A PROCESS MODEL FOR AIR BENDING

A so called 'three-section' model for air bending is presented. It is assumed that a state of plane strain exists and that Bernoulli's law i s valid. The material behaviour is described with Swift's equation, an d the change of Young's modulus under deformation is addressed. As com pared with other models, the model described in the paper is capable o f generating information such as required punch displacement and the u nfolded blank size, very accurately. With in-process measurement of th e spring-back angle, the punch displacement can be calculated even mor e accurately.