Fabrication of Saddle-Shaped Surfaces by Flame Forming Process

The flame forming process is widely used to manufacture ship hull plates. The saddle-shaped surfaces have different curvatures in perpendicular angles of planes and the manufacturers face an anti-clastic curvature. In this article, the manufacturing of saddle-shaped surfaces utilizing the flame forming process is investigated. The spiral irradiating scheme is used for forming. In order to study the effects of process parameters (pitch of spiral path, number of irradiation passes, and the movement pattern (In-to-Out or Out-to-In)), several experiments have been carried out. Determining the effect of process parameters for fabrication of this type of sheet leads to the precise manufacturing with reduced costs and lower production time. After the implementation of the experiments, the displacement of the sheet is measured and the saddle-shaped surfaces are manufactured successfully by the spiral irradiating scheme. The final part has large deformations and the curvature can be clearly observed. The deformation of the saddle-shaped surface is noticeably increased by reducing the spiral path pitch (110% increase in height of the center point of the sheet). Also, it is proved that the Out-to-In spiral path movement pattern leads to larger deformations than In-to-Out ones. Besides, the deformations of manufactured saddle-shaped surfaces are increased by increasing the number of spiral passes.