A study on bending direction of sheet metal in laser forming

Concave laser forming and convex forming are all required for the complicated curved surface plate forming. Concave laser forming can be readily obtained by temperature gradient mechanism, while convex forming may be achieved based on buckling mechanism. To achieve precise control of bending direction of plate, buckling critical condition is analyzed when the buckling mechanism plays a dominant role, and a judgment criterion of working conditions of buckling mechanism, Fbuckling value, is derived. To verify the validity of the Fbuckling value, the experiments and numerical simulations are carried out. The results suggest that the bending direction of the plate can be exactly judged according to the Fbuckling value. In addition, the effects of the heating location and starting point on the bending direction are discussed, which provide further insight into the convex forming process and is helpful for the parameter selection of future process planning.