Bend Allowance For Aluminum Sheet

When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched.

Bend allowance for aluminum sheet.

90 degrees bend angle. Bending is a manufacturing process that produces a v shape u shape or channel shape along a straight axis in ductile materials most commonly sheet metal. If you design your bent sheet metal parts in cad software that has a special sheet metal environment use it. It exists for a reason.

Understanding the bend allowance and consequently the bend deduction of a part is a crucial first step to understanding how sheet metal parts are fabricated. Figure 2 illustrates the sheet that is bent with the bend angle of 90 degrees. When making bends it takes material specifications into account. Bend allowance and k factor.

Most sheet metal materials will conform to the calculations. V die width is 6 8 times the plate thickness. Therefore the bend allowance added to the flange lengths is equal to the total flat. After bending the sheet we need to do some measurements as shown in figure 2.

The value of the bend allowance that comes from sheet metal suppliers and manufactures as well as engineering textbooks are provided in bend tables and bend table looks pretty much like the following excel spreadsheet. From there we can calculate the k factor and the bend deduction. We will start by calculating the bend allowance. When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched.

The bend table approach is probably the most accurate approach for calculating bend allowance. As this happens you gain a small amount of total length in your part. Understanding the bend allowance and consequently the bend deduction of a part is a crucial first step to understanding how sheet metal parts are fabricated. This page also includes a link to a on line sheet metal bend allowance calculator.

Calculate unfold size with bend allowance chart. 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 bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the 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.

The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal. Commonly used equipment include box and pan brakes brake presses and other specialized machine presses typical products that are made like this are boxes such as electrical enclosures and rectangular ductwork.