A study on different opening roller wire configuration

P R E PA R E D B Y:
SAGNIK GHOSH*
*Department of textile technology, Government
college of engineering and textile
technology,serampore
EMAIL:email2sagnikghosh@gmail.com
C O N A C T I N F O : 7 0 0 1 4 7 9 7 6 7 / 7 8 9 0 2 4 2 7 2 5
A STUDY ON DIFFERENT OPENING ROLLER WIRE
CONFIGURATION USED AND ITS APPLICATION
AREA
Sunday, April 1, 2018
1

CONTENTS
 Opening roller:it’s types and comparative
study
 Introduction
 Opening roller wire configurations:key
parameters
 Type of teeth.
 Teeth specifications.
 Surface speed of opening roller.
 Condition of teeth.
 Detailed study of some standard opening
roller wire configuration
 Opening roller rpm vs single yran strength
 Opening roller rpm vs imperfection and
u%
 Speed bypass system by suessen
 Fibre breakage
 Developments in opening roller
 Two-piece opening roller dia 65 mm by
RIETER
cost-cutting and a time-saving innovation
of the classic opening roller
 Opening rollers (semi automated)
 Two-piece opening roller diameter
bd,bda&bt
 Conclusion
 Acknowledgement
 References
2

INTRODUCTION
Generally opening is done in two stages as
follows:
1.Opening to flocks-in the blowroom;
2.Opening to fibres-in the card and open-end
spinning machine;
Opening out- in which the volume of the flock is
increased while the no. of fibres remains
constant thus reduction in specific density.
Breaking apart- in which two or more flocks are
formed from one flock without changing the
specific density.
Breaking apart is sufficient for cleaning but
opening out is necessary for blending and
aligning.
In case of rotor,the opening roller separates the
fibres from the slivers(carded or drawframe
sliver) as it is fed in,and,after 2 or 3
rotation,delivers them to the feed tube in which
the airflow takes them to the rotor by airflow.
Trash particles are extracted by centrifugal
forces in first 90 degree revolution.
It has a diameter of 50-80 mm(also known as
beater roller or disintegrator).
It must have an optimum speed(as lower speed
causes lapping of fibres ,thick and thin
places,higher speed damages the fibres causing
inadequate opening,it can also cause melting
for thermoplastic fibre at high speed).Naturally
the surface speed is selected in between 800-
2500 m/min.
Naturally the teeth profile,angle and heights of
teeth,teeth density ,clothing type have a huge
impact on quality of opening.
3

OPENING ROLLER:IT’S TYPES AND
COMPARATIVE STUDY
 The main purpose of the opening roller is to open the fibre sliver to individually aligned
single fibres. The efficiency of the opening fibre on the roller surface depends on the
total opening force affecting the fibres, caused by the opening roller tooth. Well
straightened, aligned and parallelised fibres of the opened sliver are expected to build
twisted rotor yarn bodies efficiently. There are two kinds of opening rollers: the pin
roller and sawtoothed roller
 The saw-toothed roller can be made of garnet wire mounted or of a multiple leaf saw-
toothed assembly. The specification and speed of the opening roller are important
factors which influence combing effects [1]. It can be seen that along with an increase
in opening roller speed, the degree of fibre separation improves.
 A pin roller is better than a saw-toothed roller, especially in low speed conditions. The
contents of short fibre will increase when the speed of the saw-toothed roller increases;
however, there is no change when the pin speed increases. Nevertheless, it needs an
advanced manufacturing technique and is hard to make [2].
4

OPENING ROLLER:KEY PARAMETERS
 Action of opening roller is similar to that of licker-in in card but is more intense
because of higher order of speeds. Fibres are almost individually removed from the
fringe held by feed plate and feed roller. Apart from individualisation, extraneous
trash, foreign material and neps are removed by opening roller action. Amount of
opening and fibre separation achieved in opening roller region has critical
influence on evenness of yarn.Performance of opening roller is decided by
 Type of teeth.
 Teeth specifications.
 Surface speed of opening roller.
 Condition of teeth.
5

Type of teeth
 Two types of teeth are common: Pin type and Saw tooth type. Pin type has a higher
wear resistance, longer life and further it results in fewer fibre breakages. But fibre
removal from opening roller to transport tube is much more smoother with saw tooth
wire even at high speeds. However, opening roller speed has more critical influence on
fibre breakages with saw tooth type teeth. Pin type roller is however more difficult to
manufacture and does not offer the wide range in tooth specifications as saw tooth wire.
Nibikora et al[3] found better yarn quality with pin roller than saw tooth roller with spun
silk/cashmere blended yarns.
Teeth specifications
Important teeth specifications are rake angle a, distance between adjacent teeth t and
width of the base of the teeth band height of wire h (Figure next
slide). t and b determine the number of teeth per unit area.
Number of teeth per unit area = 1b x t
6

TOOTH SPECIFICATION:RAKE ANGLE
 Rake angle
Rake angle is the angle front edge makes with horizontal (Figure). It is described as
positive negative or neutral.The angle is neutral if the leading edge of tooth lies in
vertical.
Action of opening roller will increase as rake angle reduces and at the same time fibre
breakages will increase. Most usual clothing have a rake angle of 66 to 80° for cotton
and 90° and above for synthetics. For coarse cottons and waste with higher trash,
opening roller with lower rake angle is preferred. For finer cottons higher rake angle
should be used. For man-made fibres, 90° or negative rake should be used.
 Simpson and Murray4 found that lower rake angle a leads to more fibre breakages and
poor yarn quality with cotton yarns from medium staple (29 mm). Wire with 90° rake
angle resulted in inferior yarn quality because of poor fibre individualisation while 60°
rake angle gave more fibre breakages. Trash removal was better with lower rake angle.
Rake angle 75° gave the best yarn quality. Trash removal was better with lower rake
angle. Kirschner and Bay5found that negative rake wire gives less rotor dust than
normal wire with man-made fibres.
7

TOOTH SPECIFICATION:
TOOTH HEIGHT,TOOTH DENSITY
 Tooth height
Higher height increases intensity of combing action and ensures better individualisation
and trash removal and should be preferred for coarse trashy cottons. Lower height
should be used gentler action but fibre individualisation will be inferior.
 Tooth density
It is nothing but the number of points per unit surface area.It is not simply the total no.
that is significant,but also the no. available per unit time;i.e. the product of point
density and the speed of the movement of the surface. For short staple cottons and
waste higher tooth density in the range of 12 to 18 teeth per cm2is recommended. For
man-made fibres lower tooth density in the range of 5 to 9 teeth per cm2 should be
used. Some common opening roller tooth profiles are given in Figure.
Mathematically, Points/inch^2=645/[Basewidth(mm)*Pitch(mm)]
Points/cm^2=100/[Basewidth(mm)*Pitch(mm)]
Base width
This influences the point density.The narrower the base,the greater the no. of turns that
can be wound on the roller and correspondingly higher the point population.
8

TOOTH HEIGHT,RAKE ANGLE,BASE WIDTH
9

TOOTH HEIGHT,TOOTH DENSITY
Height of the clothing
The height must be very uniform.It can also exerts an influence on the population,since
shorter teeth for a given tooth angle,leaves space for more teeth.Where shorter teeth is
used,fibres are less able to escape from the action of clothing.
Tooth pitch
This is nothing but the tip-to-tip spacing.
Base of the tooth
The base is broader than the point in order to give the tooth adequate strength and also to
hold the individual widings apart.
Tooth hardness
In order to process as much material possible with one clothing,the tooth point must not
wear away rapidly.Each tooth has to be hard at the tip and soft at the base.
10

 OK 36 Viscose staple fibre and blends, h = 1.2mm, t = 4 mm, tooth density =
14.06t/cm2, a = 90°OK 37 - Man-made fibres, h = 2 mm, t = 4.7 mm, tooth density =
13.3 t/cm2, a = 99°OK 40 cotton and blends with high cotton content, h = 3.6 mm, t =
2.62 mm, a = 65°OK 61 blends of cotton and man-made fibre, polyester/viscose, 100%
man-made fibre, h = 3.6, t = 3.93 mm, a = 75° OS 15 Polyacrylonitrile staple fibre, OS
21 Cotton and Polyester, OB 20 100% cotton at high speeds.
Vigo and Barella6found that coarse Polyester/viscose yarns are less affected by opening
roller tooth height and density. But OK 37, which has lower tooth density and higher
height, gives a better yarn quality than OK 36 with finer yarns. OK 36 results in more
fibre breakages with such material. Vaughn and Cox7found that opening roller type
does not have much effect on yarn quality.
11

Specification of some wire profiles
OK 36 OK 37 OK 40 OK 61 OTHERS
Used for: Viscose
staple fibre and
blends
Angle of tooth= 90°
Used for: Man-made
fibres
Angle of tooth = 99°
Used for:Cotton and
blends with high
cotton content
Angle of tooth= 65°
Used for:Blends of
cotton and man-
made fibre,
polyester/viscose,
100% man-made
fibre. Angle of
tooth= 75°
OS 15 is used for
Polyacrylonitrile
staple fibre,
Height of the tooth=
1.2mm
2 mm
3.6 mm
Width of the base of
the tooth= 3.93 mm
OS 21 is for Cotton
and Polyester and
the tooth= 4 mm
the tooth = 4.7 mm
the tooth = 2.62 mm
Angle of tooth= 75° OB 20 is used for
100% cotton at high
speeds.
Tooth density =
14.06t/cm2
Tooth density = 13.3
t/cm2
OS 25 is used for
delicate fibre.
12

 B-174
 Preferably used
for cotton,highly
suitable for
viscose.
 Good fibre
separation,more
aggressive front
flank,higher teeth
density,sharper
points.
 Favourable wear
conditions.
 B-174-4.8
 Same as previous
with better fibre
transport due to
modified tooth
shape.
 Suitable for cotton
with a small
amount of
honeydew.
 Wider tooth
spacing(4.8mm
instead of 2.5mm
in B174).
 S-21
 Suitable for
polyester and
polyacrylic,not
much sharply
inclined,for gentle
opening.
 Also for P-C
blends.
 S-43
 No merry-go-round
fibres.
 Suitable for
polyacrylic,gentle
opening of fibre
beard and good
separation of fibres
to avoid lapping of
fibres.
13

Clothing with low tooth density and low tooth height, type S 43, is used in particular
for man-made fibers with a tendency to lap due to high metal/fiber cohesion, such as
polyacrylic. Especially gentle opening is possible with this clothing and at the same
time the fibers are more readily released from the clothing.
Clothing shape S 21 is characterized mainly by a less sharply inclined and thus also
less aggressive front flank, which is suitable for gentle processing of thermally more
sensitive man-made fibers in particular, especially polyesters and their blends.
For carded and combed cottons and viscose, clothing with a large, i.e. more aggressive
front flank, higher tooth density and sharper points (type B 174) is usually used.
For critical cottons, also those containing a small amount of honeydew, the use of
clothing type B 174-4.8 is recommended, which is characterized by a modified clothing
shape and wider tooth spacing (4.8 mm instead of 2.5 mm as in B 174).
14

SPEED
There is an optimum opening
roller speed at which best yarn
quality is obtained as shown by
Rakshit and Balasubramanian8
and other workers. Figures
show how single thread, U%
and imperfections vary with
increase in opening roller speed
in 14s Ne yarn. Strength
improves with increase in
opening roller speed, reaches a
maximum and drops with
further increase in speed. But
U% and imperfections initially
reduce steeply with increase in
opening roller speed and later
marginally with further
increase in speed. With increase
in opening roller speed, fibre
individualisation improves
leading to better yarn quality.
15

 Further removal of trash particles and foreign matter improves with individualisation of
fibres leading to fewer imperfections in yarn. However, fibre breakages occur because
of opening roller action, which increases with speed. Therefore yarn strength improves
initially with speed reaches an optimum and deteriorates beyond a point. However,
improvement from individualisation and trash removal at high speed overweighs the
effect of fibre breakages resulting in marginal improvement in evenness and
imperfections.
 Fibre removal from opening roller teeth to transport tube is also hampered at high
opening roller speeds. Leading end of fibre forms hook upon removal by opening
roller9. Hooking tendency and breakages increase at higher opening roller speed.
Optimum speed depends upon fibre and its properties. Optimum roller speed is around
8000 to 9000 rpm for coarse and trashy cottons, 7000 to 8500 for long staple cottons
and 6000 - 7000 for man-made fibres.
16

 Shahid et al10 also found similar trends with viscose jute blends. Tenacity and
elongation increase initially and unevenness and imperfections reduce with opening
roller speed and afterwards strength reduces and imperfections increase. Using Box and
Behnken factorial design, Salhotra and Balasubramanian11 found the optimum opening
roller speed to be around 7000 rpm. Kong et al12 quantified the amount of opening by a
measure called number of points per fibre (ppf).
ppf = Number of opening roller points per unit time. Total number of in feed fibres
over the same time.
Studies on 60 tex yarn showed that irregularity and imperfections reduces with increase
in ppf up to a critical level beyond which no reduction is found because of increased
fibre breakages. Duru and Babaarslan13found strength reduces but unevenness and
hairiness reduce with increase in opening roller speed with polyester/waste blends.
7000 - 8000 rpm provides most effective cleaning. Fibre straightness and alignment
improves with increase in opening roller speed at constant airflow speed and with
increase in airflow rate at constant opening roller speed14.
17

RPM VS IMPERFECTION% RPM VS UNIFORMITY%
OPENING ROLLER RPM VS IMPERFECTION
AND U%
18

 Barella and Vigo15 conclude that best yarn quality was obtained at opening roller speed
above 6000 and TM of 160 for 23.57 tex yarn for processing conditions remote from
optimum. Optimum values of opening roller speed and TM were found to be different for
yarn regularity and tenacity.
 Another important function of opening roller is to remove trash and foreign matter from
cotton and molten chips from man-made fibres. As fibres in individual state carried by teeth
of opening roller, trash and foreign matter being heavy are ejected into a trash box below.
One of the problems encountered in rotor spinning is due to fibres circulating around
opening roller. Instead of moving into transport tube some fibres continue to move with
opening roller because of inadequate suction at entry point of transport tube. If suction is
increased, trash removal under opening roller suffers.
 To overcome this problem, Suessen have provided in their compact spinbox a bypass
opening with adjustable air intake, after the area of trash extraction (Figure next slide).
Incoming air at this point meets the teeth of opening roller tangentially with the effect that
fibres are lifted out of the interspaces of saw teeth. This helps to improve fibre removal from
opening roller to transport tube. At the same time air speed at trash extraction point is kept
lower by adjusting the air intake in bypass to achieve efficient trash removal.
19

Fig: Spinbox with adjustable
bypass
Bypass opening at opening roller helps to produce
a cleaner yarn with fewer imperfections. Suessen
have also developed Speed Bypass for man-made
fibres, which are more prone to recirculate. To
facilitate easy passage of fibres to the transport
tube, the gap between opening roller and housing
is increased from bypass region to the junction of
opening roller and transport tube. Another method
tried to reduce circulating fibres around opening
roller was tried out by introducing high-pressure
slot ejector at the entrance in a research project by
Voidal16. Trash content removed by opening roller
depends upon trash in input sliver and varies
between 35 - 50%.
 Micronaire value of opening roller lint is found to
be much lower than that of input material
indicating that low micronaire fibres being
weaker get broken and removed along with trash.
High level of trash in the input sliver leads to
rapid wear of opening roller teeth and causes
accumulation of fine trash and dust in rotor
groove. Normally trash in input sliver should be
below 1.2 - 1.4%.
SPEED BYPASS SYSTEM BY SUESSEN
20

FIBRE BREAKAGE
 A certain amount of fibre breakages is inevitable and arises because of the action of
teeth on material at high speeds. Several methods are used to determine the extent of
fibre breakages. One common method is to stop the machine and collect fibres
deposited on rotor as ring. By doing this several times, sufficient amount of material
can be collected to test fibre length. Mean fibre length of the fibres thus collected is
compared with that of input sliver.
% Fibre breakages = (l - l1 )/ l ×100,Where l = mean length of fibre in input sliver and
l1 = mean length of fibre in rotor ring.
 Another method is comparing short fibre % in input sliver and that in rotor ring. Effect
of opening roller speed on fibre breakages with different cottons is studied and the
results are shown in Figure 9.
Sunday, April 1, 2018/
21

Figure 9: Fibre breakage % with increase in
opening roller speed
Figure 10: frequency of fibre vs length of
fibre in mm
 Figure 9 shows that opening roller action is
associated with certain amount of fibre
breakages at all speeds. Order of fibre
breakages is nearly same as opening roller
speed is increased from 4000 to 6500 rpm
but increases markedly as speed is
increased to 9000 rpm. Further, fibre
breakages are more with long staple cottons
because of longer combing action by
opening roller. Breakage of long fibres is
further corroborated by the frequency
distribution of fibre length of material at
different opening roller speeds, shown in
Figure 10. While a peak indicating mode is
seen around 28 mm in raw cotton, the peak
is completely absent at 600 and 9000 rpm
speeds. So the loss in strength of yarn at
opening roller speed of 9000 rpm is
because of higher fibre breakages. But the
improvement in evenness and
imperfections at 9000 rpm is because the
improved fibre individualisation outweighs
the effect of higher fibre breakages.
22

Developments in opening roller
 Opening roller consists of a pinned or
saw toothed combing device mounted
on a core. After long period of working,
teeth wear out and need to be replaced
by a new one. To reduce replacement
cost, several manufacturers, like
Burckhardt, Rieter have developed
sleeves with combing device, which can
be removed and refitted on the core. By
this only the sleeve needs to be replaced
at the time of wear and the core, which
has minimum wear, can be reused.
Further sleeve can be fitted other way
round so as to change rake angle.
 Wear and tear of teeth is more with
trashy cottons and polyester fibres with
delustrant titanium dioxide. To reduce
wear of teeth hardened teeth with
diamond and nickel coating have been
developed. Nickel polished rollers are
also available Rieter offers extra
resistant XR coating for polyester
fibres. Ekatex offers partial or complete
coating of opening roller with
electroless nickel dispersions with
controlled incorporation of hardening
particles.
23

Two-piece opening roller dia 65 mm by RIETER
Cost-cutting and a time-saving innovation of the classic opening roller
24

OPENING ROLLERS (SEMI AUTOMATED)
75 mm dia opening roller equipped with:
 Standard bearing PLC76-3 KK
 Bearing with lubrication bushing
PLC76-3-7 KK
 Opening roller wire OK40, OK61,
OK37, OK36, OK74, OS21, 6087
 Possibility to supply single heads
(balanced or unbalanced)
 Type and finish:
 D - nickel diamond coated
 NP - needle polished
 S - standard
 K - kanai
65 mm dia opening roller equipped with:
PLC76-3-7 KK
OK37, OK36
(balanced or unbalanced)
 S - standard
25

TWO-PIECE OPENING ROLLER DIAMETER
BD,BDA&BT
65 mm dia two-piece opening roller
PLC76-3-7 KK
OK37, OK36
including clothing carrier
 S - standard
75 mm dia two-piece opening roller
PLC76-3-7 KK
OK37, OK36, OK74, OS21, 6087
including clothing carrier
 S - standard K - kanai
"PP" modification of types with diamond-coated
wire:
The highly abrasion-resistant coating of diamond
micro particles dispersed in Ni layer can be found
only on the toothed wire instead of on the whole
surface of an opening roller head
26

CONCLUSION
 The main factors influencing combing
effects are the wire work angle and tooth
density. For spinning different materials,
various types of saw-toothed roller must be
used.Severalchoices exist for the opening
roller wire.The wire most used in the
industry is sawtooth shaped and hardened
with diamond and nickel. Depending on the
fibre being used, the angle of the wire is
selected to allow for the most effective
combing and fibre removal. Several studies
have been published on the effect of opening
roller clothing in rotor spinning. The main
findings relate to the angle of the tooth and
point density required to obtain effective
fibre separation with minimal fibre
breakage. It was reported that there is a
marked increase in twist efficiency with an
increase in opening roller speed. The
increase in twist efficiency is the result of a
decrease in the percentage of sheath fibres.
Greater fibre separation at higher opening
roller speeds reduces the possibility of some
fibres becoming wrapper simply because
they happen to entangle with the fibres
undergoing belt formation. The slightly
increased number of twists at high opening
roller speeds can be attributed to the high
degree of fibre separation at high speeds.
The teeth shape and number of teeth on the
surface coating material are important
features affecting the opening force and
opening efficiency of a sliver on a rotor
spinning unit. Increasing the opening roller
speed raises fibre separation efficiency and
maintains a better twist insertion rate
27

Acknowledgement
 I take this opportunity to express my profound gratitude and deep regards to
Mr. Susanta Sekhar De for his exemplary monitoring and constant
encouragement throughout the course of this subject.
 I am obliged to project members (Entire department), for the valuable
information provided by them in their respective fields . We are grateful for
their cooperation during the period of my assignment.
 Lastly, We thank almighty, my teachers, friends for their constant
encouragement without which this assignment would not be possible.
Sagnik Ghosh
28

REFERENCES
1.Palamutcu S., Kadoglu H.; Effect of processing on the twist of 100% polyester OE rotor
yarns, Fibres &Textiles in Eastern Europe 2008, Vol. 16, No.4(69) pp.24-28.
2. Wang S., Yu X.; Textile yarns, Shanghai,Novembre, 2006.
3. I Nibikora, J Wang and J Wang: Optimum Selection of Opening Roller and Navel for
Rotor Spun Silk/Cashmere Blend Yarn, Fibres and Textiles in Eastern Europe, 2010, 18, 5,
pp 35.
4. J Simpson and M F Murray: Effect of Combing Roller Wire Design and Rotor Speed on
Cotton Yarn Properties, Textile Research J, 1979, 49, pp 506.
5. E Kirschner and E Ray: Evaluation of Measures for Reducing Rotor Deposits on OE
Spinning Rotor on the Basis of Deposit Characteristics, Textil Praxis Int, E 0671 Ex2 (Engl
Edn), VI - IX, German original, 1978, pp 132.
6. J P Vigo and A Barella: Influence of Opening Roller Type on Properties of Open-end
Polyester- Viscose Yarns, Textile Research J, 1981, 51, pp 34.
7. E A Vaughan and T S Cox: Effect of Opening Roller Design and Operating Speed on the
Properties of Open-end Yarns, Am SocMechEng Tech Publ TS-Tex - 3, 1975, pp 1
8. A K Rakshit and N Balasubramanian: Influence of Opening Roller Speed, Rotor Speed and
Rotor Diameter in Open-end Yarn Quality, Annual Conference of Textile Association, 1985.
29

REFERENCES
9. A K Rakshit: Studies on Irregularity Characteristics and Quality of Open-end Yarns, Ph D Thesis, Bombay
University, 1986.
10. M A Shahid, A K M Mahabubuzzaman, F Ahmad and A R Rashid: Effect of Rotor Variables on the
Physical Properties of Jute-Viscose Blended Yarns, Int J of Textiles and Fashion Technology, 2012, 2, No
2, pp 23.
11. K R Salhotra and P Balasubramanian: An Approach to Optimisation of Rotor Spinning Machine
Parameters, J Textile Institute, 1986, 77, 2, pp 128.
12. L X Kong, R A Platfoot and X Wong: Effect of Fibre Opening on Uniformity of Rotor Spun Yarn, Textile
Research J, 1996, 66, pp 30.
13. P N Duru and O Babaarslan: Determining Optimum Opening Roller Speed for Spinning Polyester/Waste
Blend Rotor Yarns, Textile Research J, 2003, 70, pp 907.
14. S Ulku, M Acar, T C King and B Ozipek: Fibre Alignment and Straightening in Opening in Open End
Spinning, Textile Research J, 1993, 63, pp 309.
15. A Barella and J P Vigo: An Optimum Application of Mini Computers to the Optimisation of the Open-end
Spinning Process, Part XI, The Optimisation of the Opening Roller Speed and Twist for Processing
Conditions Remote from the Optimum during Rotor Spinning of Cotton Yarns, J Textile Institute, 1980,
71, 4, pp 195.
16. P Voidal: Improvement of Operational Stability for OE-rotor Spinning Equipment,
http://www.cetex.de/html/institut/eng/download/doc/2003_oe_rotorspinning.pdf.
17.www.rieter.com.
30

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