Non-stationary effects of ring rail movement in the high-speed ring spinning process with a superconducting magnetic bearing twisting system: problem and its solution

Abstract

Currently, a major challenge in conventional ring spinning is to increase productivity. This is essentially due to friction between the twisting elements. An innovative approach to the solution is the use of frictionless twisting system based on superconducting magnetic bearing (SMB) system. However, previous studies with the SMB system were mainly restricted to an angular spindle speed of up to 30.000 rpm because of: instabilities caused by the non-stationary process forces originating from the nonuniform ring rail movement, complex interactions between the yarn dynamics and the bearing properties of the SMB, aerodynamical subsonic flow regimes of the rotating yarn balloon etc. The ring-rail movement must be taken into account especially at higher angular spindle speed, as a ring-rail cycle occurs every few rotations of the spindle and results in fast-periodic variation of the balloon form, which in turn leads to extreme yarn tension peaks. In this study, metrological investigations were conducted considering the ring rail movement at different angular spindle speeds with the SMB twisting system to understand the influence of the ring rail movement on the spinning stability, dynamic yarn path during spinning process, balloon form etc. Moreover, a concept using servo motor driven lifting mechanism is presented to solve the problem of non-uniform ring rail movement.