The following equation relates the k factor to the bend allowance.
Sheet metal bending radius formula.
A review of the bend formulas.
Where a is the bending angle t is the sheet thickness and r is the bending radius.
You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k.
This is done through the application of force on a workpiece.
As explained in my first post the bend deduction can be calculated using the following equation.
Leg length of the workpiece from the edge to the outside tangent point of the bend radius.
The force must exceed the material s yield strength to achieve a plastic deformation.
Kink a light bend typically between 5 and 15 which is used to stiffen a flat piece of metal.
With this free online tool we quickly get the sheet metal bend deduction and therefore the sheet metal blank initial flat length from the finished part measurements.
The arc length of the neutral line is the length of the sheet metal you have to leave for the bend.
The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal.
Kink a light bend typically between 5 and 15 which is used to stiffen a flat piece of metal.
Bend allowance ba 0 017453 inside radius 0 0078 material thickness complementary bend angle.
You only have to insert interior angle flange lengths k factor inside radius and material thickness.
Leg length of the workpiece from the edge to the outside tangent point of the bend radius.
Large radius bending also known as r bending large radius bending is when the inside radius is greater than 8 times the material thickness.
The bend allowance formula takes into account the geometries of bending and the properties of your metal to determine the bend allowance.
Most sheet metal materials will conform to the calculations.
Sheet metal calculator bend allowance equations and calculator.
Cells on the right will output the desired values.
Where ossb is the outside setback.
Then use the neutral bending radius to calculate the arc length of the neutral line circumference of circle multiplied by the bend angle as fraction of 360deg.
Ossb is defined as illustrated in figure 5 for different bending angles and can be calculated using the equation below.
This page also includes a link to a on line sheet metal bend allowance calculator.
Use this document to choose values that are both manufacturable and meet your needs.
Bending is one of the most common sheet metal fabrication operations.
It is most economical to use a single bend radius throughout the design but if necessary you can utilize multiple radii.