The Study Of Compact Mechanism On Cotton Compact Spinning

After appearance of compact spinning, much attention has been paid to it because it can enhance yarn quality greatly. In this paper, motions and forces of fiber band in compact zone of compact spinning are analyzed, then, the mechanical model of fiber band in compact zone is built based on the analysis. By integral of the mechanical model, the factors which affect the result of model (the additional twists and the tension of fiber band in compact zone) are analyzed based on theory and experience. Number of hairiness in the range of 3~9mm, yarn strength and yarn elongation are selected as the index points for evaluating the quality of cotton compact yarn, the relationship between the additional twists of the fiber band in the compact zone and the quality of the compact yarn is explored.Theoretical analysis and experimental study show that:1. The ultimate twists of compact yarn consist of twists inserted by ring traveler and additional twists created in compact zone.2. The fiber band in compact zone consist of the parts, including the triangle part created for the fiber band's torsion along the suction slot, the part which the section of fiber band changes from ellipse to rotundity and the part which the section of fiber band is unchanging. By analysis of those three parts, the mechanical models about the additional twists and the tension of fiber band in compact field are built., Among these threeparts, the part which the section of fiber band is unchanging does most to the additional twists of fiber band in compact zone.3. By analysis the mechanical model of fiber band in compact zone, the factors which affect the additional twists of fiber band include: the pressure in the profile tube P, the coefficient of friction between the fiber band and lattice apron μ, the length of the suction slot s and the curvature radius of profile tube pn. The additional twists of fiber band raises with the increase of p,μ and s etc, but reduce with the increase of pn. Among all the factors, what affect the additional twists of fiber band greatly are p, μ and s.4. By analysis the mechanical model of the tension of fiber band in compact zone, the pressure in the profile tube P, the coefficient of friction between the fiber band and lattice apron μ, the length of the suction slot sshould be kept in some range for the normal movement of the fiber band in the compact zone.5. The factors, the pressure in the profile tube p and the length of the suction slot s, which affect the additional twists of fiber band in compact zone are experimented. By compare, the two results of experiment and the theory are close to each other.6. By exploring of the relationship between the additional twist of the fiber band in the compact zone and the quality of the compact yarn, thenumber of hairiness in the range of 3~9mm will be reduccd greatly when the additional twist is about 5% of the twists if ring spinning yarn. Yarn strength and yarn elongation fluctuate greatly, but the minimum is bigger than that of ring spinning yarn。7. By analysis of the skid of the fiber band in the compact zone, the pressure created by frame should not be too great, but make the drafting of fiber band well, at the same time, the friction should bigger, but the friction between profile tube band and lattice apron should be littler.