Yarn Numbering
Linear density determination establishes the fineness of spun flax products by relating mass to length within a controlled conditioning environment. Metric Count Nm 80 defines a linear density where eighty thousand metres of single linen yarn weigh exactly one kilogram under standard atmospheric conditions of sixty five percent relative humidity and twenty degrees Celsius. Production facilities in Chinese spinning mills rely on this classification to set drafting rollers and ring frame speeds during wet or dry spinning operations.
Mass variation across a delivery bobbin alters the resulting linear density classification. Lower count values designate coarser strands intended for heavy drapery applications, whereas higher designations specify finer outputs destined for luxury apparel.
Spinning Tolerance
Processing parameters demand strict adherence to nominal linear density targets despite the natural irregularities inherent in bast fibres. Metric Count Nm 80 permits a standard commercial mass deviation tolerance of plus or minus two point five percent across a one thousand metre test skein drawn from the spinning frame. Quality control laboratories at export facilities weigh conditioned test lengths on analytical balances to verify conformity before baling.
Uneven pectin removal during the previous boiling stage creates localized diameter fluctuations that register as count anomalies during electronic capacitance testing. Supervisory technicians adjust roving feed rates when sample weight measurements drift outside established mill acceptance criteria.
Export Specification
Commercial documentation accompanies every consignment leaving the mill to certify that the physical properties match the contractual obligations agreed upon by buyer and supplier. Metric Count Nm 80 appears on the mill test certificate alongside breaking tenacity and twist multiplier values to form the primary contractual baseline for international linen transactions. Overseas garment manufacturers inspect these documents to ensure the supplied material performs consistently on high speed knitting and weaving machinery without excessive breakage.
Buyer acceptance criteria often impose stricter twist and hairiness limits than basic mill standards require for domestic distribution. Contractual disputes regarding delivery quality rely entirely on conditioned laboratory retesting of samples drawn independently at the port of destination.
