Allowances For Bending Sheet Metal

August 29 2020.

Allowances for bending sheet metal.

Also known as press braking flanging die bending folding and edging this method is used to deform a material to an angular shape. Most sheet metal materials will conform to the calculations. The bend table approach is probably the most accurate approach for calculating bend allowance. We will start by calculating the bend allowance.

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. The bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the flat length. You only have to insert interior angle flange lengths k factor inside radius and material thickness. Cells on the right will output the desired values.

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. Childress last modified date. Bending is one of the most common sheet metal fabrication operations. 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.

When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched. 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. As this happens you gain a small amount of total length in your part. 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. 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. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal.

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. After bending the sheet we need to do some measurements as shown in figure 2. 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. Sheet metal calculator bend allowance equations and calculator.

This is done through the application of force on a workpiece. 90 degrees bend angle. This page also includes a link to a on line sheet metal bend allowance calculator.