Research On The Laser Induced Thermoforming Of Lightweight Aluminum Alloy Plate

In recent years, the lightweight metal plate, especially the aluminum alloy plate, has been applied more and more widely with the rapid development of the aerospace, marine, automotive and other industries. With traditional techniques, the bending of the metal plate is achieved by using a mold. However, for some parts with complex shape and large size, it will take a long time and high cost. Laser induced thermoforming is a brand new technique to bend the metal plate without a mold, and it has been attracting more and more attention. This study is about the laser induced thermoforming technique for the aluminum alloy plate.Firstly, the thermoforming features of the 5A06 aluminum alloy are analyzed. The power of the laser, the spot diameter, scanning velocity, position of the scanning line and the number of scans are the main parameters when using the laser induced thermoforming technique to bend the metal plate. In this study, orthogonal tests will be performed to figure out how will these parameters affect the bending angle of the aluminum alloy plate during the process of the laser induced thermoforming, and the single-factor tests will also be carried out to investigate the relationship between the bending angle and every single factor. At the same time, the change of the microstructure and the hardness of the aluminum alloy after being heated by the laser will be analyzed.During the process of laser induced thermoforming, the bending angle of the plate varies along the direction of the scanning line, which is called the “Edge Effect”. This phenomenon will decrease the forming accuracy. In this study, the temperature field during the forming process will be analyzed to figure out the reason of the “Edge Effect”. Based on the analysis, we proposed the scanning scheme with varying laser power to reduce the “Edge Effect”, and both of the simulation results and the experiment results could prove the effectiveness of this scanning scheme.In some special areas, the structural plate with stiffeners is used in placing of the flat plate, with its features of high strength and light weight. In this study, we will build a FEM(finite element model) to simulate the forming process of the structural plate. We will analyze the temperature field, the stress field and the stain field to figure out the mechanism of laser induced thermoforming. To reduce the uneven deforming of the structural plate, two schemes are proposed and the effectiveness is proven.