Modeling Elementary Cross Sectional Variances to Predict Wet Spinning Breakage
Modeling elementary fiber cross-sectional variance predicts wet spinning end breaks by identifying localized cell wall stress concentrations under drafting tension.
Sliver Drafting Waves
Density Irregularity
Periodic thickness variations in drawn fiber bands occur during the drawing stage of spinning preparation. In the drawing frame, sliver drafting waves represent these alternating thick and thin regions that arise from uncontrolled fiber movement. This phenomenon affects the yarn count uniformity before the twist is applied to the yarn.
It establishes a limit on yarn quality, as these waves cannot be corrected in later stages.
Mechanical Origin
The waves occur because shorter fibers are not held by either the feed rollers or the draw rollers. These floating fibers move at uncontrolled speeds through the draft zone, clustering together to form a thick place, followed by a thin place. This movement is influenced by the distance between the rollers, which must be set according to the average length of the flax fibers.
If the roller setting is too wide, the size of the waves increases.
Defect Prevention
Correcting this problem requires the use of faller bars that control fiber movement in the draft zone. In linen mills, technicians adjust the pin density of the fallers to match the fiber characteristics. This mechanical control reduces the sliver drafting waves and ensures a uniform input for the spinning frame.