Hydroforming process optimization of aluminum alloy tube using intelligent control technique

In this study, to determine the optimal loading path of tube hydroforming process, a database-assisted fuzzy process control algorithm proposed previously by the authors was applied to T-branch forming with a counterpunch. The tubular material used is aluminum alloy (A6063-T1) and has an outer diameter of 42.7 mm and wall thickness of 1.2 mm. Control variables is axial feed, counterpunch displacement, and internal pressure. The first two variables are dependent on the last one, which is an independent variable. In the control algorithm, new evaluation functions are adopted for buckling at the shoulder part of the branch and for contact fitting with a counterpunch. For a “virtual control system” including fuzzy algorithm with the evaluation functions, an explicit dynamic finite element code is used in the simulation. The experiments are carried out using a fuzzy controlled path obtained by the virtual control system, compared with the conventional manual control path that is attained by a trial-and-error approach. As a result, a T-branch product is successfully hydroformed. This result shows that the fuzzy control algorithm and virtual control system can provide an adequate loading path in the hydroforming process for an aluminum alloy tube.