Bending Sheet Metal Bend Allowance

Sheet metal k factor bend allowance and flat length calculations k factor in sheet metal bending is a constant used to calculate sheet metal flat length or flat pattern.

Bending sheet metal bend allowance.

Radius of a bend is determined by the hardness and thickness of the metal. The material thickness will be measured in decimal form not by the gauge number. Most sheet metal materials will conform to the calculations. Therefore the bend allowance added to the flange lengths is equal to the total flat length.

The most important considerations when bending metal is the min. 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. For bends between 0 and 90 degrees the formula is as follows.

The total length of the flatten sheet is equal to the sum of l1 that s the first length and l2 plus 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. A line through the thickness of the bend called the neutral axis does not change in length when the part is bent. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal.

For bends over 165 there is no need to calculate bend allowances as the neutral axis stays pretty much in the middle of the detail. The bend allowance region is shown in green in my diagram this is a region wherein theory all deformation occurs during the bending process. Radius metal will crack at the outside heel of the bend. This page also includes a link to a on line sheet metal bend allowance calculator.

Bend allowance is used to account for bends in sheet metal fabrications. When bends are made smaller than the required min. The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend. ß bending angle for bends between 90 and 165 degrees the formula is.

Sheet metal calculator bend allowance equations and calculator.