Enter the bend allowance, inside bend radius, material thickness, and bend angle into the calculator to determine the K Factor for sheet metal bending in Autodesk Inventor.

Inventor K Factor Calculator

K-Factor BD / OSSB

Enter any 4 values to calculate the missing one


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Inventor K Factor Formula

The following formula is used to calculate the K Factor in sheet metal bending:

K = \frac{\frac{BA}{A_r} - R}{T}

Variables:

  • BA is the bend allowance (any consistent length unit)
  • R is the inside bend radius (same length unit as BA)
  • T is the material thickness (same length unit as BA)
  • A is the bend angle (degrees)
  • A_r is the bend angle in radians (A_r = A \cdot \pi / 180)
  • K is the K Factor

To calculate the K Factor, convert the bend angle from degrees to radians, then apply the formula using the bend allowance, inside radius, and material thickness (using consistent length units).

What is a K Factor?

The K Factor is a ratio that represents the location of the neutral axis with respect to the thickness of the sheet metal being bent. It is a critical value used in sheet metal design to predict how the material will deform during bending. The K Factor varies depending on the material, the type of bending operation, and the specific machinery used.

How to Calculate K Factor?

The following steps outline how to calculate the K Factor:


  1. First, measure the bend allowance (BA).
  2. Next, measure the inside bend radius (R).
  3. Then, measure the material thickness (T).
  4. Measure the bend angle (A) in degrees and convert it to radians (A_r).
  5. Use the formula to calculate the K Factor (K).
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

bend allowance (BA) = 2.10 mm

inside bend radius (R) = 1.00 mm

material thickness (T) = 1.00 mm

bend angle (A) = 90 degrees