2. Main processes of tyre building:
1) Calendaring
2) Ply cutting
3) Tread extrusion
4) Bead wire
5) Green tyre building
6) Air bag
7) Curing
8) Quality checking
3. 1) Calendaring:
The calendar provides plies by coating the cord by
specified compound from mixing dept. The major units
involved are:
1) let off unit
2) pre heating unit
3) ply coating unit
4) cooling unit
5) pricking unit
6) winding unit
Tyre cord stand:
A track is made to shift the roll forward. A lifter motor is
present to shift the roll towards the machine. The tyre
chords with different EPI are present on it.
4. Sequence of operations:
I. Let off unit:
Let of unit is used to stretch the tyre chord and provide
tension in it. The tension brakes are applied the brakes are
pneumatic in nature. Bladders inflate to stop the disc of
rolls.
II. Pre heating :
5 heating rolls are present to stretch the chord. Usually the
width is 58 inches. They are heated by the steam in drums.
The cord is heated so that the coating is done easily and
the cord takes the required width
III. Calendaring:
Inverted L shaped calendar with 4 drums. Heated by same
phenomena of steam. The coating of compound is done
from up and down side of the rolls. The compound is fed
by conveyer on upside. While fed manually from
5. downside.
IV. Air deflation:
A needle like structure is fitted and moves back and forth
for the trap air to be removed.
V. Feeding compound:
2 warming mills are present to masticate the compound.
The feeding conveyer takes the compound up to feed.
The compound is also fed from downside for downside
coating.
On front side cutters are adjusted to cut the extra
compound at edges.
6. VI. Cooling:
Six cooling drums are present to cool the coated ply. The
ply is rolled over the drums to have maximum contact
area. The cooling is done by water supply inside drums.
VII. Winding:
Two winders are present to roll the ply over the liner. One
is used at a time. The length of liner is 300m. A tag is
placed on the roll mentioning compound, type of ply, date.
7. Banana rolls:
Banana rolls are present to adjust the ply and avoid
wrinkles. They are present on input and output of
calendar.
Prickling rolls:
The ply is the passed through prickling rolls which prick the
ply and remove the trap air.
Control panel:
The control panel has following buttons to control the
operations:
1) On/Off motor
2) Set the nip of rolls
3) Bell ringing
4) The rpm of motor
8. Thickness:
The thickness is checked by the gauge after short intervals.
Gauge tolerance:
+ - 0.03 mm gauge range is acceptable.
Faults:
1)Ply fault
2)Miss coating
3)Joint wrinkles
4)Cord crush
Type of cords:
Nylon 6 cord is used dipped in RFL
(resorcinol formaldehyde latex)
Type EPI
840 D1 20
840 D2 16,22,28
1260 D1 28
1260 D2 20,24
1680 D2 20,24
1890 D2 20,22
The cord is dipped in RFL to increase longitudinal strength
and to provide adhesive support.
9. 2) Ply cutter:
The ply cutter cuts the plies at specified angle
(mostly 54 degrees) and widths. The ply rolls are
brought from the calendar. All the plies to the
builder machines are supplied from here.
10. Main steps:
The ply width and angle is set on the panel.
The plies are cut periodically
The plies after cutting are wound in the liner.
Lifter motor:
Lifter motor to adjust the rolled ply from calendar to the
cutter stand. The controller is attached to forward/
backward/ up /down motion
Winding, re winding rollers:
Forward, backward, jog controls are present for the roll to
adjust. The motor is present to unwind the ply. The motor
is controlled by sensors. When the lower sensor operates
the motor stops. When the middle sensor operates the
motor starts.
Banana rolls:
For removing wrinkles while unfolding of ply.
Servo motor:
It is used to length measurement of ply by calculating its
revolutions. The revolutions are taken as input by program
and gives commands to cutter to cut after required length
11. Cutter motor:
4 sensors are present at the ends of platform of cutter for
the motion of cutter and its up/ down motion by jacks
Cutter control panel:
Buttons:
i.Single piece/continue
ii.Conveyer return/ advance
iii.Emergency stop
iv.Auto start
v.Manual /auto
vi.Cutter up/ down
vii.Power off/ on
viii.Winder counter
ix.Cutting width
x.Conveyer on/off
xi.Cutting length input
12. 3) Tread extruder:
Tread:
Tread is the upper surface of the tyre. The pattern on the
tyre is made on the tread. Tread comes in contact with the
road so I must be strong. The tread is divided into portion:
1) Sidewall
2) Crown
3) Shoulders
The tread is extruded through extruder by applying the
appropriate dye according to size
13. Specifications of the extruder:
Model: XJ200
Motor power: 110KW
Screw diameter: 200mm
Productivity: 1800 Kg/h
Screw speed: 67rpm
Voltage: 680V
Current: 120A
Compound used: T100
Two warming mills for milling the compound.
1 lubricator tank for extruder
Barrel temp:
73 degree
centigrade
Extruder head
Temp: 100 degree centigrade
14. Main steps:
At start steam is supplied for head heating, cold water is
supplied for cooling.
Extruder head is opened by pneumatic jack.
The die width is set by screws above it to set the
thickness of tread
Dual tread dies are used.
Upper extruder is standby or for special sizes.
Dancing rolls are used to synchronize speed of
conveyers for smooth movement of tread.
The tread is shifted upward and passed through cooling
conveyers.
Sensor is present in the pit for tread detection and
movement of cutting conveyer.
At last the cutter cuts the length according to reuired
length given as input
Cutter:
Two jacks are present for cutter motion:
1)For left right motion
2)For up down motion
Two sensors are present at the ends of cutter boundary to
define it’s boundaries
1)1st sensor downs the cutter and move
2)2nd sensor stop and cutter up.
15. Drying:
Two blowers and sponge rollers for drying. The tread is
completely dry to supply to building machines
Cutter controls:
The cuter control panel has following controls:
1.Length
2.Speed control
3.Cutter set backward /forward
4.Operation manual/automatic
5.Cutter motor on /off
6.Take up conveyer on/off
7.Blower on/off
8.Counter for counting cuts
Weight of tread:
Weight of tread is done to check its accordance with the
specs.
The length of tread is kept 30 to 35 mm greater for the
shrinkage factor
16. Tread specs:
Tread is kept 20mm to 30 mm long due to shrinkage
Width is kept 5mm greater
In winter shrinkage problem is greater
Braker tread is marked with coloured lining and is heavy
Size Length Width Weight
(mm) (mm) (g)
2.25-17 1430 140 950-970
2.50-17(s) 1430 155 1100-1130
2.50-17(b) 1430 155 1230-1260
2.50-18 1530 155 1180-1200
2.50-18(b) 1530 155 1320-1340
2.75-18 1530 180 1470-1500
3.00-17(s) 1440 204 1600-1650
3.00-17(b) 1440 204 1720-1750
3.00-18 1530 206 1875-1890
90/90-18 1530 212 2350-2400
3.50-8 830 235 1170-1200
3.50-10 1030 235 1200-1230
70/90-17 1435 165 1300-1350
(sample)
18. Tire bead is the term for the edge of a tire that sits on
the wheel. Wheels for automobiles are made with a small
slot or groove into which the tire bead sits. When the tire is
properly inflated the air pressure within the tire keeps the
bead in this groove. Bead is the supporting part of the tyre
and sticks inside the rim of tyre on fitting. The rim provides
strength to tyre.
Weight of roll: 393 kg
Wire diameter: 0.93 mm
Two bead wire machines are present
First has 7 wire rolls
Second has 6 wire rolls
Heater:
The wire is passed through heaters for heating it to make
coating easy. 150 A current taken by heater
Extruder:
40 to 50 mm sheet of B100 is given to extruder for coating
the wire
19. Cooling drums:
The wire is passed through cooling drums for sticking the
compound properly
Balancing pulley system (accommodator) :
The wire roll are continuously in motion. While the cutter
is working the gap taken to stop the machine is
compensated by this system by up and down motion.
Guide wheels:
After passing through guide wheels the wire is transferred
to the cutter.
Cutter:
After specified turns the wire is cut. 5 pneumatic jacks are
for cutter purpose. 2 solenoid valves contract and expand
the cutter drum.
Control panel:
i.Indication Lights for heater, cooling drum,extruder motor
ii.Building select continuous/ 1 piece
iii.Bead push (back /out)
iv.Wire feeding (on / off)
v.Former chuck (close/ open)
vi.Bead hold (up/ down)
vii.Extruder speed adjust
viii.Counter
22. Tyre builder:
The tyre building machine makes a green tyre by collecting
all the things required to build a tyre consisting of plies,
bead wires, brakers, tread.
Major parts:
Servicer:
Servicer is used to hang ply rolls. The ply supplying is
controlled by the photo sensors. When the supply is not in
front of photo sensor the motor starts to push supply
forward.
1/2Hp x 4p motor with worm gear reducer
Bead setting guides:
Magnets attached on it for proper fixing the beads on
required position.
Under stitcher unit:
Front unit = flat roller
Rear unit = star roller
Pedal controls:
1) Clockwise rotation
2) Anti-clockwise rotation
3) 1 complete rotation
23. Main steps:
1.) 1st ply //// direction according to level set by projectors
2.) 2nd ply direction
3.) Braker (on some sizes)
4.) Bead is applied by bead guides having magnets
5.) The drum is inflated
6.) Then plies are folded ply turn up beads, turn up spring
and safety springs are present on it.
7.) Turn up stitchers are applied
8.) Tread is applied on it by applying hand stitcher on
joint.The center of tread is adjust by projector light
9.) Power stitcher and then bead stitchers are applied at
the same time.
The drum is expandable according to sizes 2.5 bar pressure
is applied to stitchers. The bead must be set in the bead
grove.
The plies are applied by the level set by the projectors
above.
When the drum inflates there is a shift of 20 to 25 degree
of angle of plies
25. 6)Air bag section:
Compound: AB900
The air bag is used during curing to be placed inside
green tyre ater shaping and then the tyre is placed
in press.
Extrusion:
The air bag extrusion is done on the tube extruder by
applying dye of specific size. The approx. lengths are cut.
Type Circumference Gauge Length
(inches) (mm) (mm)
2.25-17 6.25 10 58
2.50-17 6.5 10 60
2.50-18 6.5 10 62
2.75-17 8 11 60
2.75-18 8 11 62
3.00-17 8.5 12 0
3.00-18 8.5 12 62
3.50-8 9.5 12 34
3.50-10 9.5 12 40
3.00-16 8.5 12 56
90/90-18 8.5 12 62
110-90-16 10 14 60
26. Nozzle:
85mm, 95mm
Nozzle, cup, metal strip, nuts.
Air bag solution:
Applied inside and outside of nozzle to stick and rub by
brush and thin layer applied by rotation.
Joint:
0.4 MPa pressure my pneumatic jack.
5 min joint time.
Rest time 2 min.
Temp: 130 degree centigrade.
Air bag life:
250 to 300 tyre for regular use.
Curing:
Time: 2.25 hours to 2.5 hours.
Steam curing
Presses:
2 presses (4+3 molds)
Faults:
27. Nozzle damage, mold out,
3.50-8 air bag:
This air bag is manually. Cut outside end and other end
from inside for joint and solution applied.
Forming (only to 3.50-8):
Due to its shorter diameter this air bag is done
forming
Time: 10 min
Mold is cold, firstly air is applied only for 10 min , after
that cured for 2 hours.
Joint machine:
Steps:
Heater up
Apply air bag
Tight bolts after fixing air bag
Heater down
Join at the end.
Buttons:
1)Jack close, heater down
2)Heater up
3)Jack down
28. 7)Curing:
Air bags are dipped in silicone so that they does not stick
to tyres.
The green tyre is applied on shaping machine
Then air bag is inserted inside it
The tyres are let till the press is opened
The press open and close automatically
Each hydraulic pump operates 6 presses.
Each press has 5 molds
Each operator operates 2 presses
29. Air pressure: 17 bar
Steam pressure: 100 bar
Control panel of press:
Buttons Functions
Green Press open
Red Press close
Upper right Brake
Upper left Auto/ manual
Hydraulic pump:
Pressure: 4MPa/ 100 bar
Voltage: 420V
Power: 11KW
Motor rpm: 970 rev/min
Current: 24.6A
30. Hydraulic pump controls the opening and closing of
presses.
Each hydraulic pump operates 6 presses.
Pipeline:
Steam in line:
Steam is supplied inside the presses in parallel to all the
molds.
Steam out line:
Steam is drained out in parallel out of molds.
Steam trap is attached at the end of returning steam pipe
which after enters the return main line.
Air supply:
Pilot controlled solenoid valves control the air supply in
molds.
Main lines of supply:
i. Steam line for left presses
ii. Steam line for right presses
iii. Central pipe for air supply
iv. Lower two interconnected lines for return of steam.
v. Two black pipes for hydraulic pressure.
31. Limit switches:
Limit switches are attached on the press ends. They
control different functions like when to apply closing
pressure, when to apply high lock pressure, apply shaping
etc.
Total presses:
Total MC presses = 44
Cunrig time:
Size Time
2.25-17 14 min
2.50-17 14 min
2.50-18 16 min
3.00-17 20 min
3.00-18 20 min
Total molds = 44 x 5
Scooter press = 1
32. Production:
Per person: 300 tyres
Presses per person: 2
Molds operated per person: 10
Post curing inflation units (PCI):
Tyres after curing are applied on PCI for proper shaping.
Solenoid valves control the air supply.
4-5 kg/cm2 pressure is applied.
Total 10 tyres can be applied on single PCI.
Press malfunctioning:
Mold out:
Mold adjustment not proper resulting in problems in tyre.
Foreign matter:
Foreign matter in presses if air pressure after every round
is not applied properly.
Electrical fault:
Any programing fault, PLC, shut down etc.
Mechanical fault:
Fault of valves, hydraulic pump, leakage etc.
Less temperature:
Due to variation in steam pressure, presses remained off
for days, atmospheric conditions.
33. Production planning:
Following main factors are kept in mind:
Demand of tyre:
Which tyre is popular in market according to customer
demand.
Closing stock:
What is the closing stock of last month? Tyre present in
stock.
Closing stock= (opening stock last month + production) –
sales
Average sales:
What are the average sales on previous records?
Production target:
After observing all the factors above production target per
month is planned. Some popular sizes are made in
quantity and are specially supervised.
Man power:
How much man power is available in dept.? In green and
curing both.
34. Presses:
Number of ok presses available in dept. to achieve
required target
Molds:
Number of molds available of the specific size and time to
use that mold to achieve target.
Aspect ratio:
A.R = (section height / section width) x 100
Low profile tyres have less aspect ratio.
Section width and height are inversely related to each
other.
8)Quality checking
35. Tyre wobbling:
Factors:
1)Tread thickness variation
2)Tread dye not proper according to specs
3)Tread joint not proper
4)Ply joints applied nearby
5)Ply applied by pulling to adjust short ply
6)Shrink tread applied by pulling
7)Bead out if bead guides not proper.
Standards:
Value Quality Stamp
0 to 0.9 OEM (original Number stamp
equipment
manufacturer)
0 to 1.1 WO ( wobble ok) Double stamp
1 to 1.5 Local Simple stamp
1.5 above Rejection No stamp
Procedure:The tyre is applied on machine. The ‘ring in’
button pressed. The tyre inflates and rotated. The three
gauges are present 1 above and 2 on sides. The reading of
smaller needle is observed. Air pressure and rim width
applied according to size.
Rim width: 35.5 mm/ 40.64mm
Air pressure: 35 psi/40psi
36. FAULTS:
Fault Name Cause
Bead marking Tread width short or greater
Bead crush Variation in bead diameter
Bagging problem
Thin bead Improper bagging
Bead out Bead diameter not correct
Bead not placed in grooves
Bead cut Tyre not placed correctly in
press
Thin side Tread length short
Side wall Extra temp
Vent mark Temp/ pressure
Soft Light tread, ply same angle
Mold out Mold fitting loose
Joint mark Tread length over/ less
Foreign matter External particle
Same angle Same angle plies
Press fault Electrical/mechanical
Under cure Temp/ pressure drop
Electric fault Shutdown or press problem
Press man fault Tyre not placed properly,
Weak air bag
Air bag leak Nozzle leak, ring leak
Jali Pinhole in air bag
Bani (buckle) Air bag weak
37. Ply fault Spreading of cords
Wobble Joint of tread/
Bigger joints of ply/
Ply joints overlapping/
Tread or ply applied by
stretching
