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.
Draft Roller Clamping
Pressure Control
Mechanical force applied at the nip point of a drafting system secures fibers to prevent uncontrolled slippage during the attenuation process. Top rollers are loaded with springs or pneumatic weight to maintain a firm grip on the fiber mass against the bottom steel rollers. Effective draft roller clamping ensures that the draft ratio remains constant across the entire length of the sliver.
Friction Distribution
Surface area of the rubber cots on the top rollers distributes the pressure evenly to avoid damaging the delicate filaments. If the clamping force is too low, the fibers are pulled through the system at irregular speeds, creating thick and thin places in the yarn. Correct settings are determined by the fiber type and the total mass of the material being processed.
Uniformity Result
Consistency in the yarn count depends on the stability of this mechanical grip throughout the production run. Rollers must be checked for wear or deformation that could lead to uneven pressure across the width of the drafting zone. Maintaining the correct draft roller clamping prevents the formation of drafting waves that would otherwise degrade the appearance of the finished cloth.
Nip Geometry
Operating limits are restricted by the hardness of the roller covering and the diameter of the cylinders. Harder cots provide a narrower nip point with higher pressure intensity, while softer materials offer a wider contact area. Selecting the appropriate combination allows the mill to handle various fiber lengths without causing fiber breakage or loss of control.