TYPES OF FANCY YARN,(NEPP, SLUB,FLAKE):-

Different types of fancy yarns , their structure and manufacturing proces:-

Textile yarns are the basic elements of fabrics . For fabric, design , and production, yarn are mainly considered in terms of their colors, structures and material properties. Colors and the structure of yarn contributes, to the fabric, texture , covering power, luster and thickeness. The term " Fancy yarn" may be taken to cover, all fancy and novelty effects , while fancy doubled yarn "cover yarn" and fiber effects. Color effects and effect based on metallic components are also available. Fancy yarn that are designed mainly for their aesthetics appearance rather than performance. Many fancy yarn achieve deliberate variation in appearance by the way of color. To be more inclusive, fancy yarns may be defined as any yarn that contains deliberate variation either in the form or in color or both. The word deliberate is very important hence because all yarns are made from staple fiber are inherently variable due to the imperfections of the yarn . Spinning system and the non uniformity of fiber material.

Image of diffrent types of fancy yarn.

In the production of normal regular yarn , efforts were made to minimise these variations so that the eventual fabric uniformity and performance properties. Such as strength and abrasion resistance are maximized . In  fancy yarns , however , the variation are introduced by designed to enhance the aesthetics appearance . These yarns provide the fabric designer greater scope in achieving a more attractive and exclusive product, but also pose greater challanges as they usually suffer from poorer performance and higher costs. Fancy yarns structures are manifested in term of irregularies of curvatures of the central yarn axis and changes in the diameter ( count) of cross-sections in the yarns. The fancy yarn giving a fancy touch to the fabrics to a broad range of end uses. Significant demand for the fancy yarn is the ladies and children outwear. 

The basic structure of a fancy doubled yarn consist on "core" threads an "effect" material and a "binder" which as the name suggests, ensures that the entire structure hold together.

Different types of fancy yarn:-

It would be a futile attempt to try to describe all the varieties of fancy yarns as these are designed to differ by classification. From the point of how the variation is introduced in the yarn, fancy yarn, effects may be broadly divided into two categories:-

1) Fiber effect and 

2) Yarn effect.

Fiber effect are introduced prior to the formation of yarn effects are introduced by combining two or more yarn are after the individual yarns have already been made . The two categories can obviously be combined to make more complex effect.

(1) FIBER EFFECT;-

Fiber effect fancy yarn are created during the spinning processed prior to the formation of the final yarn. These yarns are characterised by varying sizes of fiber lumps along the yarn length. Depending on the size of these fiber lumps , these fiber effects are often futher divided into three sub categories, nepp, slub, and flake.

NEPP YARN:-

Nepp yarn or nupp yarn, has a compact yarn structure with specks of fiber , cluster distributed along the base yarn structure. Fig. 1 shows an example. These yarns are most effective when the effect fibers have contrasting colors to the base yarn fiber whereas more subtle effect can be created when the effect fiber and the base yarn have similar colors . The distribution of the effects should generally be random to avoide the moire effect as shown in Fig. 1 

Fig. 1 Nepp yarn.

The production of nepp yarns are usually achieved during the preparation of fabrics. The most widely used method is mixing prepared fibers ball such as wool into the main fiber stock before carding. The fiber effect can be varied by the mixing ratio and the card setting in addition to the usual yarn parameters of linear density and twist.

If the card setting are closer , these fiber balls will be opened upto smaller clusters and the effect will be smaller but more frequent conversely, if the card setting are more open , these fiber balls will have large and looser but less frequent effect. Due to more vigorous actin of cotton card , other wise, the fiber ball will mostly be opened up and the effect will be lost. From a performance point of view, larger effects, relative to the base yarn linear density, and effects in a looser and softer yarn . Structure with low twist level will have lower resistance to abrasion and the effects can be more easily rubbed of during fabric production and subsequent end use.

SLUB YARN:-

Slub yarns are more pronounced effects compared with nepp yarns . Fig. 2 shows an example of slub yarn. These are more commonly produced during processes after carding , but prior to the formation of final yarn. These effects can be formed by introducing additional fiber into the fiber stream in a controlled manner or by introducing deliberate to evenness in the fiber flow. The introduction of additional fiber can be carried out during drafting in the spinning process or drawing codensation in the process.

Fig. 2 slub yarn

Unevenness can be introduced by varying the drafting roller speed in traditional ring spinning. It can also be introduced by deliberately creating local mechanical faults in machine components in a spinning system, such as the opening roller, a rotor spinning system.  It is also possible to exploit the fact that fibers of dramatically different lengths tends to cluster during roller drafting, so mixing and during drafting, the shorter fiber tends to cluster together to form slub.

FLAKE YARN:-

Flake yarns contains larger and usually loose fiber cluster than slub yarns. These yarns are sometimes also called flamme yarns. Fig. 3 shown as example of flake yarn . In many ways flake yarns may be considered as more pronounced slub yarns , but these effects can only be created by controlled introduction or injectiom of additional fibers into the fibers stram before spinning.

Fig. 3 image of flake yarn.

Ref:-https://textileleaner.net