Effect of Initial Position of the Counterpunch on T-Shape Hydroforming

Abstract

The loading path is crucial to the quality of forming parts in the process of tube hydroforming. The counterpunch is usually used to control the protrusion height and also to control the evolution of thickness and avoid over thinning in T-shape hydroforming. In this study, the experiments of T-shape hydroforming are conducted, in which tubular material used is stainless steel and has an outer diameter of 103mm. A fuzzy logic-based load control algorithm is developed for optimizing the loading path, and four different initial positions of the counterpunch are designed to investigate its influence on wall-thinning and the corner radius at protrusion end. The results show that the minimum thinning can be obtained with an initial position of 12.5mm, while a smaller corner radius is obtained with an initial position of 37.5mm.