Finite element analysis on the coined-bead mechanism during the V-bending process

The coined-bead technique is commonly applied to solve the spring-back problem in the V-bending process. However, the coined-bead mechanism on the spring-back/spring-go feature has not been clearly identified yet. In this study, the finite element method (FEM) and laboratory experiments were used to investigate the coined-bead mechanism and its effects on the spring-back/spring-go feature. The features were clearly identified using a stress distribution analysis. The results revealed that the mechanism of the coined-bead technique not only increases the compressive stress on the bending allowance zone, where the spring-back feature decreases, but also increases the reversed bending zone on the leg of the workpiece, where the spring-go feature increases. Therefore, after compensating for the increases in the compressive stress and the reversed bending feature, the amount of spring-back on the bent part was decreased. The FEM simulation bending force and bending angle results were agreed with those from the experimental results.

► The coined-bead mechanism during the V-bending process is clearly identified.
► The coined-bead application decreases the bending allowance zone.
► It also increases the reversed bending zone on the leg of the workpiece.
► These features resulted in the spring-back decreases and spring-go increases.
► As these features, the spring-back on the bent part decreases.