L-PROFILE FLAT PATTERN CALCULATOR
From outside dimensions to flat length.
Unfold an equal-width L profile. Define the outside mold-line dimensions, then inspect the flat pattern.
The center mark locates the bend zone in the flat pattern. It is not a backgauge position or a machine instruction.
Flat pattern length
Calculated with your K-factor. Display is rounded; calculations retain precision.
One recent calculation per tool, on this browser only.
BendTab calculation record
BendTab — L-profile flat pattern Model: bendtab-geometry-1.0.0 Method: K-factor Thickness T: 1 mm Inside radius R: 1 mm Bend angle A: 90 deg (amount bent) K-factor: 0.4 Outside dimension X: 50 mm Outside dimension Y: 50 mm Strip width W: 40 mm Included angle θ: 90° BA: 2.199115 mm BD: 1.800885 mm OSSB: 2.000000 mm Effective K-factor: 0.400000 Flat length: 98.199115 mm Bend zone: 48.000000–50.199115 mm from left edge 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
A clearly defined, single-bend model.
The two straight sections are X − OSSB and Y − OSSB. Their sum plus the bend allowance is the flat length. The highlighted zone is placed between the straight sections.
This tool models an L profile with one bend, constant thickness and width, and no holes or cutouts. It does not check tooling access, bend collisions or material failure.
Understand outside dimensions and deduction →