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    // Bending and flat pattern · 9 min read

    K-factor and flat length: calculating bend deduction per DIN 6935

    Flat length depends on where the neutral fiber lies during bending. DIN 6935 gives a structured way to calculate it from the r/t ratio.

    August 8, 2026 · By Glintify

    K-factor is not one universal number

    The neutral fiber shifts with inside radius and material thickness. Sharp bends place it closer to the inside radius; larger radii move it toward the center.

    DIN 6935 connects geometry to the blank

    The standard derives a correction factor from the inside-radius-to-thickness ratio. That value determines bend allowance and bend deduction.

    Calculate per bend when possible

    Complex parts with different radii should not use one rough K-factor everywhere. Per-bend calculation makes the blank size and nesting basis more reliable.

    Check your flat pattern basis

    We can show how Glintify calculates flat pattern and flags uncertain unfolds.

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