Fibre Diameter and Prickle Threshold Measurement
topic
Fibre diameter prickle threshold testing is based on the established neurophysiological finding that individual fibres protruding from fabric surfaces cause prickle sensation when they exceed a critical diameter above which they generate sufficient force on skin mechanoreceptors to trigger a neural response, with fibres below this threshold deflecting under skin contact force without triggering sensation. Fibre diameter distribution measurement by airflow, optical, or laser scanning methods characterises the proportion of coarse fibres in a fleece or yarn that will generate prickle-inducing surface protrusions after fabric construction. The prickle factor calculated from the proportion of fibres above the critical diameter threshold predicts the prickle potential of knitted fabrics and correlates with subjective panel prickle ratings in standardised forearm contact trials.
Role
Fibre diameter prickle threshold testing provides the quantitative basis for softness certification programmes in the wool industry — enabling wool growers, processors, and brands to specify fibre diameter distributions that guarantee itch-free next-to-skin performance, underpinning premium merino wool certification schemes where guaranteed softness is the commercial proposition that justifies price premiums of three to eight times commodity wool prices.