Spinning i

3/27/2021 Build your mind not your pocket!! 1
By Natinael Kokeb (Textile engineering lecturer at Bahirdar University

OBJECTIVES
1.To determines the type of motion transmission elements and its function
2. To analysis why these selected motion transmission elements are being used i.e. why we use other
motion transmission elements rather the selected ones.
3. To analysis how builder motion occurs by using motion transmission elements in roving frame.
4. To determine the tasks of builder motion in roving frame.
5. To know to which parts are motion transmitted through proper selected motion transmission elements
i.e.to analysis the effects when we use other than the selected motion transmission elements.
6. To know the effects of motion transmission elements in drafting arrangement; creel; bobbin rail;
bobbin drive and spindles.
7. To analysis speed variations in bobbin drive; creel zone; and drafting rollers.

MAIN TASKS OF ROVING FRAME
1. Attenuation-drafting the sliver into roving.
2. Twisting the drafted strand.
3. Winding the twisted roving on bobbin.
➢ Advantages of roller chain drives;
• Do not slip
• Maintain constant and precise speed
• Good service life
• Easy to install and repair
• Long distance motion transmission.
➢ Disadvantages of roller chain drives;
• noisy
• need lubrication
• weight of the chain
❖ Since the V belt is short, it is subjected to the action of load
and fatigue a greater number of times. Further, its ability in
absorbing the shocks is poor. and the flat belt have the
same application but the difference is we use flat belt on
smooth pulley or cone and the other difference is the
length they transfer power and the flat belt have slippage.

GEARS AND GEAR DRIVES
A.Parallel
1.Spur gear
2.Helical gear
3.Rack and pinion
B.Intersecting
1.Bevel gear
C.Non-intersecting and Non-parallel
1.Worm
Gears are generally used
for one of four different reasons:-
• To reverse the direction of rotation
• To increase or decrease the speed of rotation
• To move rotational motion to a different axis
• To keep the rotation of two axis synchronized
Bevel gear
Spur gear

Ratchet change wheel
This determines the amount by which the belt is shifted at
each operation of the ratchet and therefore must be adjusted
precisely to the increase in bobbin diameter. It used to control
lifting of cone belt in cone drive to produce tapered end of
roving package and doffing purpose when required length of
roving length in bobbin. Generally; ratchet is used to
1. To form tapered end of package by shifting cone belt.
2. To shorten lifting distance after each layer.
3. To know how many numbers of layers wound in bobbin.
ratchet wheel

This continuously reducing rotation rate of bottom conedrum is
transmitted via gearing to the differential and is there superimposed on
the constant speed of the main shaft.
During winding of the roving
bobbin, the flyer rotation rate is
normally held constant. Winding
is effected only when the
difference between the speeds of
the flyer and bobbin is equal to
the delivery speed.
Differential gear

Materials Cradle length
Cotton up to 1 1/ 8”
Synthetic fibers 40mm
36mm
Cotton above 1 1/ 8
Synthetics 50 mm
43mm
Synthetics 60 mm 50 mm
Spacers are used between top and
bottom aprons to create space
between them. The gap between
the top and bottom aprons at the
front end decides the pressure
existed on the fibres and the fibre
control.

1

On the main shaft is mounted, another mechanism called, a
‘differential motion’. The function of the differential motion is to take
drives from two different sources and give an output of a combined
nature. (The input drive from one source (main motor) is
superimposed on the input drive from the second (bottom conedrum)
and an output, which is a combination of both source drives, is
delivered).
The differential motion will ‘add’ the speeds of the main shaft
and that of the bottom cone drum output, so that the speed of
the bobbin is always higher than the spindle speed. Further, if the
drive from the bottom cone drum is cut off to the differential, the
spindles and the bobbins will be rotating at the same speed.
The output of the differential motion is used to drive the bobbins
through a gear train, as indicated in the gearing diagram.

Attenuation = Draft  100/ (100-P) where, P is the percentage waste.
If there is wastage, then attenuation will be more than expected due to draft. So,

❖Axial flutes are now replaced by helical flutes for better grip of
fibers and motion smoothness of top rollers.

The ratio between the speeds of the
delivery and feed of the drafting device
is called “mechanical draft”.

size of condensers should be selected according to the volume of the fibre.

Twist (tpm) decreases with increasing tex count according to
t=k/texn where t is
twist in turns/metre, k and n are constants.
High twist level ----> Production loss
.......................------> Drafting problem in ring Spinning.
Low twist level -------> false drafts
....................................Roving break
As the count increases, in order
to hold the fibers, twist
multiplier also increases, so
that corresponding twist per
inches also increases.

In most of the industries, top mounted flyer is used since it allows automation of the doffing operation. The flyer
is supported at top and driven by gear wheel running by toothed belts.
Closed flyers are mainly used for high speed operation. It also has advantages of reduced spreading of the legs
at high operating speeds.

Flyer top
❖ The passage of roving at the entry point of the
flyer determines the degree of twist and the
winding tension.
❖ If the roving has only low twist or is coarse,
so that there is a risk of false drafts the strand
passes through the flyer top to the guide
groove without wrapping (A).
❖ A half turn of wrap as shown in (B), is
selected for high speed frames winding large
packages with high twist levels. The wrap
enables better control of roving tension and
the package build becomes more even
winding to the harder coils.

• The additional false twist reduces the roving break in the
Spinning.
• Spinning triangle is reduced so that quality of roving is
improved.
• Fly and lap formation also reduced.
• False twist enables compact rovings which increases the
bobbin capacity and leads to higher flyer speeds
False twist

Bobbins placed in these front and back row spindles will the following differences in the spinning
conditions following variations.
• The angle of approach of the roving to the flyer top is different for the two rows. This will create
different rolling conditions at the entry point of the roving to the flyer top.
• Both rows of spindles will have different spinning triangles .
• Difference in the unsupported lengths (L), i.e the lengths between the drafting arrangement and the
flyer top.
• Difference also occurs in twisting of roving which leads to variation in fineness between the front
and rear ends.
Disadvantage of arranging bobbins in two rows

• The pressure arm made up of steel yoke is
attached to the lower end of the hollow flyer
leg.
• It guides the roving from exit of the flyer leg to
the package.
• The roving is wrapped two (A) or three (B)
times around the yoke depending upon the fibre
type and twist level.
• No. of turns determines the roving tension and
package hardness.
• If this is high, then a hard, compact package is
obtained. If it is too high, false drafts or roving
breaks may happen.
THE PRESSURE ARM

Advantages of leading bobbin are:
1.Fewer roving breaks or faultily drafted places at the
winding point because the drive transmission path
from the motor to the spindle is short, whereas that
of the bobbin is long
2. No unwinding of the layers during roving
breakage and
3. Speed reduction with increasing package
diameter. However, with a leading spindle, the bobbin
speed must be gradually increased with increasing
package diameter which demands more power.

❖ Variation in bobbin speed originates from the cone drums.
When the builder motion shifts the cone belt, the rotation rate
of the lower cone is changed.

Roving frame calculation
Where TCP=twist change pinion

1.Calculate the TPI on simplex if the diameter of back roller is 15/16”, rpm
of B.R is 10, rpm of flyer is 1000 and draft is 6
Given:
Db= 15/16 inch, rpm Br= 10, rpm flayer=1000, draft=6, TPI=?
so/n:
Draft=( ss Fr/ss Br), ss Br= Db*rpm Br=*(15/16)in*10=29.45in/min
So, 6=ss Fr/29.45In/min,
Ss Fr= 6*29.45In/min=176.71In/min
Tpi= spindl rpm/Ss Fr =(1000 rpm/176.71In/min)=5.66 ans
If twist constant is given as 520, what is the no. of teeth in the twist change
pinion(TCP)?

• Coils per inch

Find out the total draft of m/c, draft of every zone. And the draft constant of m/c. radius of the 2nd
roller 7/8’’
• Show that the draft in the front zone is 3.

Ring frame

❖ The roving bobbins (1) are creeled (A) in appropriate holders (3). Guide rails
(4) lead the rovings (2) into the drafting arrangement (5) which attenuates
them to the final required count.
❖ The drafting arrangement (B) is inclined at an angle of about 45 – 600. It is
one of the most important assemblies on the machine since it has
considerable influence on irregularities present in the yarn.
❖ After the drafting arrangement, the machine have twisting and winding zone
(C).
❖ Upon leaving the front rollers, the emerging fine fiber strand (6) receives the
twist needed to give it strength. This twist is generated by the spindle, which
rotates at high speed. Each revolution of the spindle imparts one turn of
twist to the fiber strand. Spinning of the yarn is thus complete.
❖ In order to wind up the twisted yarn to bobbin mounted on Spindle( 8) , a
traveller (9) is required to cooperate with the spindle. The traveller moves
on guide provided on the ring (10) encircling the spindle.
❖ The traveller has no direct drive; instead, it is carried along by the yarn it is
threaded with. The speed of the traveller is lower than that of the spindle
owing to significant friction generated between the traveller and ring.
❖ This difference in speed enables winding of the yarn to bobbin.
❖ Winding of the yarn on to the bobbin is done by raising and lowering the ring
rail. The traverse stroke of the ring rail is less than that of the bobbin height.
The ring rail must therefore be raised by small amount after each layer of
coils.
Principles of operation

Advantage of ring spinning over new spinning technologies:
➢ It is universally applicable, most of the textile fibres can be spun to
required fineness.
➢ The yarn spun from this machine demonstrate excellent quality features
like uniform structure and good strength.
➢ It is easy to operate as compared to other spinning machines.
➢ The “know-how” for operation of the machine is well established.
➢ It is flexible as regard to quantities in terms of blend and lot sizes.

Disadvantages associated with ring spinning are:
➢ More process stages. Roving stage exists as an extra process compared to the
other systems.
➢ Yarn breakages are more frequent as a result of ring traveller friction and yarn
to air drag forces. Interruptions, broken ends and piecing up problems exist
because of the yarn breakages.
➢ The high speed of the traveller damages the fibers.
➢ The capacity of the cops is limited.
➢ Energy cost is very high.
➢ Low production rate.

The distance between the central axes of two pairs of rollers is called as roller
setting. If the pairs of rollers are set too wide apart, there will be plucking of the fibres
instead of even attenuation, and the material that comes forward is full of thick and thin
portions. On the other hand, if they are set too close, drafting becomes difficult and many
of the long fibres get gripped by both the pairs momentarily.
The fibres get either damaged or broken.
Assignment:- discuss on what types of rings with travelers are suitable for manmade and
synthetic fibers? And discuss on traveler number used for polyster, viscous and coton
spinning?
Anti-wedge rings with spin or clip type of travelers are most suitable for man-made
fibre processing. The cross section of the travelers should be half round.
Travelers for polyester blends have to be about 4-5 numbers heavier and those for
viscose, 3-4 numbers heavier as compared to travelers used for 100% cotton yarns.

hardness of top roller
➢ Soft - 60° to 70° shore
➢ Medium - 70° to 90° shore
➢ Hard – above 90° sore
❖ What will happen if drafting roller hardness is very low?
Covering having hardness less than 60° shore is normally unsuitable
because they cannot recover from the deformation caused by squeezing
out on each revolution of the roller. Also they wear out at the faster rate.
Why traveler clearer is used?
Due to deposition and entangling of flying loose fibres and untwisted fibres on traveler, mass of
traveler is increased that result in increased yarn tension which finally induce an end break.

A good ring should have the following features:
1. Best quality raw material
2. Good, but not too high, surface smoothness
3. An even surface
4. Exact roundness
5. Good, even surface hardness which is higher
than that of the traveller
6. Optimal running-in conditions
7. Long operating lifetime
8. Correct relationship between ring and cop tube
diameters
)
1
:
2
.
2
1
.
2
(
2
.
2
2 upto
Coptube
Ring
−
=


9) Correct relationship between ring diameter and tube height
10) Horizontal disposition
11) It should be exactly centered relative to the spindle








−
= 225
.
0
2
.
0
Tubeheight
Ring

Main and cross layers

Spinning Geometry
• On its path from roving bobbin to cop, the fiber strand
passes through the drafting arrangement, thread guide,
balloon control ring and traveller
• These parts are arranged at various angles and distances
relative to one another which give varying deflections and
paths of travel for the yarn.
• The set of dimensions and different angles are called
spinning geometry which has a significant influence on
the spinning operation and the resulting yarn, primarily
upon:

1. Tension conditions 4.inding-in of the fibers
2. Number of end breaks 5.Yarn hairiness
3. Yarn irregularity 6.Generation of fly
• The turns of twist in a yarn are generated at the traveler
and travel against the direction of yarn movement to the
drafting arrangement
• Twist must run back as close as possible to the nip line of
the rollers, but it never penetrates completely to the nip
because after leaving the rollers, the fibers first have to
be diverted inwards and wrapped around each other

• Accordingly, at the exit from the rollers, there is always a
triangular bundle of fibers without twist which is called
spinning triangle
Most end breaks originate at this weak point because the yarn
tension in the balloon can be transmitted almost without hindrance
as far as the drafting arrangement whereas twist in the spinning
triangle is zero and does not attain its full value in the adjoining
yarn section because of friction at the thread guide.

• A short spinning triangle represented a small weak point
and hence few end breaks.
• However, if the spinning triangle is too short, the fibers on
the edge must be strongly deflected to bind them in
• A long spinning triangle implies a long weak point, and
hence more end breaks. But the edge fibers are better
bound into the yarn which gives a smoother yarn and less
fly.
• Low inclination of the drafting arrangement with respect
to the horizontal results in a large angle of deflection.
This will give a long spinning triangle. However, steeper
inclination results in small angle of deflection and hence
short spinning triangle.

Ring calculation
• Winding speed = VSpdl - VT
• But winding speed = L
• Therefore, L = VSpdl - VT
• = dnspdl - dnT
• = d( nspdl – nT)
• =>
d
L
n
n spdl
T

−
=

The length of one winding coil is dw, therefore
the length of the yarn wound every minute is
L= (ns-nt) dw
Where ns-nt are the number of yarn coils wound in one
minute, ns is the r.p.m. of the spindle, nt is the r.p.m. of
the traveller, dw is the diameter of winding.
• The length of the yarn wound onto the bobbin in one
minute is equal to:
L = Vf.r. Kc = df.r.nf.r.Kc

Where vf.r. = L1 is the length of the strand delivered by the
front roll per minute
Kc is the contraction coefficient.
Then the formula for yarn winding is as follows:
(ns-nt)dw = vf.r.kc
And
• which means that the travelers' lagging behind depends
on the speed of yarn delivery and on the winding
diameter.
w
c
r
f
s
t
d
K
v
n
n

.
.
−
=

Let spindle speed be 13, 500rpm, front roller delivery
15m/min, and layer diameters at tip and base 25mm
and 46mm respectively.
*Traveller speed at the base, nTB, is:
nTB= 13, 5000 - 15, 000 = 13, 500 - 104 = 13,396rpm
46
*Traveller speed at the tip, nTT is:
nTT =13,500 - 15,000 = 13,500-191 = 13,309rpm
25
Using spindle speed,
Twist/m =13,500/15 = 900.00
Using traveller speeds,
Twist/m at the base = 13,396/15 = 893.07
Twist/m at the tip = 13,309/15 = 887.27

Rotor spinning
Card sliver

Tasks of rotor spinning machine
1. Opening almost to individual fibers (fiber separation)
2. Cleaning
3. Homogenizing through back-doubling to improve
evenness
4. Combining (forming a coherent linear strand from
individual fibers)
5. Ordering (the fibers in the strand must have an
orientation as far as possible in the longitudinal direction)
6. Imparting strength by twisting and
7. Winding to a cylindrical (weaving) or conical
(knitting) cross-wound packages

Spinning Conditions
1--Rotor speed was 46,400 r.p.m.
2--Opening roll speed was 6,200 r.p.m.
3--Opening roll type was OK 40
4--Rotor diameter was 54 mm
5--Navel type used was:
a--smooth for maximum strength at high twist
b--grooved for spinnability at low twist
Rotor spinning

Rotor Diameter D
Current minimum: 28 mm
Minimum D > Staple Length
Must have sufficient size so that longest
fibre does not form a complete loop
Smaller rotor higher speed
➢ Opening Roller Speed
Higher speed gives better fibre opening.
Optimum depends on fiber, yarn and rotor speed.
If opening roller speed is too high, fibre
striping by air may not be complete, leading
to more yarn faults.

Nozzle

Piecing:
• Feed the yarn from the package into the spinning box
(up to the nozzle)
• Start fiber feeding
• Bring the yarn to the rotor groove
• The fibers in the rotor groove connect to the yarn end
• Start draw off the yarn (spinning process is started)
• Process fully performed & controlled by the robot
Fault: Moiré effect
• Caused by trash particle sticking in
the rotor groove
• As a result: Periodic yarn fault (“MO-Fault”)
• Yarn cleaner can detect MO-Fault and
stop the process
• Rotor cleaning needed to remove the trash

Fiber separation and fiber flow:
• The opening roller opens the sliver to single fibers
• Trash particles fall out through the trash window
• The fibers are transported with air through the fiber
channel into the rotor.
BYpass:
Allows settings for the trash removal:
• BYpass open: highest trash extraction (fine yarns, e.g.
Ne 30)
• BYpass half open: medium trash extraction (medium
and coarse yarns, e.g. Ne 10 denim)
• BYpass closed: lowest trash extraction
(spinning of man made fibers)

Factors Affecting Rotor Spinning of Fine Cotton Yarns
1) Raw Materials and Their Properties
2) Preparation for Spinning
3) Sliver Weight and Spinning Draft
4) Yarn Count Range
5) Yarn Twist
6) Yarn Properties
a) Yarn Appearance
b) End Breakage in Spinning
c) Yarn Evenness
d) Yarn Tenacity

Back doubling = Rotational speed of rotor/Lead of the yarn at the separation point
D = Rotor diameter; t/m = twist per metre
Steel novels are used for synthetic fibers of rotor spinning, Because at
higher speeds, steel novel has the advantage of better heat conduction and
hence less heating of the fibres, so that fibre damage can be avoided.
Evenness of rotor yarn is increased by means of back doubling.

• The point at which the ribbon is pulled from the rotor
groove is called the peel-off point, P
• Since the ribbon is pulled at the delivery roller speed, Vd,
the peel-off point circulates the circumference of the rotor
at a rotational speed of Vd /πDR, where DR is the rotor
diameter
• This means that, relative to the doffing tube, the peel-off
point rotates faster than the rotor such that
NP = NR + Vd /πDR

limitations of rotor yarn
a. Strength of yarn is less due to less migration of fibres
b. Finer count is not possible
merits of rotor yarn over ring spun yarn
a. Fibres are compactly oriented.
b. More abrasive strength
c. Production speed is 200 m/min whereas ring spinning production
speed is 20 m/min
d. More uniformity of yarn
e. Hairiness is less
f. Elimination of cop to cone winding, i.e Direct package is obtained
g. Elimination of conversion of sliver to roving

rotor yarn is weaker on average than ring yarn but,
being more even, has better appearance and is
relatively free of weak spots that may cause yarn
breaks in later processes.
Features of Rotor Spinning
❖ Yarn properties: lower tensile strength than ring yarns; good
uniformity and cleanliness.
❖ Application: for woven, warp knit and knitted materials.
❖ Advantages: low manufacturing cost; fully automated.
❖ Limitations: not the same range of application possibilities as
ring-yarns.

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