1. Raw Material Purification Stage
Raw cotton passes through a loosening and impurity removal device to remove impurities such as leaf debris and cotton seeds. It is then formed into loosely structured laps by a lap forming machine. This process requires an impurity removal rate of over 85%, and a lap weight unevenness rate of less than 1.2%.
2. Fiber Refining Stage
After the laps enter the carding machine, they are combed through the cylinder-flat working area to produce continuous carded sliver. This stage focuses on eliminating fiber entanglements, achieving a fiber straightness of 75%-80% and a nep count of no more than 25 per gram.
3. Sliver Homogenization Stage
Six to eight carded slivers are combined and drafted in a draw frame. Three combining steps ensure a more even fiber alignment. The weight unevenness of the output sliver is reduced from 4.5% to less than 1%, providing uniform feeding conditions for subsequent spinning.
4. Primary Twisting and Forming Stage
The combined sliver is drafted 5-12x on the roving frame and twisted through flyers to form densely structured roving. The twist coefficient of the roving is set between 105 and 120 to ensure adequate strength without compromising subsequent spun yarn drafting.
5. Final Spinning and Forming Stage
The roving is drafted 30-50x on the ring spinning frame and twisted through travellers to form finished yarn that meets Tex or Ne standards. The spinning process requires precise control of twist unevenness within 3.5% and strength CV values within 9%.
Throughout the production process, parameter settings for each process are dynamically adjusted based on the raw cotton quality and yarn application to ensure progressive quality optimization from lap to finished yarn.