Bend Allowance Table For Sheet Metal

The bend allowance bend deduction of the sheet metal specified in k factor by configuring and utilizing a sheet metal gauge table we can speed up the process of selecting the correct wall thickness based on gauge value and selecting the correct bend radius based on available tooling we can also automate the process of selecting the appropriate k factor.

Bend allowance table for sheet metal.

The tables below show bend radii and minimum bend sizes for materials and tooling combinations stocked by protocase. The required die width is 12 mm and tonnage per meter is 22. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal. This page also includes a link to a on line sheet metal bend allowance calculator.

We will start by calculating the bend allowance. The material thickness will be measured in decimal form not by the gauge number. Most sheet metal materials will conform to the calculations. Therefore even a simple bench with enough room to bend 3 m pieces will do the job.

Calculate unfold size with bend allowance chart. Therefore the bend allowance added to the flange lengths is equal to the total flat length. 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. Sheet metal bend radii if these guidelines are not followed more research and or some form of analysis may be requried.

Bend forming 0 l a b 0 43t t thickness deduction 0 43t. After bending the sheet we need to do some measurements as shown in figure 2. To use the tables below. Table 1 preferred recommended 90 degree bend radii for various sheet metals.

It is possible to choose other bends but tooling charges may apply. Figure 2 illustrates the sheet that is bent with the bend angle of 90 degrees. The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend. My workpiece s bending line is 3 m so the overall needed force is 3 22 66 tonnes.

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. You will need to know your material thickness mt the bend angle b the inside radius ir and the k factor k. When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched. From there we can calculate the k factor and the bend deduction.