Count is very important factor for the Textile Yarn Manufacturing. Maintaining the yarn count is mandatory to retain the quality of a yarn and fabrics According to the Textile Institute “Count is a number of indicating the mass per unit length or length per unit mass of yarn”.
There is several count system of yarn. These count systems have been divided in two ways. One is Direct System where length is fixed and another is Indirect system where weight is fixed.
Direct
System (Length Fixed):
A). Tex:
Weight
of yarn in gm present in 1000 meter length.
It is a universal system of counting the yarn.
B). Denier: Weight
of yarn in gm present in 9000 meter length. It is basically used for manmade fiber.C) Pounds Per Spindle: Weight of yarn in lbs present in 1440 yards length.
Indirect
System (Weight Fixed):
A). English Cotton Count:
No. of hanks of 840 yds present in 1 lb of yarn.B) Metric Count: No. of hanks of 1000 meters present in 1 kg of yarn.
C) Worsted count: No. of hanks of 560 yds present in 1 lb of Yarn. It is basically used for Wool.
D) Woolen Count: No. of hanks of 20 yds present in grain of Yarn.
Methods of Yarn Count:
ü Wrap
reel and balance method.
ü Quadrant
balance method.
ü Knowles
balance.
ü Beesleys
balance.
ü Sliver,
roving count by measuring drum.
ü Count
data system.
ü Auto
sorter by user.
Measurement of Yarn Count:
In a yarn structure, fibers represent the main component.
The other component is air pockets created by the technology forming the
structure. The knowledge of the real fibres volume within the yarn allows to
better estimate various textile fabrics properties. Yarn diameter is used to
predict fabric structural parameters such as width, cover factor, porosity, and
fabric comfort and so on. Since thousands of ends or picks are presented
side-by-side in the woven or the knit fabrics, a slight change in yarn diameter
can result in a substantial change in the overall fabric cover factor.
Measuring yarn diameter and compressibility and their effect on fabric quality
is important to both the fabric designer and the textile technologist. In fact,
the dimensional and mechanical characteristics of fabrics are dependent on yarn
diameter, thread spacing of warp and weft in woven fabrics, courses and Wales
per unit length and stitch length in knitted goods.
Many researchers studied the yarn diameter and they estimated it using empirical formula. One of the most commonly used expressions for estimating yarn diameter is that developed by Peirce in 1937 [7]. In this expression, yarn density was assumed to be 1.1 g/cm3. In a recent study, Elmo hazy et al in 1993 [5] developed empirical expressions for estimating the diameters of ring-spun, rotor-spun and MJS air-jet spun yarns. These expressions (Table 1) were developed by an extensive microscopic testing of actual yarn thickness for a wide range of yarn count and twist levels.
Measurement the rotor spun cotton yarn diameter using the image analysis method. The used yarns count range from 6 Ne to 20 Ne and they found that the actual yarn diameter can be predicted by using the formula shown in Table 1. The formulae shown in Table 1 indicate that yarns made by different spinning systems and of equal nominal count will exhibit different values of yarn diameter. This is a result of the difference in fibre arrangement and fibre compactness of different yarn types.
Many researchers studied the yarn diameter and they estimated it using empirical formula. One of the most commonly used expressions for estimating yarn diameter is that developed by Peirce in 1937 [7]. In this expression, yarn density was assumed to be 1.1 g/cm3. In a recent study, Elmo hazy et al in 1993 [5] developed empirical expressions for estimating the diameters of ring-spun, rotor-spun and MJS air-jet spun yarns. These expressions (Table 1) were developed by an extensive microscopic testing of actual yarn thickness for a wide range of yarn count and twist levels.
Measurement the rotor spun cotton yarn diameter using the image analysis method. The used yarns count range from 6 Ne to 20 Ne and they found that the actual yarn diameter can be predicted by using the formula shown in Table 1. The formulae shown in Table 1 indicate that yarns made by different spinning systems and of equal nominal count will exhibit different values of yarn diameter. This is a result of the difference in fibre arrangement and fibre compactness of different yarn types.
We should point out that the formula for ring spun yarn
developed by El Moghazy in 1993 [5] tends to produce a value of yarn
diameter that is slightly higher than that estimated by Peirce equation. The
main reason for the difference was due to discrepancy in the value of yarn
density, particularly in the course to medium range of yarn count. Using a
combination of capacitive and optical measures of different yarns, the density
of cotton ring-spun yarns can range from 0.85 to 1.2 g/cm3 depending
on the spinning process, fibre characteristics, and structural parameters
(count and twist).
The majority of the studies were interested in the determination of the apparent yarn diameter However, the knowledge of the real fibres volume within the yarn allows to determine the real yarn diameter. Thus, the real diameter is defined as the measurement of the yarn dimension without air. Indeed, the determination of the real diameter influences so much the fabric geometrical and mechanical properties. In this paper, the authors discuss the development of an experimental device allowing the determination of the real yarn diameter and study the effect of yarn and fibre properties on the yarn packing fraction.
The majority of the studies were interested in the determination of the apparent yarn diameter However, the knowledge of the real fibres volume within the yarn allows to determine the real yarn diameter. Thus, the real diameter is defined as the measurement of the yarn dimension without air. Indeed, the determination of the real diameter influences so much the fabric geometrical and mechanical properties. In this paper, the authors discuss the development of an experimental device allowing the determination of the real yarn diameter and study the effect of yarn and fibre properties on the yarn packing fraction.
The yarn sample undergoes a uniform tension while mounting
on the grips. The tension of 1 cN/ tex was applied to the yarn sample according
to the French Standard NF G07-079 [3] for removal of crimp. The first yarn
sample edge was fixed on one grip and they applied the pre-tension and they
fixed the second edge on the other grip. 500 mm test length yarn is maintained
right between the grips of the twist tester and subjected to twist increase (a
step of 50 turns). For each twist step, a yarn photo is captured and examined
by a Motic microscope with 40x magnification. For analysis of the yarn images,
"Image-Pro-Plus 2.0" software was used. The image analysis was
performed using the sequence: process, image, acquise, segmentation, processing
and measurement.
With regard to the external structure, the yarn can be divided into two basic elements: the yarn core and hairiness. The core is defined as a part of the yarn that forms a compact agglomeration of fibres. It has a cylindrical form and a variable diameter. On its surface the fibres are laid along the curves characterising the twist. The rest of the yarn, consisting outlying fibres or their agglomerations, constitutes hairiness. So the yarn diameter can evaluated by determined the edges of the yarn core. For determination of them, the images were processed (Figure 2) and the yarn diameter was measured.
Average of 10 measurements were taken in 10 different positions throughout the yarn length. The initial study of variation it was decided to take 100 readings. So the average of yarn diameter was calculated by the following equation [1].
With regard to the external structure, the yarn can be divided into two basic elements: the yarn core and hairiness. The core is defined as a part of the yarn that forms a compact agglomeration of fibres. It has a cylindrical form and a variable diameter. On its surface the fibres are laid along the curves characterising the twist. The rest of the yarn, consisting outlying fibres or their agglomerations, constitutes hairiness. So the yarn diameter can evaluated by determined the edges of the yarn core. For determination of them, the images were processed (Figure 2) and the yarn diameter was measured.
Average of 10 measurements were taken in 10 different positions throughout the yarn length. The initial study of variation it was decided to take 100 readings. So the average of yarn diameter was calculated by the following equation [1].
(1)
where: `d : average diameter in mm Li : diameter of yarn
at position i in mm
A statistical study was carried out in order to determine the more influent parameters on yarn packing fraction. This study allowed us, using Principal Components Analysis (PCA) [2] and contribution analysis (Path method) [4], to limit the number of factors. The principal component analysis (PCA) is an extraction method of the principal factors based on a quantitative analysis of the correlations [2]. Its goal is to study and to reduce the survey space of variables in order to simplify the raw data, to find out (graphically) some links and to identify some macro features (principal components). This method consists on subjective grouping of the correlated variables, which were represented graphically by the coordinates corresponding to two centred and reduced principal variables.
A statistical study was carried out in order to determine the more influent parameters on yarn packing fraction. This study allowed us, using Principal Components Analysis (PCA) [2] and contribution analysis (Path method) [4], to limit the number of factors. The principal component analysis (PCA) is an extraction method of the principal factors based on a quantitative analysis of the correlations [2]. Its goal is to study and to reduce the survey space of variables in order to simplify the raw data, to find out (graphically) some links and to identify some macro features (principal components). This method consists on subjective grouping of the correlated variables, which were represented graphically by the coordinates corresponding to two centred and reduced principal variables.
Wrap reel and balance method is one of the methods of yarn count, so it must need a sophisticated yarn wrap reel .
ReplyDeleteThe machine looks nice, and I want to exchange the information about Yarn Count Tester since I have been interested in it for a long time.
ReplyDeleteThanks. Where can I get more information about yarn count?
ReplyDeleteThanks for your sharing. Yarn Wrap Reel is a needed tester.
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ReplyDelete