Unevenness test of Yarn

The unevenness test of yarn is one of the multiple tests conducted on filament yarns in the quality control lab at SIRANG.

For filament yarns, it is essential to measure tenacity and breaking elongation as well as the unevenness of yarn.

A yarn evenness test machine is employed to evaluate this quality parameter of yarn. This machine measures unevenness based on capacitance variations, which are proportional to the linear density changes. The outputs of the yarn evenness machine include statistical data, diagrams, spectrograms, standard deviation-length curves, etc.

Yarn Unevenness Test Process (P.O.Y 260Dtex/144F)

Yarn is put through the openings, and the right slot is chosen by the software program. The yarn with a length of 400 m is drawn at a rate of 400 m/min under standards. This machine can also implement a drawing rate of 800 m/min. The graph scale, twist speed and direction are set to 12.5%, 6000 rpm, and z-directional, respectively. The test is conducted for a standard time of 150 seconds. The number of repetitions and duration are adjustable.


  • Request for the polyester yarn quality control test (ASTM D1425 and ISO 16549)