Bend Deduction Formula Sheet Metal Bending

Lf d1 d2 bd.

Bend deduction formula sheet metal bending.

Most sheet metal materials will conform to the calculations. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal. You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. Calculate the value bend allowance for required sheet metal bend by using below formula.

As explained in my first post the bend deduction can be calculated using the following equation. Geometry of tooling imposes a minimum bend dimension. 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. Ba 0 017453 inside radius 0 0078 material thickness bend angle which is always complementary the length of the neutral axis is calculated as a bend allowance taken at 50 percent of the material thickness.

Ossb is defined as illustrated in figure 5 for different bending angles and can be calculated using the equation below. The material thickness will be measured in decimal form not by the gauge number. You only have to insert interior angle flange lengths k factor inside radius and material thickness. Where ossb is the outside setback.

The mold line lengths are the distances measured to the outside mold line and are equal to the flange lengths plus the setback. Use the minimum bend dimension values in the charts below for your minimum closeness of cutout to a bend. As with bend allowance bend deduction comes from the same sources tables and manual testing. The formula is as follows.

This page also includes a link to a on line sheet metal bend allowance calculator. The values of the setback bend allowance and bend deduction can be calculated from the sheet thickness bend radius bend angle and k factor. The diagram shows one such mechanism. Bend allowance bend deduction 2 ossb.

The bend allowance formula takes into account the geometries of bending and the properties of your metal to determine the bend allowance. You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. The flatten length of the parts that are lf equals d1 plus d2 minus the bend deduction. Sheet metal calculator bend allowance equations and calculator.

Bend allowance ba π 180 r k t a. Refer to the chart for values for folder as well as various press brake tooling combinations. Where a is the bending angle t is the sheet thickness and r is the bending radius. Therefore the bend deduction equals the difference between the mold line lengths and the total flat length.

Calculate the value of bend deduction from the values of bend allowance and outside setback. Cells on the right will output the desired values. In machinery s handbook the k factor for mild cold rolled steel with 60 000 psi tensile strength is 0 446 inch. Learn more about bending.

Another method that solidworks uses is the bend deduction method.