Factors and Productivity in Rotor Yarn Spinning Process
Chinmoy Das Mithun, Md Anas Imam, Rifat Bin Sattar, Md Tanvir Rahman Dept. of Yarn Manufacturing Engineering
Shahid Abdur Rab Serniabat Textile Engineering College, Barishal
(Affiliated by Bangladesh University of Textiles)
Email: akash.adnan0900@gmail.com
Introduction: The low productivity and high production cost of ring spinning have forced machine manufacturers and technologists to look for other methods of yarn manufacturing. Rotor spinning is a complete solution to the problem. During the past 40 years, rotor spinning has established itself as an effective and important yarn manufacturing process. Rotor spinning overcomes all the problems of ring spinning by separating twisting and winding in the yarn manufacturing process. The production rate of rotor spinning is six to eight times higher than that of ring spinning. With rotor yarn spinning process, multiple different raw materials can be processed (cotton, wool under special conditions, flax as additive, chemical fibers, for example, viscose, polyacrylonitrile, polyester), and very different yarns can be produced. For different material and different characteristics of yarn, the spinning elements, such as opening cylinder, rotor, and pull-off nozzle, have to be adjusted in shape and material. In spinning practice, a large number of spinning components are available on the market.
Rotor Yarn in Spinning: In textile spinning sector, open ended spinning or break spinning is considered as rotor spinning. Here, total process flow chart is less than combed yarn as well as carded yarn. One important point should be pointed out here that, roving formation in simplex machine is not needed in rotor spinning where drawn slivers are fed to the machine directly.
Medium to low quality yarns are produced here which are used for making dungaree, denim, chino, and twill as well as any heavy fabric. Production rate of open-end rotor spinning is higher than ring spinning process where coarse yarns are made within a range of 5 to 40 cotton count. Rotor spinning is too much popular in use because of the higher production rate and less wastage percentage as well as highly usable in denim to make blue jeans.
In rotor yarn spinning process, a minimum of 70 to 100 fibers in the yarn cross section is necessary. Because of this process-inherent restriction, rotor yarns cannot be spun as fine as ring yarns (minimum of 50 to 70 fibers per cross section). The tenacity of rotor yarns is lower than that of comparable ring yarns. Rotor spinning is much more economical than ring spinning, however, because the flyer spinning process is omitted. Rotor spinning is fully automated and delivers cross-wound bobbins ready for further processing without any additional winding step.
Fig: Rotor yarn spinning process
Properties of Rotor Yarn: Important properties of rotor yarn have mentioned in the below:
Less amount of power needed during rotor yarn manufacturing.
Stiffness is higher in rotor yarn.
Breaking strength is lower in rotor yarn.
Mass irregularity is better here.
Co-efficient of variation (CV %) of strength is higher here.
It has higher abrasion resistance.
Possibility of producing rotor yarn count ranges from 3 to 60Ne.
Energy consumption with productivity is lower in case of rotor yarn production. Volume is greater here than ring spinning.
Why Rotor is Called Open End Yarn? Rotor Spinning is a more recent method of yarn formation compared to Ring Spinning. This is a form of open-end spinning where the twist is introduced into the yarn without the need for package rotation. The fiber layer is stripped off the rotor groove and the resultant yarn wound onto a package. This is possible because it combines three manufacturing processes Speed frame, Ring frame and Winding – into one single step. So it is called open-end yarn.
Fig: Rotor yarn
Raw Materials Used In Rotor Yarn Spinning:
Short staple spinning m/c (up to 60 mm fiber length) require
Principles of Rotor Yarn Spinning Process: Rotor Spinning is a more recent method of yarn formation compared to Ring Spinning. This is a form of open-end spinning where the twist is introduced into the yarn without the need for package rotation. Allowing for higher twisting speeds with a relatively low power cost.
In rotor spinning a continuous supply of fibers is delivered from delivery rollers off a drafting system or from an opening unit. The feed for rotor spinning is card, drawn, or combed sliver.
The fibers are sucked down a delivery tube and deposited in the groove of the rotor as a continuous ring of fiber. The fiber layer is stripped off the rotor groove and the resultant yarn wound onto a package. The twist in the yarn being determined by the ratio of the rotational speed of the rotor and the linear speed of the yarn.
Fig: Open end rotor spinning
Sliver is fed into the machine and combed and individualized by the opening roller. The fibers are then deposited into the rotor where air current and centrifugal force deposits them along the groove of the rotor where they are evenly distributed. The fibers are twisted together by the spinning action of the rotor, and the yarn is continuously drawn from the center of the rotor. The resultant yarn is cleared of any defects and wound onto packages.
The production rates of rotor spinning are 6-8 times higher than that of ring spinning and as the machines are fed directly by sliver and yarn is wound onto packages ready for use in fabric formation the yarn is a lot cheaper to produce.
Rotor spun yarns are more even, somewhat weaker and have a harsher feel than ring spun yarns. Rotor spun yarns are mainly produced in the medium count (30 Ne, 20 tex) to coarse count (10 Ne, 60 tex) range. End uses include denim, towels, blankets socks, t-shirts, shirts, and pants.
The use of this system has two basic advantages. It is fed by a sliver, not as with the ring frame by roving, and so eliminates the speed frame from the process line. It can also be modified to remove any remaining trash, there by improving the yarn quality.
Open-end spinning produces a different type of yarn to ring frame spinning. Open-end yarns tend to be more uniform, lower in strength, more extensible, bulkier, more abrasion resistant and more absorbent. It is likely that with all of these differences, only some of which are beneficial, that open-end spinning will not replace ring spun yarn as originally thought, but will be a complimentary product.
Open-end spinning operates at a rate up to five times that of ring spinning and can be effectively used for cotton, polyester-cotton blends, as well as other short and medium staple systems. Synthetic staple fibers such as polyester alone cannot be effectively open end spun due to a dusting of oligomer from the fibers that interfere with the spinning action of the rotor.
Lower power consumption per unit quantity of yarn produced
Higher speed of twist insertion resulting in very high yarn delivery speed
A significant resulting increase in productivity
Larger delivered package size
Elimination of some processes such as roving and winding more uniform yarns
Factors and Productivity in Rotor Yarn Spinning Process: This article showed that there are many factors by which we can improve productivity and quality of rotor yarn, but our emphasis was on one of the most important factor which yielded very important results. We focused on raw material staple length and machine efficiency. By using the same raw material with good staple length, we achieved better results in the form of high production and high profit. The other benefit is that due to increase in staple length, short fibers percentage also decreases and results in the form of less TPI and less yarn breakage. Breakage is one of the big factors due to which efficiency of department is disturbed. Productivity increases with a variation in a raw material staple length and machine efficiency is directly dependent on the staple length of a raw material. In the production of yarn we should keep many things in mind which can control and enhance the productivity and quality parameters. Productivity can be enhanced by restructuring each process or using fully automated machine. While producing yarn, quality of raw material or other parameters have their own importance. On the other hand, we should realize that without participation of each individual nothing can be done. So, companies should make the policies which are favorable and helpful to both managers and workers.
Skilled labour, automated machinery, raw material quality and energy issues have an impact on production of yarn. If any company has a grip in these issues then, that company can survive in this competitive market in a better way.
With the growth of production, the company earns more profit and can create more vacant positions for the new jobs to increase or install new machinery. For this they need more investment or capital and new labour will help in increasing the productivity and quality.
High profit or high investment in every business is the first preference, but in the textile sector the high profit with customer satisfaction is the key issue. Customers should be satisfied by the textile sector in order to retain a long term relationship with them. Customer’s trust must be kept on top priority by each and every company.
Conclusion:
Rotor spinning is the most wide system in the open-end yarn manufacturing industry. The productivity of this method is high in comparison to the ring-spinning method. It has brought revolutionary change in yarn manufacturing industry. Rotor spinning has its great advantages with regard to production rate, use of floor space, and labour. The economic advantages of rotor spinning very soon became evident and have increased in the course of its development with the result that its breakeven point has moved further in the direction of finer yarn counts.
References:
Mechanics of Rotor Spinning Machines by Ibrahim A. Elhawary
Textile Technology – An Introduction, 2nd Edition by Thomas Gries, Dieter Veit, Burkhard Wulfhorst
Textile Engineering – An Introduction Edited by Yasir Nawab
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
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