Attenuation Factor
Mechanical settings governing the relative speed of the feed and delivery rollers in a spinning frame control the final thickness of the yarn. The wet spinning draft ratio determines the degree to which the roving is stretched as it passes through the hot water trough. Higher ratios produce a finer thread while lower settings result in a thicker and heavier product.
Linear Reduction
Roller speeds are calculated using the surface speed of the front roller divided by that of the back roller. If the front roller moves ten times faster than the back roller, the material is attenuated by a factor of ten. Production managers adjust these gears to meet the specific yarn count required for a customer order.
Efficiency Record
Stability in the mill depends on maintaining a stable tension during this stretching process to avoid frequent breakage. Fluctuations in the ratio cause uneven patches in the yarn which appear as defects in the woven cloth. Constant monitoring of the draft assembly ensures that the resulting thread meets the uster standards for mass uniformity.
Weavers often reject batches where these irregularities exceed the contract limit because they interfere with the high speed operation of modern looms.
