Study On Laser Shock Forming Of Sheet Metal

Laser shock forming (LSF) is a novel technique that laser-induced shock wave is used to shape sheet metal. It is new application of laser in sheet metal forming. Based on the preliminary study on LSF, this paper studied characteristics of laser shock forming in detail, analyzed primary factors which affect the deformation of sheet metal, measured distribution of residual stress in deformed sheet metal, and simulated the process of laser shock forming. All of these provide plenty of data for modifying theory parameters, quantitative analyzing the relation between deformation of sheet metal and laser parameters, boundary conditions, properties of sheet metal, magnitude of Shockwave pressure and its loading time, and establishing formula between deformation and some parameters. In this paper, the main contents and results as following:1) The forming mechanism of the laser-induced Shockwave and the dynamic response of sheet metal acted on the laser Shockwave loading were described. Functions of overlay and coated paints and its effect on deformation were analyzed. And some overlay and coated paints were introduced.2) On the base of experiments, the influence of pulse energy, beam diameter and confining boundary to deformation of sheet metal were studied. The results show that when the pressure of laser-induced shock wave exceeds over dynamic yield stress of sheet metal, laser power has greatest effect on deformation, and the deformation of sheet metal increases with the increase of laser power in a nonlinear way until sheet metal was fractured or breached.3) Results of double laser shocking experiments show that multi-laser shocking can obtain more deformation or forming area. The convex region between two laser shocking zones will affect uneven degree of forming area. So in the process of laser multi-shock forming, pulse energy and interval between laser shocking zones should be optimized.4) After observing the surface quality of deformed area, the results show that the surface roughness of deformed area obviously decreases and the surface of deformed area becomes smooth, this indicate that LSF can refine microstructure of deformed area when it deforms sheet metal.