The Bend Allowance Calculator uses the thickness of the material, bend angle, inside radius, and K factor to find the bend allowance.
INSTRUCTIONS: Choose units and enter the following:
Bend Allowance (BA): The calculator returns the answer in inches (in). However this can be automatically converted to compatible units via the pull-down menu.
When sheet metal is bent, the metal around the bend becomes deformed and stretched. When that metal deforms, a small amount of length is added to the original part. Deductions have to be made from desired part sizes for flat patterns to results in a correct flat size. The bend allowance is the material added to the actual leg lengths of the part in order to develop a flat pattern.
To find the bend allowance, use the formula:
BA = π/180 ⋅ B ⋅ (IR + K) ⋅ MT
where:
SheetMetal.Me (http://sheetmetal.me/formulas-and-functions/bend-allowance/)