How to calculate BA1 and BA2: Calculating the bending Allowance The unfolded blanks of the above figure would be calculated as follows: Inside Set Back = tan (Angle / 2) *Radius Outsideset Back = tan (Angle / 2)*(Radius + Thickness)ġ) The radius obtained on a bent part affects the length to which we must cut that part (before bending).Ģ) The radius obtained on bending depends 99% on the V opening we choose to work with.īefore designing the part and surely before starting to cut the blanks, we MUST know EXACTLY what V opening we will use to bend the part on the press brake.Ī larger radius will “push” the legs of our part toward the outside, giving the impression that the blank was cut “too long”.Ī smaller radius will require a blank that must be cut “a little longer” than if the radius were larger. Understanding the bending process: simple factsīend Allowance = Angle * (T/ 180)*(Radius + K-factor *Thickness)Bend Compensation = Bend Allowance-(2 * Set Back)