The Importance of Rotor Spinning
  • The Importance of Rotor Spinning
    writer

     

    The distinguishing feature of rotor spinning compared to ring spinning is the potential for higher volume production. This potential has been continuously improved as a result of continuously increasing rotor and winding speeds. Rotor yarns have always been successful because they are cheaper to produce than ring yarn and are suitable for the application areas in question.

     

    Two production stages in the rotor spinning system – spinning and winding – are combined in a single machine. Thus, cross-wound packages that are ready for sale can be obtained immediately, without winding small spinning bobbins as a first step. It also eliminates the next step of transferring, thanks to integrated yarn monitoring systems and waxing elements at each spinning point. Since carded or draw frame slivers can be processed directly in the rotor spinning system, the roving production step, which is a necessity in ring spinning, is also eliminated. Finally, the automation of operator operations on rotor spinning machines is easier than on a ring spinning machine. Automation of all operator operations has now been standardized on high-performance rotor spinning machines, and automatic can and bobbin transfer has also become a necessity in many textile mills. There has been a technological challenge not only in introducing rotor yarns to the market, but also in distinguishing rotor yarns from the structural features of ring yarns.

     

    The fact that rotor yarns are more preferred shows that it is used successfully in some end product groups, for example in woven denim fabrics and knitted fabrics. New fields of application for rotor yarns are still being developed, with the modification of the yarn properties on the one hand and the continuous improvement of the spinning stability on the other. One of the important features of rotor spinning is the separation of the functional stages of sliver opening and yarn obtaining, respectively twisting and winding of the obtained yarn.

    To achieve this, the fiber bundle must be interrupted at least at one point. This process takes place between the stages of opening the draw frame or card sliver to a single fiber and then collecting these fibers in the rotor groove where the twisting process takes place. Since each fiber comes from a tighter fiber bundle during the transfer between the opening roller and the rotor groove, and is collected in the rotor groove again, open yarn end can be mentioned here. Yarn production with the rotor spinning system is not a new process at all:

     

    • The first patent application for this method (basic (first) rotor patent by Berthelsen) was filed in 1937.

     

    • The first usable design was proposed by J. Meimberg of Spinnbau in 1951. However, this design was not developed because its performance was found to be unsuccessful.

     

    • In the 1960s, the idea was reconsidered in Czechoslovakia and the first machine suitable for industrial applications was exhibited at the Brno fair in 1965. It was held in the same year A presentation of the BD 1967 machine followed at an exhibition parallel to the 200 ITMA. These years were also the years when the commercial use of rotor spinning in spinning mills came to the fore.

     

    • In the early 1970s, Rieter, Schubert & Salzer and Platt companies formed a consortium (group of companies) to develop rotor spinning, and as a result many prototypes at different stages were exhibited at ITMA 1971. In the following years, intensive work was carried out to develop both the technological and economic potential of the rotor spinning system. These systematic studies were carried out under the following headings:

     

    • Expanding the rotor yarn count range by paying attention to yarn quality.

     

    • Optimizing the wear properties of rotor yarns, eg improving their grip on the product.

     

    • Improvement of the physical properties of the yarn in order to take into account the sudden performance increases in the downstream processing stages.

     

    As a result of continuous research and development, improvements in spinning elements and conditions have been achieved. Thus, it has become impossible to distinguish between rotor yarns and ring yarns. The rotor spinning machine itself is no longer just a spinning machine in the traditional sense, tape to thread

      

    with high production capacityIt is a computerized and complex (complex) system. Advances in economic pain depend on technological developments.more remarkable than it is. For example, in the 1960s the rotorrotor speeds of 30 000 rpm since the introduction of spinningIn practice, it has increased from the min level to 160 000 rpm.

    Today (in 2005) it is technically possible to reach 170 000 rpm without any difficulties. Compared to ring spindles, the rotor spinning unit can produce 5 to 10 times more. In countries with high wage levels, rotor spinning for yarns up to Ne60 counts is more economical than ring spinning. With more than 8 million rotors worldwide, 20% of staple fibers are spun. In some countries (eg USA, Germany) the ratio of rotor yarns to the total yarn volume is around 50%. The developments in fashion and textile applications are constantly increasing, as are the developments in the manufacturing of spinning machines, and these developments are also changing the application areas of rotor yarns.

     

    Yarns produced according to the air-jet production system have secured a certain market share, especially in the USA. Despite intensive development, certain limitations in pure cotton applications are barriers to a wider range of applications. In recent years, the share of automatic rotor spinning machines in the world is around 35%. This figure is influenced by the large number of non-automated spinning machines in China. In other parts of the world the rate is much higher.

    Shortly after the automatic rotor spinning machines entered the market, their share in Turkey exceeded 80%. Today there are also automatic can transfer systems between the draw frame and rotor spinning machine, as well as package transfer systems to the warehouse or to other stages in the queue. This has contributed to the economic development of rotor spinning. Rotor spinning is suitable for fibers up to 60 mm (2.25˝) long and therefore covers the classic short staple cotton range. Larger rotors developed by other manufacturers (Schubert & Salzer, Duesberg Busson) to process longer staple fibers, unfortunately, could not hold their own in the market. Although the yarn count range for rotor yarns is mainly between Ne 6 and Ne 40, it covers the general count range from Ne 3 to Ne 60. However, the total production yarn volume outside the above-mentioned range is small. Cotton fiber is the most predominant among the fibers processed on rotor spinning machines, with about 55% of the total yarn volume, but all short staple fibers can be spun in this system, either blended or alone. In addition to cotton fiber, polyester (PES) fibers are also used in high amounts in rotor yarn production. An annual increase of approximately 3% in fiber consumption worldwide is resulting in increasing amounts of polyester fibers. is met with.

    Viscose, modal, polyacrylic, their blends with each other and with cotton fiber occupy a certain proportion in the total yarn volume. However, the processing of these and other natural and synthetic fibers is mostly determined by fashion trends, so their ratio in the total yarn volume is seasonally and regionally variable. Another point of interest from an economic point of view in some applications is that spinning mill waste, which was not possible to use before, can be used in the rotor spinning system.

     

    With the introduction of this spinning system, rotor yarns began to be used in woven and knitted products. In many cases, the use of rotor yarns provides an advantage over ring yarns, which allows higher quality products to be produced. First of all, rotor yarns can be used successfully in cases where their unique properties coincide with the qualities sought in the product. It is seen that rotor yarns are mostly used in denim weavings, trousers fabrics, sportswear, blouses and underwear, pile products and upholstery fabrics in the ready-made garment sector. In addition, hosiery and sweaters in the apparel industry, sheets and upholstery fabrics in home textiles, technical textile applications, for example emery cloth, awning and blind fabric can also be mentioned as areas of use worth mentioning.

     

     

    Posted by %PM, 27% 808% 2016 21%:%May in Yarn Read 3171 times

The Importance of Rotor Spinning

details
Created on Sunday, 04 August 2019 19:23
Last Update: Tuesday, 10 January 2023 12:26
Published on Sunday, 04 August 2019 19:23.
impressions: 20015

Rotor spinning machines are increasingly used in the world due to their suitability for automation, high production speeds, elimination of some process steps in the spinning process, and significant reduction in personnel and space requirements. In parallel with technological developments, the usage areas are also expanding. Open-end threads are commonly in knitted products, woven outerwear, denim, workwear and technical fabrics finds use. Compared to ring spinning, production speeds increase 10 times, reduce ends down and increase productivity in enterprises thanks to higher machine efficiency.

 

 

 

rot1

 

 

Purpose of open-end spinning system

 

It is to make the fibers in the form of strips one by one, then to gather these fibers back together and attach them to the yarn with the open end (untwisted end) to ensure that the fibers receive twist.

The fibers in strip form pass through the strip feed condenser and come to the strip feed roller. With the help of the feeding roller, the strip is fed to the opening roller, which rotates at high speed (7.500 - 9.000 rpm). The feed rate here varies according to the yarn count, rotor speed and twist count. The opening roller turns the fibers it receives from the feeding roller in the direction of rotation. The trash remaining between the fibers during this turning is poured into the waste collection band by the opening roller with the effect of centrifugal force and collected in a central waste storage. Due to the high rotation speed of the rotor (50.000 rpm - 160.000 rpm), an air flow occurs in the fiber transmission channel. The fiber transmission channel is in the form of a tapered taper from the opening roller to the rotor. Due to this form, the speed of the air flow increases towards the rotor. The fibers pass through the fiber transmission channel quickly, reach the rotor rotating at high speed and hit the inner wall of the rotor. Due to the oscillating force inside the rotor, the fibers hitting the inner wall of the rotor form a ring-like structure in the rotor groove. The open-ended (without twisted inner part) yarn coming from the outlet tube and the nozzle reaches the rotor and starts to twist with the rotation of the rotor as soon as it comes into contact with the fiber there. As the yarn is pulled by the winding bobbin, new fiber will continue to be fed into the rotor, thus starting an uninterrupted operation. The separation of the twisting element and the winding element allows high output speeds (up to 200-250 m/min). The resulting yarn passes through the nozzle and outlet pipe and comes to the drafting shaft. The yarn exits the spin box via the cot and the drafting spindle. Thanks to the yarn winding device, which is quality controlled, it is wound on its bobbin. The bobbin sizes on which the yarn is wound are large and this also provides efficiency. Thread breaks and new bobbin tying that occurs during the operation of the machine are carried out by robots on both sides of the machine.

In the open-end spinning principle, the properties of the raw material used are listed in order of importance as fiber strength, fiber fineness, length/uniformity and cleanliness. During open-end spinning, the length remains in the background when compared to ring yarns. Even shorter fibers work efficiently in OE rotor spinning. The key is to fit more fibers into the cross-sectional area. However, it is necessary to avoid applications that reduce fiber strength for OE Rotor. At another point, dust absorbers should be added to the yarn preparation line. The common goal for all spinning systems during the yarn preparation stages is to increase the fiber parallelism as much as possible and to perform the cleaning process and fiber placement. According to the priorities of different spinning systems, it is necessary to be careful during the cleaning stages of the material. For this reason, it is possible to list the machine park in the OE Rotor system as follows. With the bale plucking machine, small cotton tufts from the bales lined up side by side are transferred to the air duct. The fibers pass through the metal detector placed in the conduit pipe. If a metal part is identified in the fibers passing through the metal detector, the flap on the delivery pipe changes direction. After the metal detector, the fibers reach the coarse cleaning machine. The fibers carried with the help of delivery pipes and air flow pass through the fiber inlet channel and reach the opening and cleaning drum of the machine. In this way, some opening and roughly cleaning of the fibers is achieved. Then the fibers pass through the foreign matter separator device. After cleaning the foreign materials, the fibers are blended in the mixer machine. After the mixing machine, the fibers are passed through a precision cleaner and dust absorbing machine before they reach the card. The fibers, which are passed through the carding machine and the draw frame in two passages, are ready to be spun in the form of bands in the open-end spinning machine.

These conditions underline the need to buy the “cleanest possible” cotton and further show that good cleaning equipment with high cleaning and dust removal efficiency is of great benefit to rotor spinning. Raw cotton contains a certain amount of organic and non-organic residues, dust and plant particles, while synthetic and cellulosic-based man-made fibers are generally “clean”, that is, free of trash and foreign materials (other than coarse fibers and winding residues). The majority of these materials can be removed by effective cleaning in the appropriate number of cleaning positions during the spinning preparation and carding operations. While rotor spinning machines effectively remove large trash particles and secondary fibers, dust and other smaller secondary materials can reach the rotor with the airflow and accumulate in the rotor groove. Therefore, clean raw materials are a prerequisite in rotor spinning.

Since fiber length does not appear as a dominant fiber character in rotor spinning, it is possible to use recycled fibers in rotor spinning to a significant extent. Because, during the reopening processes of recycled fibers, the fiber length becomes shorter, it becomes uneven and the rate of short fibers increases. While there is no significant fiber strength reduction at this time, the fibers are in a clean state since they have been pre-cleaned and reprocessed. Thus, there is a positive connection between the recycled fibers and the rotor spinning system. Especially in the production of coarse and thick yarns, shorter and therefore cheaper recycled cotton fibers can be used. Short to medium length cotton and cotton waste with a high short fiber content (< 1˝/25.4 mm) can be successfully spun using the rotor spinning principle. Yarns from short fibers should generally be spun at high twist coefficients. However, physical textile properties such as strength and unevenness of the yarns obtained from short fibers play a lower role in the final products, for example, in the fluffy linen fabrics, where the presence of a large number of fibers has positive effects on the piling effect.

Recycled material or fiber waste from woven and knitted material can be used in rotor spinning machines as they are particularly suitable for this application. However, the absolute prerequisite for the successful spinning of these low-cost raw materials is that these materials are opened up to a single fiber. Different machines from different manufacturers are suitable for this process. Separation takes place in several stages, starting with the cutting and tearing of fabric or yarn residues. If this process is not taken care of, the smallest fabric or yarn residue will cause breaks when it reaches the rotor. In the case of very coarse yarns, fabric or yarn residues do not cause breaks, but they can be incorporated into the yarn and inevitably show up as thick places in the yarn. However, it should be noted that yarn quality decreases with shortening in fiber length, and this particularly affects yarn strength and the number of common defects (thin places, thick places and neps). Therefore, yarns from cotton waste must be produced for use in certain application areas.