Numerical and Experimental Investigation of Convex Laser Forming Process

Abstract

Laser forming is a flexible sheet metal forming technique using laser-induced thermal deformation to shape sheet metal without hard tooling or external forces. Concave laser forming can be readily achieved, while convex forming may occur through buckling, but the buckling direction heavily depends on the sheet surface and pre-strain condition. A new laser scanning scheme is postulated, by which convex forming can be effected insensitive to the abovementioned disturbances. The postulate is successfully validated by experimental and numerical results. The effect of the scanning parameters on the certainty of the convex forming, and dependencies of bend angle on Fourier number, laser power, and dimensionless velocity, are further investigated experimentally and numerically. The simulation results are in agreement with experimental observations. The numerical simulation model developed is also used to study the transient temperature, stress state, and strain state and to provide further insight into the convex forming process.