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Department Of Textile Engineering
I/A 251,252 Tejgaon Dhaka Bangladesh
• The chief function of roving frame is the attenuation of sliver.
• Insertion of protective twist in order to hold the fine strand of
• Winding of roving into a package that can be transported,
sorted, donned on ring spinning machine.
• Liable to faults
• Causes defects
• Add to production costs
• Roving is sensitive in both winding & unwinding
Complicated winding operations
• Spindle & flyer
• A cone drive transmission
• A differentiate gear
• Builder motion.
Necessity of Roving Frame
• There are two principle reason:
– First reason is to apply drafting.
– Sliver is thick, untwisted strand that tends to be hairy and to
create fly. There fore, if we directly want to produce yarn
from sliver by discarding simplex, we need 300 to 500 draft to
do so. But the fine twisted roving is significantly better suited
to this purpose.
– Second reason is related with transportation and
space limitation on ring frame.
– Draw frame “can” is the worst conceivable mode of
transportation and presentation of feed material.
Operating region of Roving frame
The drafting arrangement
Applying pressure to
the top roller.
Spindle & flyer
Design of flyer
Winding of bobbin
Cone drive transmission
The lifter motion
The builder motion
Drafting arrangement of roving frame
• Roller Drafting system
– Conventional roller drafting system:
– 4 over 4 without apron.
– Modern Roller drafting system:
– 3 over 3 drafting system with double apron (Lakshmi Rieter
– 4 over 4 drafting system with double apron (SKF PK 1600)
SKF PK-1600 drafting system
• Draft range: Total draft 5 to 20
Total draft is distributed in each zone as follows:
– Back zone: Break draft is applicable in here. Amount of break draft is
depends upon material.
• Middle zone:
– Less amount draft is applicable in here.
– Condenser is used in middle zone to condense sheet like sliver.
• Front zone:
– Maximum amount of draft is applicable in here. Apron is
used in this zone.
• Roller type:
Top rollers are synthetic rubber coated
Bottom rollers are made of steel
Front, 3rd and back rollers (bottom) are spiral fluted.
2nd roller has granulated pin.
• Roller dia:
The upper aprons are short and made either
of leather or more commonly of synthetic
rubbers. They have a thickness of about 1
mm and are held by tensioning device.
The lower aprons are longer and usually
made of leather. They run over the guide
bar, usually known as nose bar, to position
close to the delivery roller.
The aprons co-operated with each other t
guide and transports the fibers during drafting
and they exert a very significant influence on
the drafting operations.
Applying pressure to the top roller
• The top roller must be pressed with relatively high force
against the lower rollers to ensure the guidance of fiber.
• Pressure are in the range of 100 to 250 N per roller which
may vary as per raw material and its volume.
• Pressure is applied by spring pressure, pneumatic weighting,
•Condensers are mounted on a reciprocating bar behind the
•The second condenser is provided in break draft field.
•And the 3rd one is located in main draft field.
•Spreading sliver masses are condensed to improve evenness
and lead to drafting zone.
•Reduce the high fly level and hairiness of roving.
• As the top apron are forced by spring pressure against the
lower apron, the arrangement of this apron should permit
precise adoption of minimum distance to fibre volume. In
order to be able to maintain this minimum distance, spacer
are replace ably inserted between the nose bar of the lower
apron and the cradle edge of top apron. Spacer size is 4 to 7
mm in accordance with roving hank.
• Flyer is used to impart twist
• Flyer has two legs, one with hollow path or slot
and pressure arm another for balancing the flyer
• Flyer is placed on spindle, it gets motion by
• Flyer speed has direct influence on production.
• Flyer can be varying in sizes which are specified in
inch. For example, 12”X 5.5”, 12”X6” and 14”X6”.
First no. indicate maximum height and second no.
indicate maximum dia of wound package.
• A steel yoke attached to the lower end of hollow flyer leg is
called pressure arm.
• The roving is wrapped 2 or 3 times around the yoke.
• The no. of turn determine the roving tension. For higher
tension, a hard compact package is obtained and if it is too
high false draft or roving breakage can be caused.
• Therefore, the no. of wrap depends upon material and twist
• Bobbin leading principle (For cotton spinning)
• Flyer leading principle (For jute spinning)
Bobbin leading Principle
• Bobbin speed is higher than flyer
speed at all point of winding.
• The winding on speed is constant
throughout the process.
• With the increase of bobbin dia,
bobbin speed must be decreased.
• The variation of bobbin speed with
the increase of bobbin dia must be
• Less tension on roving.
Flyer Leading Principle
• Flyer speed is higher than bobbin
speed at all point of winding.
• The winding on speed is constant
throughout the process.
• With the increase of bobbin dia,
bobbin speed must be increased.
• The variation of bobbin speed
with the increase of bobbin dia
must be constant.
• Higher tension on roving.
Recent Development of Speed Frame
1. Improved drafting system:
Modern drafting system like SKF PK 1600, SKF PK 5000 etc give
more controlling to fibre and they able to import 8 to 20 draft on
2. Higher flyer speed:
Modern flyer speed is more than 1000 rpm where as the
convention flyer reaches maximum 600 rpm.
3. Plastic flyer: lighter in weight and less power consumption in result.
4. Flyer driving from top:
Modern flyers are top mounted and having no spindle which in
turns facilitate following issues:
Auto doffing operation
Reduced flyer leg spreading
Higher flyer speed
5. Inching motion:
It initiates flyer turning slowly for piecing if the end breaks. And also
ensures less tension on roving while the machine starts.
6. Auto stop motion:
Various auto stop motions are initiates to reduce waste and increase
efficiency: Sliver stop motion, Roving stop motion, Creel stop motion,
full bobbin stop motion, Doffing stop motion.
7. Pre determine set length:
Machine stops automatically after a predetermined length of
roving is wound on bobbin.
8. Monitoring system:
Modern speed frame includes data monitoring system by
direct reading of :production, efficiency, speed of flyer,
stoppage time, quality monitoring and package built.
9. Auto doffing:
Like some ring spinning machine, simplex machine manufacturers
offer the machine having automatic doffing system where full
bobbins are replaced by empty bobbin without any help of worker.
10. Automatic tension controller:
it determines the tension on roving continuously and send data to
inverter to adjust its speed.
Faults in speed frame:
• Irregular draft
•Wrong angle of poker rod
• Top roller dia variation
•Different lifting and lowering
• Pressure variation.
distance due to faulty builder
• Rough surface of apron
• Improper roller setting
• Roving Breakage:
•Winding on speed is less than front
•Less tension on roving during
•Variation of pressure on top roller
• Sloughing off:
•Less coil/inch (if top rail speed is too
•Improper taper end
high it results excessive spacing
•Faulty taper wheel
between adjacent coil.)
•Stickiness formation on roller
•Wet roller surface
•Excessive dry roller surface
•Dust deposit on roller.
•Dirty roving bobbin:
•Excessive oiling on machine parts
•Insufficient machine cleaning
•Cracked bobbin and careless handling
Remove short fibre below a preselected length and there by
reduce length variation in the cotton mixing.
Improve fibre parallelization and fibre to fibre separation
and minimize the fibre entanglement and disorientation.
Remove neps and foreign matter
form the cotton.
Excellence of fiber quality by
Parameter/ Specification of
Line diagram of comber
Machine Setting Depends on Noil Extraction%
Type of feed
Point density on top combs
– Feed distance means feed per nip.
– Feed distance has a influence on
• Quality of combing operation
• Production rate.
High feed distance increase the production rate
but causes deterioration in quality.
Feed distance approximately correlated with fibre length.
Type of feed
• Forward feed has been chosen for higher production rate
when quality requirement is not rigorous with a noil % of
5- 12 %.
• Backward feed has to use for higher quality requirement
with a noil % of 12 to 25%
The detachment setting
• This is the distance between the bite of the
nippers and the nip line of detaching rollers.
• Higher detachment setting bring the high elimination
• The detachment setting normally lies in the
range of 15 to 25 mm.
The no. of points on comb
• Point density and the fineness of needle have to be adopted to
• The needle of top combs have a flattened X-section and are
formed with a bend.
• The point density is 23-32 needles per cm.
• Fewer needles are used for higher production with lower
Top comb Penetration
• Higher top comb penetration results higher elimination of noil.
• Lowering the top comb by 0.5mm is followed an increase in
noil of about 2%.
• The main improvement is seen in the elimination of neps.
• Over deep penetration may disturb fibre movement during
piecing. This results in deterioration of quality%.
• After combing of the fringe protruding from nippers, the
detaching roller draws some of the combed feedstock out of
• By means of this piecing operation, the roller have to lay
these strips of web on top of each other, so that first a
coherent web and finally a endless ribbon is obtained.
• This sliver produced in this way has a wave like structure, it
exhibits periodic variation.
• By using correct machine setting, it is possible to lay the
fringe on each other that unevenness in successive fringes
partly cancels out.
Parameter influence the combing operation
• Raw material
Uniformity of fibre length
• Material Preparation
– Parallelization of fibers
in the sheet.
– Sheet thickness
– Sheet Evenness
– Orientation of hooks in
Factors associated with M/C
Condition of machine
Condition of comb
Operation of combs
Types of sliver forming elements
Accuracy of the setting
Effect of combing on staple diagram
Relationship between noil% and improvement of yarn quality
A= Improvement of Yarn Quality in %
B= Noil elimination in %
a= Yarn strength
c= Yarn imperfection
Sequence of combing cycle
a. Lap feeding by feed roller: The lap is
fed into the machine between the feed
roller and feed plate. The feed roller
moves and material passes forward.
b. Lap nipping by the nipper: the nipper
moves downwards towards the feed plate,
so that the fibres are clamped between
them. Cylinder is then ready for combing.
c. Combing by cylinder: The fibres
protruding from the lap beyond the nipping
point of the two plates, are combed by the
passage of rows of needles fastened to a
cylinder which revolves and carries away
the short fibres, neps and other impurities.
d. Nipper opening and forwarding: the
nipper open again and the material
combed by the cylinder moves towards
the detaching roller.
movement: when the top nipper reach
upwards, the detaching roller have
returned parts of previously drawn off
stock by means of reverse rotation.
f. Combing by top comb: the top comb
penetrate its single rows of needles in to
the fibre fringe. Thus top comb perform
the combing operation on the upper side
g. Detaching roller forward movement:
The detaching roller begin to rotate in
the forward direction again and draw
the clamped fibres out of the sheet
which is held first by the feed roller.
h. Waste extraction by brush
Ring Spinning System
(Conventional but competitive)
• Ring frame exhibits significant advantage in
comparison with new spinning system:
– It is universally applicable; ie. Any material can be spun to
any required fineness.
– It delivers yarn with optimal characteristics, especially with
regard to structure and strength.
– It is uncomplicated and easy to operate.
– The know-how for operation of machine is well established
and accessible to everyone.
– It is flexible as regards to its quantities. (Blend & lot size)
• Attenuation of roving until the required fineness is achieved.
• To impact strength to fibre strand by twisting it.
• To wind up the resulting yarn in a form that it will suitable for
storage, transportation and further processing.
•The roving bobbins (1) are inserted in holders (3) on the creel. Guide
bars (4) guide the rovings (2) into the drafting system (5), where they
are drawn to their final count. The drafting system is at an angle of
45-60° and is one of the most important units on the machine, since it
exerts a very considerable influence on the uniformity of the yarn in
•After the resulting thin ribbon of fibers (6) leaves the delivery
roller, the twist necessary for imparting strength is provided by
spindle (8) rotating at high speed. In the process each rotation of
the traveler on the spinning ring (10) produces a twist in the yarn.
Ring traveler (9) is also necessary for taking up this yarn onto a
tube mounted on the spindle. This traveler - a remnant of the
flyer on the roving frame - moves on a guide rail around the
spindle, the so-called ring (10). The ring traveler has no drive of its
own, it is dragged with spindle (8) via the yarn attached to it. The
rotation of the ring traveler lags somewhat behind that of the
spindle due to the relatively high friction of the ring traveler on the
ring and the atmospheric resistance of the traveler and the thread
balloon between yarn guide eyelet (7) and traveler (9).
This difference in speed between the spindle and the
traveler results in the thread being wound onto the
tube. In contrast to the roving frame, the ring
spinning machine spindle operates with at higher
speed than the traveller (9). The yarn is wound up
into a cylindrical cop form by raising and lowering of
the rings, which are mounted on a continuous ring
rail. The layer traverse of the ring rail is also less than
the full winding height of the tube. The ring rail
therefore has to be raised slightly (shift traverse)
after each layer has been wound. For a time,
machines were also built featuring shift traverse
produced by lowering the spindle bearing plate
rather than raising the ring rail. These machines are
no longer available today.
Operations involve in ring frame
• Roving bobbin are mounted on creel. There is no gear
motion to rotate the creel or bobbin.
• Bobbin is rotated with the creel due to tension of moving
generated from drafting zone.
• If moving bobbin doesn’t unwind perfectly then false draft
can arise or even end breaks.
• Drafting operation reduce weight per unit length of
• Roving comes from bobbin are passed through the
drafting zone which has commonly a 3 over 3
drafting roller with double apron.
• To hold the fiber into yarn cross section and to develop
strength, spiral turns are inserted along the fibre axis.
• Travellers mounted on ring cup, twist the yarn, gets drive
directly from spindle.
• After twisting the yarn are wound on suitable package.
• Layer of yarn are wound on one above another in
different stage on package.
• Winding mechanism is performed in a way that it will be
suitable for unwinding as well.
• For proper size and shape of package, the ring rails are lifted
• The resultant bobbin will be conical shape full bobbin.
• After a required length of yarn is wound on the package,
machine is stopped for doffing.
• Doffing is the process of replacing the full bobbin by an empty
• If all roving bobbin filled on the creel are of same size, then
those bobbin will be exhausted at the same time which will
cause machine stoppage and production will be hampered.
• In block creeling arrangement, the total no. of creels are
divided in to several no. of groups, then each group contains
the roving of same length but differ from adjacent group or
• Thus all bobbin will not exhausted at the same time.
• So, there is no machine stoppage and production will run
The bobbin creel is simple in design, but it can
nevertheless have an influence on the occurrence of
If take-off from the bobbin is not trouble-free, incorrect
drafts or even thread breaks occur. This is why bobbin
suspension pivots are used nowadays rather than bobbin
holders. These are, for example, bolted onto several
support rails (triangular tubing (2)) arranged one behind
the other along the entire length of the machine, one for
each spindle. The pivots, such as the Casablancas model
illustrated, feature the actual holding device for the tube in
their lower section (6). If ring (5) is pushed right up with
the top end of the tube inserted in the pivot, retainer (6) for
the bobbin swings out; if ring (5) is pushed upward a
second time, holder (6) is retracted again, and the tube,
for example when it is empty, can be removed again. The
Nowadays bobbin creels occupy lots space in terms of
width, as very large roving bobbins are usually used.
Figure of spindle specified with different parts:
Should be studied from the book of W. klein (Volume :4,
• To hold the bobbin tightly to prevent shacking during its revolution.
• To help in winding yarn on to bobbin.
• It takes part in twisting along with ring and traveller.
• A capacity of spinning floor is mainly determined by the no. of spindle.
Influence of spindle on spinning:
• Spindles, and their drive, have a great influence on power consumption and
noise level in the machine.
• The running characteristics of spindle, especially imbalance and eccentricity
relative to the ring, also affect yarn quality and of course the no. of end
• almost all yarn parameters are disadvantageously affected by poorly running
Precaution regarding spindle:
• The mill must ensure at all time that centering of the spindle relative to
the rings is as accurate as possible.
• Since the ring and spindle form independent units and are able to shift
relative to each other in operation, these two parts must be re-centered
from time to time.
Specification of Ring:
Ring is specified by its two dimension:
Internal diameter (Ring dia)
Available ring dia (mm) for short staple cotton spinning: 36, 38, 40, 42, 44
Flange width depends on flange number.
Flange width (mm)
Ring Traveller/ Traveller
•It provides fibre band or the double thread supplied by the
feed roller with necessary torsion.
•It assists in winding the yarn on to cop with correct tension.
Two types of Traveller:
1.C- Shaped traveller
• Used on T-flanged horizontal ring
• For cotton Synthetic and blends
2. J-shaped Traveller:
•Used in vertical ring
•For coarser doubling cotton, acrylic, woolen, worsted yarn.
Spinning geometry with respect to ring and Tube
1. Ratio of ring dia “D” to tube dia “d” is 2:1 (ideally)
• The ring traveller together with the yarn as a pull element, is
set into motion on the ring by the rotation of spindle.
• If the direction of pull deviates too much from the running
direction of the traveller (α <30°), the tension load will be
• The pulling tension can be reduced by adapting ring or tube
dia (α >30°) during the winding up of the tube.
2. Ration of tube length to ring dia 5:1 (ideally)
• The tube length determine the maximum balloon length.
The shorter the balloon the higher the traveller speed can
• In practical use, the ideal ratio of tube length to ring dia has
been shown to be between 4.5:1 to 5:1.
Yarn guiding device
Lappets are mounted directly above each spindle. Lappets are designed to
lead the yarn centrally over the spindle axis. The lappet consist of thread
guide made of bent wire and a pivoted support arm. The guide is adjustably
mounted on support arm to enable centering while the arm itself is secured to
lappet rail which extend over the length of the machine. This rail along with
the lappet can be raised or lowered.
Function of Lappet:
1.Continual up and down movement
during winding of the layers.
2. Continual upward shift through a
small distance in accordance with the
Balloon Control ring:
The space between the ring and the
thread guide is correspondingly long.
Thus give a high balloon.
The effect of balloon:
A high balloon is associated with large balloon diameter, causing space problem.
The large balloon dimension lead to relatively high air drug on the yarn in the
balloon. This in turn cause increase deformation of balloon curve out of the plane
intersecting the spindle axis. This deformation lead to balloon instability.
In order to avoid this consequences, balloon control ring
are used. Each dividing its balloon into two smaller sub
balloon. In spite of its large overall height, the double
balloon created in this way is thoroughly stable even at
relatively low yarn tension.
Most end down arises from the break of spinning triangle. Because
there are very high forces executed on the strand of fibres which
haven’t yet been fully bound together. If the break occur in the
triangle then the newly created free yarn ends must be drawn to the
cop and wound on to it. During this process, the broken ends lashes
around the spindle. In absence of protecting device, the broken end
would hurled in to the neighboring yarn balloon and would cause a
end down on that spindle.
The procedure would be repeated continuously so that a wave of
ends down travel along the row of spindle.
Therefore, to avoid this circumstances, separator is used.
Requisites for good running
condition of Ring frame
•The ring are perfectly centered with regard to spindle.
•The yarn guide eyelet is well centered with regard to the
•The balloon control rings are perfectly centered with
regard to spindle
•The spindle bearing is in good condition excluding
•The ratio between bobbin diameter, bobbin length and
spindle gauge with regard to the ring dia is correct.
•Correctly adjustable traveller clearer keep the flange
traveller free from fly.
•Room climate is favorable for the yarn processed.