Definition of fancy yarn
A yarn that differs from the normal construction of single and folded yarns by way of deliberately produced irregularities related to an increased input of one or more of its components or the inclusion of periodic effects such as knots, loops, curls, slubs, etc.
To produce fancy yarn, a variety of fibers should be kept in stock or available throughout the year.
- Cottonize Linen
- Recycled fiber
- Colored Viscose
- Polyester (PSF)
System of fancy yarn Manufacturing
Basic principle of fancy yarn
A ground (core) component, an effect component and a binder in a fancy yarn are shown in the following figure:
When the fancy yarn is examined, the first ply is the binder, then the effect yarn and lastly core yarn
The basic principle of producing fancy yarn is to feed the ground and effect components at different speeds into the twisting element.
The percentage ratio of the effect component to the ground component is called overfeed ratio.
The fancy effect can be optioned in two ways:
- By twisting and or doubling technique
- With spun effect by means of fibers, the effect may be randomized & regular effects.
Criteria/Classification of fancy yarn
There are five main criteria recognized for the classification of fancy yarns. They are:
- Type of raw material used for effect making
- Number of Ground and Effect making material components
- Method of manufacture
- Type of effect produced
- End-use of fancy yarns
- Type of raw materials used for effect making:
It refers to basic material used for effect making i.e; cotton, wool, silk, polymer, polyester, nylon, blend, etc.
- No of ground & effect making material components:
The number and the type of components virtually change the structure and exterior of the fancy yarn.
- The no of components can differ from one to six and more.
- Methods of manufacture:
- There are two methods of manufacturing namely Direct and Indirect process of getting fancy effect.
- Direct group deals with the production of fancy yarn in a single step by specialized equipment viz, twister for fancy yarn making, special knitting machine, etc.
- Whereas the indirect category doesn’t use specialized equipment for the production of fancy yarn.
- Ring spinning system with some guiding attachment is the best example of this category.
Type of effect produced
The simplest of the fancy effects, a marl yarn is one in which two yarns of the same count and twist, but different colors or textures, are folded together to form a balanced yarn. The yarn diagram in the below figure shows clearly both the alternation of the colors that are the primary effect of a marl yarn and the plain structure, which is that of an ordinary folded yarn.
Spiral or corkscrew yarn
A spiral or corkscrew yarn is a plied yarn that displays a characteristic smooth spiraling of one component around the other. The figure below shows the basic structure, which can be produced relatively simply on a doubling frame or under the ring spinning system.
A gimp yarn consists of a twisted core with an effect yarn wrapped around it to produce wavy projections on its surface. This structure is shown in figure 3.
Since a binder is needed to ensure the stability of the structure, the yarn is produced in two stages. First, two yarns of the widely differing count are plied together, thick around thin. In the second stage, they are then reverse bound. The process of reverse binding removes most of the twist inserted during the first process. It is this removal of twist that creates the wavy profiles, by making the effect yarns longer than the actual length of the completed yarn
A diamond yarn is produced by folding a coarse single yarn or roving with a fine yarn or filament having contrasting color using S-twist, and cabling it with a similar fine yarn using Z twist. Multi-fold or ‘cabled’ yarns may be made by extending and varying this technique, to bring about a wide range of effects.
Figure 3: Diamond yarn.
Clearly, a true diamond yarn would show some compression effect upon the thick yarn from the thin ones, an effect which in the interests of clarity is not provided in Figure. This is a yarn that can be very useful to designers looking to create subtle effects of color and texture, particularly in relatively simple fabric structures.
These types of yarns are characterized by tight loops projecting from the body of the yarn at nearly regular intervals, as shown in figure 4. Some of these yarns are made by air-jet texturing, but most are of three-ply constructions. The three components of the yarn are the core, the effect, and the tie, or binder. The effect yarn has the loops wrapped around a core, or base yarn, and then the third ply, or binder, is wrapped over the effect ply to hold the loops in place. The individual plies could be filament or spun yarns. The characteristics of these yarns determine the ultimate design effect.
The core has been shown (in fig-4) as a single bar, rather than as two yarns twisted together and around the effect yarn, as would be the case in reality. It is this dedicated core that differentiates the bouclé from the gimp yarn since their superficial appearances are similar.
A loop yarn has a core with an effect yarn wrapped around it and overfed to produce a nearly circular projection on its surface. Figure 5 shows the structure of a loop yarn, in this case somewhat simplified by showing the core as two straight bars. In reality, the core, which for a loop yarn always consists of two yarns twisted together, which, can entrap the effect yarn.
As a general rule, four yarns are involved in the construction, of which two forms the core or ground yarns. The effect yarn or yarns are formed with an overfed of about 200% or more. It is important that these be of the correct type and has good quality: even, low twist, elastic and pliable yarn is required.
The effect yarn is not completely entrapped by the ground threads and therefore a binder is needed. The size of the loops may be influenced by the level of overfeeding, the groove space on the drafting rollers, the spinning tension, or the twist level of the effect yarn. Loop yarns can also be made with slivers in place of yarns for the effect.
- Like the loop yarn, the snarl yarn has a twisted core, although, again for the sake of simplicity, the core has been shown in Figure as two parallel bars.
- A snarl yarn is one that displays ‘snarls’ or ‘twists’ projecting from the core. It is produced by a similar method to the loop yarn but uses a lively, high twist yarn and a somewhat greater degree of overfeeding as the effect yarn.
- The required size and frequency of the snarls may be obtained by careful control of the details of overfeeding and spinning tension, and by the level of twist in the effect yarn.
- A knop yarn is one that contains prominent bunches of one or more of its component threads, arranged at regular or irregular intervals along its length (Figure 8).
- It is normally produced by using an apparatus that has two pairs of rollers, each capable of being operated independently. This makes it possible to deliver the base threads intermittently, while the knopping threads that create the effect are delivered continuously. The knopping threads join the foundation threads below the knopping bars. The insertion of twist collects the knopping threads into a bunch or knop. The vertical movement of the knopping threads results in the formation of a bunch or knop. The vertical movement of the knopping bars decides whether the knop is small and compact or spread out along some length of the yarn.
Production of knop yarn:
- Covered yarns have a core yarn this is completely covered by fiber or another yarn. The core might be an elastomeric yarn, such as rubber or spandex, or yarns, such as polyester or nylon. Covered yarns may have either a single covering or double covering. The second covering is usually twisted in the direction opposite from the first covering.
- These yarns are lighter, more resilient, and more economical than double-covered yarns and can be used in satin, batiste, broadcloth, and suits as well as for lightweight foundation garment. Most ordinary elastic yarns are double-covered to give them balance and better coverage. Fabrics made with these yarns are heavier.
- It has been used for thousands of years. The laminating process seals a layer of aluminum between two layers of acetate or polyester film, which is then cut into strips for yarns, as shown in figure 11. The film may be transparent, so the aluminum foils show through, or the film and/or the adhesive may be colored before the laminating process. The metalizing process vaporizes the aluminum at high pressure and deposits it on the polyester film.