Determining Customs Tariff Classifications for Raw Linen Fibres
Determining customs tariff classifications for raw linen fibres requires precise physical identification of retting, scutching, and hackling processing stages under HS heading 5301.
Tow Waste Percentage
Waste Ratio
Quantitative measurement determines the mass fraction of short combings and broken fibres separated from long flax during hackling operations. Laboratory technicians compute tow waste percentage by weighing discarded short fibre against total incoming raw flax mass. Lower percentage values indicate superior long fibre yield and efficient hackling machine settings.
Mill yield ledgers log these waste figures for every processed flax lot.
Processing Effect
Hackling pins split flax bundles while combing out short tangled strands to produce continuous parallel slivers. A high tow waste percentage reveals fibre brittleness caused by inadequate retting or aggressive pin density on early comb bars. Mill operators adjust pin insertion depth and comb speed to minimize unnecessary fibre breakage during combing runs.
Laboratory analysis correlates high short fibre percentages with reduced yarn tenacity potential.
Material Boundary
Excessive comb waste reduces the output volume of premium long line flax sliver available for fine yarn spinning. When tow waste percentage exceeds specified contract limits, mill procurement teams initiate raw material claims against flax suppliers for brittle or poorly retted fibre lots. The calculation tracks short fibre combings produced during mechanical hackling and does not apply to spinning flyer waste or weaving loom fly.
Hackling performance certificates document these percentage figures to establish final lot yield values.