Numerical Analysis and Multi-Objective Based on NSGA2 in Optimizing Roller Hemming

The present study investigates the roller hemming process for a specific car door panel in the flat surface straight-edge section. The optimization parameters for the roller hemming process include the roller movement value, roller speed, and prehemming process path. The main aim was to reduce roller hemming defects such as creepage/growing value and wrinkle. Parameters were estimated through finite element analysis (FEA) using DEFORM v.11. Based on the regression surface method, the roller hemming process was designed, and the effects of the parameters on the creepage/growing value and wrinkle were analyzed to build the corresponding regression model function. Using the creepage/growing value and wrinkle as optimization objectives, the non-dominated sorting genetic algorithm-II was employed for the optimization of the multi-objective process parameter combination. The optimal process parameter combination obtained from this optimization was as follows: roller movement value of 3.5 mm, roller speed of 900 mm/s, and prehemming process path with prehemming bending at 60°. This approach effectively minimized defects, thereby ensuring high-quality results in the roller hemming process. The findings of this study demonstrates the practical application of advanced optimization algorithms and FEA in improving manufacturing processes, providing a framework for future research and development in this field.