Study on multi-roller flow forming process of aluminum alloy cylinders with cross ribs

Multi-roller flow forming has the characteristics of multi-directional loading, which can improve the quality and accuracy of spun products. Roller number and parameter arrangement in a roller set will affect the material flow and rib filling in multi-roller flow forming of cylinders with inner ribs. Therefore, in this paper, a finite element model of multi-roller flow forming was established to explore the effects of roller number and parameter arrangement on the material flow mechanism and the saturation degree of inner ribs of aluminum cylinders with oblique cross ribs. The results show that increasing the roller number can limit the diameter expansion and promote the radial flow of material, thus improving the filling efficiency of rollers and the saturation degree of inner ribs, and that, selecting a large profile radius of roller for the front roller and small profile radius for the subsequent roller is beneficial to rib filling, and the greater the thinning ratio of the first roller, the more material flow into the groove of inner ribs. In addition, an aluminum alloy cylinder with cross ribs had been formed successfully in this study, which had good dimensional accuracy and mechanical properties. The hardness test was used to verify plastic strain distribution in the simulation. These results can provide process guidance for manufacturing on flow forming of cylinders with oblique cross ribs.