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.
Drawframe Sliver Drafting
Sliver Attenuation
Blending and thinning of fibre bundles are executed in spinning preparation to produce a highly uniform feed material for roving and spinning. This mechanical process, known as drawframe sliver drafting, uses pairs of rollers running at progressively higher surface speeds to pull the fibres past each other. The attenuation reduces the linear density of the input slivers to a single, controlled strand.
Fibre Parallelization
Multiple carded slivers are fed simultaneously into the drafting system to blend different fibre lots and eliminate short-term density variations. This action straightens hooked and crimped fibres along the longitudinal axis of the sliver. The resulting parallel arrangement is essential for achieving high tensile strength in the finished yarn.
Drafting Zone
The roller configuration typically employs a three-over-three or four-over-three arrangement to control the floating fibres between the nip points. Mill technicians adjust the nip distances based on the staple length of the cotton or synthetic fibres being processed. Incorrect gap settings cause draft waves, which generate periodic mass variations that cannot be corrected in later spinning stages and ultimately appear as visible stripes in knitted fabrics.
Sliver Quality
Online monitoring systems measure the output sliver mass continuously to adjust the draft ratio dynamically via auto-levelling systems. The process does not alter the individual fibre properties like length or micronaire. It establishes the uniformity necessary for high-speed yarn spinning.