Rieter

Influence on the yarn structure

Index

Yarn formation takes place in the spinning triangle. If the yarn is to have high strength, high elongation and regularity combined with low neppiness and hairiness, the fibers in the yarn must be:

  • well oriented
  • evenly distributed in length and cross-section
  • wound spirally around the axis, and
  • all fibers must be tied in under tension.

Of all the spinning systems available or known, these requirements are best satisfied by ring spinning, especially with regard to the last, very important item. However, this holds true only in conjunction with good spinning geometry, i.e. with an optimal spinning triangle. If it is too short, core fibers will be tied in without tension. They can then absorb tensile forces in the axial direction only to a limited extent, or only after the fibers in the outer layer have been broken. Since the distribution of tension forces in the final yarn is similarly uneven to that in the spinning triangle, the yarn shows the same effect. When stress is applied to the yarn, the edge fibers undergo so much elongation from the very beginning that the forces acting on them either cause the fibers to break, or in some cases to slide apart before the loading forces can act on the neighboring fibers inside the yarn. Fiber breaks proceed successively from outside to inside. The yarn has low strength. Since the twist inserted in the yarn is insufficient due to the uneven distribution of tension (the edge fibers are ultimately wrapped around the core fibers), the negative effect is reinforced. The yarn structure falls short of the optimum, and most of the yarn quality parameters suffer more or less.