Multi-points 3D Stretch-Press-Bending Process for Forming of W-Shaped Mirror-Symmetrical Structural Parts

To improve the aerodynamic performance of high-end equipment, the mirror-symmetrically 3D curved aluminum structural parts are increasingly assembled in the manufacturing industry. A new type of multi-points 3D stretch-press-bending (3D SPB) process for forming this kind of component is proposed in this paper. A prototype of this process is developed. The 3D SPB experiments are carried out. This new process realizes the complex bending for multi-directional curvature radius, which increases the material utilization by 6.79% and doubles the production efficiency. Then, the numerical simulation models are established. It has a good prediction result for the 3D springback. The maximum relative error of springback prediction is less than 20%. Besides, the effect of pre-stretching and post-stretching are investigated, which determines the most suitable forming parameters at ε s pre-stretching and 0.3 ε s post-stretching. At last, the springback direct compensation method is applied to the precise forming of the target part. Though two times adjustment, the deviation reduces effectively. The precise forming experiment is carried out based on the optimized forming parameters. The maximum total deviation is 1.52 mm, which satisfies the forming requirement. The 3D SPB process achieves the pairwise forming of the W-shaped mirror-symmetric structural parts and improves production efficiency.