The following is a brief introduction to the main quality indexes of yarn.

Generally speaking, yarn refers to the "fastness" of yarn. Due to the yarn in the production process, to withstand a certain tension and load, so the yarn must have a certain amount to ensure the normal knitting process.

Yarn can be measured on a single frame and is generally expressed in terms of breaking strength (the force applied at the moment of yarn breaking on the frame, in cN / tex (GF / Tex)).

Yarn fiber type, thickness, twist, count unevenness and quality.

2、 Sliver

Evenness refers to the degree of uniformity of yarn thickness. In theory, the thickness of the same yarn should be uniform, but in the spinning process, due to the influence of operation and technology, the yarn thickness is not uniform. The yarn with uneven thickness will produce stripes on the fabric surface, which will affect the quality of grey cloth.

Evenness is one of the important quality indexes of yarn.

3、 Yarn defect

Yarn defect refers to the defect on cotton yarn. For example, slub yarn, colored yarn, neps, impurities, greasy yarn, rust stain, etc.

Yarn defects on cotton yarn can be measured by yarn defect meter. In the production process, yarn defects will be directly brought to the fabric surface and affect the fabric quality.

4、 Twist degree

In spinning (spinning frame), the yarn is drawn and twisted at the same time. The purpose of twisting is to make the yarn better. There are two kinds of twist directions: Z-twist and S-twist. S-twist is commonly used in knitting factories.

The twist of yarn is too high, it is not easy to be bent in knitting production, and it is easy to produce yarn twist and braid, which will reduce the elasticity of the fabric, and easily form small braid yarn knot defects on the cloth surface. In addition, the loop forming parts of circular knitting machine are also vulnerable to damage where the yarn passes.

If the twist of yarn is too low, it will affect the yarn, increase the breakage rate of the circular knitting machine, increase the labor intensity of the blocking workers, and reduce the output. Too many knots will affect the fabric quality.

Generally speaking, the twist of cotton yarn used in knitting factories is lower than that of woven yarn, because knitted products require soft and bulky handle.

The twist of yarn can be measured by twist meter.

5、 Elongation

Under the action of tension on the yarn machine, it will be extended until the moment of breaking. The percentage of the elongation length to the original length is called the elongation of cotton yarn.

The cotton yarn with good elongation can cushion the effect of external force and reduce the breakage rate in the production process.

6、 Colour and lustre

The color of cotton yarn with good quality is white and bright. The color of cotton yarn is related to the quality of cotton and the grade of cotton blending. For example, the cotton yarn with poor maturity has more knots; over mature cotton has poor color, and the grey fabric is more dead (not colored).

Knitting yarn should have color that meets the quality requirements, especially cotton yarn used for dyeing yarn.

7、 Others

Other indicators of yarn are hairiness.