Standardized Air Permeability Test Parameters for Raw Flax Bundles
Air permeability fineness tests for raw flax require strict 65 percent RH conditioning, precise chamber packing density, and pre-cleaning of shive debris.
Dtex Linear Density
Yarn Geometry
Mass per unit length measurements quantify the fineness of continuous textile filaments and spun yarns. Mill specifications for fine flax spinning express thread thickness using dtex linear density, which defines the mass in grams per ten thousand metres of yarn. Modern high-speed spinning frames in Zhejiang mills rely on precise decitex values to adjust drafting zone distances and spindle speeds.
Lower numerical values correspond to finer yarns, which are required for high-thread-count linen fabrics used in apparel exports.
Count Equivalence
Traditional linen trade uses English wet-spun lea counts, but modern testing laboratories convert these values to dtex linear density for automated quality reporting. A sixty-lea linen yarn converts to approximately two hundred and seventy-six decitex, providing a direct metric equivalent for international trade documents. Mill quality managers verify linear density uniformity along yarn packages using capacitive evenness testers before clearing yarn lots for warp preparation.
Variances in decitex across a bobbin indicate uneven drafting during wet spinning, which produces visible striping in woven linen fabric. Technical datasheets accompanying export shipments list average linear density alongside coefficient of variation percentages.
Quality Control
Fabric mass calculations utilize thread linear density and weave density to predict finished square-metre grey cloth mass. Accurate dtex linear density measurements prevent yarn breakage during high-speed warping and shuttleless weaving operations. Mill weaving logs record yarn count consistency to ensure compliance with buyer fabric weight specifications.