Bend Deduction Formula Sheet Metal Bending

You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k.

Bend deduction formula sheet metal bending. Geometry of tooling imposes a minimum bend dimension. The bend deduction formula takes into account the geometries of bending and the properties of your metal to determine the bend deduction. Sheet metal calculator bend allowance equations and calculator. Bd bend deduction.

Cells on the right will output the desired values. The values of the setback bend allowance and bend deduction can be calculated from the sheet thickness bend radius bend angle and k factor. In machinery s handbook the k factor for mild cold rolled steel with 60 000 psi tensile strength is 0 446 inch. Where ossb is the outside setback.

The material thickness will be measured in decimal form not by the gauge number. You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. As explained in my first post the bend deduction can be calculated using the following equation. Bend allowance bend deduction 2 ossb.

Therefore the bend deduction equals the difference between the mold line lengths and the total flat length. 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 flatten length of the parts that are lf equals d1 plus d2 minus the bend deduction. 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. You only have to insert interior angle flange lengths k factor inside radius and material thickness. The material thickness will be measured in decimal form not by the gauge number. The formula is as follows.

This page also includes a link to a on line sheet metal bend allowance calculator. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal. Where a is the bending angle t is the sheet thickness and r is the bending radius. Use the minimum bend dimension values in the charts below for your minimum closeness of cutout to a bend.

The mold line lengths are the distances measured to the outside mold line and are equal to the flange lengths plus the setback. As with bend allowance bend deduction comes from the same sources tables and manual testing. Ossb is defined as illustrated in figure 5 for different bending angles and can be calculated using the equation below. Lf d1 d2 bd.

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. The diagram shows one such mechanism. 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.

Calculate the value of bend deduction from the values of bend allowance and outside setback.