Laser forming, is a plastic forming method using local heat stress which can form sheet materials without dies. Because no dies are required, it enables rapid prototyping and reduced production costs. Many studies have been conducted on laser forming, but almost none on the forming of curved surfaces. The aim of this study is to develop a CAM system for forming curved surfaces by laser. The scanning paths of the laser for forming curved surfaces are based on a method applied in shipbuilding industry. The method uses the maximum and minimum curvature lines as the scanning paths of a gas burner. Since the two curvature lines intersect perpendicularly, they do not influence each other. The scanning speed of the laser for obtaining the required bending angle was determined based on the basic experiments.

Laser forming is a technology which can form sheet material such as steel and plastic by irradiating a laser beam on the surfaces of material. In the forming, it does not need costly dies and molds, and forming degrees of freedom are high. However, since the forming mechanisms are complex, complete forming technology for practical use has not been developed. The objectives of this paper are to explain phenomena of laser forming by experiments and FEM analysis and to develop a forming method of curved surfaces by laser forming. The phenomena are explained by the temperature change, stress change, and plastic strain change at a laser irradiation point which was obtained by FEM analysis. Line energy is proposed for explanation of laser forming phenomena to classify the forming mechanisms, and a method is proposed in order to form curved surfaces of sheet material by irradiating a laser beam on maximum and minimum curvature lines. The effectiveness of the method was verified by a basic experiment.