cotton yarn quality depends on mixing strategy

Cotton Yarn : Quality Depends on Mixing Strategy 2014

By Mr. Sunil Kumar Sharma Published in The Indian Textile Journal, Vol. 124, No.-6, March 2014 Edition

Abstract : - Cotton is a natural fibre available easily and abundant quantity. It is a

most suitable fibre for textile spinning & clothing due to it’s good spinnability &

human friendly characteristics. As cotton is a natural fibre hence it’s properties also

affected with several other factors which create variation in fibre properties, these

variations also affect spinning processes & it’s products Quality in multi dimensions.

Each fibre characteristic impact individually and collectively on spinning process or at

ultimate product quality. Revolutionary changes observed in last two decade in the

field of spinning machineries where processing speeds greatly increased to enhance

production rate. Not only production rate of spinning machines increased but speeds

of it’s downstream processes also increased simultaneously which requires better

quality of yarn for smooth process and without any interruption to get the maximum

efficiency. Hence now it is most important to co-relate fibre properties with respect to

it’s consumer process competency. In this article we will discuss the different cotton

properties and it’s impact on spinning process and product quality in present

prospective and will try to minimize the impact of poor fibre properties on process or

product Quality through better Mixing plan selection.

Introduction : In a spinning mill control over cotton quality requires in three steps i.e.

as below : -

1. Approval of Cotton Bales : - It is very much important to purchase the right

quality cotton bales according to defined quality standards. As cotton is a natural

fibre & commercial commodity hence it’s availability, prices & quality varies

time to time based on supply & market demand, therefore it is very important to

select the require quality cotton bales at reasonable prices which should viable

for spinning industries. Approval of cotton bales should be very strict against

it’s standards otherwise this will result stock of huge quantity of off standard

bales.



2. Grading of Cotton Bales : - After reaching cotton bales in mill, these should be

tested & properly graded according to mill standards. If possible it should be

stack in warehouse grade wise.

3. Mixing Planning : - According to grade wise cotton bales stock and spinning

count pattern cotton bales to be selected for mixing plan with minimum possible

variation.

Major Critical Cotton Fibre Properties : - Followings are most common cotton

properties which measures at the time of selection of cotton bales :

1. Length : - Measured either in inches or in mm.

2. fineness : - Cotton fibre fineness usually measured in micronaire i.e. Weigh of

fibres in microgram per inch.

3. Strength : - Measured as fibre bundle breaking force in Gms per tex.

4. Maturity : - Measured either in term of Maturity coefficient or in Maturity ratio.

5. Uniformity : - Measured either in % or as an index.

6. Short Fibre Content : - Measured as %.

7. Trash Content : - Measured as %.

8. Moisture Content : - Measured as %.

9. Brightness : - Represents as Rd value against degree of reflection.

10. Yellowness : - Represents as + b value.

11. Colour grade : - Colour grade is determined with conjunction of Rd & + b

value.

All in one single value SCI.

Spinning Consistency Index (SCI) : - SCI is a calculated value based on a regression

equation. This equation takes into account all HVI properties and calculates one value

to be used on each sample tested. The SCI is an index derived with data from a large

number of cotton samples having a wide range in properties that is related to test data

from yarn spun from each sample. By multiple regression analysis the contribution of



each fibre property to yarn properties is revealed. Consequently a single SCI value is

influenced by inherent relationships of cotton micronaire, length, uniformity, strength,

Rd and +b.

The following are SCI equation for the most important HVI measurements including

colour : -

For HVI Calibration Mode :

SCI = - 414.67 + (2.9 x Strength) – (9.32 x Mic.) + (49.17 x Length in inch) + (4.74

x Uniformity Index) + (0.65 x Rd) + (0.36 x +b)

If no colour module is installed then SCI equation are as follows : -

SCI = - 322.98 + (2.89 x Strength) – (9.02 x Mic.) + (43.53 x Length) + (4.29 x

Uniformity Index)

For ICC Calibration Mode :


Uniformity Ratio) + (0.65 x Rd) + (0.36 x +b)

If no colour module is installed then SCI equation are as follows : -


Uniformity Ratio)

Effect of fibre properties on spinning process & Yarn Quality :- Each cotton

characteristic impose their own influence on spinning process & at ultimate yarn

Quality explained as below : -

Fibre Length : - Fibre length is the most important factor for spinning. Selection of

cotton fibre is usually based on fibre length only and it is also main deciding factor for

count range to be spun. Hence this impacts each & every process of spinning



operation. Following are the main influencing area’s where fibre length impact on

spinning performance & Yarn Quality :

Count pattern and spinning production rate : - Fibre length is main deciding

factor for count patter in spinning mill. Production speeds of spinning

machineries also very much depends on fibre length of cotton. In modern high

production spinning set up cotton fibre length can’t be selected as per old

traditional systems. For modern high production spinning set up cotton fibre

properties requires as below : - Table : 1 : Cotton fibre Properties requires for modern high production spinning set up

(Tested on HVI calibration Mode) Count Range

(Ne) Fibre Length

(mm) Micronaire Strength

(G/Tex) Maturity Index

Karded Yarn

Below 20sNe 26 to 27 mm 4.0 to 4.6 24 to 27 0.85

Combed & Karded Yarn

20s to 32s 28 to 30 mm 3.6 to 4.2 27 to 30 0.84 33s to 45s 30 to 32 mm 3.5 to 3.8 29 to 31 0.84 46s to 60s 32 to 34 mm 3.3 to 3.6 30 to 32 0.84

Definition : Modern High production spinning set up : - Spinning set up running with more than 50 kg. / Hrs

carding production rate, getting 40s Converted GPSS above 110 with a HOK level of below 12 in spinning,

equipped with modern autoconer.

Working performance : - Higher length variation causes poor working

performance of spinning processes, which lead lower production & huge

disturbance in process. Only achieving average fibre properties as per standard

is not guarantee for better spinning performance; hence it should be ensured that

each cotton lot should have minimum length variation. Cotton Lot’s having

higher variation should run in control quantity which given in next chapter i.e.

Mixing Plan.



Higher Irregularity or unevenness : - If cotton length not suit to spin plan or

have higher length variation, e.g. to produce the 30sNE count if cotton selected

below 28 mm length, it will lead high irregularity or unevenness in yarn and will

also causes higher autoconer cuts and fabric defects.

High Hairiness : - Cotton selected of lower fibre length will causes high yarn

hairiness, that lead high fluff generation in department, more tendency of

traveller loading, excessive EYC cuts & cops rejection at autoconer and pilling

or barre problem in fabric.

Fineness / Micronaire of fibre : - The second most important factor for a spinning

mills to decide the count pattern is fineness of cotton fibre that is commonly known

as micronaire. Same as fibe length, it is also deciding factor for cotton selection &

spin plan of a spinning mill.

No of Fibres in Yarn Cross section : - Spinning of a particular fineness of

yarn is based on the fibre length of cotton & it’s fineness which decide how

many fibres will be in the cross section of yarn. It’s seems that below 90 No.

of fibres in cross section of ring spun yarn (for coarse & medium count range)

lead major working problem at spinning with lower yarn strength while no. of

fibres more than 300 in cross section of yarn lead higher unevenness in ring

spun yarn. Hence it is recommended to use right micronaire value for a

particular spin plan. Table : 1 Recommends guideline for micronaire value for

different count range.

Higher Neps Generation : - Low micronaire value causes high neps

generation in blow room & carding, which lead higher neps & imperfection

in final yarn and white spots or dots in dyed fabric. Low fineness cotton

fibres always have tendency to form fibre entanglement or neps, hence it is

recommended to reduce blow room beaters speed and carding production rate

whenever low micronaire value cotton being processed.



Barre or shade variation : - Too much variation in micronaire value lead

barre problem or shade variation in fabric.

Genetic character : - Micronaire value of any cotton fibre strongly exhibits

it’s origin variety genetic character. If a cotton fibre fineness value does not

belongs to normal distribution of it’s origin variety, means either this fibre is

immature or it’s not belong to said variety. This type of cotton lot should be

avoided. Table -2 shows a general trend for critical cotton characteristics for

most common Indian cotton varieties. Table – 2 : General Cotton Properties of Major Indian varieties.

(Measured by HVI testing system by using HVI Calibration Mode)

Cotton Variety Major Producing States Fibre Length (mm)

Micronaire Strength (G/Tex)

Y 1 Maharashtra 22 to 25 4.5 to 6.0 18 to 24

V - 797 Gujrat 23 to 26 4.5 to 5.8 18 to 24

J - 34 Haryana / Rajasthan 26 to 29 3.8 to 4.6 24 to 28

J – 34 /F - 414 Punjab 26 to 30 3.8 to 4.6 25 to 30

H - 4 Madhya Pradesh 27 to 30 3.6 to 4.2 25 to 30

Shankar - 4 / 6 Gujrat 28 to 30 3.6 to 4.4 25 to 30

MECH - 1 Maharashtra 28 to 31 3.5 to 4.2 26 to 31

Bunny Brahma Maharashtra / Andhra 30 to 32 3.4 to 4.0 26 to 32

MCU - 5 Maharashtra / Andhra 31 to 33 3.3 to 3.8 26 to 32

DCH - 32 M. P. / Karnataka 32 to 36 2.8 to 3.2 30 to 34 Note : - Above data represents a general trend of variety followed 2 sigma limits of normal distribution.

Fibre strength : - Fibre strength is important factor for working of spinning

process and yarn strength. Fibre strength is directly proportionate to yarn strength

and working performance of spinning machines. However it seems that strength of

fibre is also related with others cotton properties like fibre length, micronaire &

maturity. Fibre bundle strength is a deciding factor for spinning machine speeds. If

fibre is not adequate stronger, then there have to compromise with production rate

and force to reduce speed of machines. Similarly ultimate yarn strength will be less

as require.



Maturity : - Maturity of cotton fibre is related with it’s growing process. A fully

mature fibre means fibre achieve their complete growth process and developed in

all respects. Mature fibres achieve & exhibit better fibre properties in all respect as

per their origin of variety characteristics, as describe in Table – 2. Fibres which not

grown in a normal condition or picked up before there complete growth will fail to

belong their specific characteristics and will be shorter, weak & fine as compared

to mature fibres.

In HVI testing the maturity index is a relative value that is calculated by using a

sophisticated algorithm including other HVI measurements, such as micronaire,

strength & elongation. It indicates the degree of cell wall thickness within a cotton

sample. Table – 3 shows Avg. test results of total 98241 No. of bales w.r.t. degree of

maturity index. Table – 3 : HVI Test Results of MECH - 1 Cotton Showing Avg. Critical fibre properties

w.r.t. different degree of Maturity Index

(Measured by HVI testing system by using HVI Calibration Mode) Total No. of Bale

SCI Maturity

Index Micronaire UHML SFC% UI Stg

100 76 0.82 2.70 25.8 12.9 76.3 17.5

800 122 0.83 3.20 28.3 8.8 81.0 25.4

9412 128 0.84 3.59 29.5 8.4 81.9 26.6

24777 134 0.85 3.82 30.0 8.1 82.7 27.7

47870 140 0.86 4.06 30.6 7.7 83.4 28.7

13482 141 0.87 4.24 30.8 7.4 83.6 29.4

1800 143 0.88 4.49 31.4 7.2 83.5 30.6

Total observations = 98241 Bales.

Cotton Yarn : Quality Depends on Mixing Strategy

By Mr. Sunil Kumar Sharma Published in The Indian Textile Journal, Vol. 124, No.

Fig – 1 : Graphical representation of Fibre Length & Strength w.r.t. Maturity Index.

Fig – 2 : Graphical representation of Micronaire & SFC % w.r.t. Maturity Index.

Hence maturity is a key parameter for cotton selection & spinning process.

various testing methods it is represented as maturity coefficient, Maturity index or

as maturity ratio. Higher the numerical value means higher will be maturity of

fibres. Low maturity value impact at spinning process or yarn Quality as below :

25.8

28.3

17.5

25.4

16.017.018.019.020.021.022.023.024.025.026.027.028.029.030.031.032.033.034.0

0.82 0.83

0.820.83

0.84

2.70 3.20 3.59

12.9

8.8

Micronaire SFC %

arn : Quality Depends on Mixing Strategy

Vol. 124, No.-6, March 2014 Edition

Graphical representation of Fibre Length & Strength w.r.t. Maturity Index.

Graphical representation of Micronaire & SFC % w.r.t. Maturity Index.

is a key parameter for cotton selection & spinning process.



fibres. Low maturity value impact at spinning process or yarn Quality as below :

29.530.0 30.6 30.8

25.426.6

27.728.7

29.4

0.84 0.85 0.86 0.87

UHML (mm)

Strength (G/Tex)

0.840.85

0.860.87

3.59 3.824.06

4.24

8.48.1

7.77.4

arn : Quality Depends on Mixing Strategy 2014

Graphical representation of Fibre Length & Strength w.r.t. Maturity Index.

Graphical representation of Micronaire & SFC % w.r.t. Maturity Index.

is a key parameter for cotton selection & spinning process. In



fibres. Low maturity value impact at spinning process or yarn Quality as below : -

31.4

29.430.6

0.88

UHML (mm)

Strength (G/Tex)

0.88

4.49

7.2



Fibre rupture : - Immature fibres breaks into multiple pieces in blowroom &

carding section during metallic action of beaters and carding wires causes increase

in short fibres & microdust which further reduce the effective length of fibre &

strength. This fibre rupture increases yarn breaks, yarn defects, spinning waste &

yarn imperfection level subsequently reduces working efficiency of spinning

machineries causing lower production, yarn recovery with lower yarn strength.

Dead cotton Neps : - Immature fibres create heavy neps during spinning process

which ultimately reflect as white dots in dyed fabric and causing fabric rejection.

Table – 3 & Fig. – 1 showing that fibre maturity is directly proportionate to fibre

length & bundle length of fibres.

Uniformity : - Settings of spinning drafting rollers depends on the length of fibres.

To obtain optimize & correct spinning draft roller settings fibre uniformity is very

important factor. Cotton fibre with low uniformity causes very high variation in

process and creates difficulties for spinners to set the right setting for particular

cotton mixing.

Short fibre content : - Fibre length below half inch i.e. below 12.5 mm consider as

short fibres. High short fibre % in cotton lead many problems in spinning process

such as high end breaks, excessive yarn defects, very high fluff generation, lower

machine efficiency, lower yarn realization and higher worker turn over.

Trash Content : - High trash content in mixing causes higher waste extraction,

high end breaks rate at ring frame & higher yarn imperfection & classimat faults.

It’s also appearing as black dots in greige fabric usually known as kitti particles.

Moisture Content : - Cotton is a hygroscopic fibre, it’s absorb moisture from a

high humid atmosphere and evaporate when store in dry atmosphere. For smooth

spinning operation cotton fibre should have moisture in range of 6 to 8 %. Moisture

content below this limit causes high fluff generation & higher end breaks, while

cotton having high moisture content difficult to open & clean in blow room -

carding, hence creating very high imperfection and yarn slubs which again causing



end downs at ring frame stage and lowering the production efficiency with increase

in yarn imperfection & defects.

Colour Grade : - Variation in Colour grade is major responsible factor for shade

variation in cotton yarn & fabric.

Grading of Cotton Bales

It is very difficult to grade a cotton Lot base on all 11 parameters as mentioned

above, hence we can decide four major critical parameters for grading of cotton

bales which represent the overall grading of cotton. These parameters may be

utilized for cotton bales procurements, stacking and finally for selecting the cotton

bales for Mixing Plan. If a mill cotton purchasing is strictly from a particular region

then there will be less chances of too much variation in colour grade, hence critical

parameters for them might be as below : -

1. Fibre Length : - Must require to decide the count pattern of spin plan.

2. Micronaire : - Must require to decide the count pattern of spin plan.

3. Maturity : - Requires to control the quality of cotton, it’s also represent to

fibre strength.

4. Short fibre % : - Requires to control the working performance of spinning

mill and yarn realization. it’s also represent to uniformity of cotton. Less the

SFC more the uniformity of fibre.

If cotton procurement of mill is from different - different region, then there

might be possibility of variation in cotton colour grade. Hence in that case colour

grade also to be taken into consideration.

Table -4 : Grading of Medium Long staple Cotton Lot's based on Critical Parameters

(Measured by HVI testing system by using HVI Calibration Mode)



Grade Fibre Length

(mm) Micronaire

Maturity Index

SFC % Stock %

A + + > 31 3.5 - 4.2 > 0.85 < 7.5 13

A + 30 - 31 3.5 - 4.3 > 0.85 < 8.0 30

A 29 to 30 3.6 to 4.3 > 0.85 < 9.0 35

B 28 to 29 3.6 to 4.3 > 0.84 > 9.0 20

C Out of above Range 2

Stock % based on assumption only for explanation purpose.

Mixing Planning

Object : To Mix cotton fibres of different bales in a homogeneous form to overcome

the variations of cotton properties and maintain the uniformity & consistency in

throughout spinning process and in yarn Quality.

Making a mixing plan may be a tedious job, but spinning performance is totally

depends on it. Hence investing time and skill on mixing plan will pay consistency

in spinning w.r.t. working & quality as a result. A practical mixing plan may be

prepared as below : -

1. First check the availability of grade wise cotton bales and spin plan.

2. Then select grade wise No. of cotton bales in ratio of present cotton bales

stock and as require for spin plan. Stock of cotton bales to be utilized in such

a manner that long staple cotton (i.e. A + + in Table – 4) to be used for fine

count pattern.

3. If present spin plan is not support to fine count range then it should be

preserved for future, if there are possibility in future.

4. To control the length variation in a selected mixing plan either we have to

consume “A++” grade cotton first or we have to preserve it till all the bales of

“B” grade cotton exhausted.

5. Refer to cotton grading system as per Table – 4, in a mixing plan either there

should be top three grade bales (i.e. A ++, A + & A Grade) to be used or

lower three grade bales (i.e. A+, A & B Grade) to be used.

6. In a mixing plan fibre length range should not exceed more than 2.5 mm and

Micronaire range to be maintained below 0.60. Refer Table – 6.



7. Low variation in fibre length require to set right the correct gauges of

spinning drafting rollers and to avoid the fibre rupture and drafting waves.

Variation in fibre length causes poor Quality & working of spinning along

with high fly generation.

8. Low micronaire range must require maintaining the uniform no. of fibres in

cross section of yarn, which ensure better yarn evenness & single yarn

strength.

9. No of cotton lot’s in a mixing plan to be selected in such a manner that

participation of each cotton lot bales should not be more than 5 %. For

example if we are making a mixing plan for 100 no. of bales than there

should be at least 20 No. of Cotton lot’s contributing 5 bales each for each

batch. This is require to avoid wide changes in mixing plan, even if there is

change of one single cotton lot then there will be only 5 % change in

particular mixing plan.

10. Replacement of cotton lot should be in decreasing and increasing order. If

one cotton lot going to exhaust in mixing that should be run out slowly and

replacement lot to be inserted in same way, which ensures minimum variation

in process during replacement of cotton lot’s. Table – 5, shows how one cotton

lot should run out and another should replace it. Table – 5 : Showing Replacement process of cotton Lot in Mixing.

Decreasing Order Increasing Order

Cotton Lot going to exhaust in Mixing Cotton Lot started in Mixing

Date Lot No.

Opening Stock of Bales

No. of Bales issued

Closing Stock Lot

No.

Opening Stock of Bales

No. of Bales issued

Closing Stock

10/09/2013 105 15 5 10

11/09/2013 105 10 4 6 251 100 1 99

12/09/2013 105 6 3 3 251 99 2 97

13/09/2013 105 3 2 1 251 97 3 94

14/09/2013 105 1 1 0 251 94 4 90

15/09/2013 251 90 5 85



11. This system ensures very little change in mixing on day to day basis. Only

one bale replacement out of 100 bales mixing will be only 1 % change in

mixing plan that is almost negligible.

12. To further minimize the variation during Lot change it should also be

taken care that same grade cotton or cotton lot with same characteristics to be

replaced.

13. If cotton procured from different – different station, then try to replace the

cotton lot with same origin or station. Table – 6 : Acceptable range for Daily Mixing plan.

Parameters Ideal Range Maximum acceptable Range

Fibre Length (mm) 2.0 2.5 Micronaire 0.6 0.8 Rd 5 6 + b 2.0 2.5

Monitoring of colour Grade : - Monitoring of colour grade is also a very

important job to control the shade variation or barre problem in resultant yarn &

fabric. Following guidelines might be useful for better control on colour grade

of cotton : -

Rd value : - Usually in Indian cotton Rd values lying in between 72 to 82. For

better control it is advisable to maintain the Rd value range below 5 in daily

Mixing plan. Refer Table – 6.

+ b : - + b value significantly differ region wise and variety wise. Indian cotton

usually lying + b value in range of 6.0 to 11.0. It is better to maintain the + b

range below 2.5 in one variety cotton mixing. Refer Table – 6.

Colour Grade : - The colour grade is determined by locating the quadrant of the

color chart in which the Rd and +b values intersect. For example, a sample with

Rd value of 72 and +b value of 9.0 would have a color code of 41-3. Colour



grade is represented in three digits as xx-y. First digit represent to brightness of

cotton. Lower the number higher will be brightness of cotton. Second digit

represents to yellowness of cotton, yellowness increases with increase in second

digit number. There are 25 colour grades and five categories of colour grades.

Indian cotton usually lying in white & light spotted categories with Middling to

good middling colour grade.

To avoid the shade variation or barre problem it is advisable that only four

adjacent cotton grade should select for mixing plan, e.g. 11, 12, 21, 22 may run

together but running 11 with 31 or 11 with 13 should be avoided.

Colour grade categories of spotted, tinged & yellow stained i.e. represented by

3, 4 & 5 number in second digit of colour grade should be strictly avoided.



Chart – 1 : USDA Colour grade chart for cotton short /medium cotton.



Table – 7 : Categories & Colour Grade for Cotton

Category Color Grades Symbols Code #

White Good Middling GM 11

Strict Middling SM 21

Middling Mid 31

Strict Low Middling SLM 41

Low Middling LM 51

Strict Good Ordinary SGO 61

Good Ordinary GO 71

Light Spotted Good Middling GM LtSp 12

Strict Middling SM LtSp 22

Middling Mid LtSp 32

Strict Low Middling SLM LtSp 42

Low Middling LM LtSp 52

Strict Good Ordinary SGO LtSp 62

Spotted Good Middling GM Sp 13

Strict Middling SM Sp 23

Middling Mid Sp 33

Strict Low Middling SLM Sp 43

Low Middling LM Sp 53

Strict Good Ordinary SGO Sp 63

Tinged Strict Middling SM Tg 24

Middling Mid Tg 34

Strict Low Middling SLM Tg 44

Low Middling LM Tg 54

Yellow Stained Strict Middling SM YS 25

Middling Mid YS 35

Use of off standards bales : - In spinning mills there should be strict control on

purchasing of cotton bales or passing for Quality specification, otherwise there

might be lot of off standard cotton bales accumulate in mill godown which will

never allow spinner to prepare a control mixing plan. However even after better

control there might be chances of some off standard cotton bales which do not

belongs to normal standard either for any single parameter or due to fail of multiple



parameters. These bales to be utilized in very control manner so it’s bad quality

should not affect spinning process and yarn produced. Based on quality parameters

of off standard bales these may be consumed in control manner (i.e. in a range of 1

to 5% according to quality parameter) as below : -

1. If there is only slight variation in any one or two parameter from standard

then such cotton bales may be considered in mixing with 3 % contribution.

For example if standard for fibre length is above 29 mm & Micronaire is

above 3.6 and actual value of a cotton Lot found 28.5 mm & 3.5 Mic value

then such cotton bales may be considered with 3 % ratio in mixing.

2. If there is significant deviation in a single value such as instead of 29 mm

fibre length observed 27 mm while rest other parameters observed within

range in that case such cotton bales may be consumed with below 2 % ratio.

3. If 2 -3 parameters fail to meet the standard specs then such cotton bales

should be strictly consumed with below 1 % ratio.

Mixing Plan monitored through Spinning Consistency Index : - Instead of

monitoring of several parameter for a mixing plan, it might be more easy to

monitor the “SCI” value of cotton properties obtained from HVI test report.

Following guidelines may be adapted for using “SCI” value in cotton grading &

mixing planning : -

1. Cotton may be graded in five grades & store in warehouse according to their

SCI value i.e. as below : - Table – 8 : Possible Grading system according to Spinning Consistency Index (SCI) (Measured by HVI testing system at HVI calibration mode with Colour Grade Module)

Grade

Spinning Consistency Index (SCI) Value Range

A + + Above 150

A + 140 to 149

A 130 to 140

B 120 to 129

C Below 120



2. According to stock position a mixing plan to be prepared and Average,

Minimum, Maximum and range should be drawn for SCI value.

3. Average SCI value of daily mixing should be maintain constant and there

should not be more than +/- 2 deviations on daily basis.

4. It should be trying that maximum & minimum range of SCI value should not

be more than 30, for an ideal mixing plan it should be maintain below 20.

5. The total range of maximum & minimum SCI value should also be monitor

on daily basis and there should not be too much variation on daily basis.

Conclusion : - Cotton is most favorable fibre for spinning industries. As cotton is a

natural fibre, hence variation in it’s properties is also an inherent characteristic. To

overcome these variations scientific & systematic control requires on cotton Quality.

Control over cotton quality in a spinning mill recommends in three stages i.e.

Approval of cotton bales, Grading of cotton bales & finally selection of cotton bales

for Mixing plan. Major Cotton fibre properties and it’s impacts on spinning

processes & yarn Quality explained in details with examples, data & graphical

representations. More emphasis has been given on SCI & Maturity of fibres.

Maturity of cotton fibre is an important parameter and also impact on others

parameters such as length, strength, elongation etc. All in one single value derived

from regression equation Spinning consistency index (SCI) is a value influenced by

inherent relationships of cotton micronaire, length, uniformity, strength, Rd and +b,

may helps spinners to monitor only one parameter for decision making.

Mixing planning is a very important function for spinning operation and

investing the time & skill for systematic mixing plan pay return as consistency in

productivity & Quality. A systematic mixing plan by maintaining the lowest possible

variation in cotton quality parameters ensures trouble free yarn production with

consistent yarn Quality. Variation in cotton colour grade is major responsible factor

for shade variation and barre problem in fabric, hence control over cotton colour



grade is most important function of mixing plan, it can’t ignore. Consuming the off

standard Quality bales are a tricky job and it should be used in very control manner

so performance of spinning process & yarn quality should not affect.

References : - Uster HVI 1000 Application Handbook.

Cotton Council International – 2008 Buyer Guide.

USDA – Cotton Classification.

Produced by : Mr. Sunil Kumar Sharma,

Dy. General Manager (QAD, PPC & Customer Care)

Mobile No. : – 09552596742, 09921417107

E_mail : - [email protected] Loknayak Jayprakash Narayan Shetkari Sahakari Soot Girni Ltd.

Kamalnagar, Untawad – Hol, Shahada,

Tal. : - Shahada, Dist. : - Nandurbar (MS)

Pin : - 425409

cotton yarn quality depends on mixing strategy

Technology

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right quality cotton

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different cotton properties

common cotton properties