Bend Allowance Table For Sheet Metal

The bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the flat length.

Bend allowance table for sheet metal.

None 90 bend unfold according to the neutral layer the distance from neutral to sheet inner side is t 3 inner r can refer to the above chart. V die width is 6 8 times the plate thickness none 90 bend 180 angle 90 deduction the deduction is 1 8 times the steel plate thickness and 1 6 times the aluminum plate. You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. Understanding the bend deduction and consequently the bend allowance of a part is a crucial first step to understanding how sheet metal parts are fabricated.

When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched. Bend allowance and k factor. The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend. From there we can calculate the k factor and the bend deduction.

The bend table approach is probably the most accurate approach for calculating bend allowance. When making bends it takes material specifications into account. Sheet metal bend radii if these guidelines are not followed more research and or some form of analysis may be requried. After bending the sheet we need to do some measurements as shown in figure 2.

The bend allowance formula takes into account the geometries of bending and the properties of your metal to determine the bend allowance. It exists for a reason. If you design your bent sheet metal parts in cad software that has a special sheet metal environment use it. We will start by calculating the bend allowance.

Table 1 preferred recommended 90 degree bend radii for various sheet metals. The material thickness will be measured in decimal form not by the gauge number.