Advance spinning techniques

Advance Spinning
Techniques
Coarse Code: YM-4013
By
Sohail AD
12-NTU-0024
National Textile University

What is Spinning?
• Spinning is an ancient textile art in which plant, animal or synthetic
fibers are drawn out and twisted together to form yarn. For
thousands of years, fiber was spun by hand using simple tools, the
spindle and distaff.
• Spinning is a major part of the textile industry. It is part of the textile
manufacturing process where three types of fiber are converted into
yarn, then fabrics, which undergo finishing processes such as
bleaching to become textiles. The textiles are then fabricated into
clothes or other products.

Definition
Spinning could be defined as;
• The drafting and, where appropriate, the insertion of twist in natural
or staple man-made fibers to form a yarn.
• The extrusion of filaments by spiders or silkworms.
• The production of filaments from glass, metals, fiber-forming
polymers or ceramics.

Spinning Process
• Spinning process basically consists of three stages;
1) Reduction of strand thickness from supply roving or sliver to
required yarn count. This is usually done by roller drafting.
2) Prevention of fiber slippage usually by twist insertion, although
there are new methods invented now. Simply binding of individual
fibers.
3) Winding on to a package which is convenient for handling and
which protects yarn.

Spinning history & 1st Spinning technique
• The origins of spinning fiber to make string or yarn are lost in time but
some history researchers said that it was some 20,000 years ago.
Spinning was totally done by hand.
• Then man invented a hand wheel to produce yarn. This was the 1st
mechanical method produced to make yarn.

Spinning machines
• With passage of time human always try to make everything easy.
• Man tried to improve the spinning wheel to omit personal effort
(Wheel was run by hand or foot manually).
• Gradual improvements in manual spinning methods lead to different
type of spinning techniques and human becomes successful to omit
personal efforts.

Classification of spinning machines
• Spinning machines are divided into two main groups;
1) Intermittent
These machines only carry winding section, while drafting and binding
are interrupted. Mule and centrifugal spinning lies in this category.
2) Continuous
Machines of this type perform the three stages of spinning process
(drafting, binding, winding) simultaneously on consecutive lengths of
material. It is sub-divided in different categories.

Continuous Spinning machines
• These are sub-divided as;
i. Conventional frame spinning machines
These machines were invented during late 18th and early 19th centuries;
a. Flyer Spinning
b. Ring spinning
c. Cap spinning
ii. Modern commercial machines
These machines became available during 1960s and 1970s as the result of
intensive research effort;
a. Open-end spinning
b. Repco self-twist spinning

Continuous Spinning machines
iii. Other spinning machine developments
This group include machines which have not yet been adopted widely
for commercial stage of application;
a. Twistless spinning
b. Spin-folding and wrapped yarn spinning
c. Front folding
d. Jet Spinning
e. Bobtex A.B.S. (aerodynamic brake spinning)
f. Bobtec I.C.S. (integral composite spinning)

Background for development of new spinning
techniques
• New spinning processes have been available in practicable form for
almost 40 years and still the most of short staple yarns are spun on
conventional systems.
• Some pros and cons of each system are always there. Keeping in mind
these pros and cons, a system is adopted and commercialized.
• Ring spinning is one of the most used conventional spinning
technique, which is still used in a great proportion.
• Now the question is “Why new systems were developed and why ring
spinning is still used.

Why is ring spinning still in use?
Ring spinning is still in use for its following salient features, to which no
replacement is available;
• Production of high strength yarns.
• Spinning of fine count yarns.
• Proper for special yarns.
• It is universally applicable (any material can be spun).
• The know-how for operation of machine is well established accessible to
everyone.
• It is flexible as regards quantities (blend and lot size).
• Since the speeds in drawing section are best controlled, yarn evenness is
excellent. But if short fibers are too much, yarn unevenness occurs.
• Fine yarns can be produced as compared to open end system.

Potential to develop new techniques
What was the potential to develop new processes to produce yarn?
Ring spinning has following drawbacks due to which man think to
develop new processes;
• Process stages are more numerous. Roving stage exists as an extra
process compared to the other systems.
• Yarn breakages are more numerous as a result of ring traveler friction
and yarn air friction.
• Interrupt ions, broken ends and piecing up problems exist because of
the yarn breakages.

Potential to develop new techniques
• The high speed of the traveler damages the fibers.
• The capacity of the cops is limited.
• Energy cost is very high.
• Low production rate.
• Additional winding process is required at the end to make bigger
packages.
Due to these disadvantages of ring frame, researchers try to develop
new systems to omit these negative points but new systems also have
their individual limitations and are confined to restricted sectors of the
market.

Disadvantages of new systems
• A yarn character different from that of the ring spun yarn, which still
represents the basic standard for comparison.
• Characteristics occasionally bordering on unusable.
• Difficulties in maintaining consistently uniform characteristics.
• Greater demands on the raw material.
• Market segments limited to (narrow count range, specific raw
material types and specific end product).
• A high level of process know how.
• Expenditure on repair and maintenance.

Advantages of new techniques
• High production rates
• Elimination of process stages
• A considerable reduction in personnel and space
• Relative ease of automation
• In some cases, with the use of auto-leveller at the cards, elimination
of even the draw frame passage.
• Less labor and power cost per kilogram of yarn.

Ring spinning in future
• Researches are on and in future may be researchers got success to
eliminate disadvantages of new systems. So, these systems may
eliminate ring spinning in future.
• The ring frame can only survive in longer term if further success is
achieved in automation of the ring spinning process. Also, spinning
costs must be markedly reduced since this machine is significant cost
factor in spinning mill.

Ring and rotor spun yarn properties
Yarn properties depend on raw material used, twist, fiber length, fiber density, individual fiber
strength and many more basic terminologies but generally ring spun yarn has following properties:
• Strongest yarn
• Finest yarn
• Softest yarn
• "Z" and "S" twist
• Lowest productivity
• Most uneven
• Most expensive
• More hairy, generally
• More torque
• Widest range of yarn counts

Ring and rotor spun yarn properties
Generally rotor spun yarns have following properties:
• More even
• Higher strength uniformity
• Higher production rate
• Fewer processes
• Lower cost
• Fewer imperfections
• Harsher hand (feel)
• Not as strong
• Limited counts-coarser yarns
• “Z” twist only

Comparison
Ring Spun Yarn Rotor Spun Yarn
Uniform with more strength than rotor spun. Uniform but less strength than ring spun.
Low flexibility. Higher flexibility than ring spun.
Dye ability is less than open end yarn. Dye ability is easy and more than ring spun.
These yarns are made coarser to medium and
medium to finer.
These are limited to coarser to medium counts.
Used for varied applications. Used for heavier fabrics such as denims, towels
and poplins.
Production rate is lower. 3-5 times faster production rate than ring spun.
Stronger at optimum twist. It has 20% more twist and 15-20% weaker than
ring spun.
All staple fibers could be ring spun. Universally
applicable.
Man-made fibers except rayon could not be rotor
spun.

Comparison
Ring spun Yarn Rotor Spun Yarn
It is expensive because of some additional
manufacturing steps.
It is cheaper because of elimination of some
manufacturing steps such as roving and comber.
It is less abrasion resistant as compare to rotor spun. It has a good abrasion resistance.
It is less absorbent because of tight packing of fibers. It is more absorbent because of loose packing of fibers.
It breaks at ring frame because of ring traveler friction. Yarn breakage is very low so less production loss.
It has more hairiness because of fiber migration during
spinning.
It has 20-40% low hairiness as compare to ring spun
because of less fiber migration.
It feels harsh because of tight packing of fibers and
more hairiness.
It is soft because of loose packing and less hairiness.
Fiber packing is uniform and more towards surface. Fiber packing is not uniform, more towards yarn axis
and less towards the surface.
It has less hooked and looped fibers. More hooked and looped fibers in rotor yarn.
It doesn’t give self-cleaning effect. It is dirt accumulative and give very good self-cleaning
effect.
It has higher C.V% in strength than rotor spun. It has less variation in strength.

Comparison
Ring Spun Yarn Rotor Spun Yarn
Ring spun could have more yarn faults. Yarn faults are decreased by 80%.
Fiber blending is not good in ring spun. It has much better fiber blending.
It has more fly liberation. It has less fly liberation.
More end breaks in spinning. 75% less end breaks.
Air permeability is low because of tight packing. Air permeability is 15-25% better.
It gives less cover in fabric formation. It gives 10% better cover.
At this time 76% staple spun yarns are ring spun
as compare to rotor spun in world.
24% are rotor spun as compare to ring spun
production.

Structure of ring and rotor spun yarn
• The yarn structure is dependent primarily upon the raw material,
spinning process, spinning unit, machine, machine settings, twist, etc.
• The structure can be open or closed; voluminous or compact; smooth
or rough or hairy; soft or hard; round or flat; thin or thick, etc.
• Both ring and rotor spun yarns are produced by twisting but there lot
of differences in both yarns due to difference of their structure.
• Structure of yarn influence a lot of yarn properties.

Yarn structure is not simply appearance. It has a greater or lesser influence on;
• Handle
• Strength
• Elongation
• Insulating capacity
• Covering power
• Ability to resist wear, damage, strains, etc.
• Resistance to abrasion
• Ability to accept dye
• Tendency towards longitudinal bunching of fibers
• Wearing comfort, etc.

Open-end Spinning
• Open end spinning or open-end spinning is a technology for creating
yarn without using a spindle.
• It is also known as break spinning or rotor spinning.
• In this process the fiber sliver is separated into single fibers and in
which the separated fiber material is brought by an air stream to a
collecting surface from which it is drawn off while being twisted.

Principle of open-end spinning
• The principle behind open end spinning is similar to that of a clothes
dryer spinning full of sheets.
• If you could open the door and pull out a sheet, it would spin
together as you pulled it out.
• Sliver from the card goes into the rotor, is spun into yarn and comes
out, wrapped up on a bobbin, all ready to go to the next step.

Advantages of open-end spinning
• High speed of twist insertion which leads to high delivery speed
• Lower power consumption
• Large delivery package
• Elimination of process steps like roving
• Cheaper raw material
• Reduced labour requirement & better working condition
• Continuous operation
• Lower yarn fault content
• No twist variation

Open-end Spinning techniques
Following spinning methods lie in open-end spinning;
1) Rotor spinning
2) Air vortex spinning
3) Electro static spinning
4) Friction spinning
5) Break spinning
6) Disc spinning

Short description
Rotor Spinning: Individual fibers converted to yarn through rotary
motion.
Friction Spinning: External surface of two rotating rollers is used twist
individual fibers into a yarn.
Air-jet Spinning: Utilizes air to apply the twisting couple to the yarn
during its formation.

Short description
Electrospinning uses an electrical charge to draw very fine (typically on
the micro or nano scale) fibers from a liquid.
Break Spinning: Sliver feed stock is highly drafted and assembled at
end of rotating yarn.
Disc spinning: Card sliver is fed to an opening roller just like rotor and
then fibers are transferred to screened surface disc where an external
twister twist fibers to yarn.

History
• The idea of producing yarn by the Rotor-Spinning technique is far
from new.
• Patent applications for this method were filed before the Second
World War.
• However, the first usable design was put forward only in the mid-
1950s by J. Meimberg at the Spinnbau company in Spinnbau showed
this machine at Brussels exhibition in 1955, but further development
of the machine was discontinued because performance proved
unsatisfactory.

Development
• 1960s; The idea was taken up again in Czechoslovakia.
• 1965; The first machine really suitable for industrial application was
shown at Bruenn fair.
• 1967; followed by the presentation of the BD200 machine at an
exhibition in parallel to the ITMA of that year.
• This was also the point of time at which the rotor-spinning came into
practical industrial use in spinning mills.
• The current market share is 20% of total staple yarn production and
is steadily increasing.
• 1970s; rapid development in technological and economical aspects.

Development
• Earliest yarn used to be a woolen-spun character (open, voluminous
and rough with low strength).
• After further research and development, now it is hardly possible to
distinguish rotor spun yarn from ring spun yarn.

Economical aspects
• Rotor speed used to be 30,000 rpm. After 20 years of development,
today speed of rotor is around 175,000 rpm.
• Production of rotor spinning is four to ten times more than that of the
ring spinning spindle.
• Rotor spinning is more economical than the ring spinning for yarn
counts up to Ne 40.

Economical aspects
• The rotor spinning is an excellent recycling device as the spinning mill-
waste (secondary materials) is utilized and used. It was not previously
possible in ring spinning.
• Rotor spinning is the first final-spinning machine to be practically fully
automated.

General Overview
This is normally used in cotton
carded spinning. The frame is fed
with slivers from the draw frames
which transform the yarn directly
into packages, eliminating the
passage on the roving frame and,
in many cases, further packaging
operations.

Principle
The main function of the spinning unit is as follows;
The sliver from the draw frame is introduced by a feeder cylinder and is
subject to the action of an opener with saw-toothed wiring which
rotates at a speed of between 6000 and 9000 rpm, separating the sliver
into single fibers, then the fibers are sent to the rotor through a
vacuum channel. The rotor, whose diameter is between 32.5 and 54
mm, rotates at a very high speed over 100,000 rpm, and compacts the
fibers partly thanks to its special shape, twisting the fibers at the same
time.

Operational Sequence
Sequence of operations performed on a rotor spinning machine is;
1) Sliver feed
2) Sliver opening
3) Fiber transport into rotor
4) Fiber collection
5) Yarn formation
6) Yarn take-up and winding

Sliver feed
• A card or draw frame sliver is fed through a sliver guide via a feed
roller(F) and feed plate (B) to a rapidly rotating opening roller(O).

Sliver feed
• Sliver fed via trumpet into the feed shoe. If the yarn breaks the sliver
fed is ceased shoe. If the yarn breaks the sliver fed is ceased
immediately.
• Feed roll has diagonal fluted to increase the clamping. Sometimes
the distance between the feed shoe and opening roller is adjusted.

Sliver opening
• The opening roller removes the fiber from the sliver as it is fed in,
and, after two or three rotations, delivers them to the feed tube in
which the airflow takes them to the rotor.
• Removal of fibers from the opening roller is by controlled air flow,
aided by centrifugal acceleration.
• The ratio of air speed to opener surface speed should be in the region
of 1.5 to 4.0. The higher ratios result in a higher yarn tenacities
because of the improved fiber orientation.

Opening roller
• Opening roller, comparable to that of the carding in-feed taker-in, but
the assembly is much smaller. Opening roll rotate at 35 m/s and
passes through the fiber beard that is slowly fed by feed roll.

Opening roller
• It rotates at 5,000 to 10,000 rpm, usually 6,500 to 8,000 rpm.
• The diameter lies between 60 and 80mm.
• High speed disadvantageous may lead to fiber deterioration or even
damage melt spot and tearing out of fiber bunches.
• Basically the opening roller speed should be as low as possible. It is
important to note, however, that too slow a speed tends to cause
fiber lapping and irregularly spaced thick and thin places in the yarn.
• On the other hand, increased opening roller speed causes higher dust
formation, higher fiber damage, reduction in yarn strength and
breaking elongation.

Opening roller
• The opening roller surface speed usually depends on the type of fiber
and the roller design.
• A higher opening speed may be required to provide increased
opening force in the following circumstances;
i. increased feed sliver count, even when the feed rate in mass per
unit time is constant.
ii. increased fiber length.
iii. the use of three-dimensional crimped fiber (compared with two-
dimensional crimp).
iv. the use of finer fibers, because of the increased fiber surface area.

Opening roller
• The clothing on the opening roll naturally exerts a great influence;
a) Type of clothing
b) Shape of teeth
c) Point density
• The card clothing used on the opening roller is usually of the rigid
metallic type, varying from a face angle of about 65° and 18.5
points/cm2 for cotton and 80° to 100° with 15 points/cm2 for
manmade fibers.

Opening roller
Clothing of opening roller is selected as;
• for carded, combed and viscose – clothing with more agressive
front flank, higher density (2.5 mm) (type B 174)
• cotton with honeydew – clothing with wider tooth space
(4.8mm) & type used (type B 174 - 4.8)
• for man-made fibers especially polyster and blends – clothing
with less sharply inclined and less sharp point (S 21)
• for man-made fibers especially polyacrylic – clothing with low
height and low density (S 43)

Opening roller
Geometry of wire clothing is as;

Opening roller
• Opening roller service life is considerably affected by the fiber
material as well as by the dirt content in the fiber.
• The main wear points are the tooth face and tooth tip.
• Service life can be extended by the shape of the tooth (e.g. sickle
shape, rounded tooth tip) and by tooth coating. Coated teeth show
much lower levels of wear.
• Diamond-coated opening rollers have proved excellent in this respect.

Opening unit
a) rotating teeth of opening roller
b) feed table
c) feed roller
d) fixed fiber beard support
e) trash removal
f) adjustable bypass system

Trash removal
• The trash particles are extracted by centrifugal forces in the first 90
degree of the opening roller revolution.
• The higher the peripheral speed, the coarse trash will be thrown away
due to centrifugal force.
• Trash can be eliminated by either pneumatically or mechanically by
small transport tube on the chamber.

Fiber transfer to rotor
• Centrifugal forces and a vacuum
in the rotor housing causes the
fibers to disengage at a certain
point from the opening roller and
to move via the fiber channel to
the inside wall of the rotor.

• After opening the fibers must be passed to the rotor, so a closed tube
serves as a means of guidance and feed the fibers directly into the
rotor wall for deposition. While the air directly into the rotor wall for
deposition.
• While the air-together with the dust flows over the rotor rim towards
the collection unit.
• This feed has got the shape of convergent tip towards the rotor which
helps accelerate the fiber, hence draft occur and remain the 1 to 5
fiber in section.

• Ideally the fiber should pass down the feed tube one at a time, but in
practice the average number of fibers in the feed tube cross section
can be as many as four.
• If too many fibers are fed along side each other, the rotor tends to
accumulate tufts of fibers, thereby increasing yarn irregularity.
• The fibers passing along the feed tube are in a relaxed state.
• As a result fiber tensions are much more evenly distributed in yarn,
causing less fiber migration than in ring spun yarns.

Shape & direction of fiber transfer tube
There are two ways of feed tube arrangements;
1) Axially
2) Tangentially
• The shape of the fiber guide channel is crucial for fiber transport and
the desired longitudinal orientation of the fibers.
• The inlet and outlet openings of the fiber guide channel must be
designed and produced so that the transfer of fibers from the
opening roller, fiber transport in the guide channel itself and the
transfer of fibers to the inside wall of the spinning rotor are trouble-
free.

• The fiber channel narrows toward the rotor, which causes
acceleration of the air and fiber flows.
• This acceleration is of great significance because it leads to further
separation of the fibers, down to between one and five fibers in
section, and also straightens the fibers.
• The narrowing region represents a second draft zone (following the
feed roller/ opening roller).

Axial arrangement:
• The only advantage of this arrangement is that it is possible to spin
either S or Z twist merely by reversing the direction of the rotor
rotation.
• On the other hand, with such an arrangement there were at least two
right-angled turns in the fiber flow path which contributed to fiber
bucking, as well as problems with air turbulence near the rotor center
and a greater incidence of wrapper fiber.
• As a result, the disadvantages of this arrangement outweighed the
one marginal advantage.

Tangential arrangement:
• Latest designs have adopted a tangentially-placed feed tube. The tube
is usually tapered thinner towards the exit end so that the
accelerating air aligns and straightens out the fibers before their
leading ends emerge from the tube to contact the smooth surface of
the faster-moving rotor slide wall which slopes at an angle of from 20
to 40 degrees to the rotor axis.
• This increases the likelihood that the fibers are fully straightened
before they enter the actual collecting groove.
• Only disadvantage of this arrangement is that only Z twist is possible.

Fiber collection in rotor groove
• The centrifugal forces in the rapidly rotating rotor cause the fibers to
move from the conical rotor wall toward the rotor groove and be
collected there to form a fiber ring.
• The amount of rotation given to a fiber as it moves into the collecting
groove depends on the rotor diameter, the slide wall angle, and the
axial distance from the feed tube exit to the collecting groove.

Yarn formation
• The rotor rotates at high speed creating a centrifugal force.
• To start spinning, a length of yarn already wound onto the package of the
take-up mechanism is threaded through the nip line of the delivery rollers
and into the draw-off tube.
• Because of the vacuum, the tail end of this yarn is sucked into the rotor.
• The rotation of the rotor pulls the yarn end onto the part collected ribbon
of fibres through the air drag and the centrifugal forces, and
simultaneously inserts twist into the yarn tail.
• A little of this twist propagates into that part of the ribbon in contact with
the yarn tail, binding it to the yarn end.

Yarn formation
• The yarn is pressed against the rotor wall by the high centrifugal
force, and the separation point therefore rotates within the rotor.
• Each revolution of the yarn at this point inserts one turn of twist. The
yarn twist penetrates in to the fiber ring in the collection groove,
where the fiber are bound together to form a yarn.

Twist Insertion in rotor spinning
• In rotor spinning, the fiber collecting surface, (rotor groove), is v-
shaped and therefore fibers are usually translated from a triangular to
a circular shape. The fiber assembly, being formed in the rotor
groove.
• In order to begin spinning, one end of an existing yarn (Y), is
introduced into the rotor through the yarn withdrawal tube.
• The free end of the seed yarn is thrown to the peripheral surface of
the rotor by the centrifugal force produced.
• The high speed of the rotor causes the yarn end to rotate in the same
direction as the rotor itself.

Twist Insertion in rotor spinning
• When the rotating end of the yarn touches the fibers assembled in
the rotor groove, it acts like a crank and twists the yarn section
following the draw-off nozzle outside the rotor.
• In this way, twist is produced primarily outside the rotor, between the
draw-off nozzle and the subsequent yarn deflection or yarn nip point.
Direction of
Yarn Rotation
Draw-off
Nozzle
Yarn in Rotor
Groove
Yarn Rolling
Movement on
Nozzle
Yarn
P
O

Twist Structure
• The rotor groove enter as a thin stream of fibers and it takes many
layers to make up sufficient linear density to make a yarn. There are
many doublings, which tend to even out any short-term irregularities
in the yarn. Thus, rotor yarns tend to be more even.
• On the other hand, these doublings have an adverse influence on the
twist structure of the yarn.
• The first few layers make the core of the yarn and the other layers
twist without any firm link being established between the layers. Due
to the lack of interlinking, these layers form concentric sleeves. These
sleeves easily slip when the yarn is subjected to a tensile load.

Twist structure
• Apart from the layers, which form the body of the yarn, the fibers
caught by the rotating yarn arm also form a layer.
• These fibers are irregularly distributed throughout the length of the
yarn and wrapped around the yarn with a non-uniform winding angle
and hardness. Thus, the twist in the core is not the same as in the
outer layers.

The Rotor
This is the main part of this spinning technique. Different factors of rotor that
effect the final product and spinning process are;
1) The rotor form
2) The groove
3) The rotor diameter
4) The rotational speed; together with
5) The rotor bearing
6) The coefficient of friction between the fiber and the rotor wall
7) The air flow conditions inside the rotor
8) Liability to fouling

Rotor Cleaning
• An essential element of a functioning spinning unit is automatic rotor
cleaning capability. This is one of the major advantages of the rotor
spinning system compared with other spinning processes, which are
unable to clean the raw material fed in again at the spinning position
itself.
• Essentially, two systems are used to clean the rotors: pneumatic
cleaning by means of compressed air and mechanical cleaning by
means of scrapers. Both systems are also used in combination.
• During rotor cleaning the surface of the draw-off nozzles and the
draw-off tube are also cleaned.

Rotor drive and bearing
• Nowadays, the rotors on all rotor spinning machines are driven using
the friction drive principle, i.e. by a tangential belt in contact with the
rotor shafts on each side of the machine.
• Rotor drives are classified in two types;
1) Direct
2) Indirect

Direct drive
• Direct rotor bearing in which tangentially driven rotor shaft(a) is
encased in ball bearing housing(b).
• The ball bearing rotates at the same speed (rpm) as the rotor shaft
driven by the tangential belt. This bearing principle limits rotor
speeds to approx. 110 000 rpm.

Indirect drive
• Indirect rotor bearing, in which the rotor shaft, also driven
tangentially, runs on two pairs of supporting discs arranged side by
side.
• With the support disc bearing the rotor speed is reduced at a ratio of
1:8 to 1:10 relative to the bearing of the supporting discs, depending
on the diameter of the discs, so that these bearings run at speeds of
only 16 000 to a maximum of 20000 rpm (depending on the diameter
of the supporting discs), even at rotor speeds of 160 000 rpm.

Indirect drive
• For one thing, this bearing system permits much higher rotor speeds
than direct bearings, and at the same time the service life of indirect
bearing systems is significantly higher than that of directly driven
bearing systems.
• High-performance rotor spinning machines operating at speeds of up
to 160 000 rpm are therefore operated only with indirect rotor
bearing.

Indirect drive
Tangential belt (a) is engaged with the rotor shafts via pressure rollers
(b) to drive the rotors.

Yarn take-off
The yarn is taken from the rotor by the delivery shaft and pressure
roller (a), diverted virtually at right angles in the process by draw-off
nozzle (b) projecting into the rotor and guided out by draw-off tube (c)
immediately following this.

Yarn take-off
• At take-off the yarn continuously rolls off on the surface of the draw-
off nozzle due to the rotation of the rotor.
• This rolling-off temporarily inserts additional twist into the yarn
(contrary to the direction of twist of the yarn), thus creating the false-
twist effect required for spinning stability, which can be up to 60 % of
the set yarn twist.
• The greater the false-twist effect, the higher the spinning tension.

Yarn Piecing
• If a yarn breaks, the spinning process is interrupted at the particular
spinning position. Re-starting the spinning process is called "piecing".
• The robot "pieces" the newly spun yarn onto the yarn-end to be
found on the package.
• Number of robots vary with respect to machine length. Four types of
robot option are available;
i. Machines with one robot
ii. Machines with two robots
iii. Machines with three robots
iv. Machines with four robots

Yarn Piecing
• The use of only one robot per machine is economically justifiable only
for very short machines.
• If one robot is used for longer machine lengths then it takes more
time for robot to reach to every spindle that decreases efficiency by a
great proportion.
• One robot is suitable for 20-50 spinning positions.
• Two robots are applied on machines with 240-280 spinning positions.
• Three robots are applied where a 3rd robot works as alternative to
other two on one side of machine.
• Four robots are used for machines with 500 spinning positions.

Position of piecing robots
Machines with two robots

Machines with three robots

Machines with four robots

Piecing process
• Robot locks onto the spinning position with an end down.
• The feed roller starts. Fibers are fed into the rotor where they form a
fiber ring.
• The yarn end, prepared by the Robot is "dropped" into the rotor and
connects itself with the fiber ring.
• The yarn is withdrawn from the rotor. The fiber ring is broken and the
spinning process starts.

Step-wise piecing process
A. The end of the thread is taken off the package and inserted in the rotor at the same time as
starting fiber feed.
B. The piecing is formed under processor control and thread take-off is started.
C. The piecing is examined electronically and then wound onto the package.

Yarn take-up and winding
• Once the yarn tail enters the rotor, the
delivery rollers (K) are set in motion
to pull the tail out of the rotor. The
pulling action on the tail results in a
peeling of the fibre ribbon from the
rotor groove. The newly formed yarn
(Y) is wound up on a cheese (P) by a
winding drum. A yarn stop motion
interrupts material supply to the
opening roller (O) when an end
breaks. Capacitive or optical sensors
incorporated in the yarn path record
yarn faults (thick and thin places),
enabling them to be cleared in limits
are exceeded.

Yarn Package formation
Cylindrical
• package angle 2° to 4°20
• max. diameter 350 mm; max.
• package weight up to 6 kg;
Conical
• package angle (2° - 4°51’)
• max. diameter 280 mm;
• package weight depends on package density.

How to calculate of package density?
Density () = Mass / Volume
Density () = yarn net mass (g) / yarn volume (cm3)
Standard values for package density for yarns made from cotton and
cotton-like fibers:
packages for package dyeing: γ = 0.33 - 0.38 g/cm3;
hard packages: γ = 0.38 - 0.42 g/cm3
Volume of cone: 1/3  r2 h

Anti-Patterning device
”to remove pattern zone and pattern winding”
• Mathematical relationship between tranverse ferquency & rate of
revolution of package (1:1, 1:2, 1:3)

Length Measurement
• Diameter of package base (old method)
• Measuring length device (new method)
• Technical standard of length variation is ±0.5%.

Yarn waxing device
• It is used to achieve the maximum reduction of coefficient of friction
by 40-50%.
• Amount of application is 0.5 – 3 gram / kg of yarn.

Auto-Doffing
• Package change on automated rotor spinning machines is actuated
when the preset length of yarn or package diameter is reached.
• When the package has reached the preset yarn length, the spinning
position is switched off by the electronic length measurement device.
• The full package is placed on the package conveyor belt in the center
of the machine by a robot arm, and at the same time spinning is
started on an empty tube.

Selection of raw material
Rotor can produce yarn from;
1) Cotton
2) Cotton waste
3) Cotton noil
4) Blend of two or more of these materials
5) PES
6) PAN
7) PA
8) CV
9) All other possible blends

Raw material requirement
Fiber length for cotton
a. Cotton waste < 7/8” (Ne 15)
b. Short staple < 1” (Ne 18)
c. Med. Staple < 1” (Ne 35)
Fiber length for man-made fibers
a. Staple lengths 32-40mm up to 60mm (Ne 50)
Fiber fineness
a. Cotton 2.8-4.5
Fiber strength
Greater strength should be selected because there is a linear relationship
between yarn and fiber pressley strength.

Dirt and dust:
The rotor spinning machines reacts very sensitively to the trash content
of cotton. Coarse particle specially the seed husk are caught in the
rotor groove and prevent and resist the yarn formation at this point, as
a consequence the fiber agglomeration occurs.
Other foreign matters:
Mineral dust, honey dew, foreign fibers, synthetic fibers and yarn
elements.

• Fiber length influences;
i. Spinning limit
ii. Yarn strength
iii. Yarn evenness
iv. Handle of product
v. Luster of product
vi. Yarn hairiness
Productivity influence on
the end-breakage rate;
the quantity of waste;
the required turns of twist
(which affects the handle);
general spinning conditions.

Fiber maturity
a. mature fiber 50 – 80% of cross section
b. immature fiber 30-45%
c. dead fiber less than 25%
Effect of Immature fiber
a. loss of yarn strength
b. neppiness
c. high proportion of short fibers
d. varying dyeability
e. process dificulities, mainly at carding machine

Fiber cleanness
Impurities
a. up to 1.2% = very clean;
b. 1.2-2.0% = clean;
c. 2.1-4.0% = medium;
d. 4.1-7.0% =dirty;
e. 7.1 % and more =very dirty
Findings of Uster Technologies
Amount of neps per gram in
100% cotton bales;
a. up to 150 = very low;
b. 150-250 = low;
c. 250-350 = average;
d. 350-450 = high;
e. above 550 = very high.

Preparation of raw material
Process flow of a rotor spun yarn is as;
Fiber/Bale → Blow Room → Lap/Chute
↓
Lap/Chute → Carding → Sliver (Carded)
↓
Carded Sliver → 1st Drawing frame → Drawing Sliver
↓
Drawing Sliver → 2nd Drawing frame → Drawing Sliver
↓
Drawing Sliver → Rotor Spinning → Rotor Yarn

Blow room:
High cleaning effect is needed regarding the dust and dirt, required few
machine but effective.
Cards:
It reduce the dirt content about 0.1%-0.2% and part of dust. B/R, Card
and drawing expected to extract 1/3 of the dust. Web crushing bring
significant cleaning effect for high to medium dirt content by bring
significant cleaning effect for high to medium dirt content by the
cotton.

Draw frames:
Dust is to be removed and need sliver evenness over the short and long
lengths. The higher parallelization, the better fiber opening would be,
so two passage of drawing frame are used. Sliver coiling is also
important to avoid doubling, knots and loops.
Combing:
Preferably-nice to do. However, the benefits arises not only in quality
but also; lowers end down rate, increase efficiency and spinning limit
shifted.

History
• R & D in former Soviet Union for the possibility of forming the yarn
strand from the aid of electrostatic field.
• Battelle Institute only has had degree of success!
• The Electrospin Corp. (USA) had demonstrated the machine based on
this principle at the 1971 ITMA in Paris.

Operating Principle
• Roving input enters double-apron drafting arrangement, fiber
attenuation takes place at draft of 180-200.
• Fibers exit freely from front roller and must be collected to form a
fiber strand & twisted (Yarn formation).
• An electrostatic field is generated in between the front roller and
twist imparting unit.
• Twisting is not an issue.
• A high voltage about 30,000 – 35,000 is to the twist element.
The electrostatic field is the main complexity of this method!

Process
• Electrostatic field is generated by
earthing the FR and applying high
voltage of 30,000 - 35,000V to the
twisting element.
• Fibers take up charge and form dipole
i.e. one end becomes (+)ve and other
is (-)ve both in a fiber when entered
into the electrostatic field.
• An open yarn projects from the twist
element into the field, which is (-)ve
charged and always attracted to FR.

Process
• Thus, high degree of straightening
between TE and FR.
• Fibers leaving the FR are attracted to
the yarn due to charges and hence
join continuously to the yarn.
• Since the yarn rotates, the fibers
bound-in.
• A yarn is formed continually and is
then withdrawn by the withdrawal
rollers.
• The yarn is passed to the take-up
device for winding into the cross
wound package.

Problems associated wit this process
1) Charging of the fibers, dependent on the air humidity. According to
fiber type, a specific and highly uniform environment must be
created. The machine may need to be air-conditioned.
2) The charge on each fiber and its movement dependent upon its
mass. Short fibers will act different that the long fibers.
3) A limit must be set to the no of fibers available in the field,
otherwise cause a mutual disturbance.
4) The same effect is observed with high through put speeds; there is
corresponding limit on a production rate.

Specifications
• Spinning position per machine : 20 (Experimental machine)
• Delivery speed : up to 40m/min
• Raw material : Cotton
• Cotton range : Ne 20-40
• Form of feed stock : Roving
• Type of yarn : Conventional single yarn
• Yarn characteristics : Good yarn quality at low
production speeds, ring
spun yarn character

Specifications
• Advantages : Yarn structure similar to ring spun yarn
• Special features : Yarn quality strongly dependent upon
ambient conditions
• Remarks : Ozone formation

Introduction
• “VORTEX spinning” is a technology which uses an air vortex to spin out the
yarn.
• Fibers formed by these air flows possess a unique structure, and this
provides the yarn with a wide range of functionalities.
• New Technology
• Modified form Air Jet spinning.
• Can be used for wider range length of fiber.

Introduction
• An entirely new technology “to spin yarn with the vortex flow of
compressed air” created VORTEX, a quite new type of yarn.
• In VORTEX spinning, the tip of the fiber is focused to the center of the
yarn by the vortex of compressed air so that the center of the yarn is
always made straight without twisted. The other tip forms the outer
layer that twines another fiber.

History
• Goetzfried and Lord investigated extensively and has been testing.
• Polish Company Wifama - Polmatex presented the machine in
industry.
• Several machine of this type are being used in Poland.

Air Vortex yarn structure
• Two Part structure
• Core
• Sheath/covering fibers

Principle
In this spinning method yarn is
formed by;
• an air vortex in a tube (1).
• For this purpose, air is sucked by
a vacuum source (6) into the
tube through tangential slots (2).
• This incoming air moves upward
along the tube wall in a spiral
and finally arrives at the upper
tube seal (3).

Principle
• Since the top of the tube is
closed by the seal (3), the air
then flows to the center of the
tube and moves down again to
the vacuum source.
• Thus an air vortex (5), rotating
continuously in the same
direction, is generated at the
seal (3).

Principle
After the Air-Vortex formation;
• Opened fiber material is allowed
to enter the system through a
tangential opening (4).
• The rising air stream grasps this
material and transports it
upward into the vortex (5).
• To form a yarn, an open yarn end
is passed into the tube through a
passage in the upper seal (3).

Principle
• The vortex grasps this yarn end
and whirls it around in circles in
the same way as the fibers. Since
the upper yarn length is held by
the withdrawal rollers and the
lower end is rotating, each
revolution of the yarn end in the
vortex inserts a turn of twist into
the yarn.

Twist Insertion in Vortex Yarn
• In Vortex, the twist insertion process of spinning a staple yarn, a
strand of fibers is held on one end while the strand length is made to
rotate on its axis.
• The rotation of the strand causes the fibers to adopt helical forms
and increase the number of turns of twist.
• With the insertion of the twist, the fibers are packed together to-form
a continuous yarn with special structure and properties.

Twist Insertion in Vortex Yarn
• The center of the yarn is not twisted. Twisting is given toward the
outer side of the yarn, twisting at the center of the yarn is loose,
while the outer side is fully twisted.

Features of Air-Vortex Yarn
• The Air-Vortex yarn provides diversified excellent functions. These
functional and fashionable features make Vortex highly recognized as
the most appropriate material for casual wear.
• Many apparel companies leading the global market are developing
high-value-added product using Vortex.

Low Hairiness
• Since it has the least hairiness among all the types of spun yarn,
VORTEX enables to create textiles with unique excellent
characteristics such as anti-pilling and anti-abrasion performance.
• In VORTEX yarn, occurrence of lint is also suppressed, and this
reduces troubles in post-spinning processes, and prevents
deformation by repeated washing.
• The picture below shows how VORTEX is strong against pilling and has
clear appearance.

Low Hairiness
Yarn and Garment comparison of Ring and Air vortex yarn

Moisture Absorbance
• The field of casual clothing and sports wear requires fine absorbency
and wash resistance.
• VORTEX’s fiber structure itself is superior in moisture absorption and
diffusion, which provides refreshing comfortableness absorbing sweat
on hot summer days.
• For outdoor activities in hot and humid environments, VORTEX
ensures fresh-to-wear clothes. This is an ideal material for casual
scenes.
• It is Superior in absorbing water.

Moisture Absorbance
• Air vortex yarn diffuses water quickly, as compared to ring spun yarn.

Low Pilling
• Pilling is a phenomenon where fibers are inter-twisted into a ball-like
shape by frictions between the surface of a textile and that of
another.
• On the casual fashion market, how to suppress pilling has been a
significant challenge. Since it is of structure with less hairiness,
VORTEX remarkably suppresses pilling, and has created new markets.
• Because VORTEX not only has less long hairiness but also is structured
so that fibers forming a textile hardly slide, so frictions between
VORTEX-made textiles almost do not cause pilling.

Low Pilling
• Pilling test result of single jersey knitted from Rayon 100% Ne 30/1.

Low Pilling
• Comparison of pilling in Vortex and Ring.

Wash-resistance
• Against repeated washing and drying, VORTEX produces the minimal
quantity of lint. This is one of VORTEX’s unique features never seen in
other types of yarn, and comes from its yarn structure with less
hairiness and firmly retaining yarn inside.
• VORTEX is also resistant to washing, hardly causing fiber loss, size
changes, skewness or color fading, so many fabric manufacturers
highly evaluate this feature.

Wash-resistance
• Change in dimension

Wash-resistance
• Color resistant

Problems in this system
• One associated problem is the correct ordered binding-in of the
fibers, i.e., achieving adequate strength in the yarn. achieving
adequate strength in the yarn.
• For this reason, synthetic fibers of For this reason, synthetic fibers of
highest attainable uniformity are mainly used.
• Variability in twist level in spun yarn, twist can vary within a very wide
range.

Advantage in this system
• Absence of any kind of rapidly rotating machine parts.

Specifications
• Spinning positions per machine : 192
• Delivery speed : 100 – 150m/min
• Raw material : Synthetic
• Count range : Ne 7.5 - 30
• Form of feed stock : Draw frame sliver
• Type of yarn : Conventional single yarn
• Yarn characteristics : Low strength, twist variability,
rough surface
• Advantages : No rapid rotating parts, simple m/c
• Special features : Cotton can’t be spun
• Field of end use : Undemanding woven goods

Products
Due to its characteristics such as;
• less hairiness,
• resistance to pilling,
• moisture absorption function,
• and washing resistance,
VORTEX yarn is used in a variety of products worldwide as the most
suitable material for everyday-use casual wear.

Products
These products include living goods such as;
• towels,
• sheets and pajamas,
• and everyday clothes,
• sportswear such as sweatshirts, T-shirts and socks.

Introduction
• Friction (DREF) spinning system is an Open-end spinning system.
• Along with the frictional forces in the spinning zone the yarn
formation takes place.
• The DREF system is used to produce yarns with high delivery rate
about 300mpm.
• It produce a highly uniform yarn from diverse stock including short or
difficult to handle at high production rates and low labor and energy
expenses.

Working Principle
• This is an open end type machine.
• Drawing sliver is the input and must be opened to individual fiber.
• The formation of yarn is carried out by using suction to bring the individual
fibers into engagement with the rotating open end of the engagement
withy the rotating open end of yarn e.g. Perforated drum.
• Binding-in and imparting strength, are effected by continual rotation of
yarn in convergent region of continual rotation of yarn in convergent region
of two drums which rotate.
• Yarn formed by the frictional contact of these drums.
• This must be then withdrawn and finally wound on a cross wound package.

Working principle
Yarn fineness is determined by the ratio
of fiber mass feed per unit time to the
withdrawal speed of yarn.
TPI is determined by the relationship
between yarn revolution and
withdrawal speed.
The rate at which twist is imparted is
much lower than that which would be
expected from the yarn rotating
between two drums; this attributed due
to the slip and is a complex detail.
The count range is same as produced as
by rotor, so directly competitors to each
other in market.

Yarn formation in Friction spinning system
The mechanism of yarn formation is quite complex. It consists of three
distinct operations.
1) Feeding of fibers
2) Fibers integration
3) Twist insertion.

Feeding of fibers
• The individualized fibers are transported by air currents and
deposited in the spinning zone.
• There are two methods of fiber feed
1) Direct feed
• Fibers are fed directly onto the rotating fiber mass that outer part of
the yarn tail.

Feeding of fibers
2) Indirect feed
• Fibers are first accumulated on the in-going roll and then transferred
to the yarn tail.

Fibers Integration
• The fibers through feed tube assembles onto a yarn core/tail within the
shear field, is provided by two rotating spinning drums and the yarn core is
in between them.
• The shear causes sheath fibers to wrap around the yarn core.
• The fiber orientation is highly dependent on the decelerating fibers arriving
at the assembly point through the turbulent flow.
• The fibers in the friction drum have two probable methods for integration
of incoming fibers to the sheath.
i. the fiber assembles completely on to perforated drum before their
transfer to the rotating sheath.
ii. fibers are laid directly on to rotating sheath.

Twist Insertion
• The fibers are applied twist with more or less one at a time without
cyclic differentials in tension in the twisting zone.
• Therefore, fiber migration may not take place in friction spun yarns.

Classification
Feed
• Single sliver feed
• Multi-sliver feed (Dref-2 & Dref-3)
Opening assembly
• One opening assembly
• Two opening assemblies (Dref-3)
Separating of collecting and twisting functions
• Collection and friction unit separated
• Friction assembly also serves as collecting device
Number of friction surfaces
• One friction surface (Dref-1)
• Two friction surface

Classification
Type of friction assembly
• Perforated drums
• One perforated drum with one smooth drum (blind drum)
• Two discs
• Disc and roller in combination
• Two cross belts

Classification
The Most widely used with following Characteristics:
• Single sliver feed
• One opening roller
• Friction assembly also act as collection device
• Two friction surfaces
• Two perforated drums or one perforated drum with one blind drum
in combination

DREF-II Friction Spinning
• Friction spinning was first developed when Fehrer produced the DREF
friction spinning system in 1973.
• In this machine, the pre-opened fibers were made to fall onto a
perforated cylindrical drum, the rotation of which imparted twist to
the fiber assembly.
• Due to problems in controlling the flow, slippage occurred between
the fiber assembly and the perforated roller, which reduced the twist
efficiency.

DREF-II Friction Spinning
• Later the DREF-II friction spinning machine was developed to overcome
this problem.
• This machine incorporates a specially designed inlet system which provides
the required draft. These drafted slivers are opened into individual fibers
by a rotating carding drum (opening roller) covered with saw-tooth wires.
The individual fibers are stripped from the carding drum by centrifugal
force supported by an air stream from a blower.
• The fibers are then transported by additional rollers to two perforated
friction drums. The mechanical friction on the surface of the drums twists
the fibers.
• Suction through the perforation of the drum assists the twisting process
and helps in the removal of dust and dirt.

DREF-III friction spinning
• The DREF-III friction spinning machine was introduced into the market in 1981.
This machine was developed to improve yarn quality, extend the yarn count up to
18s Ne and produce multi-component yarns.
• The DREF-III uses a core-sheath type friction arrangement.
• In this machine an attempt is made to improve the quality of yarn by aligning the
majority of fibers in the direction of yarn axis. The remaining fibers are wrapped
round the core fibers to form a sheath. The sheath fibers are wrapped round the
core fibers by the false twist generated by the rotating action of drums.
• Two drafting units are used in this system, one for the core fibers and other for
the sheath fibers. This system produces a variety of core-sheath type structures
and multi-component yarns using different core and sheath fibers in the count
range of 1-18sNe with delivery speeds as high as 300 m/min.

Dref-2000
• It is the latest development in friction spinning demonstrated in ITMA
99.

Dref-2000
• DREF-2000 employs a rotating carding drum for opening the slivers
into single fibers and a specially designed system being used for sliver
retention.
• The fibers stripped off from front the carding drum by centrifugal
force and carried into the nip of the two perforated spinning drums.
• The fibers are subsequently twisted by mechanical friction on the
surface of the drums.
• Drums are rotates in the same direction.

Advantages of DREF-2000
• Insertion of twist in ‘S’ and ‘Z’ direction is possible without
mechanical alterations to the machine.
• Yarns up to 14.5s Ne can be produced at speeds of 250 m/min.
• Reduced yarn preparation costs due to high sliver weights (card
slivers).
• Dust extraction for secondary fibers.
• Low energy costs due to the use of only 1 fan for 12 spinning heads.
• Feeding of all types of filaments, yarns and components as yarn cores,
in order to attain high yarn strength and production speeds,
voluminous yarns and specific product characteristics.

DREF-2000 Application and Fields
• Blankets for the homes, hotels, hospitals, camping, military uses, plaids etc.
• Cleaning rags and mops from cotton waster and various waste-blends
• Deco- and upholstery fabrics
• Outerwear and leisure-wear
• Filter cartridges for liquid filtration
• Secondary carpet backing for tufting carpets
• Canvas and tarpaulins for the military and civil sectors
• High-tenacity core yarn for ropes, transport and conveyor belts
• Asbestos substitutes for heavy protective clothing (protective gloves, aprons etc) packing, gaskets,
clutch and brake-linings, flame retardant fabrics etc.
• Filter Yarns for the cable, shoe and carpet industries
• Carpet Yarns (Berber carpets, hand-woven and hand-knotted carpets) and filler weft yarns for
carpets

Properties of Friction Spun Yarns
• Friction spun yarns (DREF) yarns have bulky appearance (100-140%
bulkier than the ring spun yarns).
• The twist is not uniform and found with loopy yarn surface.
• Usually weak as compared to other yarns.
• The yarns possess only 60% of the tenacity of ring-spun yarns and
about 90% of rotor spun-yarns.
• The breaking elongation of ring, rotor and friction spun yarns is equal.

Properties of Friction Spun Yarns
• Depending on the type of fiber, the differences in strength of these yarns
differ in magnitude.
i. 100% polyester yarns-strength deficiency is 32%
ii. 100% viscose yarns-it ranges from 0-25%
• In polyester-cotton blend, DREF yarns perform better than their ring-spun
counterparts.
i. 70/30% blend yarn-superior in strength by 25%
• DREF yarns are inferior in terms of unevenness, imperfections, strength
variability and hairiness.
• The friction spun yarns are more hairy than the ring spun yarns
• DREF yarns are most irregular in terms of twist and linear density while ring
spun yarns are most even.

Properties of Hybrid Yarns/DREF core yarns
• If one yarn creates out of 2 or more single yarn components is called hybrid
yarn.
• Hybrid yarns are used;
For reinforced plastics
Properties of the yarn
• Core/Sheath structure with centric position of the reinforcing filament.
• Zero twisted reinforced filament gives best strength result.
• Definable fiber matrix proportion.
• Protection of the reinforcing filament through the sheath fibers.

Hybrid Yarns/DREF core yarns
For liquid filter cartridges
Yarn Properties
• Huddle fiber arrangement for
best filter action
• High elongation values
• Long yarn length knotless
• Uniform yarn with high tensile
strength
For heat proof woven and knitted
fabrics
Yarn properties
• Flame resistance
• High temperature resistance
• High tear abrasion resistance
• Good wearing comfort
• Good care properties
• Skin friendly

For Secondary carpet backings
Yarn Properties
• Steady high tensile strength
• High uniformity of the yarn
• Long knotless length of the yarn
• Good non-rotating properties
• High chemical resistance
• Good thermal transfer
• Dust free product
• Electric insulation
• Good dimension stability for carpets

For asbestos substitutes
Yarn properties
• High yarn volume
• Good temperature resistance
• High tensile strength
• Low elongation
Cut proof woven and knitted fabrics
Yarn properties
• High cut resistance
• Good wearing comfort
• High dimension stability

Advantages of Friction spinning system
• It can spin yarn at very high twist insertion rates (ie.3,00,000
twist/min).
• The yarn tension is practically independent of speed and hence very
high production rates (up to 300 m/min) can be attainable.
• Improved dirt particle retention and up to twice the filter service life.
• Considerable reduced yarn production costs (up to 50%) due to lower
yarn mass requirement, lower preparation costs, lower spinning costs
and lower personnel expenses.

Limitations of Friction spinning system
• Low yarn strength and extremely poor fiber orientation made the friction
spun yarns very weak.
• The extent of disorientation and buckling of fibers are predominant with
longer and finer fibers.
• Friction spun yarns have higher snarling tendency.
• High air consumption leads to high power consumption.
• The twist variation from surface to core is quite high; this is another reason
for the low yarn strength.
• It is difficult to hold spinning conditions as constant.
• The spinning system is limited by drafting and fiber transportation speeds.

Specifications
• Spinning positions per machine : 4 – 38
• Delivery speed : 280m/min
• Raw material : Wool, Bast fiber, Synthetic fiber
• Count range : Ne 0.18 – 5
• Form of feed stock : Card sliver
• Type of yarn : Normal OE yarn
• Yarn characteristics : Woven spun character, round, even
• Advantages : Spinning of waste, Elimination of
process stages
• Special features : Cotton can’t be spun
• Field of end use : Home textiles, Carpets, Blankets,
Recycling, Technical products

Platt Saco Lowell’s (PSL) Master spinner
• Platt Saco Lowell’s (PSL) Master
spinner is also a true open-end
(OE) friction spinning system.
• It differs from the DREF-II in
respect of fiber feed and the
construction of the friction
drums.

Principle
• The principle of operation of this
machine is shown in Figure.
• A draw frame sliver (1) runs from
a can into an opening assembly.
This consists of a feed roller and
an opening roller (2), and opens
the fiber strand in the same way
as the opening device in rotor
spinning.

Principle
• The separated fibers pass
through a specially shaped fiber
channel (3), carried by an air
flow from a vacuum inside the
suction roller (4) into the
converging region between the
two friction rollers.
• One of these rollers is perforated
to act as a suction roller,
whereas the second roller is
solid(5). A yarn (6) is formed in
the convergent zone.

Principle
• A secondary suction duct at the
end of transfer duct helps to give
fiber orientation, and therefore to
keep the fibers parallel to the yarn
axis, resulting in improved fiber
orientation and fiber extent in the
final yarn.
• In the twisting assembly, one
friction drum is perforated and
includes a suction slot while the
other is a solid roller which
provides effective friction transfer.

Reason for failure in industry
Platt Saco Lowell’s (PSL) Master spinner machines have not been
successful in the longer run, mainly for two reasons:
• Inadequate yarn strength, i.e. low utilization of the fiber properties,
and
• Inconsistency of the spinning results

Twist spinning & Self-twist spinning

Twist spinning
This method of spinning is used mainly in worsted spinning mills. Two
systems are available:
• Duospun, from Ems SA and Huber and Suhner AG; and
• Sirospun, from Zinser Textilmaschinen GmbH.
• The difference, and the only patentable aspect of the process, lies in the
procedure adopted when one of the two ends leaving the drafting
arrangement breaks.
• In the Duospin process, the two yarns are recombined almost instantly,
whereas the Sirospun system interrupts spinning at this single spinning
position.

Principle and working
• Two rovings are passed individually through a slightly modified, but
generally conventional drafting arrangement of a normal ring spinning
machine.
• The fiber strands, attenuated by a draft in the normal range, leave the
delivery roller separately. At this point, they are each subjected to
twist generated by a common spindle (cop); thus, within the spinning
triangle, they are twisted into two single yarns, and these are
simultaneously bound together to form a composite yarn.
• Each of the two single strands and the resulting composite yarn
contains twist, and the direction of twist is the same for both the
single ends and the composite product.

Twist spinning with modified ring frame

Advantages
• This twist-on-twist (ZZ or SS) produces a yarn that is somewhat more
compact, with a firmer core, than the usual ply yarn with opposing
twist (ZS or SZ).
• It primarily offers economic advantages, because the production of
the ring spinning and winding machines is roughly doubled (two ends
instead of one at approximately the same speed).
• In addition, plying and twisting are eliminated.

Application
• It is used for worsted spinning and is running successfully.
• In worsted spinning, twist spinning has therefore secured a certain
share of the market. However, due to the different twist structure, it
cannot completely replace the conventional 2-fold yarn process.

REPCO Spinning (Self-twist spinning)
• Platt Saco Lowell has obtained a license from CSIRO for the self-twist
spinning process. The corresponding machine has been called the
Repco Spinner.
• This process of spinning involves inserting alternating S and Z twist in
the fiber strands that come from the drafting system. This is done by
passing the slivers between the draft rollers which rotate along the
axis as they rotate to deliver the threads.

Operating principle
• Eight roving strands (2) run from a
creel (1) into a double apron
drafting arrangement (3), where
they are drafted in a normal
drafting range.
• A friction assembly (4) adjoins the
drafting arrangement and consists
of two reciprocating friction rollers.
In passing through this device, the
fiber strands leaving the drafting
arrangement are subjected to
alternating twist.

Operating principle
• Before the turns of twist can cancel
each other out, the strands are
brought together in pairs with a
phase shift between the
components of the two strands.
• This produces the previously
described self-twist (ST) twofold
yarn.
• The four yarns proceed to a
winding device (5), where they are
wound onto cross-wound
packages.

Process of REPCO machine
• Pairs of roving are fed onto the drafting rollers.
• The roving slivers are drawn out on succession of these drafting
rollers and pass through a pair of synthetic rubber covered rollers
which rotate axially.
• The rollers wrap the strands around each other.
• After the rollers complete their side ways motion in one direction, the
movement is then shifted in the opposite direction.
• The resultant yarn therefore has alternating sections of S and Z twist.

Advantages
1) Low yarn tensions
2) Low end breakages rate
3) Finer count
4) High speed of twist insertion
5) Low energy consumption
6) Low space requirement
7) Low personnel demand
8) Low-noise process
9) Low cost
10) Low Spinning waste
11) Low maintenance

Limitations of REPCO Spinning
• Yarn clearing
• Streaky appearance
• Not suitable for knitting
• Strength

Specifications
Spinning position per machine : 4(5)
Delivery speed : upto 300 m/min
Raw material : wool & synthetic fibers
Count range : 9/2 - 45/2
Feed stock : roving
Type of yarn : two folded
Advantages : low energy, space and
personnal
Industry : worsted spinning

Uses of self-twist yarns
• Used in Knitwear fabrics

Uses of self-twist yarns
• Used for making socks, sweaters
and other winter cloths.

Reason for failure
• Platt Saco Lowell discontinued the further development of this
process (the Platt Saco Lowell company no longer exists).
• The twist structure of the Repco yarn is different from that of a
conventional 2-ply yarn.
• The twist insertion is dependent on friction and thus quite delicate to
adjust and keep constant.

Introduction
• A wrap yarn is a composite structure comprising a core of twisted or
twist-less fibers bound by a yarn or continuous filament.
• The wrap yarn always thus consists of two components; a twist free
staple fiber component (core yarn) and wrapping filament yarn
(around the core).

Principle
• A roving or sliver feedstock (1) is
drafted in a three-, four- or five-
roller drafting arrangement.
• The fiber strand delivered runs
through a hollow spindle (3)
without receiving true twist.
• In order to impart strength to the
strand before it falls apart, a
continuous-filament thread (4) is
wound around the strand as it
emerges from the drafting
arrangement.

Principle
• The continuous-filament thread
comes from a small, rapidly
rotating bobbin (5) mounted on
the hollow spindle.
• Take-off rollers lead the resulting
wrap yarn to a winding device.

Manufacturers
• Lessona, Mackie and ParafiL are major manufacturers of wrap
spinning systems.
• Most common wrap spinning system is ParafiL by Suessen company.

Parafil system
• Three, four, or five roller drafting
arrangements are used, depending
upon the raw material to be
processed.
• The hollow spindle permits rotation
speeds of up to 35 000 rpm and is
designed as a false-twist assembly.
• The fiber strand does not pass directly
through the spindle vertically; instead,
shortly after entering the spindle, the
strand is led out again and back
around the spindle, with a wrap of
about one-quarter of the spindle
periphery.

Parafil system
• In this way, as the spindle
rotates, the strand is provided
with twist between the drafting
arrangement and the head of
the hollow spindle.
• These turns of twist are canceled
out again in the spindle head in
accordance with the false-twist
principle. This false twist
prevents the strand from falling
apart in the length prior to
wrapping with filament.

Features of Parafil system
• Slivers are used as feedstock, the roving frame is eliminated.
• Parafil yarn (called Parallel yarn by Suessen) is usually more even than
ring-spun yarn.
• Its strength is also better because of the filament and because of the
high degree of parallel orientation of the fibers.
• Covering power is high and hairiness low.

Use of Parafil yarns
The yarns are used primarily for:
• Machine-knitting yarn
• Velours (home and automobile upholstery materials)
• Woven goods (men‘s and ladies‘ wear)
• Carpet yarns (mainly for tufted carpets).
• At present, the process is more suited to the long-staple than the
short-staple field, i.e. for fiber lengths above 60 mm.
• In ParafiL yarns, the filament makes up 2 - 5% of the yarn.

Technological & Economic Inter relationships
• High percentage of filament always has a disturbing effect.
• More often in the coarse-yarn sector, and to some extent in the
coarse-to-medium- yarn range.
• The high price of filament relative to staple fibers exerts a strong
influence on costs.
• Economic production of fine yarns using the wrap-spinning process is
therefore not possible, due to higher raw material costs.
• Fine filaments in the 20 - 110 dTex count range are usually used.
• Most common are polyamide fiber, polyester fiber, and viscose.

Adhesive processes / Twist-less spinning

Introduction
• This process of spinning involves the arrangement of fibers parallel to
each other, bonding them together with the aid of a bonding agent.
• In this process, the fibers are placed at an angle to the axis of the
yarn, leading to decreased translation of the strength in the axial
direction of the yarn.
• Since yarns are commonly subjected to axial tensile forces, the fiber
strength is not fully utilized in the twisted yarns.
• In twist-less yarns with cotton and synthetic fibers, the staple fibers
are held together by means of adhesives.

Achievements in this era
Pioneer achievements using the adhesive have been made by:
• The Vezelinstitut TNO (Holland), with the Twilo process,
• Reiter (Switzerland), with the Pavena process, and
• Bobtex Corporation (Canada), with the Bobtex process.
• The line of thought is very attractive, but the realization has proved
just as difficult. These processes have so far been unable to achieve
acceptance, and Reiter has abandoned this line of development.

The Twilo process
• In this method, which is used on machinery made by
Signaalapparaten, of Holland, third passage draw frame sliver is used
as feedstock.
• The first passage is usually carried out on a blending draw frame at
which a small percentage (5-11%) of adhesive fibers is blended with a
sliver of cotton, synthetic fiber, or viscose.
• The adhesive fibers can be poly(vinyl alcohol) (PVA) fibers, which
become tacky and activated at a water temperature of about 70°C.
The addition of water is therefore a precondition for bonding.

Principle
• The draw frame sliver (1) passes
into a first drafting zone (2) of a
four-line drafting arrangement and
is here pre-drafted in a still-dry
condition with a draft of 5-10.
• The pre-drafting zone (2) is
followed by the wetting position
(3), which also contains a false-
twist assembly.
• Here, the use of a water-jet leads
to twisting of the strand (false
twist).

Principle
• Thereafter, the final attenuation is
performed in a twist-free condition
in a second two-line drafting zone
(4), with a draft of up to 40.
• To ensure that the strand leaves
the drafting arrangement (4) as
narrow and compact as possible,
the drafting arrangement is
followed by a second false-twist
device (5).
• This device also serves to assist
warming of the yarn to about 70°C
(7).

Principle
• A steam-jet is therefore used
here for twisting. Finally,
cylindrical cross-wound
packages above the machine
take up the yarn.
• Instead of adhesive fibres,
Signaalapparaten now also uses
a bonding agent as an
alternative means of imparting
strength.

Process parameters
• In this process, cotton and pure synthetic fibers can be processed,
and so can blends.
• The range of fiber linear density lies between 1.4 and 6 dTex, with
staple lengths in the range 30-80 mm.
• The finer the fibers, the more adhesive fibers must be used. The latter
usually have a linear density of 1.7 dTex and length of 40 mm.

Yarn parameters
• The yam is not round but flat and therefore gives an end product with
high covering power.
• Because of the binder, the yam is stiff with low elongation.
• The evenness corresponds to that of ring-spun yarn.
• The strength is partly dependent upon delivery speed.

Features of Twilo process
Characteristics of the process are:
• Relatively high energy consumption.
• The use of water in a spinning mill.
• The adhesive fibers or binder must be washed out, and are therefore
lost; if they were not washed out, the end-product would be
unusable.
• A great deal of specific know-how is needed.

Specifications
• Raw material : Cotton & Synthetic fiber (up to 80mm)
• Count range : Ne 6 – 40
• Form of feed stock : Draw frame sliver
• Type of yarn : Bonded yarn
• Yarn characteristics : Flat, high covering power, good
evenness
• Advantages : Elimination of twist
• Field of end use : Bath towels, Interlinings, coating
material

Bobtex process
The Bobtex spinning machine (the name "Bobtex" is derived from the
name of the inventor, Bobkowicz) has two spinning positions and
produces a multiple-component yam, which is composed of:
• A core of mono- or multi-filaments making
up 10-60% and forming the yam carrier (a);
• A polymer intermediate layer (20-50%) (b);
and
• Staple fibers embedded in the intermediate
layer to provide a covering layer and
making up 30--60% (c).

Principle
• In the course of production of this yarn,
as shown in, the filament (2) runs through
an extruder (3), after which a coating of
molten polymer (1) remains stuck to it.
• Before this polymer can solidify, opened
staple fibers forming a covering layer are
pressed into the molten material in the
unit (4).
• This unit represents an opening assembly
for the attenuation of two draw frame or
card slivers (5) fed in from the side.
• A false-twist device (7) ensures good
binding-in of the staple fibers.
• The resulting yarns are wound onto large
packages on the base of the machine.

Specifications
• Raw material : Filament/polymer/fibers
• Count range : Ne 2 – 20
• Form of feed stock : Card sliver
• Type of yarn : Three component yarn
• Yarn characteristics : High covering power,
stiffness, evenness, wool spun
characteristics
• Advantages : High production, Package mass up to 50kg
• Field of end use : Sacks, carpet backing, Industrial woven
fabric
• Special features : High consumption of energy and water

False twist spinning methods
• Yarn manufacture using the air jet primarily produces fascinated yarns
using the false twist principle.
• Hence, we discuss about the principle of false twisting before going
into actual air jet spinning.

Principle
• If a fiber strand A is held firmly at two
spaced points by clamps K1 and K2
and is twisted somewhere between
them, this strand always takes up the
same number of turns of twist before
and after the twist element (T).
• If the clamps are replaced by rotating
cylinders (Z1 and Z2) and the yarn is
allowed to pass through the cylinders
while twist is being imparted, the
result is governed by the false-twist
law and is different from the case of
the stationary yarns, as previously
assumed.

Principle
• A moving yarn entering the section
(b) already has turns of twist
imparted in section (a). In the
example illustrated (B), there are
turns of Z twist.
• As the twist element is generating
turns of S twist in the left hand
section, this simply means that
each turn of the Z twist imparted in
the first section (a) is canceled by a
turn of S twist imparted in the
second section (b).

Principle
• The fiber strand thus never has
any twist between the twisting
element and the delivery
cylinder.
• In a false-twist assembly, turns
of twist are present only
between the feed cylinders and
the twisting element.
• This principle is exploited, for
instance, in false-twist texturing.

Yarn structure
• The idealized structure of the fascinated yarn, consists of parallel
fibers held together by wrapper fibers. The wrapper and core fibers
are composed of same staple fiber material.
• Since there is no real twist in the core, this type of yarn structures
facilitate high production rates.

Yarn formation
• Figure demonstrates the
principle involved in the
production of fascinated yarn
using the false twisting method.

Spinning elements
A variety of devices can be imagined as twist-imparting assemblies;
• Pneumatic (one or two jets)
• Hydraulic
• Mechanical
• Perforated drums
• Double discs
• Double belts
• Rotating tubes, etc.
Some mechanical assemblies would require a higher spinning tension than
the pneumatic systems.

Introduction
• The Air jet spinning method, in which the yarn is obtained from staple
fibers because of the action of the swirled air jet alone, has been very
attractive mainly because it has become possible to eliminate such
movable elements as the spindle and the traveler in ring spinning, or
the centrifuge in rotor spinning.
• Sliver is fed into the machine and is further drawn out to the final
count and twist is inserted by means of one or two nozzles containing
high pressured air. The resultant yarn is cleared of any defects and
wound onto packages ready for use in fabric formation.

Invention & Manufacturing
• An invention by the Japanese company Murata was the next step in
the progress of air-jet spinning methods.
• At the beginning of the 1980s, this company manufactured (and still
manufactures) an air-jet spinning frame in which the yarn is formed
by means of the false-twist MJS (Murata Jet Spinning) method and
the product continuity is maintained during the whole spinning
process.
• This spinning method (MJS) in comparison with the previous one (OE)
has enabled to miniaturize the spinning chamber (the swirl chamber
diameter equals 3 – 3.5 mm).

Invention & Manufacturing
• To supply the spinning chamber with compressed air (overpressure
chamber).
• To improve the yarn quality. The yarn obtained with this method has a
carrier almost without twist, which is braided on the yarn surface.

Operating principle
• Air-jet spinning is a pneumatic method
which consists of passing a drafted strand
of fibers through one or two fluid nozzles
located between the front roller of a
drafting system and a take up a device.
Look at the figure which demonstrates
the Murata principle of producing
fascinated yarns with two nozzles N1 and
N2.
• The drafting system drafts the input
material into a ribbon like form with
parallel fibers. Air is injected into the two
nozzles N1 and N2 at high pressures,
which cause swirling air streams in
opposite directions.
• N2 works as false twist element and
produce yarn from fiber ribbon.

Working
• The feed material is a draw frame
sliver fed from a can (1) which is
passed to a drafting arrangement
(2), where it is attenuated by a
draft in the range of 100 - 200.
• The fiber strand delivered then
proceeds to two air jets (3 and 4)
arranged directly after the drafting
arrangement.
• The second jet (4) is the actual
false-twist element.

Working
• The air vortex generated in this
jet, with an angular velocity of
more than 2 million rpm, twists
the strand as it passes through
so that the strand rotates along
a screw-thread path in the jet,
achieving rotation speeds of
about 250 000 rpm.
• The compressed air reaches the
speed of sound when entering
the central canal of the false-
twist element.

Working
• The ability of the vortex to impart torque
is so high that the turns of twist in the
yarn run back to the drafting
arrangement. The fiber strand is
therefore accelerated practically to full
rotation speed as soon as it leaves the
front roller.
• The edge fibers which ultimately bind the
yarn together by becoming wrapping
fibers are in a minority.
• The resulting bundled staple-fiber yarn
passes from the take-off rollers (6)
through a yarn-suction device (7) and an
electronic yarn clearer (8) before being
wound onto a cross-wound package (9).

Distribution of twist
Distribution of twist in running
fiber strand in MJS is shown in
figure.

Yarn structure
• The air-jet spun yarn consists of an untwisted core of parallel fibers and a
surface wrapping of fibers.
• The core fibers account for approximately 85-95% of the yarn mass.
• The surface wrapper fibers are helical in nature unlike the wrapper fibers in
the rotor yarn. The wrapper fibers are not uniformly distributed over the
length; sometimes they are more on the surface and sometimes very few
are on the surface. Their frequency and tightness being influenced by the
fiber physical properties and the spinning process parameters.
• “The high level of constriction of the straight core fibers by the surface
wrapper fibers results in high bending modulus of air-jet yarns”.

Yarn properties
Hairiness:
• Compared to yarn spun using other spinning processes, air-jet-spun
yarn displays the lowest hairiness.
• The advantages of low hairiness range from cost savings in the
knitting process to unique advantages in the textile product in terms
of abrasion, wear resistance, pilling and wash fastness.

Yarn properties
Abrasion and wear resistance:
• Yarn abrasion is directly related to yarn hairiness and the integration
of the fibers in the yarn strand.
• One advantage of air-jet-spun yarn is clearly apparent: Lower
abrasion will result in significantly less soiling and less fiber fly during
downstream yarn processing, thereby extending cleaning intervals on
the machines.
• The abrasion resistance of the yarns is a further important criterion in
subsequent downstream yarn-processing stages and the yarn's
serviceability properties in the textile fabric.

Advantages of Air-jet spinning
• Creates functional & fashionable yarn
• Integration of three processes; roving, spinning & winding by the MJS
• Integration of four processes; roving, spinning, winding & doubling by
the MTS
• User-friendly in operation management
• The spinning speed of 340m/min
• User-friendly in quality control
• Totally saves space, labor & energy

Advantages of air jet yarns
• Less hairiness & Clear appearance
• High resistance to Pilling & abrasion
• High moisture absorption
• Less shrinkage & High wash resistance
• Can be spun with various other materials such as cotton, synthetic
fiber, regenerated fiber and blended fiber.
• Yarn structure also suitable as core yarn.

Raw material requirements
• In air-jet spinning, the requirements imposed on the raw material and
the quality of spinning preparation are very high.
• Yarn count and usable fiber length are also limited in comparison to
ring spinning.
• The feed sliver must be very clean, the short fiber content may not
exceed a certain level, and the fibers must display good parallelism.
• The better these preconditions are fulfilled, the higher the machine
efficiency.

Advance spinning techniques

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Advance spinning techniques

Similar to Advance spinning techniques (20)

More from Sohail AD

More from Sohail AD (10)

Recently uploaded

Recently uploaded (20)

Advance spinning techniques