BA = bend allowance (mm)
Sheet-metal bend allowance
Neutral-axis arc-length estimate for one bend, using radians for angle.
VERIFIED FORMULA RECORD
BA = θ(R + Kt)
Neutral-axis arc-length estimate for one bend, using radians for angle.
Variables and units
θ = bend angle (rad)
R = inside radius (mm)
K = approved K-factor
t = thickness (mm)
Conditions and limitations
- K-factor is based on actual material/tooling/bend condition
- Preliminary flat development only
Source: J. G. Bralla, Handbook of Manufacturing Processes; approved shop bend-test data controls final blanks.