Slub Yarn: Types, Properties, Manufacturing and Uses
Mohammad Mahbubur Rahman (Maya)
AGM, M.Hossain Cotton Spinning Mills Ltd
What is Slub Yarn?
A slub yarn is one in which slubs have been deliberately created to produce the desired discontinuity of effect. Slubs are thick places in the yarn that may take the form of a very gradual change, with only a slight thickening of the yarn at its thickest point. Alternatively, a slub may be three or four times the thickness of the base yarn and the increase in thickness may be achieved within a short length of yarn. The yarn pictures in Figure 1 should give a clear impression of the structure of the yarn itself.
Slub yarn refers to yarn that has been purposely spun with slubs (thicker sections along the yarn) while it was once seen only as a defect, slub yarn is now intentionally created to give fabric more personality.
The slub effect can be produced by a variety of means, each offering its own benefits and challenges. The finer slubs can be used simply to introduce a subtle but pleasing variation in the surface appearance of a plain fabric, and are used often for this purpose in both upholstery and apparel fabrics. On the other hand, the heavier slub effects produce stronger variations in the fabric surface, and can become a design element in their own right. The yarns are used both in knitted and woven fabrics, although it is worth recalling that, until very recently, most of the methods for producing slub yarns carried the penalty that the thick place in the yarn was followed immediately by a thin place, rather than by a simple return to the basic yarn count being spun.
Slubs can also be produced by adjusting the card settings so that the fiber stock is ‘rolled’ to form neps or slubs. This is simply the opposite of the normal carding action. It is possible to produce slubs by varying either the cylinder-doffer setting or the doffer speed. However, this technique is rarely employed because it is very difficult, and therefore time consuming, to alter the speed of these large cylinders. A better yarn can be produced by using fibres that have good cohesion between them.
Types of Slub Yarn:
Types of slub yarns on the basis of visual effect:
- Pattern/regular slub yarns
- Non-pattern/irregular slub yarns
- Multicount slub yarns
- Both are pattern and non-pattern slub yarns.
Properties of Slub Yarn:
The slub yarn has outstanding tensile strength, which is why it can withstand scratch. It is abrasion resistant which also depends somehow on the Slub parameter. The Slub yarns are also very much susceptible to damage during their usage due to the lack of migration of the fibers in the base and the injected yarns. They are resistant to shrinking and are durable in nature. Despite all the properties of slub yarns, they are all tensile sensitive in nature. Slub yarn is a very cost-effective option and readily available to use.
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Affect the Visual Effect of Slub Yarn:
There are four factors are affect the visual effect of slub yarn. They are:-
- Number of slubs per kilometer (NSm)
- Diameter (dia) of slub
- Length of slub
- Distance between slub.
All these parameters are selected by computer. Slub vision software is used for this purpose.
Suppliers of Slub Yarn Attachment M/C:
- Amsler – Germany
- Jiangyin CF Tex Tech Co Ltd – China
- Caipo – Italy
- Pinter – Spain
- Slub-O-Generator of Fancytex – Gwalior, India, etc.
Some ring frame machine manufacturer are supplying the ring frame with inbuilt mechanisms for slub and multicount yarns. Some popular machine manufacturers are-
- Marzoli – Italy
- Zinser – Germany
- Toyota – Japan, etc.
Slub Yarn Manufacturing in Ring Frame:
- In the ring frame, there is a servo motor with slub gear and another with twist gear.
- Back and middle rollers get motion from the same gearing and the front rollers get motion from separate gearing.
- Slub is produced by the speed variation of back and middle rollers.
- Break draft is always maintained properly, otherwise roving breakage will be created.
- Back roller speed will be increased continuously after a certain time. As a result more material will be feed, whereas during that time the draft of front zone remains constant. So a thick place in the final yarn will be created after a certain time.
- The controller controls the following:-
- After how much time (mili second) the speed of back roller will be increased.
- How longer the increased speed will remain.
- Amount of speed that to be increased.
- Twist gear is optional, the speed of front roller is fixed when twist gear is not used.
- Twist is controlled by changing the speed of front roller.
Production of Slub Yarn in Rotor:
Description: In rotor spinning, slub is produced by the speed variation of feed roller. When the feed roller speed is increased, the over feed takes place and as a result slub is created.
End Uses of Slub Yarn:
There are endless uses of slub yarns in our life, Slub yarn are used mainly in fashion industry, ready-made garment industry, high-end shirting materials, value-added knitwear, home textiles, woolen knitting industry, furnishing industry and handicraft industry, etc., for creating eye catching designs in fabrics and other end products. Besides, slub yarns are used in traditional fabrics such as upholstery, lace, curtains and household fabrics in general. But it is becoming more popular in the production of denim on ring spinning, shirting and knitwear.
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.