Determining Recovered Yarn Linear Density from Woven Fabrics
Determining recovered yarn linear density involves unraveling measured lengths, removing crimp under standardized tension, and correcting dry mass for size.
Metric Count Nm
Indirect Count
An indirect numbering system defines the fineness of yarn by measuring the length of a unit mass of material. The metric count nm represents the number of meters of yarn that weigh exactly one gram. A higher number indicates a finer yarn, whereas a lower number denotes a thicker yarn.
Count Conversion
Converting between different yarn count systems allows mills to use varied machinery without recalculating fabric densities. To convert the metric count nm to the English cotton count, a constant factor of zero point six is applied. This math helps weavers compare woolens with cotton yarns.
Testing Process
Accurate determination requires wrapping a specific length of yarn on a reel and weighing it on a precision balance. The metric count nm is computed by dividing the measured length in meters by the mass in grams. This test is repeated across several bobbins to find the average shipment value.
Manufacturing Choice
Spinners use this count to select the appropriate knitting needle sizes and machine gauges for garment production. When the metric count nm is high, fine-gauge knitting machines can produce lightweight fabrics with uniform loop structures. Conversely, a low count is preferred for heavy sweaters and industrial blankets that require thickness and warmth.
Matching yarn fineness to machine gauge is a primary checkpoint for preventing needle breakage and fabric irregularities.