@willsunagency/k-factor-calc

Precision sheet metal K-Factor, Bend Allowance (BA), Outside Setback (OSSB), and Bend Deduction (BD) calculation engine for mechanical engineers and CAD designers.

🌐 Interactive Online Tool: CADGuide.tools K-Factor Calculator

What is K-Factor in Sheet Metal Fabrication?

When a flat sheet of metal is bent, the inner surface is compressed and the outer surface is placed under tension. Between these two zones lies the Neutral Axis, where the material experiences zero deformation (no tension, no compression).

The K-Factor is the mathematical ratio between the location of the neutral axis ($t$) and the total material thickness ($T$):

$$K = \frac{t}{T}$$

Accurate K-Factor calculations prevent costly re-fabrications and scrap by predicting the exact unbent flat blank length required before placing a part on a press brake.

For visual interactive calculations with material lookup tables, use the CADGuide.tools K-Factor Online Calculator.

Installation

npm install @willsunagency/k-factor-calc

Or run via CLI:

npm install -g @willsunagency/k-factor-calc
k-factor-calc 2.0 2.0 90 0.44

Mathematical Equations Used

1. Bend Allowance (BA): $$\text{BA} = \frac{\pi}{180} \times \text{Angle} \times (R + K \times T)$$

2. Outside Setback (OSSB): $$\text{OSSB} = \tan\left(\frac{\text{Angle}}{2}\right) \times (R + T)$$

3. Bend Deduction (BD): $$\text{BD} = 2 \times \text{OSSB} - \text{BA}$$

API Usage

const { calculateSheetMetalBend } = require('@willsunagency/k-factor-calc');

const result = calculateSheetMetalBend({
  thickness: 2.0,       // Material thickness in mm (T)
  insideRadius: 2.0,    // Inside bend radius in mm (R)
  angleDegrees: 90,     // Bend angle in degrees
  kFactor: 0.44         // K-Factor (typical for mild steel air bending)
});

console.log(result);
// Output:
// {
//   thickness: 2,
//   insideRadius: 2,
//   angleDegrees: 90,
//   kFactor: 0.44,
//   bendAllowance: 4.5239,
//   outsideSetback: 4,
//   bendDeduction: 3.4761,
//   neutralAxisOffset: 0.88
// }

Typical K-Factor Reference Values

| Material | Bending Process | Typical K-Factor | | :--- | :--- | :--- | | Mild Steel / Cold Rolled Steel | Air Bending | 0.40 - 0.45 | | Mild Steel | Bottom Bending | 0.45 - 0.48 | | Stainless Steel 304 / 316 | Air Bending | 0.42 - 0.46 | | Aluminum (Soft 3003 / 5052) | Air Bending | 0.38 - 0.42 | | Aluminum (Hard 6061-T6) | Air Bending | 0.40 - 0.44 | | Brass & Copper | Air Bending | 0.35 - 0.40 |

For comprehensive CAD guides, design rules, and CNC press brake bend compensation tables, visit CADGuide.tools Guides.

License

MIT © CADGuide.tools