Experimental and simulation studies of springback in rubber forming using aluminium sheet straight flanging process

Rubber forming is very widely used in aircraft manufacturing. Springback of rubber forming process is an important and decisive parameter in obtaining the desired geometry of the part and design of the corresponding tooling. In this research, the rubber forming of aluminium sheet was conducted. To investigate the springback, the straight flanging was employed in die design. The deformation process was studied by preparing the sheets with different thicknesses and different die radii. The influence of process parameters (time and pressure) on the rubber forming process was studied. Based on the analysis of experimental results, it was found that springback of straight angle decreased with the increase of blank thickness t, whilst increased with the increase of the die radius r. The springback can be eliminated with the bending ratio r/t < 2. The increase of forming pressure and time of rubber forming had little effect on the springback when the blank coincided with the die face. Springback of flanging in rubber forming process was smaller than that of stamping. In the jogged flanging, a better shape was formed by using the polyurethane.