60 90 and 120 and we will calculate k factor bend allowance and bend deduction for them.
Sheet metal bend relief formula.
D 2 5t r see below the height can be less but it required secondary operations and is far more costly.
The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend.
Therefore the bend allowance added to the flange lengths is equal to the total flat length.
The bend allowance formula takes into account the geometries of bending and the properties of your metal to determine the bend allowance.
We are going to review three bending scenarios with three different bending angles.
This page also includes a link to a on line sheet metal bend allowance calculator.
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.
To eliminate this a bend relief is added so the edge of the sheet metal is perpendicular to the bend.
For bends between 0 and 90 degrees the formula is as follows.
The material thickness will be measured in decimal form not by the gauge number.
In general a minimum bend relief is equal to the material thickness plus the inside bend radius.
Sheet metal calculator bend allowance equations and calculator.
The diagram shows one such mechanism.
Geometry of tooling imposes a minimum bend dimension.
The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal.
Form height to thickness ratio to determine the minimum form height for sheet metal use the following formula.
The bend deduction sometimes called the bend compensation describes how much the outside of the sheet has been stretched.
Most sheet metal materials will conform to the calculations.
5 edge distortion an exaggerated example of edge deformation is pictured in figure a below.
Refer to the chart for values for folder as well as various press brake tooling combinations.
You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k.
ß bending angle for bends between 90 and 165 degrees the formula is.
