Calculating Bend Allowance For Sheet Metal

This page also includes a link to a on line sheet metal bend allowance calculator.

Calculating bend allowance for sheet metal.

The material thickness will be measured in decimal form not by the gauge number. The bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the flat length. Sheet metal bend allowance calculator determines the bend allowance amount of metal to be added to the total layout when forming sheet metal. 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.

Now that we have both leg length 1 and 2 we can use the following equation again to calculate the bend allowance. When bends are made smaller than the required min. To calculate the neutral axis distance from the inner face t we can subtract inside bend radius from r. 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. A is the bending angle in the above equation so. To calculate r which is the radius of the arc on the neutral axis we can use the following equation. Therefore the bend allowance added to the flange lengths is equal to the total flat length.

Radius metal will crack at the outside heel of the bend. And by having t and the sheet thickness t we can calculate the k factor as follow. Where ba is bending allowance. Radius of a bend is determined by the hardness and thickness of the metal.

Most sheet metal materials will conform to the calculations. Sheet metal calculator bend allowance equations and calculator. You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. The most important considerations when bending metal is the min.