Raw Cashmere Classing and Guard Hair Percentage Estimation
Raw cashmere value hinges on clean down yield and optical verification of residual coarse hair content below zero point five percent by mass.
Guard Hair Content
Fleece Composition
Weight fractions of coarse protective fibers within a harvested fleece determine the processing steps needed to extract the valuable fine undercoat. The guard hair content is the percentage of thick, coarse fibers present in a raw cashmere lot. High levels of these coarse fibers require intensive mechanical separation to prevent them from contaminating the finished yarn.
Dehairing Action
Mechanical dehairing machines separate the soft down from the fleece by taking advantage of density and diameter differences. A high guard hair content increases the number of processing passes required through the carding and air-separation chambers. Each pass exposes the delicate down to mechanical stress, which can lead to fiber breakage and a reduction in the average staple length.
Minimizing the residual guard hair is essential because coarse fibers of more than thirty micrometres cause a prickling sensation against the skin.
Standard Limit
International quality standards for finished cashmere yarn enforce strict limits on the permissible amount of these coarse fibers. The residual guard hair content in high-grade garments must remain below one half of one percent by weight. If this limit is exceeded, the fabric fails softness audits and cannot be marketed as premium cashmere.
Mill Control
Inspection laboratories use projection microscopes or automatic optical analyzers to count the number of thick fibers in a yarn sample. This verification at the yarn stage prevents defective material from entering the knitting and weaving departments, ensuring consistent hand feel in the finished garments.