Study on hybrid hydroforming process of sheet metal with multi-concave and convex surface parts

By means of numerical simulation and experimental, the liquid filling forming process of an aluminum alloy double concave and convex curved sheet part was studied. The quality of forming parts, especially the thinning rate, is compared and studied during different hydroforming process. The results show that the thinning rate of the product is more than 25% regardless of the passive or active liquid filling drawing. However, the maximum thinning rate of the product is less than 20% when the hybrid hydroforming is carried out in a set of die with passive liquid filling in sequence, followed by pulsating reverse liquid filling. The method has reference significance for improving the forming quality of the parts with concave and convex surface of thin plate.