diametric unevenness and fault classification of yarn...

2018

ISSN 1229-9197 (print version)

ISSN 1875-0052 (electronic version)

Fibers and Polymers 2017, Vol.18, No.10, 2018-2033

Diametric Unevenness and Fault Classification of Yarn Using Newly Developed

Diametric Fault System

V. K. Yadav1*, S. M. Ishtiaque

1, S. D. Joshi

2, and J. K. Chatterjee

2

1Department of Textile Technology, Indian Institute of Technology Delhi, New Delhi 110016, India

2Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India

(Received April 8, 2017; Revised August 12, 2017; Accepted August 16, 2017)

Abstract: The work presents the applicability of the developed Diametric Faults system through industrial trail to understandthe influence of different yarn spinning systems, yarn fineness and opening & cleaning system on yarn diametric unevennessand yarn faults. The Diametric Faults system measures the diametric yarn unevenness and classifies the faults of yarn basedon their geometric dimensions. Detailed analysis of the yarn fault classes with additional information related to added volumeon faults, fault length and frequency of yarn faults for different classes of yarn fault is also possible. The developed systemcombines the measurement of yarn imperfections and fault classification as one system. The Diametric Faults system provesto be an alternative practical solution to measure the yarn irregularity in terms of diametric unevenness along the yarn length,instead of existing most popular approach considering the variation in mass per unit length. Further, it is established that theresults obtained from the proposed system, are also confirming the expected trends noticed with considered variances in astandard manufacturing process.

Keywords: Classification of yarn fault, Diametric unevenness, Yarn diameter, Yarn fault characterisation

Introduction

The characterisation of yarn faults based on their con-

figuration opens the opportunity for developing a scheme for

classification and measurement techniques. It has been

established that faults having different configurations can be

differentiated on the basis of their configuration [1]. One of

the main objective of the staple fibre spinners is to regulate

the orientation of hundreds of fibres, having varying

properties, into a yarn of required mass uniformity per unit

length of yarn [2]. Therefore, it is high time to address the

measurement limitation of presently prevailing mass variation

concept along the yarn length [3,4]. Further, the yarn consists

of faults which deviate to quite a considerable extent to

intrinsic yarn diameter and length [5-9].

Unevenness has become synonymous with the mass

variation as obtained by the capacitance based measurements.

However, the basis for all fabric related calculations is the

yarn diameter which ultimately translates into the behaviour

as perceived by human eye. Hence it is important to measure

the diametric variation on continuous basis and obtain a

more realistic measure of the yarn diameter. Further, the

commercially used methods visualise the yarn cross-section

in a single projection view only. However, generally the

spun yarns cross-section is non-circular and approximates an

ellipse [10,11]. Hence it is usually desirable to evaluate two

orthogonal diameters of a yarn simultaneously to assess

diameter variations in both directions.

Accordingly, a Diametric Faults system is being developed

by the present authors and the system is capable of (a)

monitoring of yarn faults; (b) measurement of diametric

unevenness of yarn and yarn faults and; (c) classification of

yarn faults on the basis of their configurations [12]. The

Diametric Faults system measures dimensions of faults and

accordingly classifies the yarn faults on the basis of their

lengths and lateral sizes and provides a numerically based

objective and quantitative yarn fault classification system

[12]. The proposed system can generate yarn diameter as

well as cross-sectional area signals and can extract the yarn

faults based on the longitudinal and lateral size. It is further

observed that the dimensional characteristics of thick and

thin faults obtained from diameter and cross-sectional area

signals are identical [12]. However, the applicability of the

area signal is found to be better since the information about

the increase of volume of faulty region of the yarn are more

near to reality. Further, it also provides the yarn cross-

sectional eccentricity, a measure of yarn roundness, as estimated

using Horwitz’s approach [13]. Detailed analysis of the yarn

fault classes related to extra volume add-on, fault length and

frequency/location of faults along the yarn length is also

possible. The classification of faults in terms of cross

sectional size and length is comparable to the commercially

available yarn faults classification systems [12].

Present work reports the applicability of the proposed

system to study the influence of different spinning systems,

yarn fineness and opening & cleaning systems on yarn

characteristics in terms of diametric variation along the yarn

length.

Experimental

As the yarn samples to be spun were meant for yarn

diameter measurement, it was important to choose a material

which is not biased for any effect due to its fibre properties.*Corresponding author: [email protected]

DOI 10.1007/s12221-017-7337-y

Diametric Unevenness Using Diametric Fault System Fibers and Polymers 2017, Vol.18, No.10 2019

Hence, it was decided to use cotton fibre, which inherently

include adequate amount of fibre property variation in

respect to length, fineness etc. For all the yarn samples,

uniform yarn tension of 0.3±0.1 g/tex was used during the

measurement. Yarn cross-sectional eccentricity, e, is derived

using the expression , where a and b are the

length of semi-major and semi-minor axis of ellipse

respectively, and estimated using Horwitz’s approach [13].

Eccentricity indicates the flatness and is considered

as a measure of roundness [14].

Table 1 gives the fibre properties of used cotton. Following

three industrial trails are carried out to establish the

applicability of the Diametric Faults system.

1) Influence of two different spinning systems: Ring and

Compact

2) Influence of two different makes of opening and

carding (O&C) system: O&C1 and O&C2

3) Influence of yarn fineness: 24.6 tex and 14.7 tex on

compact spinning system

The process sequences of samples preparation are given in

Figure 1.

Results and Discussion

All four yarns with the proposed combinations, as described

in Figure 1, were tested on the newly developed Diametric

Faults system and these yarns were also evaluated on

commercially available system for comparison.

Comparison of Compact and Ring Yarn

This study deals with the comparison of ring and compact

yarn of 24.6 tex, produced on both the systems.

Yarn Diameter and Yarn Diametric Unevenness (CVd%)

The results of yarn diameter and diametric unevenness

(CVd%) are given in Table 2(a). It is observed that compact

yarn gives lower diameter as well as lower yarn diametric

unevenness (CVd%) than corresponding ring yarn.

Yarn Cross-sectional Area and Yarn Cross-sectional

Area Unevenness (CVca%)

The yarn cross-sectional area variation curves using cross-

sectional area signal are given in Figures 2 and 3 and the

results are tabulated in Table 2. The results confirm that

mean cross-sectional area of compact yarn is lower than

corresponding ring yarn. Further, it is noticed that the

maximum and minimum range of cross-sectional area in

case of compact yarn is higher than corresponding ring yarn.

It is also depicted from Table 2(b) that cross-sectional area

unevenness (CVca%) value of compact yarn is found to be

lower than corresponding ring yarn. The lower CVca% of

compact yarn can be supported by the lesser number of thick

and thin faults than corresponding ring yarn. But it is

interesting to note that eccentricity value of compact yarn is

a2

b2–( )/a2

1 e2–

Table 1. Properties of the cotton used

Fibre properties Values

Micronair (inch) 4.06

Length (UHML) (mm) 29.34

Strength (gm/tex) 30.68

Trash content (%) 3.67

Total (Neps/gm) 112

Figure 1. Process sequence of sample preparation.

Figure 2. Yarn cross-section area profile of 24.6 tex combed compact yarn.

2020 Fibers and Polymers 2017, Vol.18, No.10 V. K. Yadav et al.

found to be lesser than corresponding ring yarn. The obtained

eccentricity value clearly indicates that compact yarn is more

circular than corresponding ring yarn.

The results of diameter profiles of 24.6 tex compact and

corresponding ring yarns of 200 m yarn length are given in

Figures 2 and 3. It is depicted that CVca(m)% and

CVca(mm)% for compact yarn are found to be lower than

corresponding ring yarn. The results of variance-length

given in Table 3 and variance-length curve given in Figure 4

clearly depict that CVca% of compact yarn, at different

reference length, is always lower than corresponding ring

yarn. The lower CVca% of compact yarn can be supported by

the lesser number of thick and thin faults than corresponding

ring yarn.

The results of CVca% at different considered sections of

the yarn are given in Figures 5 and 6. It is further noticed

Figure 3. Yarn cross-section area profile of 24.6 tex combed ring O&C1 yarn.

Table 2. Yarn cross-sectional area and yarn diameter characteristics

(a) Yarn diametric characteristics

SampleIntrinsic yarn Dia

(mm)

Mean Dia

(mm)

Dia standard

deviation (mm)

CV of yarn Dia

CVd%

Max Dia

(mm)

Min Dia

(mm)

24.6 tex Combed Compact 0.206 0.263 0.029 10.95 0.605 0.181

24.6 tex Combed Ring O&C1 0.219 0.291 0.034 11.81 0.541 0.176

24.6 tex Combed Ring O&C2 0.233 0.294 0.033 11.11 0.53 0.192

14.7 tex Combed Compact 0.153 0.194 0.021 11.13 0.386 0.124

(b) Yarn cross-sectional area characteristics

Sample

Intrinsic

cross-section

area (mm2)

Yarn cross-section area Yarn eccentricity, e

Mean

(mm2)

Standard

deviation (mm2)CVca%

Max

(mm2)

Min

(mm2)Mean

Standard

deviation

24.6 tex Combed Compact 0.0332 0.0576 0.0155 26.97 0.9859 0.0217 0.500 0.2295

24.6 tex Combed Ring O&C1 0.0378 0.0718 0.0195 27.13 0.2868 0.0043 0.520 0.2219

24.6 tex Combed Ring O&C2 0.0427 0.0731 0.0185 25.35 0.2684 0.0212 0.508 0.2223

14.7 tex Combed Compact 0.0183 0.0319 0.0081 27.48 0.1437 0.0051 0.506 0.2446

Table 3. Variance-Length analysis based on area signal

Reference

length

(mm)

24.6 tex

Combed

Compact

24.6 tex

Combed

Ring O&C1

24.6 tex

Combed

Ring O&C2

14.7 tex

Combed

Compact

1 31.01 38.30 36.80 34.06

10 20.92 23.98 22.89 22.40

50 11.76 12.18 11.37 11.98

100 9.31 9.46 8.84 9.19

250 6.53 7.14 6.51 6.32

500 5.17 6.10 5.45 5.03

1000 4.18 5.30 4.84 3.99

2000 3.41 4.81 4.35 3.06

3000 3.06 4.60 4.16 2.74

4000 2.84 4.45 3.95 2.49

Note: Variance values are percentage coefficient of variation (CV%).


that mean cross-section area and CVca(mm)% are found to

be lower for compact yarn than corresponding ring yarn.

The compact spinning system, used for present experimental

purposes, condenses the fibre ribbon coming out of drafting

system by means of pneumatic compaction with the help of

a perforated roller. The fibre condensation happens after

drafting but before the yarn twisting by generating aerodynamic

forces. Therefore, the width of the fibre ribbon reaching the

spinning triangle is very small which makes possible that all

the fibres are perfectly caught by the spinning triangle [15].

The fibre ribbon emerging from the nip of the first top roller

get influenced by the aerodynamic forces developed by the

vacuum inside the perforated drum. These forces guide the

fibres to the nip of the second top delivery roller. The drafted

ribbon of fibres finally gets compacted laterally by means of

aerodynamic forces. The above-mentioned process is mainly

responsible for reduction of yarn diameter in comparison to

corresponding ring yarn.

Further, the compacting of the fibre ribbon takes place on

the surface of the perforated metal drum which has a high-

quality surface finish. The coefficient of friction between the

surface of the drum and fibres moving on drum is very low.

Figure 4. Variance-Length (V-L) curve of area signal.

Figure 5. Sections wise profile of 24.6 tex combed compact yarn.


This facilitates the lateral shifting of the compacted fibre

ribbon. Thus, fibre ribbon structure delivered by the nip of

the delivery roller forms a very small spinning triangle

which makes possible that all the fibres are perfectly

embedded in the fibre ribbon and caught by the spinning

triangle. Because of this pneumatic compaction, it reduces

the yarn cross-sectional area, makes yarn more circular and

improves the CVca% in comparison to the corresponding

ring yarn [15,16].

Classification of Yarn Faults

A comparative study of compact and ring spinning system

is carried out as per the process plan given in Figure 1. The

results of yarn faults, measured on proposed Diametric

Faults system using cross-sectional area and classified on the

basis of volume approach, of 24.5 tex compact and ring yarn

of 200 meter measured length are given in Tables 4 and 5. It

is noticed that compact yarn shows lesser number of total

faults than corresponding ring yarn. It is seen that total

number of thick faults are lesser than thin faults. The

observed trend is valid for both compact and ring yarns at

±35 % and ±50 % sensitivity. The observed difference is due

to the used drafting system which results in improper control

of the fibres during drafting [17]. The positive control of

fibres in the drafting zone as a result of pneumatic compaction,

in the case of compact spinning system, is responsible for

lesser number of thick and thin faults than ring spinning

system.

Yarn faults can occur due to infinite reasons and can be

classified into three broad classes i.e. faults resulting due to

raw material; faults resulting due to process; and faults

produced at yarn spinning system. The raw material and

carding process give rise to the fault from the lower class

whereas the faults in the upper class are due to drawing and

spinning. It has been experienced that with the same cross

sectional size classes, the short length faults in general,

occur more frequently than the longer length faults. Further,

it is known that the process and machine parameters of

preparatory system affects the yarn evenness and may also

have an influence on the frequency of occurrence of thick

and thin faults [17]. It is an established fact that the thin and

thick faults are responsible for yarn unevenness. Extensive

mill experiments have in fact shown that the same factors

which influence the yarn unevenness also influence the level

of faults. These factors are, namely, the short fibre percentage in

cotton mixing; the type of drafting system and draft distribution

of yarn manufacturing system; the quality of fibre opening;

carding and combing process. The generation of thick faults

are due to the presence of unopened fibre clusters in the

sliver, and are therefore, dependent only on the degree of

fibre individualization achieved prior to drafting system and

also drafting irregularities. In general, the effect of carding is

far more pronounced on the number of thick faults than on

the number of thin faults [17].

Characteristics of Yarn Faults

The yarn faults are further characterized in terms of fault

dimensions and different derived index. The Table 6 shows

that the fault length and additional volume occupied by the

all thick faults present on a known measured length of the

yarn is found to be lower for compact yarn than corresponding

ring yarn but total number of thick faults are higher for ring

yarn in comparison to compact yarn. Results of compact

yarn also confirm lower mean cross-sectional area of thick

faults than corresponding ring yarn. Accordingly, it is

noticed that volume add on per fault and volume add on per

Figure 6. Section wise profile of 24.6 tex combed ring O&C1 yarn.


(b) 24.6 tex combed ring O&C1 yarn

Thick total 3 13 21 26 119 39 38 0 0 0 0 0 0 259

% Deviation

in

volume

250 0

259

150 0

100 1 10 11

75 1 6 7 12 26

45 1 7 8 69 28 15 128

30 3 9 14 15 44 3 1 89

20 2 3 5

10 0

5 0

0 0

0 1 2 3 4 8 10 20 40 80 160 320 640

0 0

6

-5 0

-10 0

-20 0

-30 0

-45 1 1 2

-75 1 1 1 3

-100 1 1

Thin total 1 2 1 0 2 0 0 0 0 0 0 0 0 6

Table 4. Distribution of faults at sensitivity of ±35 %

(a) 24.6 tex combed compact yarn

Thick total 1 8 18 16 55 14 14 0 0 0 0 0 0

% Deviation

in

volume

250 0

126

150 0

100 1 1 1 3

75 1 1 1 7 10

45 1 4 3 21 10 6 45

30 8 13 12 32 2 1 68

20 0

10 0

5 0

0 0

0 1 2 3 4 8 10 20 40 80 160 320 640

0 0

0

-5 0

-10 0

-20 0

-30 0

-45 0

-75 0

-100 0

Thin total 0 0 0 0 0 0 0 0 0 0 0 0 0 0


(d) 14.7 tex combed compact yarn

Thick total 1 3 14 17 87 38 29 0 0 0 0 0 0

% Deviation

in

volume

250 0

189

150 2 2

100 1 1 2

75 1 9 8 18

45 1 5 9 46 24 17 102

30 1 2 8 8 38 4 1 62

20 1 2 3

10 0

5 0

0 0

0 1 2 3 4 8 10 20 40 80 160 320 640

0 0

1

-5 0

-10 0

-20 0

-30 0

-45 0

-75 1 1

-100 0

Thin total 0 1 0 0 0 0 0 0 0 0 0 0 0 1

Table 4. Continued

(c) 24.6 tex combed ring O&C2

Thick total 3 13 23 25 71 40 18 0 0 0 0 0 0 193

% Deviation

in

volume

250 0

193

150 0

100 1 3 3 7

75 1 1 2 4 6 2 16

45 3 2 6 6 38 26 13 94

30 9 16 16 27 5 73

20 1 1 1 3

10 0

5 0

0 0

0 1 2 3 4 8 10 20 40 80 160 320 640 1288

0 0

-5 0

-10 0

-20 0

-30 0

-45 0

-75 0

-100 0

Thin total 0 0 0 0 0 0 0 0 0 0 0 0 0 0


unit length are found to be lower for compact yarn than

corresponding ring yarn for both ±35 % and ±50 % sensitivity

levels. But mean thick fault length of compact yarn is higher

than ring yarn at ±50 % sensitivity level and is lower at

±35 % sensitivity level than corresponding ring yarn.

The results of dimensional characteristics of thick and thin

faults of different lengths belonging to a specific volume

size (volume percentage increase) at ±35 % sensitivity level

of four yarns under study are reported in Tables 7 and 8. It is

depicted that volume add-on per fault, volume add-on per

Table 5. Distribution of faults at sensitivity of ±50 %

(a) 24.6 tex combed compact yarn

% Deviation

in

volume

250 0

14

150 1 1

100 1 1

75 1 4 1 6

45 1 1 3 1 6

30 0

20 0

10 0

5 0

0 0

0 1 2 3 4 8 10 20 40 80 160 320 640

0 0

0

-5 0

-10 0

-20 0

-30 0

-45 0

-75 0

-100 0

24.6 tex Combed Ring O&C1

% Deviation

in

volume

250 0

50

150 0

100 3 4 1 8

75 1 9 3 13

45 1 2 3 6 15 1 28

30 1 1

20 0

10 0

5 0

0 0

0 1 2 3 4 8 10 20 40 80 160 320 640

0 0

0

-5 0

-10 0

-20 0

-30 0

-45 0

-75 0

-100 0


unit length and mean fault length at different level of volume

percentage increase are found to be lower for compact yarn

than corresponding ring yarn. However, cross-sectional area

CV% does not show any specific trend. A similar exercise

was also carried out for thin faults and results are given in

Table 9. It is noticed that at ±50 % sensitivity level both the

yarns do not show thin faults in the yarns but at ±35 %

sensitivity level only O&C1 ring yarn shows thin faults.

Table 5. Continued

(b) 24.6 tex Combed Ring O&C2

% Deviation

in volume

250 0

32

150 0

100 1 2 1 1 5

75 2 3 5

45 1 6 1 3 9 20

30 1 1 2

20 0

10 0

5 0

0 0

0 1 2 3 4 8 10 20 40 80 160 320 640 1288

0 0

-5 0

-10 0

-20 0

-30 0

-45 0

-75 0

-100 0

(c) 14.7 tex Combed Compact Yarn

% Deviation

in volume

250 0

33

150 1 1

100 1 1

75 7 1 1 9

45 1 3 4 12 2 22

30 0

20 0

10 0

5 0

0 0

0 1 2 3 4 8 10 20 40 80 160 320 640

0 0

0

-5 0

-10 0

-20 0

-30 0

-45 0

-75 0

-100 0


Yarn Characteristics of Different Makes of Opening and

Carding Systems

In the proposed study, an attempt has been made to study

the influence of different type of spinning preparatory

systems i.e. opening and carding systems on yarn characteristics.

Finally, 24.6 tex ring yarn was produced using two different

opening and carding (O&C) systems as illustrated in Figure 1.


The results of yarn diameter and yarn diametric CVd(mm)%

of 24.5 tex yarn are given in Table 2 and it is observed that

mean diameter of O&C1 yarn is found to be lower than

corresponding O&C2 yarn. The intrinsic yarn diameter also

follows the same trend. Further, it is noticed that the

maximum and minimum range of yarn diameter is higher for

O&C1 than corresponding O&C2 yarn. But it is interesting

to note from Table 2 that diametric unevenness (CVd%)

value of O&C2 yarn is found to be lower than corresponding

O&C1 yarn.

Yarn Cross-section Area and Yarn Cross-sectional

Unevenness (CVca%)

The yarn cross-section area signal variation curves of both

the yarns are shown in Figures 3 and 7 and the results are

tabulated in Table 2. It is observed that mean cross-section

area of O&C1 yarn is found to be lower than corresponding

O&C2 yarn and intrinsic cross-section area also follows the

same trend. Further, it is noticed that maximum and

minimum range of yarn cross-section area is little lower for

O&C2 yarn than corresponding O&C1 yarn. As depicted in

Table 2 the cross-section area unevenness (CVca%) and

eccentricity value of O&C2 yarn are found to be lower than

the corresponding O&C1 yarn. The obtained eccentricity

value clearly indicates that O&C2 yarn is having more

circular cross-section than corresponding O&C1 yarn at

99 % confidence level. The confidence interval for the

difference in the mean at 99 % confidence level is found out

to be 0.0122-0.0127 and actual difference of 0.012 in the

Table 6. Volume characteristics of faults based on cross-section area signal

Yarn typeFault

class

Mean CS

area

(mm2)

Max CS

area

(mm2)

Min CS

area

(mm2)

Vol

addon

(mm3)

Total

length

(mm)

No. of

faults

Vol addon

per fault

(mm3)

Vol addon per

unit length

(mm3)

Mean fault

length

(mm)

Sensitivity Level ±35 %

24.6 tex

Combed

Compact

Thick 0.053 0.068 0.03 31.87 746.55 126 0.253 0.043 5.93

Thin 0 0 0 0 0.00 0 0 0 0

Total 0.053 0.068 0.03 31.87 746.55 126 0.25 0.04 5.93

24.6 tex

Combed

Ring O&C1

Thick 0.07 0.174 0.051 102.35 1713.81 259 0.395 0.06 6.62

Thin 0.067 0.093 0.052 -0.49 17.78 6 -0.082 -0.028 2.96

Total 0.070 0.174 0.051 101.86 1731.58 265 0.38 0.06 6.53

24.6 tex

Combed

Ring O&C2

Thick 0.066 0.093 0.027 68.34 1181.05 193 0.354 0.058 6.12

Thin 0 0 0 0 0.00 0 0 0 0

Total 0.066 0.093 0.027 68.34 1181.05 193 0.35 0.06 6.12

14.7 tex

Combed

Compact

Thick 0.033 0.054 0.021 34.07 1325.23 189 0.18 0.026 7.01

Thin 0.03 0.03 0.03 -0.02 1.98 1 -0.02 -0.01 1.98

Total 0.033 0.054 0.021 34.05 1327.20 190 0.18 0.03 6.99

Sensitivity Level ±50 %

24.6 tex

Combed

Compact

Thick 0.058 0.072 0.038 7.46 89.86 14 0.533 0.083 6.42

Thin 0 0 0 0 0.00 0 0 0 0

Total 0.058 0.072 0.038 7.46 89.86 14 0.53 0.08 6.42

24.6 tex

Combed

Ring O&C1

Thick 0.072 0.175 0.048 26.2 292.80 50 0.524 0.089 5.86

Thin 0 0 0 0 0.00 0 0 0 0

Total 0.072 0.175 0.048 26.2 292.80 50 0.52 0.09 5.86

24.6 tex

Combed

Ring O&C2

Thick 0.072 0.096 0.051 11.67 138.75 32 0.365 0.084 4.34

Thin 0 0 0 0 0.00 0 0 0 0

Total 0.072 0.096 0.051 11.67 138.75 32 0.36 0.08 4.34

14.7 tex

Combed

Compact

Thick 0.03 0.047 0.02 7.36 193.55 33 0.223 0.038 5.87

Thin 0 0 0 0 0.00 0 0 0 0

Total 0.030 0.047 0.02 7.36 193.55 33 0.22 0.04 5.87


mean is outside this confidence interval.

The results of area profile of O&C1 and O&C2 yarns are

given in Figures 3 and 7. It is observed that the value of

CVca(m)% and CVca(mm)% of O&C2 yarns are lower than

Table 7. Dimensional characteristics of thick faults based on fault sizes at sensitivity of +35 %

Vol %

Inc

Mean CS

area

(mm2)

SD

(mm2)

CS area

(CV%)

Max CS area

(mm2)

Min CS

area

(mm2)

Vol addon

(mm3)

Total

length (mm)

No. of

faults

Vol addon

per fault

Vol addon

per unit

length

Mean fault

length

(mm)

24.6 tex Combed Compact

5 0 0.00 0

10 0 0.00 0

20 0 0.00 0

30 0 0.00 0

45 0.0566 0.0096 16.94 0.0678 0.0398 9.65 314.52 68 0.1418 0.0307 4.63

75 0.0536 0.0069 12.79 0.0615 0.0400 13.69 314.03 45 0.3041 0.0436 6.98

100 0.0492 0.0126 25.72 0.0648 0.0301 6.59 97.27 10 0.6590 0.0678 9.73

150 0.0481 0.0109 22.61 0.0625 0.0374 1.92 20.74 3 0.6407 0.0927 6.91

250 0 0.00 0


5 0 0.00 0

10 0 0.00 0

20 0 0.00 0

30 0.0617 0.0029 04.77 0.0641 0.0585 00.42 14.81 5 0.0833 0.0281 02.96

45 0.0684 0.0094 13.80 0.0958 0.0591 15.65 410.80 89 0.1759 0.0381 04.62

75 0.0820 0.0232 28.28 0.1299 0.0510 50.66 908.50 128 0.3958 0.0558 07.10

100 0.0615 0.0069 11.13 0.0696 0.0530 20.90 252.80 26 0.8040 0.0827 09.72

150 0.0718 0.0163 22.64 0.0891 0.0548 14.72 126.89 11 1.3383 0.1160 11.54

250 0 0.00 0


5 0 0.00 0

10 0 0.00 0

20 0 0.00 0

30 0.0531 0.0061 11.53 0.0578 0.0429 0.34 12.34 3 0.1138 0.0276 04.11

45 0.0613 0.0123 20.15 0.0833 0.0341 12.27 318.47 73 0.1681 0.0385 04.36

75 0.0665 0.0103 15.47 0.0900 0.0574 37.84 660.14 94 0.4026 0.0573 07.02

100 0.0726 0.0112 15.42 0.0895 0.0572 9.75 117.51 16 0.6093 0.0830 07.34

150 0.0751 0.0104 13.86 0.0926 0.0637 8.14 72.58 7 1.1630 0.1122 10.37

250 0 0.00 0


5 0 0.00 0

10 0 0.00 0

20 0 0.00 0

30 0.0383 0.0022 05.64 0.0400 0.0359 00.15 11.85 3 0.0508 0.0129 03.95

45 0.0360 0.0028 07.88 0.0417 0.0288 05.53 320.94 62 0.0892 0.0172 05.18

75 0.0290 0.0057 19.54 0.0376 0.0221 18.67 757.41 102 0.1831 0.0247 07.43

100 0.0383 0.0075 19.58 0.0470 0.0286 06.82 185.16 18 0.3788 0.0368 10.29

150 0.0288 0.0092 31.99 0.0408 0.0210 00.93 21.23 2 0.4630 0.0436 10.62

250 0.0272 0 00.09 0.0273 0.0272 01.97 28.64 2 0.9833 0.0687 14.32


corresponding O&C1 yarn. This can be supported from the

results of variance-length and variance-length curves given

in Table 3 and Figure 4 respectively because CVca% of

O&C2 yarn is found to be lower at different reference length

in comparison to corresponding O&C1 yarn. Yarn cross-

section area signal variation curves of different sections of

yarn of defined segment are shown in Figures 6 and 8. It is

noticed that mean cross-section area and CVca(mm)% are

found to be lower for O&C2 yarn than the corresponding

O&C1 yarn.

The observed trend can be supported with the following

explanation. The primary objective of the preparatory

process is to open, clean, and parallelize the fibres with

minimal fibre breakage and entanglement to improve the

quality of yarn [18,19]. Accordingly, the machines are

sequenced to carry out the gradual fibre opening. The type of

machines and the sequence used in O&C2 system are

responsible for gentle and progressive opening to achieve

the required degree of fibre opening in few steps in

comparison to O&C1. The highest possible opening or the

lowest possible tuft weight is achieved by gradually

increasing the wire point density and peripheral speeds of

opening rollers in few steps to avoid unnecessary stress on

the fibres [18,19]. The inbuilt provision of face changing of

cotton sheet which is passing through series of opening

rollers under unclamped condition further enhance fibre

opening.

The quality of carding process is decided by the available

area of the main cylinder. The revolving flats with an

optimum number of flats are indispensable for cleaning, nep

removal and short fibre separation. The revolving flats

require a well-prepared fibre web. Higher pre-opening area

and increased post-carding area available in O&C2 system

ensures intensive carding with cleaner sliver and a higher

fibre individualization in the sliver, thereby leading to better

quality potential of the machine.


In the proposed study 24.5 tex yarn was produced by using

two different makes of opening and carding systems (O&C1

and O&C2) as illustrated in Figure 1 and the results are

shown in Tables 4 and 5. It is depicted that total number of

faults in the yarn made with O&C1 are higher than yarn

from O&C2 and trend is valid for both ±35 % and ±50 %

sensitivity levels.


The detailed analysis of thick and thin faults of 200 meter

yarn length based on cross-sectional area signal at two

different sensitivity levels is given in Tables 4 and 5. The

volumetric characteristics of yarn faults are given in Table 6.

It is noticed that O&C2 yarn show lower number of thick

faults and total length occupied by thick faults than

corresponding O&C1 yarn. Accordingly, the volume add-on

and mean cross-sectional area of thick faults are lower for

O&C2 yarn than O&C1 yarn. It is further observed that

volume add-on per fault, mean fault length and volume add-

on per unit length for O&C2 are lower than corresponding

O&C1 yarn and trends are valid for both ±35 % and ±50 %

sensitivity levels. The results of the dimensional characteristics

of thick and thin faults of different lengths belonging to a

specific volume size (volume percentage increase) at ±35 %

Table 8. Dimensional characteristics of thin faults based on fault sizes at sensitivity of -35 %

Vol %

decrease

Mean CS

area

(mm2)

SD

(mm2)

CS area

(CV%)

Max CS

area (mm2)

Min CS

area

(mm2)

Vol addon

(mm3)

Total

length

(mm)

No. of

faults

Vol addon

per fault

Vol addon

per unit

length

Mean fault

length

(mm)


-5 0 0.00 0

-10 0 0.00 0

-20 0 0.00 0

-30 0 0.00 0

-45 0.0634 0.0010 01.50 0.0641 0.0623 -0.13 6.42 2 -0.0638 -0.0199 3.21

-75 0.0847 0.0146 17.22 0.0935 0.0679 -0.15 5.43 3 -0.0500 -0.0276 1.81

-100 0.0522 0.0001 00.21 0.0523 0.0521 -0.22 5.93 1 -0.2224 -0.0375 5.93


-5 0 0.00 0

-10 0 0.00 0

-20 0 0.00 0

-30 0 0.00 0

-45 0 0.00 0

-75 0.0297 0 0 0.0297 0.0297 -0.02 1.98 1 -0.0237 -0.012 1.98

-100 0 0.00 0


sensitivity level of yarns are reported in Tables 7, 8 and 9. It

is observed that at ±50 % sensitivity levels, both the yarns do

not show any thin fault in the yarn, but at ±35 % sensitivity

level only ring O&C1 shows thin faults.

Table 9. Dimensional characteristics of thick faults based on fault sizes at sensitivity of ±50 %

Vol % Inc

Mean CS

area

(mm2)

SD

(mm2)

CS area

(CV%)

Max CS

area

(mm2)

Min CS

area

(mm2)

Vol addon

(mm3)

Total

length

(mm)

No. of

faults

Vol addon

per fault

Vol addon

per unit

length

Mean fault

length

(mm)


5 0 0.00 0

10 0 0.00 0

20 0 0.00 0

30 0 0.00 0

45 0 0.00 0

75 0.056 0.0035 6.17 0.0613 0.0501 1.77 32.59 6 0.2954 0.0544 5.43

100 0.0598 0.0068 11.3 0.0718 0.0479 2.87 40.98 6 0.4787 0.0701 6.83

150 0.0376 - 0.34 0.0378 0.0375 0.59 5.43 1 0.588 0.1083 5.43

250 0.0711 - 0.28 0.0713 0.0708 2.22 10.86 1 2.2209 0.2045 10.86


5 0 0.00 0

10 0 0.00 0

20 0 0.00 0

30 0 0.00 0

45 0.072 - - 0.072 0.072 0.08 1.98 1 0.0836 0.0423 1.98

75 0.072 0.0165 22.96 0.1021 0.0565 9.52 136.28 28 0.3399 0.0698 4.87

100 0.0628 0.0065 10.34 0.0694 0.0545 7.87 84.93 13 0.6054 0.0927 6.53

150 0.0559 0.007 12.48 0.0659 0.0478 8.73 69.62 8 1.0907 0.1253 8.7

250 0 0.00 0


5 0 0.00 0

10 0 0.00 0

20 0 0.00 0

30 0 0.00 0

45 0.0513 0.0008 1.56 0.0522 0.0508 0.33 6.91 2 0.1649 0.0477 3.46

75 0.0698 0.0110 15.71 0.0789 0.0528 4.99 73.57 20 0.2495 0.0678 3.68

100 0.0830 0.0098 11.84 0.0891 0.0685 2.22 23.21 5 0.4436 0.0956 4.64

150 0.0815 0.0104 12.77 0.0959 0.0640 4.14 35.06 5 0.8288 0.1182 7.01

250 0 0.00 0


5 0 0.00 0

10 0 0.00 0

20 0 0.00 0

30 0 0.00 0

45 0 0.00 0

75 0.0320 0.0071 22.05 0.0427 0.0222 3.29 112.08 22 0.1495 0.0293 5.09

100 0.0275 0.0086 31.15 0.0470 0.0213 2.42 058.26 9 0.2687 0.0415 6.47

150 0.0256 - 00.84 0.0259 0.0253 0.70 010.37 1 0.7047 0.068 10.37

250 0.0272 - 00.09 0.0273 0.0272 0.95 012.84 1 0.9538 0.0743 12.84


Comparative Study of Different Yarn Fineness

The proposed study deals with the comparison of two

yarns of different fineness i.e. 24.5 tex and 14.7 tex made on

compact spinning system.


The results of yarn diameter and CVd(mm)% given in

Table 2 shows that the maximum and minimum range of

yarn in case of 24.5 tex yarn is higher than corresponding

14.7 tex yarn. It is also depicted from Table 2 that diametric

unevenness (CVd%) value of 14.7 tex is higher than 24.5 tex

yarn.

Yarn Cross-section Area and Yarn Cross-section Area

Unevenness (CVca%)

The results of mean yarn cross-section area and yarn

cross-section area unevenness are given in Table 2. It is

observed that mean cross-section area of 24.5 tex compact

yarn is higher than corresponding 14.7 tex compact yarn.

Further, it is noticed that maximum and minimum range of

yarn cross-section area in case of 24.5 tex yarn is higher than

corresponding 14.7 tex yarn. It is also depicted from Table 2

that yarn cross-section area unevenness (CVca%) value of 14.7

tex is higher than 24.5 tex yarn.

The yarn cross-section area variation curves of 200 meter

length of 24.5 tex and 14.7 tex scanned yarns shown in

Figures 2 and 9 respectively and Table 2 shows that the

CVca(m)% and CVca(mm)% of 14.7 tex yarn are higher than

the corresponding 24.6 tex yarn. The yarn variance length

and corresponding variance curves of both the yarn fineness

Figure 7. Yarn cross-section area profile of 24.6 tex combed ring O&C2 yarn.

Figure 8. Section wise profile of 24.6 tex combed ring O&C2 yarn.


are given in Table 3 and Figure 4, respectively and confirms

that CVca% of 14.7 tex yarn is always higher than corresponding

24.6 tex yarn. The higher CVca% of 14.7 tex yarn can be

supported by the higher number of thick and thin faults in

case of 14.7 tex yarn than corresponding 24.6 tex yarn.

It is interesting to note that eccentricity value of 14.7 tex

compact yarn is found to be higher than 24.5 tex compact

yarn. It confirms that 24.5 tex yarn is more circular than

14.7 tex yarn. The observed trend can be explained on the

basis of yarn packing density. It is an established fact that

yarn packing density of finer count is higher than coarse

count. However, due to the presence of relatively less

number of fibres in the yarn cross-section, cross-section

shape deviates from circularity. The results of CVca% at

different considered sections of the yarns are given in

Figures 5 and 10. It is observed that mean cross-section area

is found to be higher for 24.6 tex yarn. However, CVca(mm)%

is higher for 14.5 tex yarn.


In the proposed study yarn of two different fineness i.e.

24.5 tex and 14.7 tex were produced on compact spinning

system as per the sequence of flow given in Figure 1. The

results of Diametric Faults system of 24.5 tex and 14.7 tex

yarns using cross-sectional area signal are given in the Table

4 and 5. It is noticed that 14.7 tex yarn shows higher number

of total faults than 24.5 tex yarn and trend is valid at both the

sensitivity levels.


The characterization of yarn faults in terms of fault

dimensions and index are tabulated in Table 6. The study of

Figure 9. Yarn cross-section area profile of 14.7 tex combed compact yarn.

Figure 10. Section wise profile of 14.7 tex combed compact yarn.


thick faults shows that at ±35 % sensitivity level, the total

number of thick faults, volume add-on and total length

occupied by thick faults are higher for 14.7 tex yarn but

mean cross-sectional area of thick faults are lesser than 24.5

tex yarn. Accordingly, it is noticed that volume add-on per

fault and volume add-on per unit length are lower but mean

fault length is higher for 14.7 tex yarn than 24.5 tex yarn.

But the study of thick faults at ±50 % sensitivity shows that

for14.7 tex yarn, volume add-on per fault, volume add-on

per unit length and mean fault length are found to be lower

than corresponding 24.5 tex yarn.

The results of dimensional characteristics of thick and thin

faults of different lengths belonging to a specific volume

size (volume percentage increase) at ±35 % sensitivity level

are reported in Tables 7, 8 and 9 respectively. It is depicted

that volume add-on per fault, volume add-on per unit length

and mean fault length at different level of volume percentage

increase are found to be lower for 14.7 tex yarn than

corresponding 24.5 tex yarn. However, cross-sectional area

CV% does not show any specific trend.

Conclusion

The Diametric Faults system provides the classification of

faults based on their geometric dimensions and presents

flexibility to the user to choose the boundary limits for fault

classification. It is observed that total number of faults, yarn

diameter and cross-sectional area and their respective CV%,

total length of faults, volume add-on on faults, volume add-

on per fault, volume add-on per mm and mean fault length

of compact yarn were found to be lower than corresponding

ring yarn.

The comparative study of two different opening and

carding systems gives lower total number of faults, total

length of faults, volume add-on on faults, volume add-on per

fault, volume add-on per mm and mean fault length in case

of O&C2 system in comparison to corresponding O&C1

system. The yarn diameter and mean cross-section area of

O&C2 were found to be higher than O&C1 but yarn

diameter and mean cross-section area CVca% of O&C2 were

found to be lower than corresponding O&C1. Further, it is

observed that finer yarn give lower yarn diameter, cross-

section area, volume add-on per fault, volume add-on per

mm in comparison to coarser yarn. However, yarn diameter

and mean cross-section area CV%, total number of faults

and total length of faults are found to be higher for finer

yarn. The total volume add-on and mean fault length of finer

yarn was found to be higher for finer yarn at ±35 %

sensitivity but lower at ±50 % sensitivity level.

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