(A) study on designing of 3D-laser forming process for circular sheet metal

Abstract

Laser forming process is a promising technology in shipbuilding, automobile, aerospace and manufacturing industry. This process includes the non-contact forming of sheet metal by utilization of thermal-mechanical stresses induced by laser. Laser forming requires no hard tooling i.e. punch & die system, and spring back action. Therefore it has precise control and many advantages for manufacturing and rapid-prototyping process. The laser forming process of sheet metal has been extensively analyzed, but a few studies have been conducted in the area of process design of 3D laser forming. This study describes the effect of irradiation path strategy and transition geometries in 3D laser forming. The experiments were conducted on three kinds of geometries that are circle, ring and referenced rectangular plates. The results show that curved path irradiation strategy has fewer deformations than linear paths. The observed geometries have segment angle of $5 \sim 180 degree$ (half-circular plate). Process designing of 3D laser forming has been analyzed. Inverse problem for axis-symmetric geometries with focusing on class of shapes is handled by using the distance-based algorithm, made by Prof. S.J. Na & Kim. The implementation of algorithms was confirmed. The used geometries are quarter-circular ring plate and half-circular ring plate. A free curve was taken as a target shape and connected forming points give the concentric paths strategy. The path radius was found an additional variable during establishment of data base. The study was extended to get the dish shape of a full-circular ring plate as a empirical way. To investigate the reason for distortion of plate caused by concentric paths, an additional series of experiments were conducted. Those experiments include the ring plates having the segment angle of $5 \sim 330 degree$. Gap between free edges was decreased gradually to monitor the whole process thoroughly. The use of radial paths with varying radial l...