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Ceat Ltd, Halol, Vadodara Dept. Of PS&RT, CUSAT
IN-PLANT TRAINING REPORT
Done At
CEAT TYRE LIMITED
Halol, Vadodara, Gujarat
Submitted in partial fulfilment of the requirements for the award of thedegree of
Bacelor o! Tecnolo"#
In
Polymer Science & Engineering
B#
Mu$e% $u&arRe"'No()*+**
De.t' o! Pol#&er /c0ence and Ru11er Tecnolo"#
2C3/AT, Coc0-++, 4erala5
APRIL 2013
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ACKNOWLEDGEMENTS
I thank to GOD almighty for giving me courage and pleasure to pursue my task
successfully throughout my project work.
I feel privileged to my In-plant training and Project work in Indias leading tyre
manufacturing industry CEAT LTD,!alol "adodara #ujarat.
I wish to e$tend my special thanks Mr T!m Th!ma" %E$ecutive director & Mr G
#$$i%ri"h$a$%"P !ead-design and compounding '&( andMr &a'!( G)!rg) %"P
!ead product management '&( for giving me such great opportunity.
I e$press my gratitude toDr S*$il KN K*tty !)( Dr KE G)!rg) %Professor Dr
Ra$i &!")+h%Professor Dr Th!ma" K*ria$%Professor (ept. of Polymer Science &
'u**er +echnology ,S+ /ochi for arranging my training and project work at ,eat ltd.
+he person most thanked is MR S*ith Nair #0 & head of compounding '&( ,eat
1td. !alol #ujarat. !is invalua*le and professional guidance personal attention e$pertise
and encouragement throughout the course of this work have ena*led me to complete the
same successfully.
I gratefully acknowledge Mr Lalit Pa$-)y%"P production ,eat 1td. for his e$pertise
proper guidance encouragement during the work.
I wish to e$tend my sincere thanks to Mr G)rg!ry A$t!$y %#0 & plant head Mr
A"h.ath %*mar %0anger tech. and Mr/)llra for their support and encouragement
during my project work.
I acknowledge at this moment the appreciations recognitions favors advices and
encouragement from all amily m)m()r" of ,eat 1td. !alol "adodara has given to me.
I once again sincerely thanks all those who have helped me directly and indirectly during
my project. I take this opportunity to thank all a'*lty m)m()r" "ta" ! !*r
-)+artm)$t a$- my -)ar 'la""mat)"for supporting me throughout my college life.
I heartily acknowledge my +ar)$t" a$- amily m)m()r" for their love appreciations
recognitions and encouragement.
M#KES K#MAR
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CONTENTS
1 INTROD#CTION44444444444444
44 3 5 6
2 STOCK
PREPERATION4444444444444 7
5 78
3 T9RE
:#ILDING4444444444444444
7; 5 83
6 T9RE
C#RING44444444444444444
86 5 8 5 ;2
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8 TESTING ON RADIAL
T9RES444444444 ;3 5 ;>
INTROD#CTION+yre is composed of fi*er reinforced ru**er matri$ nd the main
functions of a tyre is to cushion the ride and provide some means of direction
to the vehicle. 2ut *oth the concepts are opposing. 3hen the cords are at an
angle parallel to the circumferential direction of the tread tyre will give good
directional sta*ility and steering response. 2ut riding will *e harsher. 3hen
the cords are at right angel to the tread circumference the ride will *e softest
and the lateral sta*ility will *e poor. +he *ias tyre was constructed in terms ofa compromise in cord angle to get intermediate performance properties.
2ut the idea *ehind radial ply tyre was to eliminate this compromise in
cord angle and to divide the carcass into two parts. )ne to provide the
desired ride 4uality i.e. radially running plies cords and the other to provide
directional 4ualities.
radial tyre consists of a radial carcass and a sta*ili5ing *elt
underneath the tread. 'adial carcass consists of reinforcement layer of
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fa*ric cords running from one *ead to another at 677to the tread ,entre
line and is designed to hold the air pressure. +he sta*ili5ing *elt consist of
reinforcement layer of high modulus fa*ric cords or steel running
circumferentially around the carcass at an angle of 89-::7
to the tread,entre line *eneath the tread and designed to transmit driving *reaking
and cornering tor4ue. +he function of tread and the sidewall are separated
to a great e$tent such that major shortcomings of *ias construction are
eliminated. +his construction re4uires greater num*er of components than
*ias tyre and very precise placement of component is also necessary.
flow diagram is drawn in ne$t page illustrating steps involved in
manufacturing of passenger car radial %P,' tyre.
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.
6
ead !e"#"$%
"'"$% area
Pl a$d elt Cale$dar"$
Rad"al pl( )*t
+'tr*!"o$
Copo*$d
elt )*tt"$%
Tread- S"de
all
ead
/ree$ t(re 0*"ld"$%
C*r"$%
Tr""$%
Pl(
elt
$$er l"$er
"$al "$!pe)t"o$
U$"for"t( te!t
are o*!"$%
Ra ater"al!
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2 STOCK PREPERATION?
C!m+!*$-i$g Mi@i$g?
1ike *ias compounding radial tyre compounding is normally done in
three stages- master *atches repass and final. In ,E+ tyres ltd. !alol radial
compounding is done in two separate *an*uries provided with modern
accessorise. )ne is for final compound and other for master *atch.
2oth *an*uries consists of two hori5ontal rotors with four wings. +hey
are rotated at a synchronous speed which produce a very high shear rate
during mi$ing. ;or the master *atch mi$ing 2an*ury instead of dump mill and
cracker mills a twin-screw e$truder and a two-roll calendar are used for sheet
out. +his will produce proper *lending with very high uniformity among the
compounds. +hey are provided with a +.,. at cham*er sides rotors and
drop door to maintain highest level of shear during the mi$ing process. +he
final *atch producing 2an*ury is e4uipped with a +.,. on the ram in addition
to the a*ove-mentioned places for *etter temperature control. 'am of *oth
*an*uries is operated *y hydraulic mechanism for o*taining higher pressure
with *etter uniformity.
;or a synchronous rotor the large wing has a heli$ angle of :
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RAW MATERIALS?
+he *road classification of raw materials used for manufacturing tyres
is@
0aterials used for various ru**er compounds
2 0aterials used for tyre reinforcements
, u$iliary materials
A Mat)rial" *")- !r tyr) '!m+!*$-"
+he essential ingredients used in a ru**er compound *y its function is
as given *elow
'aw ru**er
ctivators
'einforcing agents
Process oils
ntidegradants
"ulcani5ing agents
ccelerators
Process aids
Special additives
'u**er as such is a soft semisolid material which does not have anyproperty re4uired for a tyre compound vi5. elasticity strength hardness tear
end fle$ resistance 'aw ru**er when heated with vulcani5ing agents
*ecomes elastic stronger and harder and this process is called vulcani5ation.
!owever the ru**er is to *e heated for :=hrs for achieving full vulcani5ation.
+o increa>e the speed of vulcani5ation accelerators are used. +hus with
vulcani5ing agents and accelerators the vulcanising time is reduced to >7
minutes at practical vulcani5ing temperature. ctivators are used to improve
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the efficiency of accelerators and it improves the strength and elasticity of the
vulcani5ates.
vulcani5ate thus made of raw ru**er vulcani5ing agents
accelerators and activators are still soft. ;or improving the strength hardness
tear wear and fle$ properties suita*le for a tyre compound reinforcing agents
are added. +he major reinforcing agents are car*on *lacks and silica.
Incorporation of fillers is difficult and to facilitate easy incorporation process
oils are added. 0ost of the ru**ers are suscepti*le to degradation when
su*jected to heat fle$ and weather and to take care of this antidegradants are
added.
Process aids are added to the compound to improve processa*ility at
e$truder calendar or to improve surface tack.
)ften low cost fillers are added to reduce cost *ut this method is used
only for some particular compound application. Sometimes special additives
like corrosion inhi*itors *onding agents hardening agents are added for
specific vulcani5ate properties.
RAW RUBBERS:
Nat*ral R*(()r
Aatural ru**er occupies the top position as the general-purpose ru**er.
It gives good strength tear wear and fle$ resistance good crack growth
resistance good processa*ility and tack low heat *uild up and good a*rasion
resistance. It is slightly inferior in crack initiation skid resistance and traction.
It finds application in carcass compounds tread compound for heavy-duty
truck tyres. 'SS-= and ISA'-:7 are the major used grades.
,repe grades are used in non-critical applications.
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R)'laim R*(()r
'eclaim ru**ers are de-vulcanised ru**er manufactured from waste
ru**er products. +his is however a low cost ru**er and has good
processa*ility. !owever due to inferior dynamic properties it finds applications
like (" tyres and flaps
Styr)$)5(*ta-i)$) R*(()r S:R
+his is the first synthetic ru**er developed. It offers good strength and
tear good crack initiation resistance good a*rasion resistance good
processa*ility. It also offers very good skid resistance and traction. 2ut it has
inferior crack propagation and higher heat *uild up and poor tack.
S2' is mainly used in passenger tyres *ecause of its high skid
resistance and traction. It is used generally in *lends with P2( for *etter fle$
resistance and traction. S2' is also recommended for high hardness *ead
compound.
P!ly(*ta-i)$) R*(()r
It offers the *est a*rasion resistance and fle$ resistance. It has low heat
*uild up good heat resistance and good weather resistance. It is inferior in
processa*ility skid resistance traction lug chip resistance and surface tack. It
finds application in sidewall compound and light duty truck treads in *lends
with natural ru**er. It is also used for passenger treads in *lends with S2' for
*etter wear and fla$ resistance
:*tyl R*(()r
+he outstanding air impermea*le together with high heat resistance
makes *utyl the *est ru**er for inner tu*es. Its halogenated varieties are used
in tu*e less tyre interlinear. It also finds application in curing *ladders *ecause
of its high heat resistance EP(0 'u**er.
+his is new generation synthetic ru**er which offers e$cellent heat and
weather resistance and good fle$ resistance. It finds application in tu*es
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where it reduces the softening of *utyl tu*e in service. It is also used for radial
tyre sidewallB especially in white sidewall a *lend of A' with halo *utyl is used
for weather resistance and colourfastness.
: /#LCANISING AGENTS
SULPHUR
The cross linking of rubber is generally achieved by addition ofsulphur or sulphur donors.
+here are two types of sulphur
Solu*le sulphur
Insolu*le sulphur
+he commonly used sulphur donors are
+0+( %+etra methyl thiuram disulfide
(0(S %(imorphoilinyl disulfide
+he sulphur donor system gives *etter heat resistance than sulphursystem *ut inferior fle$ resistance.
ACCELERATORS
ccelerators are classified *ased on the speed of vulcani5ation.It is also classified as primary accelerator and secondaryC accelerator.
Secondary accelerator is the one which is used as *ooster to a
primaryaccelerator +he commonly used accelerator in tyre industry is as
follow@
T9PE CEMICAL NAME #SE IN T9RE
Slow (iphenyl guanidine Secondary accelerator in
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ccelerator S2' compounds
0ediumfast
accelerator
,yclohe$yl*en5othia5ylSulphenamide%
,2S
+ertiary *utyl*en5othia5ylSulphenamide %+22S
0orpholinothio*en5othia5ylSulphenami
de
%02S
(icyclohe$yl*en5othia5ylSulphenamide%(
,2S
sed in *ead compounds
Primary accelerator in
S2' compound
3idely used in tyre
industry
sed mainly in retread
materials
;ast
accelerator
0ercapto*en5othia5ole%022+
0ercapto*en5thia5ole disulfide%02+S
2utyl tu*e
;lap compounds
ltra fast
accelerator+etramethylthiuram disulfide%+0+(
+etramethylthiurammonosulfide%+0+0
0ainly for *utyl and
secondary accelerator for
S2' compounds
Secondary accelerator in
tread *ase compounds
Super ultra
fast
accelerator
Dinc diethyl dithiocar*amate%D(,'epair compounds
ACTI/ATORS
+he general activators are 5inc o$ide and stearic acid. Instead 5inc
stearate can *e used *ut a higher dosage is re4uired.
C REIN=ORCING AGENTS?
+he commonly used reinforcing agents are car*on *lack and
precipitated silica.
+here are three types of *lackC *ased on the manufacturing techni4ue
they are
,hannel *lack
+hermal *lack
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;urnace *lack
In furnace *lack there are different grades characteri5ed *y the particle
diameter and structure. s the particle diameter decreases the reinforcement
increases. !igher the reinforcement higher the strength the modulus tear
fle$ a*rasion resistance and higher the heat *uild up. s the structure
increases modulus increases *ut fle$ fatigue resistance decreases. +he heat
*uild up increases slightly.
Precipitated silica offers *etter tear resistance than car*on *lack.
!owever the heat *uild up is higher and silica is not easily dispersi*le in
ru**er.
#rade
Particle
(iameter
%nm
Structure
%(2P Aopplication
S; :: 88: ?7+ruck treads cap sidewall and *ead
insulation.
;E; 8=? 8:7)uter ply cushion 2reaker tread *ase
,ompound S4ueegee
#P; ?7 67 Inner ply inner liner for tu*eless flap
Precipitated
silica>7 A 'adial tyres )+' tyre tread
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D PROCESS OIL
+hese are used to improve car*on *lack incorporation in a ru**er
compound and also to improve compound process a*ility at calendar and
e$trusion. Process oils are classified *ased on the "#,
,lass "#, Staining!eat
resistance
,ompati*le
'u**ersse
romatic 8 es #oodA' S2' P2
'eclaim
#eneral purpose
process oil
Aapthenic 7.6 0ild 2etter -(o- 3hite sidewall
Paraffinic 7.9 Ao 2est 2utylFEP(0+u*e
2ladder
E ANTIDEGRADANTS
,hemicals name Staining)$ygen
resistance
)5one
resistancese
Styrenated phenol Ao 0ild Ail 3hite sidewall
(ihydrotrimethylGuinoline 0ild #ood Ail,arcass
compound
cetone amine condensate Strong #ood Ail,arcass
compound
(i-aryl p-Phenylenediamine Strong "ery good 0ild+read and
Sidewall
(imethyl*utylparaphenylen
ediamine
"ery
strongE$cellent 0ild
+read and
sidewall
0icrocrystalline wa$ no Ail E$cellent+read and
sidewall
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= PROCESS AIDS
Process aids are those su*stances which are added to ru**er compound for
reducing viscosity of the stock for increasing tack for improving process
safety or for improving the surface finish. +he various types are given *elow@
+ype Aame ;eature se
Pepti5er
Dinc salt of
pentachlorothio
phenol
;aster *reakdown of A'
during master mi$ing
0astication
purposes
+ackifier
Phenol
formaldehyde
+ackifier I resin
;or *etter surface tack
Ply sidewall and
cushion
compounds
'etarder
,yclohe$ylthiopth
alimideImproves scorch
Safety
Practically added
in all compounds
G SPECIAL ADDITI/ES
15
,lass Aame pplication
(ry *onding
2onding agents
'; 'esin !000
Precipitated silica
;or *etter *ond strength In
SteelFglassFaramidskim compound
!ardening
agents
+hermosetting P;
resin
;or hard compounds like *ead
insulation filler etc
,orrosion
inhi*itor
,o*alt comple$es ;or steel cord skim compound for
'educing corrosion
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22 MIBING #NIT
In a ru**er industry mi$ing is the foundation step upon which every
further step is dependent on. 0i$ing is the most critical component of ru**er
processing. +he aim of mi$ing is to produce a product that has the ingredientsdispersed and distri*uted sufficiently thoroughly that will process satisfactory
in the ne$t process cure efficiently and give the re4uired properties for the
end application. 0i$ing re4uires deciding the formulation what e4uipment to
use and the times speeds pressures temperatures. +he aim should *e to
minimi5e the la*our energy and e4uipment cost per unit volume of product.
(ue to the partly elastic nature and very high viscosity of ru**er power
intensive sturdy machinery like mi$ing mills and internal mi$ers arenecessary.
In ,E+ +yres !alol there are two 2an*ury continuously in operation
to get compounded ru**er for further processing. mong two 2an*ury one is
for master mi$ing and another one for final mi$ing.
:AN:#R9?
+he 2an*ury mi$er is a tangential type internal mi$ing machine in
which two slightly spiralled rotors revolve side *y side toward each other
within a cham*er shaped like two short cylinders lying together with adjacent
sides open. +he cham*er has a top opening called hopper which can *e
closed *y a pneumatic means for inserting the material and a *ottom gate
which can *e hydraulically opened to drop out the contents after mi$ing.
+he 2an*ury is charged *y raising the ram completely out of hopper
and dropping in *ales of ru**er weighed up properly to fill the cham*er. +he
ram is then lowered under pressure and the ru**er forced and held in the
cham*er while it is kneaded and *lended *y the rotors. 2reakdown of ru**er
is accomplished *y the shearing action *etween rotor *lade tips and rotor
walls and *etween rotor-rotor with one rotor running slightly faster than the
other to prevent sticking to the *lades.
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:AN:#R9 CONSTR#CTION
+he physical demands upon 2an*ury mi$er are enormous. 'u**er is
e$tremely tough compounds are a*rasive pressures and temperatures
developed are high. ;or the purpose of description the machine parts can *e
divided into following categories.
A OPPER ASSEM:L9
RAM?
'am consists of a rod and floating weight. +he ram utili5es not only its
own weight *ut also an additional e$ternal force to e$ert a certain pressure on
the mi$. +raditionally the ram is operated pneumatically. n air-operated
piston in a cylinder holds it. In the raised position the ram *ottom is a*ove to
the hopper door allowing the introduction of material into the mi$ing cham*er.
+he ram is raised *y compressed lu*ricated air. It is lowered *y floating %no
air or *y regulated air pressure. Aormal pressure used is =.< -H.H /gFcm :.
Sealing of the pneumatic piston rod is a very sensitive design element.
nother pro*lem with the pneumatic ram is the variation of ram pressure ram
pressure decreases when ram goes down. "ariations in ram pressure have a
*ig effect in mi$ing 4uality.
+he tell-tail rod of ram indicates the position of floating weight. (uring
normal mi$ing the material inside the cham*er moves the ram up and down.
+he total up and down motion of the ram is directly indicated *y the tell-tail rod
to the operator who can there *y assess the status of the mi$ing process.+he floating weight may have several configurations
a Single slope " *ottom.
* Single slope ;lat *ottom.
c (ou*le ga*le " *ottom.
d (ou*le ga*le ;lat *ottom.
OPPER?
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+he hopper of the mi$er is simply a *o$ through which ingredients are
fed and through which the ram weight travels. +he front of the *o$ is a hopper
door through which material is fed through a conveyer. +he hopper door is air
operated and hinged at the *ottom. chute is provided near the hopperassem*ly to provide the weighed car*on from the day *ins *y means of
automatic car*on discharge system. ll hoppers are e4uipped with a method
for venting gases and powders which accumulate in the hopper area *y
means of air suction. +his makes the area near *y the mi$er clean and tidy.
TE PNE#MATIC S9STEM?
+he floating weight or ram cylinder and the cylinder operating the
hopper door are air actuated. +hese are actuated *y means of sensors fitted
near to the hopper assem*ly. +he flow of air to the weight and hopper
cylinders is controlled *y solenoid-operated valves which are actuated *y
switches on the 2an*ury control panel.
: MIBING CAM:ER
It is the section of the mi$er *elow the hopper assem*ly and a*ove the
*edplate. +he important parts of mi$ing cham*er are
CAM:ER SIDES?
+he portions of the mi$er that enclose the mi$ing cavity are the
cham*er sides. +hese sides consist of heavy shells *ored with laterally drilled
holes for the circulation of steam andFor water. +he internal surface of the
cham*er is treated with satellite for wear resistance.
END =RAME ASSEM:L9@
It supports the cham*er with rotors. Each end frame assem*ly
consists of the frame the rotor *earing seals and the rotor end plates. +hey
are made of heavy iron castings with spherical roller *earings including
thermocouple for *earing temperature measurement. +here are two ends in
the 2an*ury mi$er the water end and the drive end. +he water end is the area
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through which the heating or cooling water is introduced. +he opposite is the
connection point of for the machine drive arrangement. ,ooling water passes
through large drilled passagesB the design used causes tur*ulence of water
and good heat transfer. +he *ores are welded with hard wear resistantmaterial clamp plates and *olts secure the sides to the end frames which
ena*les the fitting on site of new sides without machining or causing serious
distur*ance to end frames.
ROTOR?
+he two rotors perform the mi$ing action *y rotating in opposite
direction and at slightly different speeds. Each rotor have *lade like
projections called wings. +he edge of the rotor wings are called 'otor tip. +he
rotors are set in the mi$ing cham*er so that the long wing of one rotor is
opposite the short of the other. In CEAT Tyr)", al!lB the rotors are = winged
designs. +his helps in the increase of the rotor surface area and *etter shearB
intern helps effective and faster heat transfer.
+he two types of rotor design are
8. +wo wing rotor
:. ;our wing rotor
two-wing rotor has one short wing and one long wing. four-wing
rotor has two of each. +he rotors turn within the cham*er toward each other
and at une4ual speeds. +his is done so that the relative wing-to-wing positions
are constantly changing. 2ecause of the shape of the rotor wings materials
are always sheared against mi$ing cham*er and then toward the other rotor.
+he curvature of the rotor wings causes the materials *eing forced *ack and
forth from one end of the mi$ing cham*er to the other. Since the rotors are
running at une4ual speeds the mi$ is also *eing pushed from side to side in
the cham*er. 'otors have varying speeds of rotation with faster *reakdown
*eing o*tained as speeds go up.
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+he rotors are one piece steel castings accurately shaped on the
mi$ing *lade profiles. +here are no internal joints which could cause leakage.
Steam or water circulating through the centre of each shaft controls the
temperature. 0ost rotors have spray cooling. Spray heads which have smallenough orifices to properly *reak-up the water stream are used.
D#ST STOP?
+here are four dust stops on each 2an*ury one at each point where
rotor shaft passes through the *ody. +heir function is to seal the mi$ing
cham*er around the rotor shafts. 1u*rication is critical for the satisfactory
operation of dust seal. +wo types of dust seals are in use ;! and SS.
In the ;! type dust seal hydraulic cylinders are used to load the
sealing rings against the rotor ends they are so arranged that as the rotors
move a$ially during mi$ing the sealing rings are always in contact with the
rotor ends. +he frictional heat generated *y ;! dust stops is low and heat
sensitive stocks can *e mi$ed at high rotor speeds without cured particles
*eing formed. +he design eliminates all areas where material could *e
trapped and su*se4uently causes contamination.
In the SS type dust seal design the sealing faces are preloaded *y
springs and additional sealing pressure is generated during mi$ing *y a small
process oil feed which loads the *ack face of the floating ring and which
cannot escape *ecause of the compound in the mi$ing cham*er. floating
metal split ring rides in a collar against the *ack of a flange on the rotor end
plate. +hese two surfaces are kept flooded with light ru**er process oil and
as the compound forces its way into this joint this oil traps and holds it. ny
e$cess oil enters the *atch and is harmlessly a*sor*ed.
Earlier rotating 2a**itt or *ron5e sealswere usedB *oth the life and
sealing of these were poor. ,ompounds and ru**ers were forced through the
seals and were lost their way into *ron5e *earings on which rotors turned and
damaged them and journals. ;loating rings of tin nylon and many others weretried *ut jamming of journal rings resulted in failures.
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DISCARGE DOOR?
;''E1 ; :?7 2an*ury is furnished with drop type discharge door.
+he drop door is mounted on a support shaft which pivots parallel to the shaft
rotor. +he offset hinge arrangement allows swinging down and away from the
door opening permitting the finished *atch to discharge. hydraulic rotating
device called ')+, opens and closes the door. hydraulically operating
door latch locks the door in place when the door is closed and creates a tight
seal.
)lder *an*uries are e4uipped with a wedge shaped doors which slide
hori5ontally on a pair of rails into position. +he rails lift the door very slightly as
it reaches the closed position *ut wear on rails is rapid. 1arge pistons move
them and demands close original fitting and proper maintenance to prevent
leakage. Proper maintenance of the piston and rails are difficult and
e$pensive. nd failures which prevent the opening with a *atch inside can *e
disastrous. +heir movements are also slow. +he new drop door type is faster
and thus shortens cycle times. Some pro*lems of metal lining failure and
metal failure in swing arms have noted in them.
+he drop door top has passages with inlet and discharge fittings for the
circulation of cooling water or steam. +he door top is normally cooled to
prevent the sticking of stock at the time of discharge. ,ooling or heating the
door top is also effective in controlling the *atch temperature. +he discharge
door profile has an ape$ to eliminate Cdead spotsC while allowing the re4uired
thermocouple projection. +wo thermocouples are sometimes fitted in the door
one for normal operation and one for a safety override.
MIBING ACTION?
It is a popular misconception that all the mi$ing in a *an*ury takes
place in the gap *etween the rotor tips and the cham*er walls. t the start of
the cycle when the polymer is normally in large pieces and the powders are
still loose the initial *reakdown and mi$ing takes place in the large space*etween the rotors and against the door top. s the material softens flow over
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the rotor tips starts to take place *ut until the viscosity of the mi$ has fallen
sufficiently most of the work is done *etween rotors along the rotor heli$
angles and *etween rotors and discharge door top. +he area just in front of
rotor tip is similar to the nip of a mill and causes internal shear in the material.
+he mi$er should *e cooled to remove heat generated *y the
mechanical energy of mi$ing. !eat transfer and cooling efficiency is
dependent on the temperature differential *etween material *eing mi$ed and
machine components. t the start of the cycle when the feed material is cold
and stiff most work is done *etween the rotors as the mi$ing progresses the
material softens and deforms to make e$tensive and close contact with the
rotor mi$ing cham*ers walls and door top at which point they all are availa*le
to transfer heat from compound to the machine components and so to remove
it *y the cooling water. +he material at the door top is su*jected to high
pressures and a highly tur*ulent action.
C 9DRA#LIC S9STEM
+he discharge door the door latch dust stops and grease pumps are
actuated *y hydraulic oil under pressure. +he hydraulic system consists of two
major assem*lies the pumping assem*ly and the control valve assem*ly.
P*m+i$g A"")m(ly?
,onsist of a motor driven vane type mounted on a reservoir tank. )il is
pumped to the control assem*ly which directs high-pressure oil to various
components of the system.
C!$tr!l al)"?
,ontrol valves are electric solenoid type and are energi5ed from the
2an*ury control panel. +hese valves are providing directional control for the
hydraulic fluid so that the drop door can *e opened or closed and the door
latch engaged or disengaged.
D ACCESSOR9 E#IPMENTS
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1 W)ighi$g '!$)y!r" a$- ))-i$g '!$)y!r
Each 2an*ury is e4uipped with electronic weighing conveyor *alance
and feeding conveyor. Electronic weighing conveyor has two load cells with a
capacity of
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day *ins automatically get filled with car*on *lack when the lower limit of the
car*on level is reached.
+he *lack stored in the day *in is collected to a hopper near to 2an*ury
with an automatic weighing system and conveys to 2an*ury through a chute
opening at the sides of the hopper assem*ly.
+he parameters affecting the easy fluidisation and conveying of car*on *lack
areB
0oisture content
Pellet hardness
Pour density
;ineness content
Pellet si5e distri*ution
3 T)m+)rat*r) '!$tr!l *$it
+he introduction of drilled sides improved rotor cooling and *etter water
circulation in the door top coupled with rotor action has dramatically improved
the cooling efficiency of *an*ury mi$er. 3hen the surface temperature of the
metal in contact with ru**er is too low the ru**er slips on the cold surfaces.
;or good dispersion and *etter mi$ing it is necessary to put shear strain
energy into the mi$ this can occur only when the ru**er is gripped *etween
the rotor tip and cham*er wall or *etween rotors. ;or this reason it is not
desira*le to have the mi$ing cham*er too cold as the frictional contact
*etween ru**er and metal is influenced *y temperature.
+, assem*ly consists of a tank divided into three divisions each
receiving cold water and hot water and over flow water which is corrected for
temperature. 3ater from rotor cham*er and drop door is mi$ed with factory
cooling water at >?->97,. +his mechanism
of sensing and actuating the water flow is done *y sets of solenoid valves.
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+hese temperature corrected water is then circulated *y means of > pumps
with varying capacity depending upon the amount of water to *e circulated.
0i$ing of the compound should do as per timeFtemp given on the mi$ing
specification card.
6 D*"t '!ll)'t!r"
2an*ury is e4uipped with dust collectorB this is to collect the fly off dusts
of car*on *lack chemicals and vapours. +he car*on dust collector system is
designed to return the car*on *lack into one place from all 2an*ury.
7 Oil "t!rag) ta$%"
+here is a centrali5ed tank for oil storage. +his is connected to the
2an*ury through pipelines. +his oil is collected in small tanks kept near*y
2an*ury. +here are : tanks one for process oil and the other for hydraulic oil.
8 Oil +i+)li$)
)il pipelines are used for delivering different oils. (ifferent oils
collected are process oil for mi$ing & for dust seals and hydraulic oil for
pressure application mechanism. )il is o*tained *y operating solenoid valve
which in turn operates the diaphragm valve of pipelines. )il is measured in
litters in the cali*rated measuring tank. )il pipelines are connected to the
measuring tank with diaphragm valve for control. +he oil pipelines are
e4uipped with electric heat tracing to maintain the oil temperature at around
H7 degree
; Oil 'harg)r
2ottom of the oil tank is connected *y a pipeline with motor driven
pump which injects oil into the 2an*ury through a pipeline. )il is charged to
the 2an*ury from *oth front and *ackside at side-*ottom level through oil
injecting valves. +hese are non-return valves. +he measured volume of oil is
taken into the oil charger from the measuring tank *y operating diaphragm
valve of the tank and is held till the specified temperature %H7 7, in the mi$ing
cycle is reached. fter each addition oil for the ne$t mi$ is collected andweighed properly and kept ready.
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:at'h ! mill
n 9=-inch mill has *een provided in each 2an*ury. +he *atches
dumped on mill from the 2an*ury is further mi$ed and passed directly on to
the *atch off unit. +he num*er of cuts given is two for master and one for final
*atches. In the mill the compounded is *lended well and sheeted to the
re4uired width and thickness to effectively cool the compound. 2lender *ars
are provided to facilitate the cross mi$ing action there*y attaining more
uniformly mi$ed compound.
10 :at'h ! *$it
,omponents of the *atch off unit
1 Ta%) a.ay '!$)y)r5+i!t)- ty+)? 5
+his is e4uipped with varia*le speed drives to control the speed of
*atch off.
2 Im+r)""i!$ +ri$t)r *$it? 5
+his is to print the compound code *y impression method. +his
identification further helps to sent sample to the 'heo la* without any
am*iguity in the material code.
3 Sh))t !*t mill? 5
+his is in si5e similar to that of dumping mill. +his is e4uipped with knife
arrangement and correct nip gap setting to get re4uired gauge and width to
the sheet. +he compound from this mill is conveyed to the dipping tank.
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6 Di+ ta$% -!*(l) '!m+artm)$t .ith "tirr)r", 'ir'*lati$g +*m+" a$-
'!!li$g? 5
(ip tank contains diluted soap solution to avoid sticking of ru**er
compound at the lay down unit. Soap solution that overflows or moves
outside the tank is collected in an underground tank. +his collected soap
solution is filtered and pumped to the dipping tank to avoid the material loss.
+o maintain proper concentration of soap solution and to ensure the mi$ing of
pumped soap solution stirrers are also provided.
7 P*ll !*t m)"h ()lt .ith h*gg)r '!$)y)r"? 5
+he compound after dipping is pulled *y two-mesh *elt moving together
*y enclosing the compound. +his mesh provides dripping of e$cess soap
solution though the holes.
8 =)"t!!$ '!!li$g ra'% .ith a$"? 5
+his is the longest portion of the lay down unit. +his contains moving
chain *elt with *oth sides connected with *ars. 'u**er sheets from the
hunger conveyer are fed to the moving *ars of the cooling rank. +hese *arsact as hangers for the ru**er sheet and maintain specific loop length. +his
length is maintained to ensure proper drying of the sheet. +he entire length of
the cooling rack is fitted with =-< sets of cooling fan units on *oth sides. Each
fan unit contains =-9 individual fans. Sides are covered *y metallic covers to
ensure the retention of the cooling air.
; P)$-*l*m '!$)y)r
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facilitated packer stacker system at few *an*uries. +his is a wigwag lay down
system which automatically lays down the compound without any manual
operation with proper laying of sheets with e$cellent consolidation.
8: 3eighing ta*le@ -
sually a skid consists of = *atches from *an*ury. +o check this
parameter each skid is taken to the weighing ta*le for weightment.
PROCESS?
+ake off section is situated in front of dip unit with two adjusta*le knives
having a cutting width of H77-677 mm. It includes a hinged take off conveyerwhich receives the ru**er sla* from the mill and conveys it to dip tank. +he
take off conveyer is provided with an impresser type printer to imprint figures
into ru**er sla*.
t the *eginning of the *atch off unit compound sheet is dipped into the
anti tack solution. +he dip unit is a sheet steel reservoir mounted in a
structural steel frame. fter passage through take off the ru**er sla* is
received *y a *elt this *elt conveys the strip through dip solution and
thereafter to the cooling festoon rack. +he ru**er is retained on *elt and
guided upwards *y hugger *elts. 2atch is carried in continuous sheet form
over the chain *ars running in cooling conveyor. t the cooling conveyor
cooling fans are mounted one side of the conveyor which e$pedites cooling
compound sheets on to the am*ient temperature.
Stock code is em*ossed and written with crayon throughout in all
*atches and compound code is tied to the last sheet of the each *atch at the
point of lay down in order to distinguish *etween different *atches. 2an*ury is
e4uipped with fi$ed *ar chain cooling conveyor system and the other end has
*een mounted with wigwag system. +he compound sheets are passed
through the wigwag and laid on the skid in continuous sheets.
C!m+!*$-i$g "tag)"?
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(epending upon composition and processing re4uirements
compound mi$ing is done in following stages.
Ma"t)r (at'h mi@i$g?
t master *atch mi$ing stage ru**er is intimately mi$ed with fillers
processing aids activators antio$idants wa$es etc. 0aster *atch mi$ing is
usually done at temperatures around 8>7-8H7 Jc. 0aster *atching improves
the physical properties of those compounds where a high degree of car*on
*lack dispersion would *e achieved. +he master *atches can *e varied
depending on the compound i.e. the master *atch recipe may *e the same
as the compound recipe *ut without curatives or it contains only ru**er filler
sand some softeners.
Since high speed and high- pressure internal mi$ers are used for
master *atching it is not advisa*le to incorporate accelerators in the master
*atch as the temperature of the ru**er is likely to e$ceed. +he master
*atches have poor *lack dispersion so a milling operation is essential to
achieve ade4uate dispersion of the car*on *lack.
R)5+a"" "tag) mi@i$g?
In re-pass stage master *atch is further re-mi$ed to improve
dispersion ofthe compound. +his is also done at a temperature range of 8:7-
8H7J,. (uring re-pass stage the compound viscosity is reduced according to
the re4uirement of su*se4uent operations. +his is usually done for very hard
compounds like high car*on loading and the car*on *lack is incorporated intwo stages for getting *etter dispersion.
=i$al '!m+!*$- mi@i$g? In this stage master *atches are converted into
final compounds. +his is usually mi$ed around 677, to 877J,. In final stage
mi$ing curatives like sulphur accelerator retarder etc. are added to the
master *atch.
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D#MPING CRITERIA
+here are num*er of varia*les such as temperature power energy
mi$ing time etc. which influence the mi$ 4uality. In a company where large
production of ru**er compounds is made some optimisation has to *e set in
the mi$ing parameters to get ru**er compound with ade4uate properties.
+ime temperature and energy are the main dumping criteria. In 8stand :nd
2an*ury = set points are fed in the software of the 2an*ury on those set
values of energy mi$ing se4uence and dumping time are carried out during
the mi$ing. ;or other *an*uries set values of temperature and energy are fed
in the software. If temperature is e$ceeded from a set value dumping takes
place irrespective of the set energy values.
:ASIC OPERATING C9CLE?
8 Start operation -(ischarge door closedi. 'am up
ii. !opper door open
: 0i$ing started -'u**er K chemical powders
> ,lose hopper door
= ,harge car*on *lack is fed
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CONTROLLA:LE =ACTORS
8. 2atch si5e:. Se4uence of addition
>. 'am cylinder pressure
=. 'otor speed
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' /=ell
/e$erall(, !ell "! de)rea!ed 0(
a. ?oer ;"!)o!"t(
0. H"%er eat of !to)= or e9*"pe$t). ore or= perfored o$ !to)= : H"%er ar *p
d. Add"t"o$ of reor=
e. U$der:"'ed !to)=
f. ?o ead pre!!*re
Sell "! "$)rea!ed 0(> :
a. H"% ;"!)o!"t(
0. ?o teperat*re! of !to)= or e9*"pe$t
). H"% ead pre!!*re
d. A$( !)or) "$ !to)=
Ade9*ate )o$trol! of all te!e ;ar"a0le! are 0*"lt "$to )opo*$d"$% for*lat"o$!,
pro)e!!"$% !pe)"f")at"o$! a$d e9*"pe$t de!"%$. Caref*l o0!er;a$)e of all te!e are
fea!"0le a$d "ll re!*lt "$ 0ot 9*al"t( a$d 9*a$t"t( of prod*)t"o$.
Para&eter% o! E:trudate
a' THERMAL /HRIN4AGE
Te $o$:@eto$"a$ $at*re of r*00er pol(er! a$d e;er )a$%"$% for*lat"o$! *!ed "$ te
t(re "$d*!tr( a=e te e!ta0l"!e$t of !r"$=a%e e9*at"o$! ;er( d"ff")*lt. T"! ea$! tat
ea) )opo*$d 0ea;e! d"ffere$tl( "t re!pe)t to !r"$=a%e. @at*ral r*00er )opo*$d!
te$d to a;e "%er !r"$=a%e. Var"at"o$! "$ "'"$% a$d ar *p prod*)e *) %reater
;ar"at"o$! "$ $at*ral r*00er e'tr*!"o$! ta$ "$ te !($tet") r*00er e'tr*!"o$!. Te
;ar"a0"l"t( "$ d"e$!"o$! "ll 0e te "$"* e$ te e'tr*date a! te "$"*
e$trapped !tre!!. Te!e !tre!!e! are )a*!ed 0( te 0a!") pol(er reolo%")al rea!o$!, or 0(
teperat*re. /";"$% a loop of oderate !"#e "ed"atel( after te d"e fa)"l"tate! rel"e;"$%
te!e !tre!!e!. A lar%e loop "ll "$trod*)e !tre!!. Al!o, a for)ed !r"$=a%e "ll fa)"l"tate
rel"e;"$% of !tre!!e!.
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1' /HAPE /TABILITY
+;e$ to*% lo ;"!)o!"t( "$)rea!e! prod*)t";"t( a$d 9*al"t( of te e'tr*date, te( !a%,
)ollap!e, a$d al!o "ll %et 0adl( defored "$ !*0!e9*e$t !ta%e! of operat"o$ !*) a!!t"t)"$%.
+.%.> Tread !t"t)"$% "$ T(re 0*"ld"$%
c' TAC4
/e$erall( "%er e'tr*!"o$ teperat*re fa)"l"tate! "%er ta)=. Hoe;er after a tre!old
teperat*re, re;er!al of "$!ol*0le "$to !ol*0le S*lp*r ta=e! pla)e, a$d a( affe)t
ta)="$e!!. All !to)=! te$d to 0e !t")="er "f r*$ at "%er teperat*re! $at*ral r*00er !to)=!
;ar( ore ta$ !($tet"). Soot !*rfa)e! are !t")="er ta$ ro*% !*rfa)e!. Soft !to)=! areal!o ta)="er. S*rfa)e ta)= a( 0e affe)ted 0( )ool"$% ;er( rap"d )ool"$% !peed! *p 0loo
a$d loer! ta)=. A"r )ool"$% a$d !lo ater:)ool"$% a"$ta"$! ta)="$e!!. Sto)=! rapped
ot "$to l"$er! a( lo!e ta)= 0e)a*!e of te rap"d "%rat"o$ of te pro)e!!"$% o"l a$d re!"$!
to te !*rfa)e.
>' E6TR3DED COMPONENT/
Te a
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Depe$d"$% *po$ te teperat*re of feed, e'tr*der! )a$ 0e )la!!"f"ed a!
1. Hot feed e'tr*der!
2. Cold feed e'tr*der!
Copar"!o$! of ;ar"o*! a!pe)t! of ot a$d )old feed e'tr*der! are %";e$ 0elo.
S. @o. HOT ++D +BTRUD+R CO?D ++D +BTRUD+R
A D+S/@ PARA+T+RS
1 Sort 0arrel ?o$% 0arrel
2 ?oer ?-D rat"o 4>1 to 5>1 H"%er ?-D rat"o 18>1 to 15>1
3 Copre!!"o$ rat"o appro'.1 Copre!!"o$ rat"o 1
4 Dept of te fl"%t "! 1-6tof D"a. Dept of fl"%t "! 1-t to 1-18tof D"a.
5 Co$!ta$t or ;ar"a0le p"t) Var"a0le p"t)
6 Co$!ta$t fl"%t dept Var"a0le fl"%t dept
PROC+S@/ ACTORS
1 Copo*$d pre ared Cold )opo*$d
2 Te$de$)( to !)or) ?e!! !)or)"$%
3 eed ;ar"e! "$ teperat*re &
;"!)o!"t(Co$!ta$t teperat*re & ;"!)o!"t(
4 D"ff")*lt to a"$ta"$ )o$!"!te$)(
of e'tr*dateetter d"e$!"o$al )o$trol
5Prod*)t"o$ e9*"l"0r"* atta"$ed
"t"$ a !ort t"eTa=e! lo$%er t"e for e'tr*!"o$ to !ta0"l"#e
C +CO@OC ACTORS1 H"%er "$;e!te$t ?oer "$;e!te$t
2 H"%er la0o*r )o!t ?oer la0o*r )o!t
3 Re9*"re! lar%e floor area ?e!! !pa)e re9*"red
4 ?oer fre9*e$)( of repla)ee$t
of !)re a$d l"$er re9*e$t repla)ee$t of !)re a$d l"$er
5 H"%er o*tp*t ?oer o*tp*t
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+ PART/ O7 AN E6TR3DER
Te e'tr*der )a$ 0e d";"ded "$to !"' 0a!") part! for ea!e of de!)r"pt"o$.
a. Te arrel
0. S)re
). eed opper
d. Head
e. D"e.
f. Dr";e a$d
%. Teperat*re )o$trol
"%> D"a%ra of e'tr*der
a' BARREL
Te 0arrel e$)lo!e! te !)re a$d "! ade of arde$ed !teel. Te "$$er l"$"$% of 0arrel "!
ade "t a ;er( ard allo(. all! *!t 0e ea;( to re!"!t te rad"al pre!!*re! de;eloped
"$!"de. +;e$ %reater are te lo$%"t*d"$al pre!!*re! a! te !)re %e$erate! e$oro*!
!eparat"$% for)e! "$ p*!"$% te !to)= tro*% te re!tr")ted d"e. Te!e for)e! are ta=e$ *p
"$ te rear 0( tr*!t 0ear"$%! a$d te a!!";e$e!! of te!e 0ear"$%! re;eal te a%$"t*de of
te pre!!*re! de;eloped.
Te )a!t o*ter 0arrel a! a t"0le or 0*!"$% "$!ert "t r"0! r*$$"$% d"a%o$all( aro*$d "t
"$ te pre!!*re area. e$ te t"0le "! "$!erted "$ te 0arrel, te !pa)e! 0etee$ te r"0!
35
http://www.google.co.in/url?sa=i&rct=j&q=extruder+diagram&source=images&cd=&cad=rja&docid=XWGqRqzVIR577M&tbnid=kamAaaIac2_BtM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.ineer.org%2FEvents%2FICEE1997%2FProceedings%2Fpaper233.htm&ei=MbVeUeDRFsTJrAfruIHoDQ&bvm=bv.44770516,d.bmk&psig=AFQjCNGsb7m_xphJQPq9c8OSSBawF6Sl6w&ust=1365247606703618 -
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for te )a$$el! tro*% ") te )ool"$% ater )"r)*late!. Te t"0le "$ t*r$ )o$ta"$!
a$ e'treel( ard etal reo;a0le l"$er, ") pro;"de! a ear re!"!ta$t !*rfa)e
!*rro*$d"$% te !)re. T"! )a$ 0e repla)ed rap"dl( a$d e)o$o")all( e$ or$.
Te r*00er )opo*$d "! !eared 0etee$ te all! of te 0arrel a$d fl"%t! of te !)re 0(
te fr")t"o$ 0etee$ r*00er a$d 0arrel. or t"! rea!o$, te 0arrel !o*ld $ot 0e )ooled too
lo, a! )o$de$!at"o$ of ater o$ te all "ll red*)e te fr")t"o$ a$d )a*!e "$eff")"e$t
e'tr*!"o$. Al!o te 0arrel *!t $ot 0e ar too "%, a! t"! "%t )a*!e !)or)"$%.
Te o*tp*t of a$ e'tr*der "! depe$de$t o$ te relat";e %r"p 0etee$ te !)re a$d 0arrel,
te "%er te %r"p of 0arrel, "%er te o*tp*t.
1' THE /CRE?
Te rotat"$% !p"ral !)re "! te eart of te e'tr*der. t "! a treaded !aft, ") l"e! )o:
a'"all( a$d or"#o$tall( "$!"de te 0arrel. t "! )o$$e)ted "t a otor a$d rotate! a$t":
)lo)=:"!e. Te "porta$t paraeter tat deter"$e! te eff")"e$)( of te !)re "! "t! ?-D
rat"o. t "! %";e$ 0(,
Te le$%t:to:d"aeter ?-DE rat"o> : Te rat"o prod*)ed 0( d";"d"$% te effe)t";e le$%t of
te !)re 0( "t! d"aeter.
+a) !)re a! %ot a def"$"te ?-D rat"o. Te ?-D rat"o "! a a1 to 12>1 for )old feed e'tr*der!.
o!t r*00er !)re! are prod*)ed fro "% ol(0de$* !teel, t*r$ed a$d %ro*$d to
!ape, flae arde$ed, a$d te$ )roe plated. T"! "pro;e! te l"fe 0( red*)"$% te
ear rate a%a"$!t te l"$er.
Te pr"ar( p*rpo!e of te !)re "! to )o$;e( ater"al alo$% te 0arrel. Te r*00er
)opo*$d "! )o$;e(ed fro te feed e$d to te d"e e$d 0( te re)"pro)at"$% o;ee$t of
te !)re a$d 0*"ld! *p !*ff")"e$t pre!!*re !o a! to for)e te r*00er tro*% te d"e.
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A! te r*00er %et! or=ed "$!"de te e'tr*der, a lot of eat "! %e$erated. A part of t"! eat
"! ta=e$ o*t 0( )ool"$% te !)re 0( )"r)*lat"$% ater "$!"de te !)re. Te !)re "! dr"lled
"$ter$all( to per"t ater to 0e )"r)*lated o$ "t! "$!"de.
C' HOPPER
$ all e'tr*der!, te !)re "! pro;"ded "t a feed opper, ") a( 0e of re)ta$%*lar or
)"r)*lar ope$"$%, ") re)e";e! )opo*$d "$ a !tr"p for )o$t"$*o*!l( a$d %*"de! "t
do$ "$to te Ffeed fl"%t!G of te !)re. Te !ape a$d lo)at"o$ of opper !e)t"o$ are
"porta$t fa)tor! "$ te )o$trol a$d o*tp*t of te e'tr*der. Te!e *!t 0e !*) tat te
feed !tr"p "ll 0e pre!e$ted to te !)re 0"te "t te lea!t "$terfere$)e a$d "$ a )o$!"!te$t
a$d eff")"e$t po!"t"o$. Te opper "! te lar%e!t )opat"0le "t te !"#e, "! off!et toard
te 0"te !"de of te !)re a! "t re;ol;e!, a$d a! %e$tl( tapered !oot !"deall! to pre;e$t
te feed !tr"p fro 0r"d%"$% a! "t fall!. Te 0arrel "! *$der)*t o$ te floor of te opper
0e$eat te !)re tat "!, "t "! )*t aa( !o tat a )leara$)e of a alf:"$) or ore 0etee$
te t"p of te !)re a$d te floor 0efore "t "! p"$)ed off.
d' HEAD
Te ead of a$ e'tr*der "! te ea$! of )o$!ol"dat"$% te roll"$% )ol*$ of r*00er
eer%"$% fro te 0arrel a$d !)re "$to a oo%e$eo*! a!! of d"!tr"0*t"$% t"! a!! to
te d"e a! e;e$l( a! po!!"0le a$d of o*$t"$% te d"e a$d a))e!!or"e!. t old! te
)opo*$d a! a re!er;o"r, ") e$!*re! e;e$ pre!!*re at te eer%"$% e$d of te e'tr*der
"$ !p"te of ;ar"at"o$ "$ feed rate.
Heat tra$!fer fro te ead "! ;er( "porta$t. *) of te %e$erated eat a! 0ee$
de;eloped e$ te !to)= lea;e! te !)re, !o teperat*re )o$trol!, ") pro;"de a$d
a"$ta"$ )o$!"!te$t )o$d"t"o$! "le te !to)= "! "$ te ead, are $e)e!!ar(. T"! ea$!
tat te ead "! eated pr"or to te r*$ !o tat te !to)= at te !tart of te r*$ doe! $ot lo!e
"t! eat "$ ar"$% te ead. After !tart *p, a teperat*re )o$troller "ll a"$ta"$
opt"* e'tr*!"o$ )o$d"t"o$!. +a) ead "! )ored or )a0ered for !tea a$d ater
)"r)*lat"o$. U!*all( 0ot pro;"!"o$! are %";e$ to eat te ead "$"t"all( a$d te$ to )ool.
Alter$at";el(, teperat*re )o$trol *$"t! are *!ed.
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!' DIE
D"e de!"%$! a$d a$*fa)t*re "! a a
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"' DRIVE
+'tr*der dr";e! *!t pro;"de ade9*ate tor9*e to t*r$ te !)re o;er "de ra$%e 8 to 288
rp "t pre)"!e !peed )o$trol. Te rotat"o$al !peed at te e'tr*der e$d "! $orall(
a)"e;ed 0( )o*pl"$% te e'tr*der !aft tro*% a %ear tra"$ "t te otor. Te %ear
red*)t"o$ !(!te "! *!ed to red*)e !peed a$d *lt"pl( tor9*e.
' TEMPERAT3RE CONTROL/
Teperat*re "! to 0e )o$trolled "$ te ead, 0arrel, !)re a$d d"e of te e'tr*der to
prod*)e %ood 9*al"t( )ro!! !e)t"o$! a$d to a"$ta"$ )o$!"!te$)(. A teperat*re )a$%e of
18IC "$ te !to)= "ll )a$%e te !ear rate 0( appro'"atel( 1.3J. T"! "ll affe)t te
rate of flo tro*% te d"e a! ell a! te d"e !ell )ara)ter"!t")!. Te )o$!"!te$)( of
teperat*re "! ore "porta$t ta$ te a)t*al teperat*re, ") a( 0e !et depe$d"$% o$
te pro)e!! a$d )opo*$d )ara)ter"!t")!.
or pre)"!e )o$trol of e'tr*!"o$, *lt" #o$e 0arrel, ead, !)re a$d D"e- D"e )lap 0lo)=
teperat*re! are !eparatel( !et a$d )o$trolled. To etod! of teperat*re )o$trol are "$
*!e>
1. D"re)t ere te )ool"$% ed"*, !a( ater "! d"re)tl( ad"tted "$to te e'tr*der #o$e!
a! re9*"red $orall( for "% )ro!! !e)t"o$ e'tr*!"o$! 158 !9.
2. $d"re)t !(!te, ere a )"r)*lat"$% fl*"d "! pa!!ed tro*% a eat e')a$%er, ")
reo;e! te eat fro te )"r)*lat"$% ed"*
CALENDERING O= =A:RIC?
PRINCIPLE O= CALENDERING
+he majority of the calendars installed in general ru**er good
companies are three roll units where as four roll calendars are normally used
*y tyre manufacturers. +he advantage of >-roll calendar is its versatility and it
can produce a sheet of ru**er and a friction or a skim coat on one side of a
fa*ric. +he main advantage of =-roll calendar is its a*ility to top the dou*le
side of a fa*ric is single operation. ,ommonly used four roll calendars are@
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8 Th) i$)rt)- L5'!$ig*rati!$
+his was the first major change in the *asic vertical calendar design. It
has all the versatility of the *asic three-roll calendar *ecause of the *ottom
and off set rolls is keyed to provide *oth even and odd sheet.
: 5r!ll '!$ig*rati!$
+his calendar is generally used in the tyre industry as the heart of high
production cord coating line speciali5ed in e4uipment capa*le of continuous
high 4uality output. +he main advantages of D-roll calendars are it eliminates
the nip force interaction and roll float. +he nip force act in a plane at 677 to
each other and roll float are minimal *ecause the direction of resultant of nip
force *eing relatively insensitive to change in these force. +he main
disadvantage is that it lacks some fle$i*ility for automatic gauge control.
,alendaring process can *e descri*ed *y means of com*ined drag flow
and pressure flow. +he clearance *etween the rollers and viscoelastic
*ehavior of the ru**er will determine the thickness of the sheet. +he counter-
rotating roll will drag the material in the converging region of the calendar nip
through the clearance. (ue to this highly converging flow a high pressure is
*uild up in the nip region. +his is also a function of compound viscosity
clearance line speed and rolling *ank height. part of dragged material is
pushed *ack *y the pressure flow. +his will results in rolling *ank in the
calendar nip. +his nip pressure causes a nip force and therefore a roll
deflection.
+he roll separating force is a calendar is given *y
;L:"'h %8Fh-8F!
3here
Lviscosity of the *ank
"Lspeed of the roll
!Lthe nip *etween the rolls
'L radius of the calendar rolls.
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;or good 4uality product following precautions should *e taken@
,onstant and steady nip feeding
,onstant stock temperature
,ord tension should *e as low as possi*le *ut sufficient to keep cord
distri*ution
,alendar to *e e4uipped with crowned rolls e$ternal roll *ending and
adjusta*le cross a$is setting
+hickness control e4uipment
Peak in tension to *e damped
2atch to *atch variation should *e avoided
0ajor changes in the line speed should *e avoided
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C!$tr!l ! ga*g)
8 Cr!.$i$g
+he calendars are huge and designed to resist great separating force
*etween their rolls. +hese forces *end the rolls and stretch side frames somuch. +he rolls must *e ground to accommodate and counteract this *ending
or deflection. So the rolls are grind with varying diameter from the middle to
the end of the roll and it is known as crown. 3arm up of the stock on mill
change in the roll temperature thickness of the skim si5e of the calendar
*ank and speed of the calendar effect the separating force and thus the *end
of the roll. +he deflection can *e calculated from the formula of deflection of a
*eam supported at *oth ends and loaded uniformly over its length. +hisproduces a regular curve which is an arc of a circle. "ariation in estimates of
total separating force resulted in total calculated deflection of 7.77: to 7.77
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> R!ll 'r!""i$g
'oll crossing is accomplished *y tilting the plane a$is of one of the two
adjacent rolls in relation to the common plane a$is of the two. +he journal
*o$es of the crowning roll slide not only towards and away from their mateson the adjoining rolls *ut can *e moved at 677 from these latter. +his is
achieved *y mechanical screw similar to roll skew downs hydraulic system
and sliding wedges. 0echanism of roll crossing is complicated.
T)m+)rat*r) '!$tr!l
,alendar reac4uires a uniform and well-controlled temperature profile
across the surface of the roll. +he temperature control system for calendar
due to the short residence time cannot compensate effectively for transient
change in feed material. So the main consideration is for maintaining
temperature sta*ility in calendared rolls. ;or this the *asic function of a
calendar temperature control system is to hold inlet temperature of the roll
constant and take away the heat developed *y normal calendaring. +he
different types of roll cooling systems used in calendars are
a C!r)- r!ll
,ored rolls are mold casted with internal cores and are machined on
the outer surface only. +hey have variation in wall thickness due to casting
irregularities. +he walls tend to *e heavy so that heat transmission for cooling
is slow and uneven. +hey can *e used at lower speeds with good accuracy.
* Drill)- r!ll"
+hese rolls have a *ored center-hole a*out 9M in diameter and a
concentric rings of 8F=M holes drilled from end to end a*out 8-8F:M *elow the
circumference and water is circulated through this. It will improve the rate of
heat transfer from roll surface and to remedy the temperature fall off at the roll
edges.
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> =))- '!$tr!l
+he supply of a material of uniform flow properties to calendar nip at
constant rate is a prere4uisite for dimensional accuracy and good surface
appearance for calendared sheets. uniform roll separation fore is important
and the temperature *and in which successful calendaring can take place
may *e 4uite narrow. +he rolling *ank si5e influences *oth temperature and
roll separating force. s calendar speed is increased the control of flow
properties and feed rate necessary for successful manufacture *ecame more
critical. ;or uniform feed rate and even feed across the width of calendar nip
a conveyor feed from the pre-plastici5ation machine terminating in a
pendulum head which can oscillate *ack and forth across the width is used.
Cal)$-)r -)"'ri+ti!$
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'oll si5e ?: N :9M inclined D calendar
'oll design (rilled'oll crowing 7.89 mm on I & I" throll
,ross a$is Ao2ending es'oll speed :H.9 rpm'oll temperature 677,'eed temperature 997,
+he roll ends are fitted with rotary joints for connection to the water
system. .
S+))- rati!
+he speed of >rdroll is specified as the speed of calendar. ll other
motors in line are synchroni5ed with motor running in > rdroll. +he speed ratio
are given *y
8F: 8@8. [email protected]
>F= 8.
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they cannot *e open unless the seat in loading position and the cam will close
the chuck when it is rotated.
2 S+li'i$g +r)""
hydraulically operated splice press is used to join the successive rollends to form a continuous we* of fa*ric supply to the calendar unit. +he
press has two electrically heated platen of si5e :77 N 8H?H7 O:7 ;
and a pressure >7 seconds. pper plate is insulated from the press head and mounted on astationary position on a *olster plate. +he lower platen is connected to a
hydraulic cylinder for closing force. +he hydraulic unit is a separate unit to
which the press is piped and each cylinder is provided with hydraulic
e4uali5ing to assure a uniform pressure throughout the length of plate
3 T)$"i!$ ")tt)r
+his tension setter is used to keep the fa*ric in tension in the line.
Aormally the tension applied in this tension setter is a*out 8777/g.
6 L)t ! a''*m*lat!r ))- r!ll
+his feed roller will draw the fa*ric from the let off at a steady rate and
synchroni5e with the other fa*ric driving mechanism in the system. +he roll
stand has one driving roll one air operated nip roll and three steel idler
passing rolls. (uring the time of edge splicing nip roll will press against the
feed roller and will prevent the loosing of the free ends of the ended fa*ric
rolls. It will also act as a hold *ack when the following accumulator provides
the fa*ric to the system towards the *eginning of a new fa*ric roll. +he
pneumatic load cell which senses the fa*ric tension so that one can control
the let off tension in mounted under the idle roller *earing. +his roll will have a
tension of a*out
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It is a top floating hydraulically operated simultaneously arranged
complete with entering and leaving idle reactor controller unit which provide
the storage of fa*ric at the time of roll change. It can store a*out 8:7m of
fa*ric in 8:7seconds. +he clearance *etween the idle rollers is >9mm.#enerally the floating carriage is in the top position having sufficient storage of
fa*ric and is move down for giving time for joining of two fa*ric ends i.e. when
the accumulator feed roll stops the fa*ric is fed into the system *y lowering of
floating platform. +he traveling platform is carried *y a chain from the four
corners. +he accumulator is provided with two control switches one for
operation at the top with full accumulator and one for operating at a*out
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C)$t)r g*i-)
It consists of pair of rollers which can move to keep the fa*ric in thecentre line. +his consists of type frame sensor that keeps the fa*ric
tracking within a preset limit. +he edges of the fa*ric will travel *etween a
sender and a receiver. +his will read the fa*ric location through an electronic
unit and transmit the mechanical action to the roll to keep the fa*ric in center.
10 S+r)a- ma"t)r (a$a$a r!ll
It consists of two *owed rolls and it is hydraulically controlled. +he
edge of the fa*ric is sensed *y a photocell. +hese must *e positioned forvarying fa*ric width. 3hen fa*ric passes over this roll against convert *ow
ness the fa*ric width reduces and when faces the concave *ow ness fa*ric
width increases.
11 E-g) )@+a$-)r
It consists of three finger lime rolls arranged hori5ontally at the fa*ric
edges. 3hile in operation the top roll will move a*ove the fa*ric and two
*ottom rollers *elow the fa*ric. +he *ottom rolls are fi$ed and the top rollers
move in and out in *etween the *ottom rolls. +his help to avoid crowdedness
of the cords at the edges or variation in ends per inch.
12 Cal)$-ar r!ll"
+he four roll calendar has an inclined D type configuration. +he chilled
cast iron rolls are mounted on the roll *earing which are attached to the main
housing of the machine. +he roll si5e of this is ?: N :9Q and a roll speed of
:H.9 rpm. Each roll has individual drives. +he rolls are maintained at a
surface temperature of 997,. +he temperature is given *y hot water at
=/gFcm:pressure circulated through drilled holes. !ydraulic pump is used at a
pressure 8< /gFcm: for roll *ending. In order to provide roll *ending higher
force is to *e transmitted. So main roll *earing is arranged at a greater
distance from the au$iliary *earing. +wo hydraulic cylinders are used which
act on roll journal to provide uniform gauge. +he *ending force can *e preseton hydraulic cylinder on *oth sides. +he common line speed of the calendar
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is H7mFmin. +he fa*ric is entered *etween :ndand >rdrollers. +he compounds
are fed *etween I & II and III & I". 2etween the rollers I & II and III & I" a
frictional ratio of 7.H is given. +he roll *ending pressure is applied *etween I
&II is a*out =
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It consists of three rolls to provide a tension of :7-:77/g of the
calendared fa*ric to keep the coated fa*ric in line.
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A'')""!ri)"
8 Warm *+ mill"
3arm up mill is a two roll mill 7f si5e :9 N 9=Q. Since the consumption
of ru**er in the calendar is very high it stores the stock from the warm up mill.!old mill is provided with a stock *lender *ar. It is cooled *y passing chilled
water. +he stock in the feed mill is conveyed to the feed mill via conveyor.
: =))- mill
;eed mill supply the compound for the calendar. +he feeding of the
ru**er is through a pendulum conveyer. +he mill is fitted with a knife to cut
the compound to the correct width which is *eing fed to the calendar. +he
mill is cooled *y passing chilled water.
Cal)$-ari$g !+)rati!$
+he dipped fa*ric after a maturation period it is taken into the
calendaring unit through ;I;) system. +he *lack cover is removed and
splicing gum is applied at the leading end of the fa*ric. +his gum has
appro$imate width of H inch and 7.7 ;.
fter a cure time of =7 sec it will automatically open. (uring this time let off
accumulator will provide fa*ric for the calendar unit.
tension stand is provided after the splice press to keep the fa*ric in
line *y the application of tension. fter let of accumulator the fa*ric will pass
through a heating 5one consisting of :7 cylindrical drum of surface
temperature of 677,. +his heating 5one will remove any type of moisture
a*sor*ed in the fa*ric surface. It will create some pro*lem in final tyre during
service. ;ollowing this a dancer roll is there to a*sor* any slack formed in the
fa*ric. In order to keep the fa*ric in centerline with specified EPI fa*ric will
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pass through centre guide rollers *anana rollers and trio canter *efore
entering into the calendaring rolls.
+he fa*ric enters into the calendar *etween second and third rollers.
+he compound to *e coated is fed though a pendulum conveyer *etween I &II and III & I" throllers. 2efore enter into to the calendar the compound is
passed through series of mill for proper *lending and *reakdown. +he
compound applied to the calendar will have a temperature of near 977,
otherwise there will *e variation in the property of the fa*ric. +his skim coated
compound is passed through post calendar dancing roll to the cooling drum.
+he cooling drum has a surface temperature of >77, to cool the fa*ric
to room temperature. fter this 5one *leeder yarns are applied to thecalendared fa*ric for proper identification. +his fa*ric then pass through
picker rolls pick *reaker to remove any air in the fa*ric. fter passing through
the wind up accumulator and wind up let off roll the fa*rics are wound on a
wind roller with a liner. In order to keep the fa*ric in centre a centre guide is
attached to the assem*ly. +his wind up rollers with identification tag is stored
in the racks and taken into the *ias cutter in ;I;) manner.
C!mm!$ -))'t" i$ th) 'al)$-ar)- a(ri'?5
,old stock and rough surface
Split fa*ric and crush fa*ric
;oreign matter
1umpy compound in fa*ric
3rinkles and folds
1oose cord and loose coating
)ff *alance coating
#um edge
Improper gauge and width
0issing cords
St))l '!r- 'al)$-ari$g
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Steel cord calendar is used for the production of steel *elt i.e. in a steel cord
calendar the two sides of the steel wires are coated with a ru**er compound
*y maintaining a specified ends per inch. +he important components of the
machines are
1 Cr))l r!!m
+he steel wires are coated with *rass material for *etter adhesion and
prevent the corrosion. +o protect this the steel wires are stored and let off
from a room called creel room. +he temperature is maintained at =7 7c with a
relative humidity of >.H /gFcm:should *e maintained in the cord for getting the
re4uired EPI. +he compounds are introduced *etween the first and second
rolls and *etween third and fourth roll. +he compound should *e warmed up to
977c *efore introducing in the calendar. +wo side coated compound is passed
through the cooling drum and wound on the liners in the wind up 5one. +he
speed of the calendar is very small to o*tain good coating on *oth sides.
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St))l .ir) '*tt)r
Steel wire cutter is used for cutting the calendared steel fa*ric into a specified
degree of angle and splices the pieces to form a continuous strip. In ,E+
tyre !alol two steel cutters are employed for cutting the calendared steel
fa*ric.
;irst the fa*ric to *e cut is loaded in the let off stand. +he ply from the let off
stand is passed through a let of festooner which control the tension in the
fa*ric. +his festooner operation is controlled *y limit switches and actuated *y
the length measuring device. fter the festooner the fa*ric enters into a
hori5ontal ta*le conveyor.
+he cutter used for cutting the steel *elt consist of two rotating roller which are
step off to each other. +he shearing action *etween the rotors gives the
cutting. +his cutter assem*ly can *e adjusted for a specified angle.
+his cut ply is transferred to the splicing ta*le *y a magnetic material and
leading end is spliced with the tail end of the wound ends. 2efore winding in
the liners gum strip is applied using gum strip assem*ly
Ca+ +li)" "litt)r?,ap ply slitter used in ,E+ +yres !alol is made *y +ech. edge (elhi. It can
operate with a line speed of >7 rpm. ,ap ply slitter is used for slitting a
calendared cap ply fa*ric into cap ply strip of re4uired smaller width. +he
main parts of this machine are
1 =a(ri' l)t !
+he fa*ric let off is controlled *y unwinding the liner. constant speed is
ensured *y the let off motor drive system. +his let off station is mounted over
a moving *ase and tensioning device operated *y hydraulic centering system.
0ovement of the *ase is activated *y the automatic centering system which
consists of a light source and receiver.
2 Slitti$g %$i)
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Slitting knife is pneumatically operated and distance *etween the knives can
*e adjusted depends on the width of the cap ply re4uired. +he silted pieces
are separated *y independently adjusta*le idle rollers which are vertically
mounted.
3 Ta%) a.ay '!$)y)r a$- .i$- *+ "tati!$
+ake away conveyor is driven *y a (,- motor. +here are four stations along
with one set of each stand *y winding up for the continuous winding f slit
rollers. +he winding is done *y engaging the roll with the conveyor. +he liner
tension from the liner let off in wind up can *e adjusted down *y a particle
*reak. ll wind ups are provided *y air motor to ensure a positive and tightwinding.
Ca+ "tri+ '*tt)r?
1 =a(ri' l)t !
;a*ric is let off from the roll *y unwinding the liner. constant speed is
ensured *y the let of dancer system. +his will also achieve centering and
proper tensioning of the ply.
2 K$i) "y"t)m
/nife fitted to a toggle shaft which are guided *y the cord direction. +he
distance *etween the knife can *e independently adjusted depends on the
width of the ply. Silted fa*rics are separated *y independently adjusta*le
vertically mounted idle rollers.
3 Wi$-*+ "tati!$.
ll winders are provided *y a tensioner device to ensure the positive wind up
tension. Some supply stations are there which can move parallel to the
winder in such a way that uniform supply of fa*ric.
A"")m(ly li$)r Li$)r +r)+arati!$?
In order to reduce the tyre *uilding cycle time in passenger car tyresB
chafer is assem*led with the inner liner in assem*ly liner preparation unit.
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Peculiarity of this unit is it uses highly sophisticated charge code digital
camera for centering the chafer and inner liner. +he different component s
of this machine is
8 S*))g)) +r)+arati!$ *$it+he s4ueegee preparation unit is com*ination of a cold feed e$truder and a
two-roll calendar. +he head of the cold fed e$truder is connected to a two-roll
calendar So that the s4ueegee with a very fine thickness and 4uality is
o*tained. +he calendar rolls are provided with two knives adjusted a particular
distance same as that of width of the s4ueegee. +his s4ueegee is pulled *y a
take away conveyor. +he speed of the calendar rolls and the line speed of the
conveyor are synchroni5ed. Speed of the conveyor is synchroni5ed. guider roll is provided for proper placing of the s4ueegee on the conveyor.
: Cha)r "*++ly
+he cut chafer can *e placed on a let of station. +here is a let off accumulator
for making the process continuous. +o place the chafer on proper position it
is passed through a moving *ase whose movement can *e actuated *y the
signals from ,,( camera.
O+)rati!$?
+he inner liner compound is introduced in the cold feed e$truder. +he
e$truded inner liner is taken through the nip of the calendar and allowed to
wind on it. +he cutting knifes are adjusted for the specified width and the cut
s4ueegee is introduced in the take off conveyor. +he s4ueegee is then passed
over the guide roller and the space of the guide roller is adjusted for proper
centering. +he moving *ase assem*ly and ,,( camera do the appropriate
centering of the s4ueegee.
(uring this time the chafers are loaded in the chafer let off assem*ly
and introduced on the inner liner through let off accumulators. +he chafers
should *e properly centered using ,,( camera. +his assem*ly is then wound
at the winding station.
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:)a- a$- a+)@ (*il-i$g *$it?
In radial high performance tyres smooth *uilding up of stress from the
rim to the carcass is necessary for *etter riding comfort and steering
response. So the dimensional sta*ility of the ape$ed *ead should *e of very
high 4uality. In ,E+ +yres !alol for the preparation of *ead with very good
dimensional sta*ility they are using a *ead ape$ing machine called ;0; -
,onti 2ead ape$ing machine. +he machine is semi-automatic. +wo *eads
can *e ape$es at a time with this machine. +he different components of the
machine are@
1 E@tr*-)r
cold fed e$truder is used for preparing predetermined profile of filer.
+he e$truder used is a ?< mm e$truder. +he e$truder is provided with a
temperature control system and the temperature of the e$truder is normally
set at 677,. ;actory cooling water is used for cooling the drum.
+he drum is rotating at very low rpm. fter cooling the filler is stored in an
accumulator. +here are five series of accumulators arranged parallel to each
other and the accumulator supplies the filler to the ne$t section. +he
controlled *y light sensors.
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3 A+)@i$g *$it
pe$ing unit consist of a servicer and a *ead placing *ladder. +his
device provides the two filler in appropriate position on the drum. +his is
achieved through photo sensing device. +o cut the filler at desired length a
hot knife is provided. +he knife is heated at :>7, for smooth cutting. +he
cutting angle is almost =
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drum. +he splicing should *e minimum and spliced portion is consolidated *y
a series of needle like structure automatically.
(uring this time the *ead servicer is ready with the *ead holder
assem*ly. 3ound *ead should *e placed on the *ead hold assem*ly in sucha way that to get a spotting of 8977*etween wound *ead splice overlap and
filler splice overlap. It will move lateral to the drum containing filler and
placed on the appropriate position. (uring the time drum e$pands and hold
the *ead. +he distance *etween the *ead and the lip of the filler should *e >
mm. +he *ead servicer moves to its original position. +hen *oth the rim
come closer to each other and e$pansion of the drum take place at the
position *etween the *eads in such a way that the *ead ape$ should *eplaced over the *ead and *end against the holder assem*ly. fter this the
rim move away and the drum is returned to the original position. +he wound
*eads are taken and placed on the rack.
igh ta(l) (ia" '*tt)r?
!igh ta*le *ias cutter is used for cutting the plies to a re4uired width
and angle from the calendared roll to produce continuous length of the fa*ric.
+he cut plies are spliced manually and wound on liners.
+he main parts of the machines are a let off unit and festooner a ta*le
conveyor cutting knife assem*ly splicing ta*le and a wind up unit.
+he let off station consist of a chuck provided with *reak for
maintaining suita*le tension in the fa*ric. ;rom this the fa*ric is passed
through a festoon drive which is operated *etween two limit switches. +his
festooner is operated *etween limit switches. +his festooner controls the
supply of the fa*ric to the other units. fter that the fa*ric is drawn through a
ta*le conveyor on which the cutting of the plies takes place. +he knife
assem*ly consists of a round knife supported on a high mass to provide
re4uired moment of inertia. +his knife assem*ly can *e set according to the
re4uired angle. Aormally the angle is set in the range of 99 7 to 6:7. +he knife
assem*ly is actuated *y a length measuring device set for specified value.
+he cutting ta*le is placed at a height from the splicing ta*le. +his cut ply fall
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Ceat Ltd, Halol, Vadodara Dept. Of PS&RT, CUSAT
down to the splicing ta*le. +his plies are spliced manually and wound in liners.
+he movement of the wind up assem*ly is controlled *y photo sensors.
Cha)r "litt)r,hafer slitter is used for the manufacture of chafer. +his involves the
cutting of calendared fa*ric from the = roll calendar and this is further silted in
ohnston slitter for further use in tyre *uilding and assem*ly liner. +he spitted
calendared fa*ric is placed on the let off roll. +he fa*ric is taken and is lead
through the centering roll to the knife assem*ly unit. +he liner is wound in
another empty sell. +he knives are pneumatically operated and engage the
cuter into the fa*ric. +he knife assem*ly is adjusted in such a way that the
center distance *etween the cutters is as per the chafer width to the slit. +he
station consist of five wind up stand can engage with the conveyer for uniform
winding. ll wind up stations are provided with air motor to ensure the positive
tight winding.
+he cut chafer is first wound on the hollow s4uare *ars and engages it
with the conveyor *y the pneumatic switch. 3hen the *ar is full raise the
stand the put new *ars for filling.
Tyr) (*il-i$g +r!')""?
:*il-i$g ma'hi$)
'adial tyres are *uilt in two stages due to the ine$tensi*le *elt package.
In first stage carcass with the side wall are prepared and the *elt and tread
packages are applied in the second stage. +he important components of the
tyre *uilding machines are given *elow
1 I"t"tag) (*il-i$g ma'hi$)
a :*il-i$g -r*m
2uilding drum is mounted on a shaft which is attached to an ., drive.
+he *uilding drum consists of a drum surrounded *y an e$panda*le *ladder.
2ladder can *e e$panded at the time of *ead application. Some holes are
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Ceat Ltd, Halol, Vadodara Dept. Of PS&RT, CUSAT
provided on the drum to introduce air *etween drum and *ladder. t the time
of tyre strip out the *ladder will deflate to promote the strip out operation.
( =i$g)r +ly -!.$ a"")m(ly
+his is an assem*ly of spring fingers mounted as an end to a ring.3hen the finger arrives at the drum edge they are opened to encircle the
overhanging plies.
' D*al (la--)r t*r$ *+ a"")m(ly
+hese *ladder turn up assem*ly is a pair of inflata*le ru**er tu*es one
side the other. +hey are clamped *y their edges in a spiral ring which forms an
air tight seal. +he ring assem*ly can move *ack and forth *y means of an air
cylinder. fter the *ead set operation the *ladder is inflated and eachassumes the shape of a donut with the ply portion to *e turn up. +hen the
push-can will push the inflated *ladder with plies end and stitches it around
the *ead.
- Stit'h)r *$it
In order to remove the trapped air *etween the plies they are stitched
well with a stitcher. +here are two types of stitchers in a first stage *uilding
machine. +hey are called *ottom stitchers and swan neck switchers. +he
*ottom stitchers consist of two rollers rotating at a specified rpm. It can stitch
the carcass at low pressure and side wall at high pressure. Swan neck rollers
are provided at *oth end of the drum. Swan neck switchers are used for final
tuck in operation. +o keep the plies in position during the application on the
drum a sponge roller is used. +hey can apply a small pressure.
) Car'a"" +li)" ")ri')r
+he cassette containing carcass ply and drum s4ueegee has separate
let off stations. +hey are provided with *reaking system to maintain the
tension during application. +he plies are centered using light sensors and cut
at specified length *y a rotating knife.
2 S)'!$- "tag) (*il-i$g ma'hi$)
a : T -r*m
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Ceat Ltd, Halol, Vadodara Dept. Of PS&RT, CUSAT
2 & + drum consists of a dou*le conical e$pansion cone which is fitted
*etween the drumCs side flanges. +he metallic flat rigid aluminum segments
among them num*er of segments form-*uilding deck is filled w