by Muhammad Mushtaq Ahmad, MTS Consultant, Lahore

In the past, a new spinning technology has been introduced to compete with ring spinning. Two of these are, airjet spinning and friction spinning, both have application in specific markets.

The open-end rotor system, on the other hand, has been very successful and has a considerable share of the short-stapled cotton spinning market. This is a result of eliminating roving, winding, with a tremendous increase in the production rate as compared to Ring spinning. However, some other technical issues, limited the commercial application of its yarn to the coarse counts yarn only. Among all technologies, conventional ring spinning remains the uncontested quality standard and continues to dominate the high value added yarn markets.

During the last two decades, components of ring spinning machines have been greatly improved changes in drafting system; drive systems and robotics have enabled large gains in productivity, flexibility and quality.

Most of the technical advances in ring spinning were aimed at improving the performances on the existing technology.

In recent years, another innovation, “COMPACT OR CONDENSED SPINNING has gained momentum, because it minimizes width and height of the spinning triangle associated with ring spinning. Introduction of this technology, began in late 1990s.[1]

Several experts have described the technical principles of Compact spinning that result in a more organized structure without peripheral fibers and with a better twist distribution. As a result of this enhanced structure, it has been shown to effectively improve yarn quality and enhance its performance during downstream processing and now is undisputed accomplishment.[2]

With the market introduction of “Compact Ring Spinning”, the situation in ring spinning has changed fundamentally. In all relevant quality criteria, genuine condensed or compact yarns are substantially superior to conventional ring yarn to such a degree that it is no longer possible to speak of a standard market value. In the best sense of the word, this is a revolution in ring spinning and, even at this point in time, one can categorically say that the future belongs to compact yarns.     

In compact spinning, the spinning triangle associated with conventional ring spinning is eliminated by pneumatic compaction. This happens by suction and compaction on a perforated revolving drum/ apron in the front zone of the drafting system.

The process is characterized by the introduction of a fourth nip point down stream of the exit from the conventional 3/3 drafting system, which acts as an aerodynamic condenser.

The aerodynamics consideration of the fibers through suction results in narrower spinning zone with individual fibers more effectively bound into the yarn assembly. This offered the potential to create a near perfect yarn structure by applying air suction to condense the fiber stream in the main drafting zone, therefore virtually eliminating the spinning triangle.

In conventional spinning, a spinning triangle is formed immediately after the drafting mechanism in the Ring Frame. The spinning triangle is a weak zone due to less twist in this region. Under normal working conditions most of the breaks occur in the vicinity of the spinning triangle. The strength of the fibrous mass in the spinning triangle determines the attainable spindle speed. Hence, if the spinning triangle is avoided or its length reduced, the achievable spindle speed could be increased. It is with this objective in mind, that compact spinning is being tried.

Rieter commercialized the first Compact Spinning system called Com®4 Spinning. However, compact spinning systems are also made by “Suessen (EliTe®), Zinser, Toyota and Rotorcraft, which are designed to accommodate the full spectrum of staple length, now being used in spinning.

These Compact Spinning systems offer the possibility of using cotton with short staple lengths to produce high quality yarns that are required long or extra long staple cottons.

Compact spinning technology has potential for improving both the quality and profitability aspects of cotton yarn manufacturing, depending on the objectives of the textile manufacture, different approaches are available. One approach could be to reduce the cost of the raw fiber while maintaining quality. Another could be reducing the twist while using the same raw fiber. Yet another is to eliminate some or all of combing while still producing acceptable yarn quality. [3]

Com 4 Operating principle

The air current created by the vacuum generated in the perforated drum condenses the fibers after the main draft. The fibers are fully controlled all the way from the nipping line after the drafting zone to the spinning triangle. An additional nip roller prevents the twist from being propagated into the condensing zone. The compacting efficiency in the condensing zone is enhanced by a specially designed and patented air guide element.

Optimal interactions of the compacting elements ensure complete condensation of all fibers. The Compact zone, consisting of the following elements:

The directly driven perforated drum is hard to wear and resistance to fiber clinging. Inside each drum there is an exchangeable stationary suction insert with a specially shaped slot. It is connected to the machine suction system.

EliTe System

After the fiber leaves the drafting system they are condensed by an air permeable lattice apron, which slides over an inclined suction slot. The fibers follow this suction slot and at the same time perform a lateral rolling motion, twist is being inserted. There is no spinning triangle.

It is of technological importance that the suction level relevant for the condensing operation is exactly the same for all spinning positions. To fulfill this criteria suction pumps are installed driven by a motor. Each suction pump covers 24/30 spinning positions. This provides short air-flow distances with identical negative pressure on all spinning positions. [4] Other than EliTe yarn Suessen have EliTwist and EliTwist EliCore.

Toyota way

When the fibers leave the drafting zone they are compacted by condense apron. Whereas, condense system is driven by front bottom roller with Toyota’s specially designed driving system. Individuals motor combined with suction units for spinning position have been arranged accordingly. This provides short air flow distances with identical negative pressure.

By applying air suction to condense the fibers stream, thereby virtually eliminating the spinning triangle, helps improve yarn characteristics.

Zinser: CompACT – The new dimension in ring spinning

The use of compact spinning technology is possible not only in the field of combed cotton yarn, but is also profitable in other fields. In this context, the compact spinning technology that is flexible and can be adapted to different applications is an important consideration.

Compact made by Zinser meets these requirements in an ideal way. With this compact spinning technology, which is based on a perforated apron, all raw materials can be processed to all major yarn counts.

The compact solution shows the advantages involved in using such a flexible system. This, however, not only applies to the field of combed cotton ring yarn, but also to carded ring yarn, blends of cotton with manmade fibers (carded and combed) and pure manmade fibers. [5]

The highlighter at a glance:

RoCoS

Compact yarn is produced by compacting the strand of fiber in a condensing zone, arranged after the drafting system, so as not to allow the formation of spinning triangle while twisting the strand of fiber into yarn.

RoCoS, the Rotorcraft compact spinning system avoids these and it works without air suction and uses magnetic mechanical principle. It is suitable for cotton and blends with synthetic fibers as well as pure synthetics from coarse to fine counts. It consists of

1. Bottom Roller.
2. Front Roller.
3. Delivery Roller,
4. with supra magnetic equipped ceramic compactor.
5. Supporting bridge.
6. Roving guides.In this system no air suction, no air pipes, no perforated drum or
    Aprons and therefore, no extra power is required. [6] Any ring spinning machine can
    be converted into Rocos system.

Other compacting systems are being offered by Pinter, Marzoli, Wuxi No. 7, Hua Fang, Jiang Dong FanJi, RIFA, Shanghai Erfanji, Song Bao, Dechang, Jingwei, etc.

The evolution of spinning technology has generally altered the relationship between fiber properties and yarn quality. Different processes will likely to involve different fiber machines interactions, which alters the optimum combinations of fiber properties. The possibility of using cotton with short staple length to produce high quality yarn, that heretofore required longer or extra long staple cottons are now possible to use in Compact spinning. In Compact, there are still doors to open, like carded compact yarn, nearly equivalent to conventional combed ring yarn. The production of blended yarns and many other possibilities are opening to a wide field for the creation and development of future products and applications.

Perspectives

Reduced yarn hairiness and improved tensile properties are the key benefit of the compact yarn. Both characteristics are crucial for yarn performance in downstream manufacturing processes. Compact spinning technology has potential for improving both the quality and profitability.

    Different approaches can be defined as follows:
1. Reduce the cost of raw material while maintaining yarn quality.
2. Reduce twist while using the same raw material. 3. To eliminate some or all the combing
    processes, while still producing acceptable yarn quality.

References / Literature Cited

1. Compact Spinning Effect on Cotton Yarn Quality: Interactions with Fiber
    Characteristics; Krifa and Ethridge; Textile Research Journal 2006.
2. Compact Spinning: New potential for short Staple Cottons. S p r i n g 2 0 0 2. Mourad
    Krifa. Eric Hequet. Dean Ethridge
3. Compact Ring spin yarns: An examination of some productivity issues.
4. Suessun EliTe forum 2006 (Pakistan).
5. Saurer Total Solutions: Compact.
6. Magnetic Compacting: Simple – Safe – Solid by Hans Stahlecker .
7. Barella, A., Yarn Hairiness 8. Compact Spinning and advantages of EliTe yarn 
    M.Mushtaq Ahmed.