A theoretical analysis of tube spinning using balls

Over the last twenty-five years a new method of manufacturing thin-walled, high-precision tubular parts has been applied: tube spinning using balls. Most of the process design is done empirically or based on industrial experience. This paper gives a method of theoretical process analysis, which covers areas of interest such as the process-zone geometry, the contact surfaces, the force, the torsional moments, the power, and the work. Of special importance is the relationship between the ball size, the axial feed and the number of balls, which determines the surface quality of the parts. Power estimation might be useful in the design of tube spinning devices, which usually require much less power than conventional ironing. Good correlation is observed between reported experimental data and values calculated by the computer application of the algorithm given in this paper.