New Spinning

System

Hafeezullah Memon

ZSTU, Hangzhou, China

Rotor Spinning:

The productivity limitation of the ring spinning system was recognized long before the commercial introduction of rotor spinning in 1967. In ring spinning, the twist insertion rate is dependent on the rotational speed of

the yarn package. This is so because of the continuity of the fiber flow during spinning. Numerous attempts have been made since before the end of the 19th century, particularly since the 1950s, to introduce a break into the fiber flow so that only the yarn end needs to be rotated to insert twist. Very high twisting speeds can thus be achieved. In addition, by separating twisting from package winding, there will be much more flexibility in the form and size of the yarn package built on the spinning machine. This increases the efficiency of both the spinning machine and of subsequent processes. Rotor spinning was the first such new technology to become commercially successful and it is the second most widely used yarn production method after ring spinning.

Developments in rotor spinning include the use of longer machines. Additionally, there is interest in potentially using rotor technology to produce core yarns and using additional components to create effect yarns. The rotor spinning machine is unlike any other machine in the short staple spinning mill in the range of tasks it has to perform, namely all the basic operations:

Sliver feed: A card or drawframe sliver is fed through a sliver guide via a feed roller and feed table to a rapidly rotating opening roller.

Sliver opening: The rotating teeth of the opening roller comb out the individual fibers from the sliver clamped between feed table and feed roller. After leaving the rotating opening roller, the fibers are fed to the fiber channel.

Fiber transport to the rotor: Centrifugal forces and a vacuum in the rotor housing because the fibers to disengage at a certain point from the opening roller and to move via the fiber channel to the inside wall of the rotor.

Fiber collection in the rotor groove: The centrifugal forces in the rapidly rotating rotor cause the fibers to move from the conical rotor wall toward the rotor groove and be collected there to form a fiber ring.

Yarn formation: When a spun yarn end emerges from the draw-off nozzle into the rotor groove, it receives twist from the rotation of the rotor outside the nozzle, which then continues in the yarn into the interior of the rotor. The yarn end rotates around its axis and continuously twists-in the fibers deposited in the rotor groove, assisted by the nozzle, which acts as a twist retaining element.

Yarn take-off, winding: The yarn formed in the rotor is continuously taken off by the delivery shaft and the pressure roller through the nozzle and the draw-off tube and wound onto a cross-wound package. Between

takeoff and package, several sensors control yarn movement as well as the quality of the yarn and initiate yarn clearing if any pre-selected values are exceeded.

Advantages of Rotor Spinning:

Lower labor cost Less power consumption Larger the package size Cheaper raw material Less floor space Easy handling Elimination of roving, so no need speed frame machine Higher productivity, as higher speed

Limitation:

Wide range of count cannot be spun More bulky yarn Higher twist factor Very finer count cannot be spun

Friction spinning

Friction spinning is an open end spinning technique. Instead of using a rotor, two friction rollers are used to collect the opened-up fibers and twist them into the yarn.

Fig. 1: Friction spinning

The fibers are fed in sliver form and opened by a carding roller. The opened fibers are blown off the carding roller by an air current and transported to the nip area of two perforated friction drums. The fibers are

drawn onto the surfaces of the friction drums by air suction. The two friction drums rotate in the same direction and because of the friction between the fiber strand and the two drum surfaces, twist is inserted into the fiber strand. The yarn is withdrawn in the direction parallel to the friction drum axis and delivered to a package forming unit.

Electrostatic spinning:

Several research teams, including some in the former Soviet Union, have investigated the possibilities of forming fiber strands with the aid of electrostatic fields. However, only the process proposed by the Battelle Institute has had a degree of success. The Electrospin Corporation (USA) demonstrated an experimental spinning machine based on this principle at the 1971 ITMA in Paris.

However, little has been heard about electrostatic spinning since then. In the process based on the Battelle principle (Fig. 2), a roving (2) taken from the roving frame is passed to a conventional double-apron drafting arrangement (3) and is subjected to a draft of up to 80-fold. The fibers exit freely from the front cylinder. They must then be collected to form a fiber strand and twisted to form a yarn. The first of these operations is performed by the electrostatic field, and twisting is carried out in a twist-imparting unit (6). Twisting presents no problems. The complexity of this method lies wholly in the electrostatic field generated between the front roller and the twist element (6) by earthling the front roller and applying a high voltage (about 30 000 - 35 000 V) to the twist element. This field has to accelerate the fibers and guide them toward yarn end (5) while maintaining the elongated configuration of the fibers. When the fibers enter this field, they take up charge and form dipoles, i.e. one end becomes positively charged and the other negatively charged. An open yarn end (5) projects from the twist element into the field. This yarn is negatively charged and is therefore always attracted to the front roller.

Fig. 2: Electrostatic spinning

Due to the dipole pattern, there is thus a relatively high degree of fiber straightening between the front roller and the twist element. Fibers leaving the roller are accelerated and attracted to the yarn as a result of the charges carried by the two parts. They join continuously to the yarn. Since the yarn rotates, the fibers are bound in. A yarn is formed continuously and is withdrawn by withdrawal rollers (8), to be passed to a take-up device (9) for winding onto a crosswound package.

The problem associated with this process is the formation of a yarn in an electrostatic field, as follows:

Charging of the fibers, and hence their behavior in the spinning zone, is dependent upon air humidity. Accordingly, for each fiber type, a specific and highly uniform environment must be created. The machine may need to be air-conditioned.

The charge on each fiber, and hence its movement, is dependent upon its mass. Short fibers with low mass will therefore behave differently from long fibers.

A limit must be placed upon the number of fibers in the electrostatic field, because otherwise they will cause mutual disturbance when charging and dipole formation takes place. Only fine yarns can therefore be produced.

The same effect is observed with high throughput speeds; there is a corresponding limit on the production rate.

Due to these problems, electrostatic spinning has no chance of being used in spinning mills.

Rotor Spinning Machines

Name/Model Number Manufacturer Place of origin

R 35, R 40, R 60, etc Rieter Switzerland

Autocoro 8, BD 6, BD

448, Belcoro, Autocoro

312, Autocoro 360, etc

SchlafhorstGermany, India

and China

Rotor Spinning Frame

(FA506)Jiangsu Textile Machinery Jiangsu, China

RS30A Rotor Spinning

Machine

Zhejiang Rifa Textile

Machinery Co., LtdZhejiang, China

CHENGLIJIACHENGLIJIA Rotor spinning

machineQingdao, China

Friction Spinning Machines

Name/Model Number Manufacturer Place of origin

DREF 2, DREF 3, DREF

2000, DREF 3000Fehrer Austria and U.S.

MTC- 61224 Machco Tex Shanghai, China

FS2800 Stewarts of America Inc U.S.

TD-IITONGDA Friction Spinning

MachineShandong, China

Electrostatic Spinning Machine

Name/Model Number Manufacturer Place of origin

ERTOEL Stewarts of America IncMelbourne,

Australia.

The textile industry of Pakistan has over 140,000 installed rotor spinning positions. Almost all the machines that were installed during the past seven years bear the name of Autocoro. As in the other countries of the

world, Autocoro yarns also in Pakistan are synonymous with high quality and economic efficiency, both in spinning and in the subsequent textile production processes.

As in the past, the Autocoro yarns produced in Pakistan today are predominantly used for denim. Nevertheless, the demand for Autocoro yarns for single jersey for T-shirts and underwear as well as for coarse knitted goods of fiber-blend yarns for leisure wear is on the rise. The great potentials for rotor yarns in the fields of medium-fine yarns, for instance for terry articles, and of fine-count yarns attract growing interest. It can safely be assumed that with the broad range of applications and the high economic efficiency of the rotor yarns, the growth of the installed basis of Schlafhorst rotor spinning machines in Pakistan will continue.

The new automatic rotor spinning machine Autocoro 360 is the answer of Schlafhorst, the Germany-based subsidiary of Saurer, to the ever more exacting demands of the market on machine flexibility and productivity. With its up to 360 spinning positions, its one, two, three or four Coromat units and take-up speeds up to 300 m/min, the Autocoro 360 is the longest and most productive rotor spinning machine offered to spinners in the world market. The machine can be fitted and supplied with a fancy yarn spinning system, named Fancy nation. The integration of the hardware components ensures highest efficiency in the production of effect yarns. The software for designing and programming effect yarns on a Laptop, specifically developed for the Autocoro 360, ensures high process reliability, reproducibility and simple handling and operation. The new Corobox SE 12 spinbox implements a novel drive concept for the sliver intake, the SDSI Single Drive Sliver Intake. Higher economic efficiency is guaranteed by the new CoroPack yarn packages weighing up to 5 kg. The Autocoro 360 is equally suited for the production of coarse yarns and of fine yarns for weaving and knitting. It can spin yarns flexibly from a wide variety of raw materials. Optimum spinning results are guaranteed in spinning yarns from cotton, even of very irregular quality, and from manmade fibers - the global growth market of the future. In the semi-automatic rotor spinning machine sector, the new types BD 330 and BD 350Fancynation have been added to the mill-proven types BD 320 and BD 321.

Highlights of the new machine types are the features: EVA Electronic Vacuum Adjustment for the electronic regulation of the spinning vacuum, Joint Spinning-in JSI for automatic start of spinning at the start of the machine, and the new sliver-intake control in the spinbox. In addition to these features, the BD 350 Fancy nation has an integrated effect-yarn spinning system. All BD-type machines spin yarns with rotor speeds up to

100,000 rpm and yarn take-up speeds up to 170 m/min. With their high levels of productivity and reliability, all the machines of the BD series stand out clearly from manual and other semi-automatic rotor spinning machines.

Here are some famous industries that offer Open End Spinning in Pakistan.

Wizi Industries (Pvt) Ltd (Wazir Group) Hamid Textile Mills Ltd Chaudhary Brothers Am Spinning & Weaving Mills Limited Seher Spinning Mills Ltd Pacific Textile Co. Ltd Pakistan M/S Skytex Skytex-Pakistan Karachi Pioneer Textile Mills Imtiaz Textile Mills Athish Cotton Mills Habib Sugar Mills Textile Division Sharmeen Pakistan (Pvt) Ltd

Rotor Spinning can produce natural fibers and synthetics fibers, but is unable to produce glass fibers or those fibers that may be harsh in feel, as they may deterirate the groove of the rotor.

Friction spinning can produce large variety of fibers, such as

Natural fibers Synthetics fibers Specialty fibers Aramid fibers Polyamide fibers Glass fibers Secondary recycled fibers Hybrid fibers

This is because the yarns are manufactured due to force imparted by the rollers rather than any other mechanism.

Electrostatic Spinning can produce the fiber of limited mass; higher mass may be serious problem for electrostatic spinning. Moreover, highly hydrophilic fibers cannot be produced by this spinning method. This is due to electric charge applied onto the fiber during spinning.