Yarn Unevenness

   Evaluation of yarn evenness

    Yarn evenness: yarn evenness is a measures of the level of variation in yarn in yarn linear density or mass per unit length of yarn.

Yarn Unevenness: The mass per unit length variation due to variation in fiber assembly is general known as yarn irregularity.

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                                    Fig. irregular yarn

Causes of yarn unevenness

There are mainly two causes of yarn unevenness.

Ø  Variation/Irregularity of fiber diameter.

Ø  Irregularity of fiber arrangement.

Causes of yarn unevenness are broadly given in below.\

1.       Inherent Variation of raw materials.

Ex: Length Variation, Fineness variation, Strength variation.

2.       Improper selection of technical and machine parameters.

Ex: m/c parameter, Roller setting, speed of the machine.

3.       Mechanical defective machenary

Ex: Defective drafting system, Defective gears, Rollers, Worn out of belts, tension.

4.       Atmospheric condition

Ex: Relative humidity, Cohesiveness, Frictional behaviors, drafting force.

Methods of the determination of yarn unevenness

1.       Graphical method.

2.       PMD (% mean deviation).

3.       Standard deviation.

Measuring principle

Ø  Direct method: cut and weight

Ø  Indirect method

v  Capacitance method (Uster evenness tester)

v  Optical method (keissokki;japan)

Fig: uster evenness tester

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Writer and editor SABBIR

I am Nur Mohammed From comilla,Bangladesh.I studied in Textile Engineering and very much fond of blogging; so try to write about Textile