1. What is Bend Deduction?

Definition: Bend deduction is the amount of material length that needs to be subtracted from the total flat pattern length to account for bending.

Purpose: It helps metal fabricators accurately calculate the required flat pattern length before bending to achieve the desired final dimensions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( BD \) — Bend deduction (inches)
• \( R \) — Bend radius (inches)
• \( \theta \) — Bend angle (degrees)
• \( K \) — K-factor (unitless, typically 0.3–0.5)
• \( T \) — Material thickness (inches)

Explanation: The formula calculates the difference between the outside dimensions and the flat pattern length needed to achieve the bend.

3. Importance of Bend Deduction Calculation

Details: Accurate bend deduction calculation ensures proper part dimensions, reduces material waste, and improves manufacturing efficiency.

4. Using the Calculator

Tips: Enter the bend radius, bend angle (default 90°), K-factor (default 0.4), and material thickness. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the K-factor?
A: The K-factor is the ratio of the neutral axis location to material thickness, representing where the material neither stretches nor compresses during bending.

Q2: How do I determine the K-factor for my material?
A: The K-factor depends on material properties and bending method. Typical values range from 0.3 (tight bends) to 0.5 (air bending).

Q3: What's a typical bend radius?
A: Bend radius is often 1-2 times the material thickness, but depends on material and tooling. Check your material specifications.

Q4: Does this work for all bend angles?
A: The formula works for angles between 0° and 180°. For angles over 180°, different calculations may be needed.

Q5: How does material type affect the calculation?
A: Different materials have different springback characteristics, which may require adjusting the K-factor or bend allowance.