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Spun Fancy Yarn

Dhananjay Chavan

Department of Textiles
D.K.T.E. Society’s Textile and Engineering Institute, “Rajwada”, Ichalkaranji-416115 Maharashtra, India
E-mail*: dhananjaychavantext@gmail.com

Abstract

Developments in spinning have generated many yarns structures like fancy yarns, intend for different domains and end use. In these yarns, irregularities like neps, knots, loops and snarls of different size and shape are arranged with varying distance between them. One of the well-known and most popular fancy yarns is the slub yarn. As an example of a textile issue that was once considered a defect, slub yarn has proven to be an advantage in some instances. There are different types of slub yarns exists viz. normal slub yarn, multi-count, multi-twist, reverse slub, and slub on slub which are discussed in this paper.


Keywords- slub yarn, multi-count, negative slub, slub on slub.


Fancy Yarn

1. Introduction to Spun Fancy Yarn

Yarn refers to a structure composed of a continuous length of interlocked fibers. They are suitable for use in the production of different types of textiles. However, fancy yarn deviates from the normal yarns. These deviations occur mainly due to the introduction of deliberate decorative discontinuities in the form of colour, structure or both. In these yarns, irregularities like neps, knots, loops and snarls of different size and shape are arranged with varying distance between them. One of the well-known and most popular fancy yarns is the slub yarn. Slub yarn is the yarn containing thick places of different thickness and length. This soft lump, or slub, would appear from time to time over each run of one thousand linear feet of yarn, and would have to be removed before the material would be ready for warping or twisting. Over time, however, the concept of yarns containing a high count of slubs as a textural and style alternative began to develop. Slub yarn can form special appearance on the surface of the fabric; it is widely used in garments and decorative fabrics. The special appearance is determined by the different parameters of the slub-yarn, including the slub length, slub distance, slub amplitude and periodicity rule of the slub.

2. Slubbing Effects

There are four basic of Fancy effects: slub, multi-count, multi-twist, and reverse slub. The various combinations among these four can create infinite yarn and fabric designs.

2.1. Slub Yarn

Slub yarns contain slubs/thick places at predefined intervals along the length of the yarn. Slub can be defined by its length and diameter. The distance between two slubs is called a pause. Slub length and pause length determine the slub frequency, i.e. the number of slubs per unit length. In slub yarn, the dimension of the slub (length and diameter) can be the same as shown in fig.1.

Figure 1: Slub Yarn [3]
Figure 1: Slub Yarn [3]

Slub Yarn is a yarn containing thick places of different thickness and length that are achieved by the programmed acceleration of back and middle rollers in case of ring spinning and the feed roller in the case of rotor spinning. Slubbing effects are produced via a program controlled drafting system using a servomotor which varies acceleration of back and middle rollers in case of ring spinning, at the same time maintaining the front roller at a constant speed. This controlled acceleration produces variation in slubs (or flames) count (TSlub), spacing (or pause) length (Lpause) and spacing count (Tpause).

To create a slub is as simple asserting its length in millimetres, its thickness (multiplier) as a percentage of the base yarn and the pause (distance between one slub to the next) in millimetres. The random variation of thickness, length and pause gives a wide range of effects, ensuring the use of slub yarns in many applications like denim, shirting, knitwear, casual wear, ladies dress material and also in curtains and upholstery.

2.2. Multi-Count Yarn

In principle, the multicount yarn consists of different yarn counts one after another along the same yarn path. Each Slub in a Slub-yarn can be extended to make a multicount yarn. The multicount yarn consists of different yarn counts of random sequence. Twist multiplier of the yarn remains unchanged in spite of varying the draft. The multicount effect is obtained through a draft variation to modify the count and the front roller speed to modify the twist. With the electronic drafting system drive using servomotor, both draft and twist can be varied in a controlled manner. Slubs of different thickness, length and twist are incorporated into the yarn during the manufacturing process of yarn.

Figure 2: Multi-Count Yarn [3]
Figure 2: Multi-Count Yarn [3]
Multicount yarn can also have short slubs on each count and this type of yarn is known as Multicount – Multi slub yarn. Multicount yarns are presently in great demand for denim yarns. In practice, a pattern repeat for multicount yarns consists of 2 to 5 yarn counts. The length of the yarn sections in the individual counts is between 0.5 and 5 metres. For denim, short length effects are interesting, as they can be seen in the trouser leg or in the sleeve. The long yarn effects are more seldom, and they are rather used for home textiles.

2.3. Multi-Twist Yarn

In this type of yarn, the yarn count does not change, but the yarn twist is changed. Different twist levels obtained will create variations in the yarn’s dye intake, thus creating a special fabric appearance. The twist difference causes a colour change in the fabric. Yarn sections with different twist absorb the colour particles differently. The yarn section which receives more twist has lower dye uptake and vice a verse. This causes the colour effects.

Figure 3: Multi-Twist Yarn [6]
Figure 3: Multi-Twist Yarn [6]

2.4. Slub on Slub

In this yarn, the diameter may vary infinite times on every single slub according to its length. So each slub may have any shape and drawing.

Figure 4: Slub on Slub [3]
Figure 4: Slub on Slub [3]

2.5. Injected Slub Yarn

Injection slub yarn is a specialized fancy yarn and it is made up of two different materials, one for slub portion and the other for base yarn. Both the material will be dissimilar in nature, colour and character. The basic principle behind the production of injection slub yarn is, slub portion will be injected at random over the continuous running of base yarn. In this process, two yarns are twisted together and short fibres are injected into the form-locking connection. These injected slubs are produced and located in just the right places. Its length, thickness, and distance can be varied to create different structural effects on the fabric.

2.6. Negative Slub

As the slub, the negative slub or reverse slub is obtained with a drafting variation that, in this case, is negative and reduces the yarn thickness. Here slub formation is without changing the front roller speed, for a perfect distribution of the twist on the yarn.

Figure 5: Reverse Slub Yarn [3]
Figure 5: Reverse Slub Yarn [3]

Conclusions

There is a great demand of slub yarns in suiting, shirting, denim and home textiles. With advanced technology now it is possible to produce a different variant of slub yarns in controlled and reproducible manner.

References

  1. Salhotra K. R., Production of Fancy Yarns and Their Uses, Nodal Centre for Upgradation of Textile Education Publication on Advances in Tech of Yarn Prod, pp 344. 
  2. Pan R., Gao W., Liu J., Wang H., Recognition the Parameters of Slub-yarn Based on Image Analysis, Journal of Engineered Fibers and Fabrics, Vol 6 (1), 2011, pp 25-30.
  3. http://www.marzoli.it/sites/default/files/pages_attach/marzoli_fancy_yarn/fancy_yarn_inglese_bassa.pdf
  4. Jiangyin CF Tex. Tech Co Ltd, China, Web: www.noveltexindia.com.
  5. Souid H., Sahnoun M., Babay A., Cheikrouhou M., Slub yarn quality optimization by using diagrams of superimposed contours, International Journal of Engineering Science & Advanced Technology, Vol.2(4), 2012, pp 796-800.
  6. Shakeel I., Pramanik P., Fancy Yarns: Slubs and Multicount, Indian Textile Journal, vol. 119(8), 2009, p24.
  7. Jansen W., Fancy Yarns in Rotor Spinning, Asian Textile Journal, March 2006, pp 68.
  8. Iqbal S. and Pramanik P, Fancy Yarns for Fancy Denim, ITEC World Textile Conference on Apparel and Home Textiles, Jenny club Coimbatore, Aug. 2007.
  9. http://www. Skeetindia.com/Injslub.html.
  10. http://www. Skeetindia.com/Negative.html.

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