Optical Fibre Diameter Analyser Calibration for Bimodal Cashmere Histogram Profiling
Calibrate OFDA optical thresholds and medullated density adjustments under IWTO-47 to accurately deconvolve bimodal cashmere histograms and verify coarse hair mass.
Coarse Hair Mass Fraction
Percentage Measurement
Gravimetric determination of fibers exceeding a specific micrometer threshold in a wool or specialty hair sample defines the coarse-fiber content. This calculation of the coarse hair mass fraction allows manufacturers to assess the tactile comfort of the final knitwear. Fibers with larger diameters cause a prickle sensation on human skin, making this metric essential for yarn grading.
Laboratory Protocol
Mechanical separation or optical analysis instruments measure the distribution of fiber diameters in the test specimen. Technicians extract the coarse hair mass fraction by isolating the thicker guard hairs from the finer undercoat before weighing. This procedure is standard for cashmere and alpaca fibers where softness dictates the commercial value of the lot.
Quality Index
High values for this percentage indicate a lower-grade fiber shipment that is unsuitable for premium apparel. The coarse hair mass fraction directly correlates with yarn hairiness and unevenness during downstream spinning. Spinners adjust machine draft settings based on these measurements.
Industrial Threshold
Industrial limits restrict the presence of thick fibers to less than three percent in top-tier garments. Where the coarse hair mass fraction exceeds this tolerance, the yarn is redirected to heavier woven goods. This re-allocation prevents costly dye variations and uneven texture in fine knitwear.