1. What is Bend Allowance?

The Bend Allowance (BA) is the length of the arc of the neutral axis between the tangent points of a bend in sheet metal. It determines the flat pattern length required to make a bend of specific angle, radius, and material thickness.

2. How Does the Calculator Work?

The calculator uses the Bend Allowance formula:

Where:

• \( BA \) — Bend Allowance (mm)
• \( A \) — Bend angle (degrees)
• \( r \) — Inside bend radius (mm)
• \( K \) — K-factor (dimensionless)
• \( t \) — Material thickness (mm)

Explanation: The formula accounts for the material stretching during bending, with the K-factor representing the location of the neutral axis in the material.

3. Importance of Bend Allowance

Details: Accurate bend allowance calculation is crucial for sheet metal fabrication to ensure parts are manufactured to correct dimensions and fit together properly in assemblies.

4. Using the Calculator

Tips: Enter bend angle in degrees, inside radius in mm, K-factor (typically 0.33 for mild steel), and material thickness in mm. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical K-factor value?
A: For mild steel, K-factor is typically 0.33, but it varies by material type and bending method. Consult material specifications for precise values.

Q2: How does bend radius affect the calculation?
A: Larger radii result in greater bend allowances as more material is needed to form the bend.

Q3: Can this be used for all materials?
A: The formula works for most ductile materials, but K-factor may need adjustment for materials with different stretching properties.

Q4: What's the difference between bend allowance and bend deduction?
A: Bend allowance is the material needed for the bend, while bend deduction is the difference between flange lengths and flat pattern.

Q5: How accurate is this calculation?
A: It provides a good theoretical estimate, but actual results may vary based on material properties, tooling, and bending process.