Wednesday, May 13, 2020

YARN APPEARANCE TEST


YARN APPEARANCE TEST:


The appearance of the yarn:

The appearance of the yarn is very important quality. The appearance of a yarn is just like a quality indicator of yarn. The customer can make a rapid decision during before purchasing of any yarn. The assessment of appearance of a yarn gives initial quality indications about all yarn regularities. It is very helpful when a customer compares two yarn of different manufacturers of same count. it directly reflects in the fabric. We can say that " the visual quality estimation of the yarn is called yarn appearance."

The user should always be conducted the appearance test of yarn before purchasing.

Apparatus used:

1 - yarn board winder.

2 - yarn package.

3 - gum tape.

Testing procedure:

* The whole testing procedure of yarn appearance test gets completed in below steps:

* The empty yarn appearance board is mounted on the board winding machine. The board is tightened by nuts 

* The  yarn traverse guide brings extreme in right side. Now this traverse guide is engaged with threaded shaft. 

* The yarn package is now mounted on the cone holder.

* The yarn is passed through different guides and tensioner as shown in below figure.


 * Finally the end  of yarn is fixed by gum tape on the yarn board.

 * The instrument  is ready to make a yarn board.

 * Now the yarn board is rotated in clockwise direction with the of hand wheel.

* During board winding, the yarn board rotates on its axis only. It doesn't  traverse.

* when  the board winding continues, the yarn traverse guide traverses to left direction as shown in above figure.

* When the board winding gets completed, the end of the yarn is cut and it is fixed on the board with the help of gum tape.

* Finally the yarn board is taken off from the board holder.



If you have only one cone, you should prepared atleast 5 yarn board. If you have a yarn lot, you have selected five cone from different bags randomly.

Observations:

Each yarn board is observed carefully. Black side and white side of the yarn board are selected one by one.




The defects to be observed to decide the yarn appearance are given below:
·       Neps
·       Slubs
·       Knots
·       Thin places
     Contamination
·       Thick places
·       Hairiness
·       Broken seeds
·       Immature fibres
·       Cleanness
·       Colour


If all above yarn regularities are minimum in the yarn, the yarn appearance will be the best. The purchaser can also compare two yarn of the same count on the basis of the yarn appearance and can select the best one.

The purchaser should always keep in his mind that effect of the yarn appearance directly reflected on the fabric surface.

 If the yarn appearance is poor, the fabric appearance will also be poor.

Since in the yarn dyed fabric, the yarn mercerizing is not done normally, therefore immature fibres present in the yarn result as undyed fibres on the yarn surface.

If there are more broken seeds in the yarn it will be reflect in processing cost too.

The thick places, thin places and hairiness level of yarn directly reflect on the fabric surface. These yarn irregularities also affect loom efficiency and fabric quality. The hairiness of the yarn causes pilling on the fabric surface.

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