Three-dimensional yarn path and bearing dynamics of the high-speed ring spinning process with a superconducting magnetic bearing twisting system including transient operation modes

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The application of a superconducting magnetic bearing (SMB) as an innovative ring-twisting element for ring spinning allows to increase the productivity of this technology up to an angular spindle speed of 50,000 rpm in comparison to the conventional ring/traveler system, where a maximum speed of 25,000 rpm is possible. However, non-stationary process forces originating from a non-uniform ring rail movement, complex interactions between the yarn dynamics and the bearing properties as well as aerodynamical subsonic flow regimes of the rotating yarn balloon are playing a particularly important role for the ring spinning process at such high angular spindle speeds and thus necessitates extensive research efforts. In order to understand the complex behavior of the new system, model-based analysis and metrological investigations on the SMB twist element and the complete yarn path is required. The main objective of this interdisciplinary joint project is to develop and to validate a new mathematical model of the yarn mechanics considering the three-dimensional yarn path and the SMB bearing dynamics for all process states, i.e. acceleration, synchronous spinning and stopping, including the non-uniform ring rail movement, the aerodynamics of the yarn balloon as well as the variation of bearing load due to natural frequency, so that the potential of the frictional free SMB system can be fully utilized. Additionally, the concept for highly efficient false twist element will be developed to improve spinning stability significantly at higher angular spindle speed. These efforts will be accompanied by advanced metrological investigations to identify the 3D balloon form, the twist propagation along the yarn path as well as the friction between the yarn and balloon control rings. All the metrological results will be used both as input parameters for the simulation and for the validation of the non-stationary mathematical model of the SMB spinning process.It is expected that the investigation and results of the proposed project will have a significant contribution to the modelling of state-of-the-art processes in textile technology as well as for the application of SMB based component for high speed machines.