Research on Incremental Forming Technology for Integral Panels with Flanges

Large aluminum alloy integral panels are the main load-bearing structure parts of the modern advanced spacecrafts and airplanes. There are various cylindrical, conical and spherical shaped integral panels in the modern advanced spacecrafts and airplanes. Large integral panels especially aluminum alloy integral plates with different flanges are difficult to be formed qualifiedly and easy to fracture in the forming process because of their structural complexity, their different uniform thickness and stiffness, large deformation. Aiming at these difficult problems, a new technology named incremental die forming is developed in order to form various cylindrical, conical and spherical shaped integral panels with different flanges qualifiedly. This technology combines with flexible strength compensation, incremental bending forming and subsection pressing forming, which has advantages of large deformability force and universal property. The forming experiments of various cylindrical, conical and spherical shaped integral panels with flanges have been carried out accurately using this method. The forming effects of the integral panels under different process conditions have been explored through experiments. These forming rules show that this technology is feasible for forming various cylindrical, conical and spherical shaped integral panels using a suitable loading path with reasonable forming parameters in a fixed position. The quality of skin and strengthening ribs of integral panels using this technology is in good state without defections, which satisfies the design precision. At last, the difficult problems that integral panels with flanges are difficult to form and easy to fracture have been solved and various cylindrical, conical and spherical shaped integral panels with flanges from a space station have been manufactured using this technology. These research results are great helpful to manufacture integral panels from spacecrafts and airplanes effectively.