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.
Yarn Thick Places
Strand Imperfection
A yarn defect characterized by a localized increase in yarn mass that exceeds a specified threshold for a short distance along the strand represents a common quality issue in spinning. Quality control technicians monitor yarn thick places using optical or capacitive sensors to ensure the yarn meets the standards required for knitting and weaving. This metric does not evaluate yarn hairiness.
Processing Problems
Drafting waves and fiber clusters that escape the drafting rollers during spinning are the primary causes of these defects. When yarn thick places occur, they can get caught in the needle hooks during knitting, causing needle breakage and machine downtime. This reduces manufacturing efficiency.
Remediation and Testing
Yarn clearing devices on winding machines detect and cut out these thick regions, replacing them with high-quality splices. When evaluating yarn thick places, a textile lab uses standardized thresholds, such as a fifty percent increase in yarn mass over a short length. These thresholds are defined by international standards like Uster.
By reducing the frequency of these defects, mills can produce smoother fabrics with a highly uniform appearance. This uniform finish is essential for high-end garments.
Commercial Standards
Yarn purchase contracts often specify a maximum number of thick places per kilometer of yarn. Shipments that exceed this limit are rejected or sold at a discount. This commercial pressure forces spinners to maintain strict quality control.