Bend Allowance Table For Sheet Metal

To use the tables below.

Bend allowance table for sheet metal.

Calculate unfold size with bend allowance chart. When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched. Therefore the bend allowance added to the flange lengths is equal to the total flat length. This page also includes a link to a on line sheet metal bend allowance calculator.

The tables below show bend radii and minimum bend sizes for materials and tooling combinations stocked by protocase. Therefore even a simple bench with enough room to bend 3 m pieces will do the job. The lowest common bench capacity is around 100 tonnes. Figure 2 illustrates the sheet that is bent with the bend angle of 90 degrees.

From there we can calculate the k factor and the bend deduction. L unfold length a outside size b outside size k k factor 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. After bending the sheet we need to do some measurements as shown in figure 2. The material thickness will be measured in decimal form not by the gauge number.

It is possible to choose other bends but tooling charges may apply. My workpiece s bending line is 3 m so the overall needed force is 3 22 66 tonnes. You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal.

Bend forming 0 l a b 0 43t t thickness deduction 0 43t. The bend allowance formula takes into account the geometries of bending and the properties of your metal to determine the bend allowance. The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend. The required die width is 12 mm and tonnage per meter is 22.

The bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the flat length. We will start by calculating the bend allowance. 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. Table 1 preferred recommended 90 degree bend radii for various sheet metals.