Cotton Fiber Length Distribution Metrics and Carded Yarn Quality
AFIS short fiber content by weight in raw cotton must remain below 8.5 percent to prevent severe mass variance and tenacity drop in carded yarn spinning.
Ring Spinning Draft
Twist Attenuation
The mechanical extension and thinning of a roving strand into a fine fiber assembly immediately before twist is inserted produces the final yarn structure. Spinning technicians adjust the ring spinning draft to determine the final linear density or count of the yarn. This drafting occurs on the ring spinning frame itself.
Mechanical Elements
A three-line drafting system with rubber aprons controls the fibers as they are drawn out. If the ring spinning draft is too high for the fiber length, drafting waves occur, causing severe yarn defects. Technicians must calibrate the roller clearances carefully.
Drafting Control
The drafting zone consists of a feed roll, a middle roll, and a delivery roll, each running at progressively higher speeds. The draft ratio is calculated as the ratio of delivery speed to feed speed. When managing the ring spinning draft, maintaining the correct tension on the fiber bundle is essential to prevent premature fiber escape.
Poor tension leads to an increase in yarn thin places. This mechanical action represents the final chance to control yarn uniformity.
Mill Calibration
The draft is modified by changing the gear ratios on the spinning frame to produce different yarn counts. When shifting production from coarse to fine yarns, the operator increases the draft ratio. This adjustability allows the mill to meet diverse customer demands.