K-FACTOR CALCULATOR
Let your test bend do the talking.
Find an effective K-factor from one measured L-profile test bend or a known bend deduction.
X and Y end at the virtual sharp, where the extended outside faces meet. Illustrated at 90°; these are not tangent-to-edge straight lengths.
Effective K-factor
A calibration for these inputs and process conditions. Display is rounded; calculations retain precision.
One recent calculation per tool, on this browser only.
BendTab calculation record
BendTab — K-factor calibration Model: bendtab-geometry-1.0.0 Method: Measured flat length Thickness T: 1 mm Inside radius R: 1 mm Bend angle A: 90 deg (amount bent) Outside dimension X: 50 mm Outside dimension Y: 50 mm Measured flat length: 98.1991148575 mm Included angle θ: 90° BA: 2.199115 mm BD: 1.800885 mm OSSB: 2.000000 mm Effective K-factor: 0.400000 Source / process notes: Not supplied. Example values are not production presets. BA = α × (R + K × T); OSSB = (R + T) × tan(α/2); BD = 2 × OSSB − BA α is amount bent in radians. X and Y are outside mold-line dimensions. Reference: https://help.autodesk.com/cloudhelp/2023/ENU/Inventor-Help/files/GUID-7B2525E4-8191-46F2-8CC3-FF422114EAE5.htm Verify process inputs and drawing tolerances against a test bend.
BEFORE YOU USE THE NUMBER
One test. One set of conditions.
Measure the flat blank, then bend it and measure the resulting outside dimensions, inside radius and angle. X and Y extend to the virtual sharp. For the example, T = R = 1 mm, A = 90°, X = Y = 50 mm and a 98.1991148575 mm blank give K ≈ 0.4.
A K-factor recovered from one test describes those conditions. It does not isolate separate K-factors from a multi-bend part or predict springback.
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