Too small drawing force results in poor cohesion between fibers, resulting in unstable fiber speed change point, wider sliver width, poor control of edge fibers, poor yarn evenness, high detail and more hairiness.
However, too large drawing force is easy to cause sudden change and decrease of drafting efficiency, resulting in deterioration of yarn stability index and higher yarn slub than NEP; If the control force is too large (some factories increase the cradle pressure to more than 250 n), the fiber may be torn during the drafting process (for example, in some factories, there are many flying flowers on the original drafting device, which is obviously improved after enlarging the gap and reducing the pressure). At the same time, the gripping distance is changed due to the large deformation of cots, and the influence of uneven rubber density on the yarn quality is also highlighted. In addition, the excessive pressure also accelerates the loss of drafting parts and the increase of power consumption per ton of yarn.
