It simply processes these variables through the equations we will discuss below. As you can see the Bend Allowance and Bend Deduction are closely related below.īelow is our simple Bend Allowance Calculator, it works by inputing the Material Thickness, Bend Angle, Inside Radius and K-Factor. In order to develop the flat pattern we add. When we calculate the Bend Allowance we find that it equals. 250” at 90° will have leg lengths of 1.625” and 2.625” respectively. In our example below a part with flange lengths of 2” and 3” with an inside radius of. The leg lengths are the part of the flange which is outside of the bend radius. The Bend Allowance is defined as the material you will add to the actual leg lengths of the part in order to develop a flat pattern. Likewise when you are trying to develop a flat pattern you will have to make a deduction from your desired part size to get the correct flat size. As this happens you gain a small amount of total length in your part. When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched. 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.
