BY:- Faissal Abdel-Hady, leader; Yehia El Mogahzy
(Auburn Textile Engineering)
In today’s spinning technology, at least 4 types of spinning systems are commercially available. These are the tradi-tional ring spinning, rotor spinning, air-jet spinning and friction spinning. Among them, ring spinning stands alone in providing high quality yarn suitable for any type of tex-tile end product. Other more recent systems enjoy much higher production speed than traditional ring spinning, but yarn quality restricts their use to only narrow ranges of tex-tile products. The primary technological limitation of ring spinning lies in the speed of the ring-traveler system. The traveler is a C-shaped thin piece of metal that is used for a limited period of time, disposed and replaced on a frequent basis. Three specific issues must be addressed to overcome this limitation:
Close View of Magnetically Suspended Spinning Ring
• the dependence of the yarn linear speed (or delivery speed) on the rotational speed of the traveler
• the continuous need to stabilize yarn tension during spinning and the dependence of this stability on the traveler speed
• the impact of traveler speed on fiber behavior in the spinning triangle
Research to date has only provided about a 15% improve-ment in traveler speed without affecting the traveler/ring contact thermal load capacity. Ring spinning is still at a production rate disadvantage of 15 to 20 times in compari-son with other spinning systems. Therefore, the challenge is how to break the traditional paradigm of ring spinning and revolutionize its principle in such a way that very high speeds can be achieved without sacrificing the traditional quality of ring spun yarns.
Our design approach is to totally eliminate the traveler from the ring spinning system and replace it with a mag-netically suspended lightweight annular disc that rotates in a carefully pre-defined magnetic field (See Figure below). By creating a non-touching environment of the rotating element for ring spinning, this system provides super high spinning rotation without the limitations of the current trav-eler system.
In the magnetic ring spinning system a bias flux is gen-erated from both permanent magnets across the air gap (shown in blue paths in Figure above), supporting the weight of the rotating disk in the axial direction. In case the floating ring is displaced from its central position, the permanent magnets will create a destabilizing force that at-tracts the ring even further away from the center. The con-trol system allows the current in the system to be controlled by feeding back information on the position of the rotor (obtained using four displacement sensors mounted radially to the floating ring) and adjusting the control currents based on this information. In simple terms, the control system re-duces the upper system current when the rotor is above the center position and increases the current when the rotor is below the center position. The total magnetic force will tend to bring the floating ring to its central position. We have now constructed the first prototype (See Photo below) and are optimizing its performance. The system was mod-eled using Simulink, to test how it performs. And the yarn balloon was analyzed using this model.
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