Bend Allowance For Aluminum Sheet

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.

Bend allowance for aluminum sheet.

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

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 bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the flat length. Most sheet metal materials will conform to the calculations. It exists for a reason.

When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched. Sheet metal calculator bend allowance equations and calculator. Bend allowance is a measure of how much extra material is required to accommodate a bend in sheet metal this is a function of the bend angle bend radius thickness of the material and a variable called the k factor bend allowances vary based on the angle of the bend the type and thickness of the material and the method used to create the. Therefore the bend allowance added to the flange lengths is equal to the total flat.

August 29 2020. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal. From there we can calculate the k factor and the bend deduction. Bend forming 0 l a b 0 43t t thickness deduction 0 43t.

The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend. This page also includes a link to a on line sheet metal bend allowance calculator. We will start by calculating the bend allowance. The bend table approach is probably the most accurate approach for calculating bend allowance.

90 degrees bend angle. Figure 2 illustrates the sheet that is bent with the bend angle of 90 degrees. When making bends it takes material specifications into account. If you design your bent sheet metal parts in cad software that has a special sheet metal environment use it.

Bend allowance and k factor. 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. Calculate unfold size with bend allowance chart. Childress last modified date.