Theoretical Study of a Spinning Triangle with Its Application in a Modified Ring Spinning System

The spinning triangle is a critical area in the spinning process of staple yarns. Its geometry influences the distribution of fiber tension in the spinning triangle and the properties of spun yarns. In earlier theoretical models, the spinning tension of the yarn acting on the convergence point is assumed to be perpendicular to the nip line of front rollers. This assumption is reasonable in the study of the conventional ring spinning triangle, but may not be appropriate for modified ring spinning systems in which the yarn spinning tension has an obvious angle with the vertical axis perpendicular to the nip line. Thus in this paper a new theoretical model is proposed by considering the inclination angle of the spinning tension. Based on the principle of minimum potential energy, the theoretical model quantitatively describes the fiber tension distribution and its relationships with the spinning parameters, shape of the spinning triangle and the inclination angle of yarn spinning tension. As an application of the proposed method, spinning triangles of a modified ring spinning system were investigated under various spinning parameters. The fiber tension distributions in the spinning triangle both with and without fiber buckling were numerically simulated and the results were compared with those from our earlier model. In addition, the properties of spun yarns produced by the modified system were evaluated and analyzed.