Study On Baffle-assistant New Spinning Process For Thin-walled Aluminum Alloy Vessel Head

Spinning belongs to successive partial plastic sheet forming methods, with high-quality, high efficiency, energy conservation and material saving. But spinning forming process is very complex with the characteristic of large strain and nonlinear deformation and may bring wrinkling and cracking defects. Thin-walled aluminum alloy vessel head has lower overall stiffness, the falnge wrinkling is more likely to happen during spinning process. The formability and forming accuracy is more difficult to control. Therefore, how to modify spinning method and improve forming quality has been a research hotspot.In this paper special vessel heads with different diameter to thickness ratio were designed. A 3D elastic-plastic spinning FEA model was established with ABAQUS and the forming quality evaluation system was built. A new kind of baffle-assistant spinning method was presented, which was compared with traditonal multi-pass spinning under different conditions. In addition, the effects of dimension and main process parameters on forming quality were discussed.The main contents include the following four points:(1) Based on ABAQUS/Explicit platform, the precise numerical simulation model of spinning was established. The forming accuracy evaluation system includes wall thickness uniformity and mould-fitting degree was built.(2) Aimed at the disadvantages of complex procedure and nonuniform wall thickness for traditional multi-pass spinning with pre-bending, a kind of quality and efficient new spinning method—baffle assistant spinning was presented. The baffle was set in the front of blank which will keep synchronous feed with roller in the axial direction. The target vessel head could be formed with one pass conventional spinning with the benefit of baffle.(3) The baffle-assistant spinning and traditional multi-pass spinning with pre-bending were compared. The wall thickness uniformity and mould-fitting degree of new method are both better. Increasing D-T ratio leads more serious weak rigidity characteristic. It is necessary to increasing pass number to overcome wrinkle for traditional method. But for new method,the part still can be shaped within one pass and the larger D-T ratio, the more significant accuracy improvement.(4) The influence rule of dimension and main process parameters were discussed. The conclusion is that reasonable parameter optimization can both improve the uniformity of wall thickness and mould-fittingdegree, while achieving high quality and efficient manufacturing.