Linear Density test of Polyester Yarn
Linear Density test of Polyester Yarn
The yarn denier, also known as the linear density, is another characteristic of yarn that determines the yarn thickness. The yarn denier test includes a wrap reel machine and a digital scale with a precision of 1 mg.
A specific yarn length is required to determine the yarn denier. This yarn length is determined using a wrap reel machine.
The wrap reel machine consists of a regular hexagon with a perimeter of 1000 mm. It has a specific mechanism that avoids yarn layer intermingling.
The twists of the wrap reel machine are adjustable. Therefore, the hank of a determined length is weighed using a scale, and the yarn denier is calculated concerning the yarn length and weight. For example, the denier of a yarn hank with a length of 100 m and a weight of 831.0 g is 83.1 dtex.
The hank denier standards include ASTM D1907, ISO 2060, and Iranian National Standard No. 28. Iranian National Standard proposes a range of ±2.5% for FDY and POY yarns up to 99 deniers and ±2% for FDY and POY above 99 deniers. For dope-dyed DTY yarn, the denier is ±2.6% for yarns up to 100 deniers and ±3% for yarns above 100 deniers.
