Calculating Bend Allowance For Sheet Metal

The material thickness will be measured in decimal form not by the gauge number.

Calculating bend allowance for sheet metal.

You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. To calculate r which is the radius of the arc on the neutral axis we can use the following equation. When bends are made smaller than the required min. Most sheet metal materials will conform to the calculations.

To calculate the neutral axis distance from the inner face t we can subtract inside bend radius from r. Where ba is bending allowance. Bend allowance is the amount of metal to be added to the total layout. The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend.

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. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal. Sheet metal bend allowance calculator determines the bend allowance amount of metal to be added to the total layout when forming sheet metal. This page also includes a link to a on line sheet metal bend allowance calculator.

Now that we have both leg length 1 and 2 we can use the following equation again to calculate the bend allowance. Radius metal will crack at the outside heel of the bend. Sheet metal calculator bend allowance equations and calculator. Therefore the bend allowance added to the flange lengths is equal to the total flat length.

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. The bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the flat length. A is the bending angle in the above equation so.