Optimization Of Air-Jet Vortex Spinning Nozzle Parameters And Research On The Knitted Fabric

Air-jet vortex spinning is a new kind of spinning method developed from air-jet spinning, which utilizes high-speed airflow produced by nozzles to finish twisting and wrapping. Now it access to everyone's recognition for it's fine-quality, short process, high yield, high degree of automation. However, due to the strengthen of this yarn is not as strong as the ring yarn; there are some limitations in applications. But knitting fabric do not have to use high strength yarn, so in this article, we develop the application of Air-jet vortex spinning yarn in knitted fabrics. The yarn body is very hard, in order to overcome this deficiency, we use viscose as raw material which is softer than any other fibers, so that both can play a complement role in spinning process, not only can improve the skew of coil, but also can improve the viscose fabric keeps its stiffness.In the second chapter, we mainly introduce the mechanism of Air-jet vortex spinning method and the self-made Air-jet vortex spinning nozzle, give the conclusion that this spinning method is incomplete open-end spinning. Then we analyzed the factors affecting the process of spinning, in three main considerations: the fiber itself, the structure parameters of Air-jet vortex spinning nozzle and the technologic parameters.In the third and fourth chapters, in order to improve the nozzle structure and technologic parameters, we did a lot of experiments, mainly to study the relationship between the structure parameters, technologic parameters and yarn quality, especially the yarn strength, yarn hairiness, yarn evenness. Some structure parameters, such as: the angle of air hole, the distance from needle to spindle tube, the angle of spindle, etc. technologic parameters, such as: nozzle pressure, the length from the front roller to the nozzle, etc. are optimized by single factor , combination and orthogonal experiments to determine theoptimal parameters.In the fifth chapter, the structure of Air-jet vortex spinning yarn is tested and analyzed by tracer fiber method and electron microscope photographs. We derived that the Air-jet vortex spinning yarn structure is similar with the ring yarn except that the Air-jet vortex spinning yarn has core fiber which is non-twist, and the core fiber is greater than the number of half fiber volume. This may be one of the reasons that why the strength of Air-jet vortex spinning yarn is lower than that of ring yarn. However the wrapped fiber wrapped very tightly, the Air-jet vortex spinning yarn body is very hard. And the yarn has much less hairiness than ring yarn which is one big advantage. In addition, we wove the Air-jet vortex spinning yarn and the ring yarn to knitted fabric in the same size, and compared the performance of the fabric. We derived that the bursting strength and the drape of Air-jet vortex spinning fabric are not as good as the ring fabric and the moisture permeability is similar with the ring fabric. While the abrasive resistance, air permeability and skewing of Air-jet vortex spinning fabric is significantly better than the ring fabric.