In welding of thin A3003 A1 sheet by a Nd:YAG laser beam, the laser pulse shape plays an important role to enhance the welding penetration stability. In order to evaluate the effect of laser pulse shape during Nd:YAG laser welding of thin Al sheet and to predict the welding performance by numerical simulation, a three-dimensional FDM analysis is presented for heating with different laser pulse shapes and related welding parameters.
The simulated results give good agreement with experimental results, where a sound weld shape and crack-free weld pool are obtained. The simulation results show that the welding stability is greatly affected by the modulation of laser pulse shape for the same laser energy and welding parameters. As a rectangular laser pulse is modulated to have three stages with high, medium and low power level for the first, second and third stage, respectively, more energy is absorbed in the melt pool and the cooling rate is reduced. The numerical simulation method can be used to determine the proper conditions for good welding performance.