What is bend allowance?
When designing a sheet metal part which is folded you need to understand what happens when a flat sheet of metal is fabricated or folded. To calculate the actual pattern dimensions you can use the bend allowance or bend deduction method. When the piece of sheet metal is put through the cold forming process of bending, the metal on the outside of the bend is often stretched while the inside is crushed. When this happens you can get a small extra amount of length of the part. W