Calculating Bend Allowance For Sheet Metal

The bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the flat length.

Calculating bend allowance for sheet metal. Most sheet metal materials will conform to the calculations. The material thickness will be measured in decimal form not by the gauge number. This page also includes a link to a on line sheet metal bend allowance calculator. The bend allowance formula takes into account the geometries of bending and the properties of your metal to determine the bend allowance.

Radius metal will crack at the outside heel of the bend. Most sheet metal materials will conform to the calculations. And by having t and the sheet thickness t we can calculate the k factor as follow. Sheet metal bend allowance calculator determines the bend allowance amount of metal to be added to the total layout when forming sheet metal.

Radius of a bend is determined by the hardness and thickness of the metal. Therefore the bend allowance added to the flange lengths is equal to the total flat length. The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend. A is the bending angle in the above equation so.

When bends are made smaller than the required min. The most important considerations when bending metal is the min. To calculate r which is the radius of the arc on the neutral axis we can use the following equation. Bend allowance is the amount of metal to be added to the total layout.

The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal. To calculate the neutral axis distance from the inner face t we can subtract inside bend radius from r. If you have a sheet metal bending product as shown in above picture with two legs of length x and y and you unbend it you will see that total length of the unbend sheet will not x y rather the length will be x y ba. You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k.