Advanced Texturing Technologies
Textured technologies have their presence in everyday products, from steel body panels and bearings to book covers and quilted toilet paper. The desired surface texture can be achieved by a number of processes but each has disadvantages, limiting extensive introduction.

Enduring crimps, coils, loops or other fine distortions along the lengths of the filaments are presented by a textured yarn, a constant filament yarn that has been treated. Heat setting in a twisted condition can texture the yarns manufactured from thermoplastic materials, while nonthermoplastic yarns can be textured by "air jet texturing" or "air texturing", wherein a forceful air flow is used to shape knotted loops in the filaments. The outcome will be a yarn with greater bulk, higher stretch and more beautiful properties.

With the use of compressed air, air textured yarns are manufactured from thermoplastic, cellulosic or non-organic filament yarns. Air textured yarns are supplied a huge quality with loops created on the surface of the filament yarn. The loop arrangement, which relies on the material used, ends in a yarn with features like those of typical staple-fibre yarn. The manufactured yarns are used for sewing thread applications, apparel fabrics, fancy yarn articles, automotive interior fittings, and home furnishing fabrics, carpets, fire blankets and a variety of other applications.

Let us now discuss major techniques used in texturing.

.False-twist texturing
.Texturing by a cold air-jet
.Texturing by a hot air-jet and a stuffer box
.Other marginal techniques.

Most textured yarns are false twist textured. Following write-up will tell about false twisting and the reason why it has been such an incredible success. First it will deal with the real twist texturing and then concludes with a note of speeds that can be reached using false twist texturing.

S and Z twist are different altogether
S and Z twist means real twist in the yarn and they are poles apart from each other; at the same time there is little difference between them. One yarn has been twisted into the opposite direction of the other yarn. Essentially, one yarn reflects what other possesses. Since S-twisted yarn will look in a fabric unlike a Z-twisted yarn, this difference is very important.

The "Real Twist" texturing principle
Thermo structure of real twisted yarn is allowed by the thermoplastic properties of synthetic yarn. Back-twisting of this yarn creates twistless yarn, in which the helix formation of the previously resulted in a twistless yarn was still visible. It is a remarkable development that the clear crimps of genuine wool or cotton in each individual filament give this yarn a look of natural fibres. Stufferbox crimps the filaments and then cuts them into staple length and spins them on a traditional machine into a spun yarn, a procedure enabling a filament yarn to look like a spun yarn. This process saves the time spent after spinning filaments endlessly.

The production steps are as follows:

Twisting on (two for one) twisters
Autoclave steam stetting
Back twisting
Cone winding

The False-Twist texturing

Just imagine that an elastic band is held between two clamps and then twist this band by turning it in the centre. You can notice real twist on left and right side. But each side is twisted into the opposite direction. One side is S, the other side is Z-twisted. Both sides have equal number of twists.

All the twist will vanish on releasing the twisting point. This was 'false twist created by you. False twist principle is being applied by all contemporary texturing machines.

Dynamics of false twisting

Imagine a drawing with the yarn twisted into two twisted directions and try to visualize the yarn to be endless. Replace the fixed clamps with feed rolls. When the yarn is moved from left to right with the peg in the twisted yarn bundle, the twist on the right side would be moved and then would fade away but the left side would continue to be twisted. All false twist-texturing machines are based on this effect. A peg generates a definite twist stop, and therefore friction disks are better options, which execute the same and have the benefit of rotating the yarn. When the procedure is begun, the twisted yarn on the right side is removed to rubbish but the twist on the left hand side continues. If the yarn breaks, the twisted yarn on the left hand side also goes to trash. If the twist were counted in both wasted ends, it would be accurately the same but in the opposite twist direction. Miles of superior quality textured yarn is manufactured between the two waste ends.

Reason behind the success of false twisting

Real twist texturing was very time-consuming and laborious. With the launch of false twisting, the process speeds of twist texturing accelerated from a few meters per minute to production speeds of more than 1000 m/min.

Bulked Continuous Filament

Unbroken threads of nylon are created into yarn. These threads are texturised to enhance their bulk and to modify from straight into twisted or bent fibre.

Twist

You can make the carpet pile more flexible by winding each carpet fibre around itself. The carpet resistance against crushing, matting and changing of texture is in proportion to the tightness of twist.

Heat Setting

To process the fibre with heat, it is locked in the twist after it is twisted. The procedure will create carpet fibres, which cannot be disentangled or squeezed under heavy foot fabric.

Tufting

After getting fed through needles, the heat-set fibre is stitched or tufted into the primary carpet backing. Amount of yarn used and closeness of the tufts to one another determine the density of carpet.

Dyeing

The tufted carpet is soaked in liquid dye then processed with a fixation solution and dried.

Here the needs on air interlacing depend on the technique of process. The 1-stage process, which is also called On-Line-Process and interlaces mono, duo, or tri-colour yarns, demands 30 to 40 hard knots per meter. These yarns are used directly in tufting. The 2-stage procedure, which is also called as Off-Line-Process, necessitates 15 to 25 soft knots for further processing in Heat Setting, Co-Mingling or Tufting.

Air-Texturing

This machine contains supply yarn creel, an appropriate winding head fixed with yarn transport together with an additional pair of feed rolls and an air jet interjected. Air texturing machines have two conventional categories: Machines with individual drives and Machines with headstock having motors, drives and shafts at each place. Since the machines are capable of treating large number of yarns and the each machine position can be fixed to manufacture a different yarn, machines with individual drives have become the standard in modern air jet technology. Aside from the few advances in winding technology used in air-texturing machinery and the technique of water application, the progress of air-texturing over the years has been relied on the growth of air-jet nozzle technology. Newer nozzles have led to the processing of a wider range of yarns at greater processing speeds, lower energy consumptions and lower noise levels.

Fibreguide Ltd., England, has increased and developed its scope of single and multi-position interlacing air jets. The range now consists of 11 different air-jet types, including Detorque, Detorque with interlace and oil dispersion jets. In addition, the company offers a wide range of Interlace jets for the production of all types of continuous filament yarns, ranging from micro-denier yarns up to BCF and industrial applications. Low-noise jet enclosures have also been introduced to enhance the interlacing performances of the multi-position FG2M and FG10M air-jet units, as well as the individual FG4 Jet.

Air texturing up to 1,000 m/min: the technology rise

Unlike false twist texturing with the speeds of up to 1200 m/mn, the speeds of air texturing until now at about 400 m/mn, in some cases up to 500 m/mn, lagged clearly behind. This made gainful air texturing of fine yarn counts unable to go beyond 100 dtex till now. With the new jet core Series-S.

Due to the well-researched geometry of the yarn channel, the speed of airflow through the jet could again be accelerated considerably. Texturing speeds could still be accelerated further because tests with developments in the circumstances close to the process and application of jet cores Series - S proved this. The primary manufacturing speed with Jet Cores S315 for core / effect operation with feeder yarns of dtex 22 - 250, is about 750 m/min, if a post heater is used to relax the unnecessary filament loops. Supplementary hot plates or heated godets before the jet, and a rise in the air pressure up to a maximum of 12 bar, facilitate further rise of the texturing speed up to 1,000 m/min. Yarns from S-cores display equally distributed loop formations and almost no propensity to flames. These yarns create a very smooth fabric look. From the very beginning, the S-Cores have been a hit and are in growing demand. In 1999 their share of Heberlein's total deliveries already reached 35%.

S-Jets make possible both higher production speeds and enlargement of range of applications for air-textured yarns.

Because of cost reasons, success already emerge in the fine yarn count segment wherein air textured yarns had no opportunity until now. Fashionable yarn mixtures are well recognized for ladies wear, sports wear and specialities for technical applications. Air-textured yarns with ease elasticity made from slightly stretchy feeder yarns are hot topics.

Conclusion

In the field of air interlacing, jets with better presentation can be anticipated. On one hand, they will fulfil the needs of accelerating process speeds, and on the other hand will take care of escalating process permanence. Opportunities are open for them to minimise a number of extra processing phases. Besides using compressed air, other means like steam will be applied because these will allow the beginning of necessary new consequences.

In terms of air jet texturing, it is advisable that faster air texturing machinery will be offered to make use of the high-speed air texturing jets. Other than new machines themselves, supplementary parts like heating and higher compressed air source will have to be used to enable texturing speeds of more than 1,000 m/min. The high suppleness of the air texturing procedure helps individual drive units. Great attempts are exerted to minimise the cost per position, which is more likely with shaft machines, at this time. In the near future the recently reached speed level must be, first of all, converted into practice and process stability must be increased on these machines. Thanks to the high flexibility of the air texturing process with an application range from approx. 22 to 18,000 dtex, and the possibility to process practically all kinds of filament yarns, not to mention the great number of yarn combinations that are possible, further market expansion can be expected.

The level of the market increase for air-textured yarns will depend considerably on the development of additional areas of end-uses. Very big, and almost not yet utilized opportunities are in applications with new feeder yarns. Examples of new, strongly progressing yarns are slightly elastic multi-filament yarns, as well as fine filament counts up to dtex 22, that only now have become interesting from a cost point of view, thanks to faster texturing jets. Pre-dominant applications of these yarns are in the areas of hosiery, ladies wear, sports and leisurewear, but also in textile automotive linings.