Multi-objective Optimization of HMGF Process Parameters for Manufacturing AA6063 Stepped Tubes using FEM-RSM

In this paper, the loading path was optimized in hot metal gas forming (HMGF) process for making AA6063 cylindrical stepped tubes. For this purpose, the response surface method (RSM) and finite element method (FEM) were applied using Design-Expert and ABAQUS softwares, respectively. The parameters of internal pressure, pressure rate, axial feeding, and punch speed were examined based on the central-composite design in the three levels. The maximum die filling and the minimum tube thinning percentages were selected as the objective functions. The analysis of variance showed that the axial feeding, internal pressure, and their interaction were the most significant parameter in the die filling and tube thinning. The optimum loading path at the temperature of 550 oC was obtained at pressure of about 7 bars, pressure rate of 0.01 bar/s, axial feeding of 7 mm from each side and punch speed of 0.02 mm/s. Experimental tests were performed for the specified process parameters. The numerical results were validated by experimental testing.