1. What is Bend Deduction?

Definition: Bend deduction is the amount of material that needs to be subtracted from the total length of the flat pattern to achieve the desired bent part dimensions.

Purpose: It's essential for sheet metal fabrication to accurately calculate flat pattern layouts before bending operations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The formula accounts for material stretching and compression during bending.

3. Importance of Bend Deduction Calculation

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

4. Using the Calculator

Tips: Enter the bend radius, angle (typically 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 represents the location of the neutral axis in the material during bending, typically ranging from 0.3 to 0.5.

Q2: How do I determine the bend radius?
A: The bend radius is usually specified by the tooling or can be found in bending charts for your material.

Q3: Why is bend deduction important?
A: It ensures the flat pattern is cut to the correct length before bending to achieve the desired final dimensions.

Q4: How does material thickness affect the calculation?
A: Thicker materials require greater bend deduction as more material is displaced during bending.

Q5: Where can I find K-factor values?
A: K-factors are often provided in engineering references or can be determined experimentally for specific materials.