: 0.380
Other Tools
Bend Allowance Calculator for Sheet Metal
This calculator helps determine the flat length of sheet metal before bending. It uses bend allowance and K-factor to calculate accurate unfolding dimensions.
Key Formula
BA = π × (R + K × t) × A / 180
- R = inner radius
- K = K-factor
- t = thickness
- A = bend angle
How to Use
- 1Enter sheet thickness
- 2Set inner radius
- 3Choose bend angle
- 4Use K-factor or table
What is Bend Allowance
Bend allowance represents the length of material that is stretched during bending. It ensures accurate flat pattern calculation.
Frequently Asked Questions
What is K-factor?
Ratio of neutral axis position to sheet thickness.
Why is bend allowance important?
Ensures correct final dimensions after bending.
Is it accurate?
Yes, with correct inputs and K-factor.