Analysis of the aircraft shell component’s surface and determination of the stretching punch’s longitudinal forming contour with Siemens NX12

It is necessary to construct a geometric model of the stretching punch in a new coordinate system, where a special surface parameterization was used to determine the longitudinal forming contour of the stretching punch’s surface. If the vicinity of its vertex is intersected by two orthogonal planes in the u and v directions, then in the small vicinity of this intersection point, there will be smooth lines i and j, which can be considered as normal sections of a smooth surface. This approach has been developed in differential geometry, where local properties of surfaces are mainly studied, and it is sufficient to consider small neighborhoods of a point for their study. The Cartesian coordinates x, y, z are chosen such that the origin of the coordinates coincides with point O, the x and y axes lie in the tangent plane to the surface at point O, and the z axis is directed along the normal to the surface at point O, represented as the vertex of the stretching punch’s surface. At the same time, we construct a geometric model of the stretching punch taking into account the direction of rolling the sheet blank. The surface of the stretching punch was oriented relative to the main line of curvature along the longitudinal forming contour, the direction of stretching during the sheet blank forming coincided with the direction of sheet rolling, and the process of designing the solid model of the stretching punch was performed in the corresponding system of vertical symmetry planes F1 and F2, translated into the space of the stretching press table. Experimentally, through verification of the calculated model, it was proven that such alignment made it possible to manufacture aircraft skin components without corrugation. A method of geometric modeling of the stretching punch in a new coordinate system using the Siemens NX12 software package was developed, suitable for practical use by enterprise technologists.