Allowance For Bending Sheet Metal

Radius of a bend is determined by the hardness and thickness of the metal.

Allowance for bending sheet metal.

When bends are made smaller than the required min. Bend allowance is a measure of how much extra material is required to accommodate a bend in sheet metal. Therefore the bend allowance added to the flange lengths is equal to the total flat length. We will start by calculating the bend allowance.

The bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the 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. Sheet metal calculator bend allowance equations and calculator. Calculating the bend allowance is necessary to create a finished product of the correct size.

You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. The bend allowance formula takes into account the geometries of bending and the properties of your metal to determine the bend allowance. This page also includes a link to a on line sheet metal bend allowance calculator. Figure 2 illustrates the sheet that is bent with the bend angle of 90 degrees.

After bending the sheet we need to do some measurements as shown in figure 2. Most sheet metal materials will conform to the calculations. Bend allowance is the amount of metal to be added to the total layout. From there we can calculate the k factor and the bend deduction.

This is a function of the bend angle bend radius thickness of the material and a variable called the k factor. The most important considerations when bending metal is the min. Bend allowances vary based on the angle of the bend the type and thickness of the material and the method used to create the bend. The material thickness will be measured in decimal form not by the gauge number.