Establishing Core Sampling Rules for Raw Cotton Quality Verification
Core sampling raw cotton requires deep core extraction, standard atmosphere conditioning, and calibrated instrument verification to secure commercial payment accuracy.
Short Fibre Index
Length Distribution
A length distribution metric quantifies the proportion of fibers in a sample that fall below a specific length threshold. High-volume instruments calculate the short fibre index to predict the spinning performance of raw cotton shipments. This value represents the percentage of fibers by weight that are shorter than twelve point seven millimeters, which is the standard threshold for cotton spinning.
Low values are preferred because they result in more efficient spinning and stronger yarns.
Processing Efficiency
High proportions of short fibers lead to increased yarn hairiness and higher breakage rates on the spinning frames. A high short fibre index indicates that the raw material will produce weaker yarn with more surface defects. Spinners use this metric to adjust the settings of their combing machines to remove the short fibers before yarn formation.
Sourcing Value
Cotton merchants discount bales that contain too many short fibers because they increase processing waste. Buyers analyze the short fibre index during purchasing to ensure they are getting high-quality, long-staple cotton. This assessment helps the mill avoid paying premium prices for fiber lots that will yield less usable yarn.
Measurement Reliability
Fibrogram curves and optical sensors provide the data needed to calculate fiber length distributions. Regular calibration of the testing equipment ensures that the short fibre index is calculated consistently across different test runs. This measurement accuracy prevents disputes between cotton suppliers and spinning mills regarding shipment quality.