Control of wall thickness distribution in synchronous multi-pass spinning

Abstract

With the development of metal spinning, the limitation of producing axisymmetric shapes has been broken through by many researchers using the synchronous spinning method in which the motion of the roller is synchronized with the rotation of the mandrel. The thickness distribution on the product formed in synchronous spinning is usually non-uniform due to the irregular motion of the roller. A method of pass design for thickness control in synchronous multi-pass spinning is proposed in this study. The effects of different parameters on the circumferential distribution of the wall thickness on cylindrical cups in synchronous multi-pass spinning are investigated. The rotational direction of the mandrel is reversed under several schemes. The cross sections of the product during forming are adjusted to control the thickness distribution by changing the concavity of the pass λ and the roller-mandrel clearance δ at different circumferential positions. The thicknesses and strains were measured during the experiment to understand the material flow. Experiments are also conducted in conventional spinning for comparison. The results showed that the torsion in synchronous spinning with oblique shapes can be reduced by reversing the rotational direction of the mandrel; the circumferential distribution of the thickness can be controlled by changing the geometry of the roller pass circumferentially.