2015 Volume 56 Issue 656 Pages 787-792
Multipass synchronous spinning is a combination of synchronous spinning, in which the roller is synchronized with the rotation of the noncircular mandrel, and multipass spinning, in which the work is gradually deformed from a flat blank into its final shape after multiple passes. When a square cup is formed from a circular blank by multipass synchronous spinning, material accumulates at the side edges. The wall thickness locally increases at the edges and ears are formed at the corners. The calculation method for the tool trajectory is improved so as to equalize the thickness and strain distribution and to suppress ear formation. Considering noncircular spinning of a square pipe from a circular pipe, an intermediate circular section is introduced into the interpolation between the blank shape and the final shape. The experimental results show that the proposed method can decrease the difference in the thickness and strain distributions between the edge and the center of the side wall and can reduce ear formation.