Yarn Hairiness

Yarn Hairiness 2013
By Mr. Sunil Kumar Sharma, Dy. General Manager – QA, PPC & Customer Care,
Published in Spinning Textiles, Vol.7, Issue-6, Nov. Dec.2013 Edition.
Page 1
Question – 1 : - What is yarn Hairiness and how it is impact on spinning,
knitting & weaving processes & yarn, fabric Quality ?
Ans. : Hairiness is characterized by the quantity of freely moving fibre ends or fibre
loops projecting from a yarn or textile fabric (woven, knitted or non woven fabrics).
In term of measurement Hairiness corresponds to the total length of the
protruding fibres in unit length of one centimeter.
Yarn hairiness is a complex concept, which generally cannot be completely
defined by a single figure. The effect of yarn hairiness on the textile operations
following spinning, knitting & weaving and it’s influence on the characteristics of
the product obtained may be as follows : -
1. High fluff – fly generation in ring frame, winding & subsequent processes.
2. Excessive yarn breaks at ring frame stage.
3. Higher yarn breaks at knitting or warp creel.
4. Pipe choking of Circular Knitting machine causing frequent yarn breaks
and hole in fabric.
5. Barre or Shade variation in fabric.
6. High pilling in knitted fabric.
7. Linting problem in terry towel.
Question – 2 : - What are the commonly used test methods for Hairiness
testing? Explain their measuring principles?
Ans. : There are two popular methods for yarn hairiness testing as below : -
1. Hairiness Index tested through OH sensor with Evenness Tester.
2. The Number of hairs in several length zone counted.
 Hairiness Index tested through OH sensor with Evenness Tester : - A
constant monochrome light source shines on the protruding hairs of the yarn
body, which scatters the parallel light. The yarn body itself is dark, because it
is not transparent. The scattered light, which is caused by those fibres
protruding outside the yarn body, is bundled by a lens system and detected by

Yarn Hairiness 2013
Page 2
an optical sensor. The scattered light results from the refraction, diffraction
and reflection at the individual fibres i.e. the protruding fibres appear to be
luminous. The electrical output signal of the optical sensor, which is
proportional to the yarn hairiness, is then converted to a digital value and
evaluated by the tester.
Total length of Protruding fibres (in cm)
Hairiness Index = --------------------------------------------------------
Total length of yarn tested (in cm)
Fig. 1 : Representation of Hairiness
 The Number of hairs in several length zone counted : - The measuring
method used is based on the photometric principle. The yarn and projecting
fibres interrupt a light beam, thus effecting a fluctuation in the measuring
luminance of the light beam. The luminance registered in this way by a
phototransistor is converted into a photocurrent, which must be amplified. In

Yarn Hairiness 2013
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order to allow the number of hairs in several length zones to be counted, the yarn
is scanned by four photo-transistors. The measured values were entered into a
logarithmic coordinate frame.
Fig. 2 : Representation of Hairiness in the Coordinate Frame
Question – 3 : - What is S3 value? What is the basic difference between two
testing methods of Hairiness testing and what is the use of both the methods?
Ans. : As mentioned above type 2 instruments provide the information that how
much number of fibres belong to a particular length. In this method total number of
hairs 3.0 mm and longer is known as S3 Value
For a textile yarn long hairs are undesirable, while short hairs are desirable for soft
feel of fabric. Hairiness value obtained through OH sensor of evenness tester is the
average of all protruding fibre length in one centimeter length of yarn, which is not
indicating the distribution of the length of hairs. Let us see an example as below : -
Two yarns samples tested on evenness tester, where Hairiness Index of both
the yarn obtained same as 5.0, while same yarn samples again tested on another
tester which gives detail analysis report for individual length of hairs shows that S3
value of sample 1 is more as compared to sample 2, which indicates that yarn
sample 1 is more hairy as compared to sample 2. Hence Hairiness index obtained

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from evenness tester is just indicative value, which is indicating the trend of
spinning process while second method is require for detail analysis of yarn hairiness
and may help to identify and eliminate the root cause.
Question – 4 : - What are the influencing factors for yarn Hairiness?
Ans. : Hairiness occurs because some fibre ends protrude from the yarn body,
some looped fibres arch out from the yarn core and some wild fibres in the yarn.
Following are the major influencing factors affecting the yarn hairiness : -
 Raw Material Quality.
 Production rate or processing speeds.
 Process parameters.
 Mechanical conditions of machines.
1. Raw Material Quality (Cotton) : - Raw material quality is most important
influencing factor for yarn hairiness. Fibre length, Fineness, Short fibre %,
Uniformity, maturity and strength each parameter impact their influence on yarn
hairiness as below : -
a. Fibre Length : - Cotton selected of lower fibre length will causes high yarn
hairiness, also lead high fluff generation and more tendency of traveller
loading which further increasing hairiness. The greater length corresponds
to less hairiness. Ref. Chart – 1.
b. Fineness : - The number of fibres in yarn cross section also affect the yarn
hairiness. The proportion of fibre ends that protrude from the yarn surface,
counted microscopically has been found to be about 31 % of the actual
number of ends present in the yarn, hence as number of fibres increases
there will be higher possibilities for increase in yarn hairiness.
c. Short Fibre % & Uniformity : - Higher the short fibre % lower will be
uniformity of cotton which ultimately lead high hairiness in yarn.

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d. Maturity & Strength : - Lower cotton maturity & fibre strength causes fibre
rupture in process and increases the short fibre % ultimate causes high yarn
hairiness.
Chart – 1 : Hairiness Index w.r.t. cotton parameters
(For 30s Combed Hosiery Yarn)
Description Test -1 Test -2 Test -3 Test -4
Fibre Length (mm) 28.3 29.5 29.8 30.2
Uniformity Ratio % 47.8 48.3 48.5 48.7
Micronaire 3.78 4.28 4.02 4.10
Strength (Gms/Tex) 21.1 21.4 21.6 22.0
Short Fibre % 10.9 9.9 9.3 8.8
Hairiness Index 7.10 6.80 6.56 6.40
2. Production rate or processing speeds : - Yarn hairiness significantly increases
with increase in spinning machine speeds or production rate. The effect of
spinning machines speeds on yarn hairiness varies according to their sequence in
spinning process, however impact of each spinning process on yarn hairiness is
given on chart -2 for reference : -
Chart – 2 : Impact of increasing speeds on Yarn Hairiness
Process Impact on Yarn Hairiness
by increasing Speed.
Carding Moderate
Br. Draw Frame & Lap former No effect
Comber & Fin. Draw Frame Moderate
Speed Frame Slightly increases.
Ring Frame & Autoconer Greatly
Hence it is advisable to optimize the spinning process speeds according to
Quality requirement.

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3. Process Parameter : - Spinning process parameters are major contributing
factor for yarn hairiness. Following are the major contributing process
parameters for yarn hairiness : -
a. Narrow Guides : - Sliver Guides, trumpets & sliver tubes at DF’s,
combers and lap former to be selected narrow as possible to condense the
sliver fleece and roving. This helps to reduce the yarn hairiness.
b. Adequate draft at BDF to Lap former : - In modern spinning set up total
drafts in Br. DF to Lap former is recommended as 7.0 to 9.0. Total draft
more than this limit may lead increase in yarn hairiness.
c. Lap batt weight : - Significantly higher lap batt weight at comber also lead
high hairiness in yarn.
d. Greater parallelization : - Better parallelization in preparatory process
helps to reduce yarn hairiness.
e. Linear density of roving : - Yarn hairiness increases when the linear
density increases. This is due to the increases number of fibres in the web
and due to higher draft requires to spin the yarn.
f. Twist at roving & yarn : - Higher the twist at roving and ring frame
results into low hairiness.
Ring frame process parameters influencing yarn hairiness : - As ring
frame is the ultimate place for yarn production, hence each process parameter
of ring frame influence on yarn hairiness, these are as below : -
i. Spinning Geometry : - Construction of spinning machine can
significantly influence the yarn hairiness, the arrangement of the drafting
elements and size of spinning triangle are the greatest important.
ii. Size of Spacer : - Selection of spacer size also significantly impact on
yarn hairiness. A wider size spacer to be selected for reducing the yarn
hairiness, however it might increase the yarn imperfection.
iii. Selection of Ring & Ring Diameter : The right selection of type of
ring, quality of rings are the greatest important for yarn hairiness.

Yarn Hairiness 2013
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Following points to be taken care while selecting the ring & ring
diameter w.r.t. yarn Hairiness : -
 2 Flange ring may consider for coarse count range i.e. below 24sNE for
lesser yarn hairiness.
 The ring diameter can be chosen 25 mm smaller at a maximum with
regard to the spindle gauge.
 The ring diameter should be in between 1.8 to 2.1 times of top of
spinning tubes.
 The ring diameter should be maximum 1/5th
of the spinning tube length.
 Ring diameter should be 2 – 3 mm less as compared to balloon control
ring.
 Ring condition & ring life is major influencing factor for yarn hairiness.
1. Right choice of Ring traveller : - Right selection of ring traveller make,
traveller number or weight, traveller profile and traveller life are very
important factor for yarn hairiness. User may select right profile, make and
traveller number by conducting several trails w.r.t. yarn hairiness and breaks
level. Widen bow height and slightly heavier ring traveller helps to reduce the
yarn hairiness. The spinning tension has a considerable influence on the yarn
hairiness, the smaller the tension the greater the hairiness, thus heavier ring
traveller results in low yarn hairiness. However if traveller is too heavy yarn
hairiness will also increase, hence adequate ring traveller weight is must
require to get minimum yarn hairiness.
iv. Thread Guide setting : - Distance of the thread guide from the top of
the tube should be 1.5 to 2.0 times of ring diameter. Bore diameter of
thread guide also impact on yarn hairiness, smaller bore size reduces
yarn hairiness.
v. Anti-ballooning ring : -Size of the anti-ballooning ring should be ring
dia + 2.0 mm and distance from ring rail to anti ballooning (ring rail in

Yarn Hairiness 2013
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starting position) should be 2/3 of the distance between ring rail to
thread guide.
vi. Traveller Cleaner setting must be applied according to ring traveller
size & count pattern.
vii. Ring Rail Lift : Hairiness changes greatly with increasing in ring rail
lift especially at the top of the bobbin.
viii. Yarn hairiness increases with bobbin tip to bobbin base by almost 25 %
due to change in degree of ballooning, yarn tension, position of ring rail,
yarn angle at ring traveller and the condition of the ring traveller.
ix. Atmospheric condition : - Yarn spun in dry atmosphere observed more
hairy hence an ambient environment to be maintained in spinning
section.
Winding process parameters influencing yarn hairiness : It has been
observed that yarn hairiness increases at modern high speed winding machine
by 20 to 30 % and it is also too much varying according to different winding
process parameters, these are as below : -
i. Higher the drum speed higher will be yarn hairiness.
ii. Higher the winding yarn tension high will be yarn hairiness.
iii. High cradle pressure also lead high yarn hairiness.
iv. Metallic yarn guides in yarn path increases yarn hairiness hence it is
advisable to replace all metallic yarn guides with ceramic yarn guides.
v. Winding atmospheric condition also impact on yarn hairiness hence
relative humidity in winding section should be kept in the range of 55 -
65 %.
4. Mechanical conditions of machines : - Poor mechanical condition of ring
frame & winding section lead sever problem of high yarn hairiness such as
eccentricity of spindles, deform spinning tubes, out ring setting, worn out rings
& ring travellers, scratched & off alignment ABC ring and thread guides,

Yarn Hairiness 2013
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damaged roving guides etc. Hence all these things to be require proper care at the
time of preventive maintenance of ring frame.
Similarly in winding section all tension devices, thread guides, drums &
suction arms require proper care and defective parts should be replaced on
priority. These abnormalities create sever hairiness variation in yarn which may
also lead shade variation or barre problem after fabric dyeing.
 Conclusion : - Hairiness is characterized by the quantity of freely moving fibre
ends or fibre loops projecting from a yarn. Yarn hairiness significantly influence
the characteristics of yarn & fabric appearance and working performance of
spinning to it’s downstream processes. There are two commonly used test
methods available for yarn hairiness testing. Hairiness index obtained from
evenness tester provides the hairiness index i.e. the total length of protruding
fibres in unit length of yarn while another method provides detail length
distribution of hairs. For a textile yarn long hairs are undesirable while short
hairs are desirable, hence terms “S3” value comes into the force which denote to
the total number of protruding fibres having length 3 mm and longer. There are
four major influencing factors for yarn hairiness which has been explained in
detail. These are as : -
 Raw Material Quality.
 Production rate or processing speeds.
 Process parameters.
 Mechanical conditions of machines.
By effective monitoring of these factors yarn hairiness may be improved
significantly and maintain at comfortable level.
Produced by : Mr. Sunil Kumar Sharma,
Dy. General Manager – QAD, PPC & Customer Care
Mobile No. : – 09552596742, 09921417107

Yarn Hairiness 2013
Page 10
E_mail : - sunil_ku67@yahoo.com
Loknayak Jayprakash Narayan Shetkari Sahakari Soot Girni Ltd.
Kamalnagar, Untawad – Hol, Shahada,
Tal. : - Shahada, Dist. : - Nandurbar (MS)
Pin : - 425409

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