Yarn Conditioning

Advanced Yarn Manufacturing Azmir Latif, MSc in textile Engineering
Yarn conditioning
In which process yarn is conditioned for better performance (such as strength, serviceability,
luster, handle etc) is called yarn conditioning. Textile fibers are subjected to various physical
operations to make in to a yarn. For example cotton fiber passes through opening, carding,
drawing and spinning to become a yarn. During these phases the original moisture content on the
fiber would have been lost and some static electricity would be carried by the fiber. The amount
of static current carried by yarn changes from fiber to fiber. Similarly the strength of any fiber
depends up on how close the present moisture content is to the original natural value.
Similarly some high twist yarn would tend to lose its twist as and when it is allowed freely,
making a lengthwise elongation.
Some fibers would tend to shrink when exposed to hot atmosphere or any treatment that involves
heat and hence higher temperature. For example polyamide, polyester etc.Some blends like
Cotton/Lycra, Viscose/Lycra require conditioning to make the width the fabric stable.
So all the above said factors, if not addressed properly would reflect badly on the final quality of
yarn or fabric.
Moisture in atmosphere has a great impact on the physical properties of textile fibres and yarns.
Relative humidity and temperature will decide the amount of moisure in the atmosphere. High
relative humidity in different departments of spinning is not desirable. It will result in major
problems. But on the otherhand, a high degree of moisture improves the physical properties of
yarn. Moreover it helps the yarn to attain the standard moisture regain value of the fibre. Yarns
sold with lower moisture content than the standard value will result in monetary loss. Therefore
the aim of CONDITIONING is to provide an economical device for supplying the necessary
moisture in a short time, in order to achieve a lasting improvement in quality.
The relative humidity in turn affects the properties of the fibre via the moisture content of the
cotton fibre. The fibre strength and elasticity increase proportionately with the increase in
humidity. If the water content of the cotton fibre is increased the fibre is able to swell, resulting
in increased fibre to fibre friction in the twisted yarn structure. This positive alteration in the
properties of the fibre will again have a positive effect on the strength and elasticity of the yarn.
A process that addresses all the above parameters is called CONDITIONING. Conditioning
process differs from fiber to fiber.
So conditioning is a preliminary process in any processing that improves and maintains the
quality of yarn.
Conditioning may be done in yarn stage on perforated paper or plastic cones/cheeses in an Auto
Clave or Horizontal beam dyeing machine as shown above.
Conditioning Process for various yarns:

1) 100% Polyester yarn: Load the yarn in the form cones wound on plastic cones, in to a beam
dyeing machine. Introduce steam and raise the temperature to 100°C at 3°C per minutes. Steam
for 15 minutes at 100°C followed by 15 minutes cooling = 1 cycle. Repeat the cycle for 4 times.
2) 100% Nylon: Load the yarn in the form cones wound on plastic cones, in to a beam dyeing
machine. Introduce steam and raise the temperature to 100°C at 3°C per minutes. Steam for 15
minutes at 100°C followed by 15 minutes cooling to a temperature of 50°C = 1 cycle. Repeat the
cycle for 4 times.
3) Silk yarn: Load the yarn in the form cones wound on plastic cones, in to a beam dyeing
machine. Introduce steam and raise the temperature to 70°C at 3°C per minutes. Steam for 15
minutes at 70°C followed by 15 minutes cooling to a temperature for 30°C = 1 cycle. Repeat the
cycle for 4 times.
4) Cotton/Lycra (40's Lycra) or Viscose/Lycra (60's): Conditioning the yarn as mentioned for
silk.
The following effects would be envisaged by steam-conditioning of yarn:
 Twist Setting - Preventing Snarling (yarn loops)
 Better Dye affinity - Eliminating static electricity
 Influencing the Cloth handle - Preventing crease-proneness
 High bulking - Humidifying
 Dye - fixing - De-crinkling
 Determining residual boiling shrinkage.
The effects of yarn conditioning on yarn properties of both ring spun and open end 100% cotton
and cotton/polyester yarns and the resultant weaving
Because of the tremendous productivity and speed, air-jet weaving machines are becoming more
evident in today's textile world. However, these increased speeds place greater stresses on filling
and warp yarns. The process of conditioning yarn offers one possible method for enhancing yarn
performance on today's high speed weaving machines. This research was conducted to determine
the effects of yarn conditioning on yarn properties, weaving stop levels, and dye uptake
performance. Four types of yarns were used in this research. They were: 13.5/1 100% cotton and
cotton/polyester ring spun, 11.0/1 100% cotton open-end, and 12.0/1 cotton/polyester open-end
yarn. Also, a 40.0/1 100% cotton ring spun yarn was used for warp yarn. The yarns were
conditioned on two types of conditioners. One conditioner used a indirect steam system and the
other used a direct steam system. Two temperature levels of 50-55 degrees Celsius and 75-80
degrees Celsius were used in both types of conditioners. The conditioned yarns were tested for
single-end strength, single-end elongation, elasticity, torque (liveliness), and hairiness. Also,
unconditioned yarns of the same type were tested to provide a baseline for comparison. This
research also examined how yarn conditioning effects slashing parameters. The 40.0/1 100%

cotton ring spun yarns were slashed and tested for size pickup, encapsulation, penetration, and
tensile properties. Finally, the yarns used for warp and filling were knitted into socks and then
dyed. The purpose of this was to determine the effect of yarn conditioning on dye uptake and
delta E properties. The 13.5/1 100% cotton ring spun yarns and the 12/1 cotton/polyester open-
end yarns were woven as filling on air-jet weaving machines. The warp yarns were also woven
on airjet machinery. All weaving trials used a plain oxford weave. The yarn tests results revealed
that yarn conditioning did not affect strength, elongation, or elasticity. There were some
instances when yarn conditioning increased yarn hairiness, especially for ring spun yarns. One of
the most consistent findings of this research was that conditioning yarn on either system at either
temperature level, significantly reduced yarn liveliness. Results indicated that the indirect steam
system, operated at a 75-80 degrees Celsius temperature level, exhibited the most reduction in
yarn liveliness. The filling stop trials indicated that conditioned yarns wove at a lower stop level
than unconditioned yarn. However, only yarns conditioned on the indirect steam system, at 75-80
degrees Celsius, wove significantly better at the 95 % confidence level. This research also
showed that filling stop levels with ring spun yarn are affected to a greater degree than open end
yarns. Slashing procedures were kept consistent throughout the trial. Yarn conditioning did not
affect any of the slashing parameters tested. Because of this, the conditioned warp yarns did not
weave at a lower warp stop level. The dye uptake trials revealed that conditioned yarns absorb
less dye than unconditioned yarn. The difference in dye uptake was great enough to result in
visible differences, as indicated by the Delta E values. There were also dye uptake differences
between type of conditioner and temperature used. The 100% cotton yarns exhibited the greatest
differences in dye uptake. This is contributed to changes in the crystallinity of the cotton fiber
when the heat and moisture of yarn conditioning are applied.
Yarn Conditioning Process
High speed spinning machines generate more friction thus giving additional heat to the yarn and
as a result of such heat transfer the yarn moisture content is vaporized. Rising speeds in spinning
result in decreased yarn quality for other processes and it is well known that dry yarns have
worse properties. For quality reasons it is absolutely important to have even distribution of this
recuperated moisture throughout the entire yarn package. Only the vacuum technology provides
the conditions for the required moisture regain. This paper attempts to comprehensively review
the yarn conditioning mechanism, process parameters of conditioning and applications of yarn
conditioning.
Moisture in atmosphere has a great impact on the physical properties of textile fibres and yarns.
A high degree of moisture improves the physical properties of yarn and it helps the yarn to attain
the standard moisture regain value of the fibre. Yarns sold with lower moisture content than the
standard value will result in monetary loss. Therefore the aim of yarn conditioning is to provide
an economical device for supplying the necessary moisture in a short time, in order to achieve a
lasting improvement in quality.
In these days there is a dramatic change in the production level of weaving and knitting
machines, because of the sophisticated manufacturing techniques. Yarn quality required to run
on these machines is extremely high. In order to satisfy these demands without altering the raw
material, it is possible to make use of the physical properties inherent in the cotton fibres. Cotton

fiber is hygroscopic material and has the ability to absorb water in the form of steam. It is quite
evident that the hygroscopic property of cotton fibers depends on the relative humidity. The
higher the humidity is, more the moisture absorption. The increase in the relative atmospheric
humidity causes a rise in the moisture content of the cotton fiber.
The fibre strength and elasticity increase proportionately with the increase in humidity. If the
water content of the cotton fibre is increased, the fibre is able to swell, resulting in increased
fibre to fibre friction in the twisted yarn structure. This positive alteration in the properties of the
fibre will again have a positive effect on the strength
and elasticity of the yarn.
Problems in conventional yarn conditioning
method
The standard conventional steaming treatment for
yarn is chiefly used for twist setting to avoid snarling
in further processing. It does not result in lasting
improvement in yarn quality. The steaming process
may fail to ensure even distribution of the moisture,
especially on cross-wound bobbins (cheeses) with
medium to high compactness (Fig. 1).
The absence of vacuum in conventional conditioning chambers prevents Conventional
homogeneous penetration. The outer layers of the package are also too moist and the transition
from moist to dry yarn gives rise to substantial variations in downstream processing of the
package, both with regard to friction data and strength.
Since the moisture is applied superficially in the wet steam zone or by misting with water jets, it
has a tendency to become re-adjusted immediately to the ambient humidity level owing to the
large surface area. Equipment of this kind also prevents the optimum flow of goods and takes up
too much space.
CONTEXXOR conditioning process by Xorella
The thermal conditioning process of the yarn
according to the CONTEXXOR process developed
by Xorella, is a new type of system for conditioning
the yarn package (Fig. 2). Thermal conditioning
uses low-temperature saturated steam in vacuum.
With the vacuum principle and indirect steam, the
yarn is treated very gently in an absolutely saturated
steam atmosphere. The vacuum first removes the air

pockets from the yarn package to ensure accelerated steam penetration and also removes the
atmospheric oxygen in order to prevent oxidation. The conditioning process makes use of the
physical properties of saturated steam or wet steam (100% moisture in gas-state). The yarn is
uniformly moistened by the gas. The great advantage of this process is that the moisture in the
form of gas is very finely distributed throughout the yarn package and does not cling to the yarn
in the form of drops. This is achieved in any cross-wound bobbins, whether the yarn packages
are packed on open pallets or in cardboard boxes.
Effect of conditioning process parameters on yarn properties
Although yarn conditioning machine can add the moisture of yarn, one must consider different
raw material and yarn counts to make different yarn conditioning programs. In spite of higher
moisture, if there is high vacuum condition, the low quality of raw cotton, coarse count and
higher ratio of short fibre would make yarn over relaxed and thus will have less strength. Thus
cotton yarn less than Ne 21s, needs less vacuum, low steam temperature, longer heating up time
and constant temperature. For PC or pure polyester fibre as well as combed yarn. It requires high
vacuum degree and high steam temperature. The time for heating up and constant temperature is
related to the actual twist but maximum should not exceed 70 minutes.
Steam temperature is set according to the types of fibers. If cotton fiber is conditioned under 100
for 20 days, it would have only 92% strength left, but polyester fibre under the same conditions
would retain 100% strength. For different fibers, there is a big difference in the flow temperature,
fusion, resolution and other index of thermo logy. Maximum temperature for cotton fiber in yarn
conditioning machine should not exceed 85 but pure polyester could reach 140. Otherwise it will
have negative effects on breakage strength and colors.
P. V. Kadole et al found that, the cycle with first cycle temperature 58C - 05 min. and second
cycle temperature 62C - 25 min. (with total time for the cycle 55 min.) gives optimized yarn
properties for 20KW (4.26 TM), 20KH (3.78) waxed, 20 CH waxed. (3.6 TM) yarns. They also
stated that in case of conditioning waxed and unwaxed yarn simultaneously with same
programme, care should be taken while selecting maximum temperature in second cycle. Always
it should be less than melting point of the wax. They showed that the combined programme helps
in achieving best yarn results at low power cost and higher production rate.
Sibel Sardag et al studied the effects of vacuum steaming process parameters (temperature and
duration) on tenacity properties of 1 00 % cotton and 100 % viscose yarns. For this purpose, the
yarns with different twist coefficients and numbers were twisted and exposed to vacuum
steaming at different temperatures and for durations appropriate to their raw material properties.
Tenacity properties of the yarns were measured before and after vacuum steaming. They found
that vacuum steaming temperature has significant effect on tenacity properties of 100% cotton
and 100 % viscose yarns but vacuum steaming duration has been found to be statistically
insignificant on tenacity properties of cotton yarns, and viscose yarns.
In another study, these authors showed that tenacity, elongation at break (in per cent), and work
of rupture of 30 tex and 20 tex PES/viscose yarns were to be enhanced due to heat-setting. They
also showed that the tenacity and elongation at break values of the yarns decreased after dyeing;

however, these values are still high when compared with those of the pre-heat setting. The
increase of temperature from 90C to 110C caused a decrease in the strength values of the yarns.
For this reason, they considered the heat- setting at 90C to be sufficient to enhance the strength
properties of PES/viscose yarns - consisting of 67% PES and 33% viscose.
Yarn conditioning machine does improve the CV of yarn and also it does not make it worse. It is
the fact that CV and neps of yarn detected by yarn evenness tester is raised rapidly for yarn, just
taken from the yarn conditioning machine. However, leaving it for 24 hours, later the data will
remain as before. The reason is after processing, a part of water gets into the inner core of yarn
and becomes relatively steady crystal water, and water attached to the surface of yarn becomes
unsteady. The difference in each part of the surface water would result in different dielectric
coefficient, which makes the yarn evenness tester give inaccurate results.
In case of cotton fiber, absorption of moisture is delayed after processing in the yarn
conditioning machine. It is therefore, better to pack or use the yarn after 30 minutes rest in the
yarn stock room. This would allow enough time for the surface water to evaporate and also to
retain the same moisture level both inside and outside of the yarn. The yarn that has been
processed in the yarn conditioning machine should not be mixed with the one which has not been
processed; otherwise, there will appear long and narrow shadow on the final product after
dyeing, especially for knitted fabric.
Major applications of the yarn conditioning
In spinning process yarn conditioning machine is used to adjust the moisture of yarn and to
improve efficiency in the next process. After processing, when the moisture level of yarn would
reach about 8.5 %, strength and elongation can be increased greatly, which help the performance
at processing line. The dealing of cone yarn would improve the efficiency on winding, doubling
and twisting and also reduce the yarn hairiness. It will be also helpful to improve warping
efficiency and to reduce the defects from rewinding and warping. Owing to the conformity of
moisture of the yarn, the efficiency of sizing and weaving will also improved ensuring the
quality of the final fabric.
The yarns after processing by yarn conditioning machine would improve the working process as
well as the quality of final fabric. Because of fixed twisting and shaping of the yarn, it will give
equal height of rising and looping, reduce the unwinding tension, stable the structure and size of
the end fabric and give better appearance. Especially it is the key process for setting the seamless
underclothes. The process of conditioning will not only stabilize the twist, but also fully relax the
yarn to reduce the shrinkage of final product.
In dyeing industry, processing after yarn conditioning machine can remove the stress on grey
fabric, which will be helpful for uniform absorption of dyes to obtain bright color as well as
uniform shade of the fabric. In garment industry, yarn conditioning machine can make fabric
with stable size, reducing the shrinkage and improving the quality. Processing yarn, especially

the chemical fiber, in the conditioning machine can greatly improve the quality and appreciation
of product.
Conclusion
Textile market is becoming sensitive buyer's market. Weaver is demanding dimensioned quality
with consistency from spinners. Therefore in order to satisfy these demands without altering the
raw material; the hygroscopic nature of cotton fibers can be used. Therefore most of the spinning
mills are now going for YCP. These modern YCP gives us even penetration of steam into all the
layers of yarns on cone & ensures even conditioning effect throughout the package. The yarn
conditioning plant supply the yarn with increased strength & elongations, that have reduced
snarling of yarn, improved working at post spinning processes like warping, weaving, knitting,
etc. Yarn conditioning reduces invisible loss to the spinners. Though its initial cost of investment
is high, but its payback period is very less.

Yarn Conditioning

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