4.0. Determination of suitable traveller for definite yarn count: A comparative

https://doi.org/10.30574/gjeta.2021.9.1.0137 Abstract The traveller imparts twist to the yarn and enables winding of the yarn on the cop. Yarn quality parameters can be improved by proper traveller weight selection which results in reducing yarn breakage, mass variation, twist variation and hairiness. High contact pressure (up to 35N/mm) is generated between the ring travellers during winding, mainly due to centrifugal force the pressure includes strong frictional forces which in turn lead to significant generation of heat. This is the kernel of the ring/ traveller problem. The low mass of the traveller does not permit dissipation of the generated heat in the short time available. Uster Evenness Tester 5 was used to determine the yarn properties such as unevenness, percentage, imperfection index, hairiness, standard variation of hairiness. Traveller number 5/0 was the best for card 30 Ne compare between traveller number 4/0 Most preeminence fact is that, the traveller speed remained same both for 5/0 and


Introduction
If we analyze the overall spinning process, we can see that count of yarn and traveller both has preeminence on spinning process. Yarn count is a number that represents the diameter of fineness [1] of yarn.Traveller is mainly used to impart twisting, winding, thread guide etc. At this experiment, as speed is important factor. When machine run at maximum speed, traveller has higher tendency to wear out. However, as long as end breakage does not occur unevenly there is a strong tendency to keep the speed of spinning up & replace traveller to maximum speed. Light weight travellers are recommended for spinning the fine yarn and heavier weight traveller for coarser yarn spinning.

Objectives
The objectives of this paper are to discuss process control activities related to the use of ring frame machine. Process control is primarily aimed at controlling machine or process parameter such as types of ring traveller, speed of ring traveller, specification of ring traveller, notation of ring traveller.The process control activities related to the use of the ring frame are discussed in detail in the following sections.

Background Study
The ring spinning machine was first invented in 1828 by the American Thorp. In 1830, another American scientiest, Jenk, contributed the traveller rotating on the ring [2].There have been many development has done in ring spinning machine for the last years but the basic concept remained unchanged. The Traveller are normally three types, they are: OS -Type, C-Type, G-Type

Various Parts of Ring Traveller
Toe gap: This will vary according to traveller number and flange width of the ring.
Height of bow: It should be as low as possible for stable running of traveller. It should also have sufficient yarn passage.

Ring contact area:
This area should be more, uniform, smooth and continuous for best performance.
Inner width: This varies according to traveller profile and ring flange.
Wire section: It plays an important role for yarn quality, life of traveller.
Yarn passage: According to count spun the traveler profile to be selected with required yarn passage.

Traveller Speed
The speed by which the traveller moves around the ring = Π DR NT m/min  Since traveller does not have a drive on its own but is dragged along behind by the spindle. High contact pressure (up to 35 N/ mm2) is generated between the ring and the traveller during winding, mainly due to centrifugal force.  This pressure leads to generation of heat. Heat produced when by the ring traveller is around 300 degree celcius. This has to be dissipated in milliseconds by traveller into the air.  Low mass of the traveller does not permit dissipation of the generated heat in the short time available. As a result the operating speed of the traveller is limited.  The maximum attainable speed of traveller without getting damaged is known as "Limiting Speed of Traveller".

Limitations of Ring -Traveller Spinning System
 When the spindle speed is increased, the friction work between ring and traveller increases as the 3rd power of the spindle rpm. Consequently if the spindle speed is too high, the traveller sustains thermal damage and fails. This speed restriction is felt particularly when spinning cotton yarns of relatively high strength. [4]  If the traveller speed is raised beyond normal levels, the thermal stress limit of the traveller is exceeded; a drastic change in the wear behavior of the ring and traveller ensues. Owing to the strongly increased adhesion forces between ring and traveller, welding takes place between the two. These seizures inflict massive damage not only to the traveller but to the ring as well. The traveller temperature reaches 400 o C to 500 o C and the danger of the traveller annealing and failing is very great.
All together restricts spindle speed, thereby production of ring frame.

Traveller Count
 It represents weight of ten equal type of travellers in grains.  OLD System: 10 travellers weigh 10 grains then traveller count = 1  ISO System: Weight of traveller in mgm OR Weight of similar 1000 travellers in gm.  10 travellers weigh <10 grains then traveller is said to be the "Ought traveller" or "Nought traveller". Denoted by N/0; where N represents traveller count.
 Higher the count heavier the traveller

Notation of Traveller
A traveller can be notified as follows- Here,

Traveller Number or size of Traveller:
Here, if the weight of 10 travellers is 10 grains then the number of those traveller is 1and so on.

Factors Considered for Selection of a Traveller
 Yarn count: Higher the yarn count, lower will be the traveler weight.  Spindle Speed: If the spindle speed is high, then the yarn tension will be high. So lighter traveler should be used to minimize tension.  Ring dia: For same spindle speed and count, with the increase of ring diameter yarn tension as well as frictional area increases. So traveler should be lighter.  Empty bobbin dia: When empty bobbin dia decreases, winding angle decreases resulting a higher yarn tension. So a light traveler should be used.  Lift of bobbin: If the lift of bobbin increases yarn tension will be higher. So traveler weight should be less.
 Cross section of traveler: We know, if frictional area increases, lighter traveler should be light.
For flat frictional area increases, traveler weight decreases.
For semicircular, frictional area decreases, traveler weight increases.
For circular, frictional area decreases, traveler weight increases

Testing of samples
USTER TESTER -6 was used to determine the unevenness and imperfection (IPI) of the yarn at a speed upto 800 m/min. The observed parameters were U%, CVm%, thin places (-50%), thick places (+50%), neps (+200%) and hairiness. The imperfection (IPI) is the sum of number of mass increase (thick place), mass reduction (thin place) and short mass increase (neps). Tensile properties viz., yarn tenacity, count strength product (CSP) and elongation (%) were measured at Uster Tensojet-4 at a speed of 200 m/min. Average of ten tests were taken for final result at each trial. Lea strength tester was used to find the lea strength tester. Count strength product (CSP) was calculated by multiplying the yarn count with Lea strength according to the British Standard (1985). Equation 1 was used to measure CSP. [2][3][4][5][6][7][8][9][10][11][12] CSP = Yarn count × Lea strength Conditioning time should be at least 48 hours or until their moisture content reaches equilibrium with that of the laboratory atmosphere. All experiments were performed at temperature 27 ± 1°C and relative humidity 65 ± 2%. Yarn imperfection is the summation of thin place, thick place and neps per kilometer of yarn.

Ring spinning frame
Spinning is the final step of yearn manufacturing process. The working procedure of ring spinning frame is taking the roving comes from simplex and produced yarn by reducing the weight of unit length. Ring is attached around bobbin. The traveler rolling on ring and enfold the yarn on bobbin. Ring spinning frame plays the vital role to spinning the yarn so it is called Ring spinning frame.

Yarn Unevenness (U %)
Spinning method has significant effect on the yarn evenness. Unevenness is an important statistical tool, for the measurement of evenness properties of carded yarn [13]. The lower the U % value, the more even is the yarn and the more even it will look in the product. Figure-6 shows the unevenness (U %) value of 30Ne carded yarn Here, if we compare the value of yarn unevenness (U %) between 5/0 & 4/0 traveller, then we can see that U% value of 5/0 traveller comparatively lower than 4/0 traveller. So, according to these value we found that 5/0 traveller is more suitable for 30 Ne carded yarn.

Yarn Irregularity (CVm %)
The measure of variation of yarn linear density or the variation of its mass per unit length is termed as yarn irregularity. Generally, yarn irregularity points out to the variation of yarn count along its length. Yarn irregularity is denoted by CV which means the co-efficient of variation [13]. It was formed that the higher the CV %, the higher the yarn irregularity. Yarn irregularities and unevenness work as a vital parameter of yarn. Irregularities is mainly caused by improper doubling, drafting, using more short length fiber than their particular length, drafting arrangement, roller, pressuring system etc. In this project using above parameter in processing we were able to get lower level of U % and CVm % value that greatly affect in achieving higher lea strength and C.S.P value of this 30Ne carded yarn. Figure-5 shows the CVm% value of 30Ne carded yarn. Here, if we compare the value of yarn irregularity (CVm%) between 5/0 & 4/0 traveller,then we can see that CVm% value of 5/0 traveller comparatively lower than 4/0 traveller. So, according to these value we found that 5/0 traveller is more suitable for 30 Ne carded yarn.

Yarn Imperfection (IPI)
Yarn imperfection is the summation of thin places (-50%) per kilometer, thick places (+50%) per kilometer, neps (+200%) per kilometer [14]. It is a good indicator of yarn quality that shows how this yarn will perform in the subsequent process such as weaving, knitting, dyeing and printing. Yarn imperfection is mainly caused by improper doubling and drafting, improper [15] drafting arrangement in draw frame, simplex and ring frame, improper pressuring system, faulty T.M and TPI selection, incorrect spacer selection etc. Yarn imperfection is the main fault of yarn that directly affect in yarn strength, lusture properties. In this project we get very lower range of imperfection value which provide greater strength of final yarn and reduce end breakage rate in winding by controlling the process using above parameter. Figure-8 shows the imperfection value of this 30Ne carded yarn. Figure 11 yarn Imperfection (IPI)

Yarn Elongation
Elongation is specified as percentage of the starting length. The elastic elongation is of decisive importance since textile product without elasticity would hardly be useable. They must be able to deform and also return to shape. Higher the value of elongation higher the ability of yarn [14] to return to its previous shape. In this project we used such kind of parameter of different machines involve in manufacturing this 30Ne combed yarn that able us to get suitable value of Elongation (E %). Figure-9 shows the elongation (E %) of this 30Ne carded yarn.

Yarn Hairiness
Hairiness means the summation of the length of all projecting fibers in yarn body. One of the important factors for the comfortability of end product, especially apparels is hairiness [16]. Hairiness is mainly caused by using fibers which length is below than particular length or breaking the long fiber in processing (fiber growth). During this project we used comber machine which main object is removing noil (short length fiber) and by removing 18 %( approx.) We achieve appropriate hairiness index for this project yarn. Figure-10 shows the hairiness index value of this 30Ne carded yarn.

Yarn Strength
Tensile testing of yarns is used to determine the breaking force elongation and toughness, of the yarn. Breaking tenacity, a ratio of the breaking force to yarn. Controlling process by using above parameter we were able to keep imperfection, unevenness, irregularities, hairiness value in range that affect the tensile strength of the yarn. Figure-11 shows the tensile strength (Tenacity CN/tex) value of 30Ne carded yarn. C.S.P (Count Strength Product) is a number which is derived by multiplication of the yarn lea strength in lbs. and yarn count (cotton count system). The higher the value of C.S.P the better the yarn is. C.S.P is the main parameter that indicates the probable performance of the yarn. The main purpose of all works presenting in this project including raw materials selection, machine arrangement, settings, speed etc for controlling the project is to attain maximum level of C.S.P of this combed yarn. In this project we achieved desired level of C.S.P by ensuring homogeneous mixing and blending, removing neps, noil, dust, foreign particles, selecting proper parameters (draft, speed, pressure, drafting arrangement etc). Figure-12 shows the value of this 30Ne carded yarn.

Conclusion
It has been observed that the traveller 5/0 gave optimum hairiness, evenness, strength and elongation values for 30Ne card yarn compare with 4/0 traveller. For traveller 5/0 as well as 4/0 speed remain same.Then, we consider the overall yarn properties a comparative study can be done by using the different traveller number of specific against the same count yarn. If we want to use 4/0 traveller fo 30 Ne card we need to research on traveller mechanism, speed and wire profile.