document
TRANSCRIPT
RADIAL TYRE TECHNOLOGY
&
DEVLOPMENT
1845: First Pneumatic tyre by J W Thompson
1888: Pneumatic tyre re-invented by John Boyd Dunlop
1890: High Tenstile Steel wire as beads by Wulch. “Clinder Type” tyre by Barlette
1906: “ Straight: sipe type” ( an improvement over Clincher type)
1913: Gray & Slopper convienced Radial tyre ( U.K.)
1916: Use of high pressure bias tyre in buses (1918 in trucks)
1924: “Balloon type” tyre invented: Problems of high heat generation
1930: Use of “Rayon” as tyre construction material
1947: Use of “Nylon” as tyre construction material
1948: First Radial Passenger tyre by Michelin for OE application using Steel Cord as belt material on a Citroen Car
1955: Tubeless Truck tyreal
1961: First Radial Truck tyre
1967: Limited release of Radial ply tyres in US on Ford Falcon
1973: “Fuel Embargo” stimulated fuel economy concept (Impetus to Radial tyres with lower rolling resistance)
1980: Introduction of Radial Light Truck tyres
RADIAL TYRE TECHNOLOGY AND DEVLOPMENT
HISTORY OF RADIAL TYRES:
The concept of Radial ply tyres can be traced back to a British patent of 1913 granted to M/s. Gray and Sloper. However, this concept remained dormant till M/s. Michclin of France released the first radial tyre in 1948. Ever since radial tyre gained ground in Europe and by late sixties, established its lead over bias tyre.
The American industry which ws geared to produce the bias ply in vast quantities, could not afford to contemplate the extensive retooling needed for the manufacture of radial tyres and went for a compromise construction viz. Bias belted tyres in the late sixties. Bias belted tyres were better than ordinary bias ply tyres upto 90 MPH speed but not as good as the radials in tread wear, rolling resistance, high speed capability etc. The onslaught of European exports of Radial tyres to the American market in the seventies followed by the revolutionary decision of Ford Motors to go on for Radial as OE fitment forced the American Industry to invest in the inventiable – The Radial Tyre. The Radial technique has spread rapidly and is about to conquer the whole world. In the west,
100% of passanger tyre market. 100% of OE light truck. 85% of replacement light truck.100% of OE truck and90% of replacement truck.are now radials.
RADIAL TYRE TECHNOLOGY
Function of a pneumatic Tyre:It is essential to know the basic performance requirements of a pneumatic tyre for a better understanding of the Radial concept. Irrespective of the type of applications these requirements remain the same.
1. Carry the load – The tyre has to carry load when mounted on a rim and inflated to the required pressure. Tyre must form an air container of adequate strength disposed inold the radial direction to air pressure acying radially. This is imparted by the construction of the tryre with reinforcing materials like Polyester body ply/steel belt.
2. Cushioning the ride – The tyre is the first line of defence against comfort. Cushioning is imparted by the air and the ability to the tyre to deform radially.
3. Transport the load - A tyre is required to transmit the engine torque and braking torque effectively to the ground to put the vehicle in motion. Good grip coupled with adequate strength in the circumferential direction underneath the contact area of the tyre are built in for efficient transporting by proper design, construction.
4. Develop cornering force - This is a unique ability of a pneumatic tyre to develop adequate cornering force to counter the centrifugal force and retain the vehicle on the road while negotiating curves, overtaking etc. This requires excellent grip and ability to undergo lateral defomation which is imparted by the Radial Direction of the body ply and flexible sidewall countour.
5. Economic performance – In this competitive world, this may be prime performance criteria. Every revolution of a tyre leads to periodic strains radially, circumferentially and laterally and this necessitates adequate flex fatigue life and wear resistance for an economic service life.
TYPES OF TYRE CONSTRUCTION: Bias construction
The above requirements were built into the early pneumatic tyres through the so called ‘Bias construction’. A bias tyre has a casing which is made of approximately 40. The number of such crossed layers called plies is having the function of load carrying capacity and related to inflation pressure and can go upto 40 plies in earthmover tyres. A bias construction is continous in its carcass structure from bead to bead.
Radial construction :
Better understanding of the requirements of a pneumatic tyre lead to the development of radial tyres. A radial tyre consists of casing reinforcement layers of fabric cords running from bead to bead at 90 designed to hold the air pressure and stabilising belt-reinforcement layers of high modulus fabric cords running circumferentially around the casing at an angle of 18 to 24 beneath the tread designed to transmit driving, breaking and cornering torques. The functions of the tread and the sidewalls are separated to a degree that the major shortcomings of the bias and bias belted tire concepts are eliminated.
Bias belted construction :
The construction has a bias casing and a circumferential belt beneath the tread.
Tyre components Bias Passanger Tyre Radial Pass Tyre
Bias Plies Radial PliesBreaker BeltBead BeadTread TreadSidewall SidewallChafer ChaferFiller Filler Shoulder Pad Rim Strip
ADVANTAGE OF RADIAL TYRES OVER BIAS TYRES
1. Efficient Engineering Design :
Radial construction is an efficient engineering design whereas bias construction is a compromise one. Radial concept permits the conversation of various precious materials that go into a tyre. In a radial tyre tread and sidewalls work independently where as in bias they work in sympathy.
2. 70 to 100 % increase in mileage :
Radial tyre can almost give 70-100% increase in mileage at no extra weight of the tyre over equivalent bias tyre under similar distortions when subjected to traction/breaking torque at contact patch. While this circumferential stress causes the tread to get pinched at its mid length point the sidewall deflection causes and laternal distortions of the contact patch force the tread elements to move and scuff violently over the road surface- termed as tread peristalsis. With inevitable abrasion taking place.
The lateral stiffness and longitudinal stretch resistance of the belt/treated assembly in a radial tyre coupled with the independent pliability of the sidewall to accommodate the entire sidewall deflection ensure full tread width throughout the conact patch with no shuffling/scuffling of the tread.
MILEAGE COMPARISON- BIAS V/S RADIAL
Bias tyre Radial tyreMileage (kms) 40016 83485No. of tyres 16 17Makes 4 Brands 2 Brands.
3. Overall fuel efficiency up by 5 to 7% for car tyres and upto 10% Truck Tyres.
Rolling resistance of radial tyre is less by 15 to 20% over equivalent bias tyre resulting in an overall fuel efficienency of 5 to 7%. A tyre while running consumes energy measured in terms of rolling resistance as a result of its internal frictions and convert it to heat. Internal friction is greater in bias tyre owing to its pantographic movement of the crossed carcass cords both at sidewall and at tread area, a motion that causes shear in the rubber compound and in the cords of the casing. External friction caused by the violent tread scuffing over the road surface – tread peristalsis is characteristic of a bias tyre and consumes considerable energy.
On the other hand the parallel cords of the body plies of a radial tyre flex together with very little shear and hence resistance to deflection. Also the stiff and andependent belt do not allow any tread peristalsis and drag saving precious energy. As a result radial tyre runs considerably cooler and this is more pronounced at higher speeds.
4. Excellent traction and breaking on both dry and wet roads.
Radial tyres offer excellent transmission of traction and breaking force to the ground due to:
i. No destabilization of contact patch.ii. Greater area of contact and hence more rubber on road.
iii. More uniform pressure distribution over the contact area because of the supple sidewall.
iv. Stiff belts supporting the tread ensure efficient transmission of torque.
v. In addition to these, the uninterrupted drainage channels at contact patch ensure excellent wet traction.
5. Safe high speed cornering :
Radial tyres develop high cornering force at reduced slip angles as its supple and relatively independent sidewall as capable of high lateral deformation without destabilizing the contact patch. The carcass of a bias ply tyre is a continous rigid structure and hence lateral deformation on a bias sidewall distorts the tread at contact patch in sympathy causing lifting of the outer edge of the tread and destabilization of the vehicle.
6. Improved riding comfort especially at high speed :
The supple and independently flexible radial sidewall enable the tread to trace the road and thus smoothen out road shocks improving ride comfort. Bias tyres with its stiff and relatively inflexible sidewall faithfully transmits road shocks especially at high speeds making ride uncomfortable.
7. Excellent high speed capability :
Radial tyres can easily sustain high speed, were as a high speed rated bias tyre can seldom sustain speeds over 100 MPH. This is because a radial tyre generates less heat and internal shear and accumulate less heat due to its relatively thinner casing and shoulder rubber.
8. Improved endurance life and retreadability :
Due to reduction in internal friction and relatively thin carcass and tread the radial tyre runs cooler, which enhance endurance life. Further, the radial dispositioning of the carcass cords susbstantially lower the compressive flexing in them, improving cord life. Radial tyre thus can give not only double initial tread life but also good retreadability.
9. Radial tyre runs quieter :
Radial tyre creates and transmits less noise of the road- roar variety because of the low dynamic rigidity of the casing and high rigidity of belt. They include tread pattern noise, tyre squeal, noise caused by thebeating of roughness of the road surface on the tyre and windage noise. Adoption of radial ply tyre enable the manufactures of cars to dispense with several pounds of sound dampening materials.
10.Excellent impact break resistance :
The supple sidewall with its nil response lag shock forces of impact without causing damage to the tyre.
RADIAL MANUFACTURING PROCESS FLOW CHART
Elimination of tread peristalsis in radial tyres alongwith its stiff belt barrier prevent penetration of external objects and greately reduced incidence of punctures. The thick inner liner rubber regulate loss of air after a puncture giving sufficient warning time.
Substantially reduced vehicle maintenance :
The supple sidewall cases out road shocks and vibration to the suspension and other vehicle parts much more efficiently than bias tyres. This results in reduced wear and tear on suspension and consequently low breakdowns. It is observes that leaf spring breakage almost disappear, bushes life doubles and shock absorbed last long with Radial tyres.
Substantial reduction in vehicle weight :
Excellent cush joining and vibration dampening enabled vehicle manufactures to reduce weight of suspensions and substantially reduced weights added for vibration dampening.
Radial tyres thus made motoring very safe :
Excellent traction braking, both on dry and wet roads, high speed capability, excellent cornering, very good impact resistabce and puncture resistance, improved riding comfort and handling, improved endurance made motoring very very safe.
The radial concept permits the conservation of precious materials and is one of the most efficient answers to the energy challenge. It made high speed monitoring very safe. In return, it requires more sophisticated and expensive tooling, more precise methods and more rigorous quality control at all stages of production and use.
MANUFACTURING PROCESS DETAILS
MANUFACTURING PROCESS
RAW MATERIAL
A. INTRODUCTION :
Pneumatic tyres contain a variety of rubber compositions, each of them designed to contribute to overall performance. Rubber compounds designed for a specific function will usually be similar but not identical in composition and properties. In some cases, there can be significant differences between compounds in tyre of various types. Tyre performance is the result of skill and experience in producing a mechanically harmonious structure of rubber compounds, fabric, beads & other components which work together to give optimum service.
B.COMPOUND INGREDIENTS :
There are a variety of indegrients from which the rubber compounder can choose to modify the physical and chemical properties of rubber. Unfortunately, however, any particular additive chosen may have a beneficial effect on one property but a detrimental effect on the other.
Indegrients in tyre compounds can be classified as (1) the rubber which may be a single rubber or a blend of rubber such as natural rubber (SBR – 1502 & 1712, PBR etc.) (2) other ingredients are below:
Ingredient category Ingrident FunctionsReinforcing agent Carbon black, silica To improve strength,
hardness, tear, wear, flex properties etc.
Activators Zinc oxide stearic acid To improve the efficiency of accelerators without/less amount will create very
slow/longer curing time.
Process aids Peptizer Tackifying resin Retarder
To improve proceddability such as dimensional stability, green tack, less scorch etc.
Process oils Aromatic,Naphthanic & Paraffinic also.
help to incorporate reinforcing agents & maintain optimum physical properties.
Anti degradents 6PPD, DPPD, TMQ, Wax, etc.
Prptect from weather(oxygen, sunlight, ozone etc.)
Specisal additives bonding agent corrosion inhibitor etc.
to improve bonding with fabrics & wire, protection from corrosion of steel wire.
Fillers china clay, rubber crumb
Non active and generally added to reduce compound cost.
Accelerators MOR, TBBS, DCBS, MBT, TMTD, TMTM etc.
to increase the rate of curing and for specific vulcanizate properties.
Vulcanizing agent sulphur to make elastic, tough. Dimensionally stable without sulphur, it becomes hard in cold & soft in higher temperature.
C. STORAGE & HANDLING :
a) All the raw materials other than fabric are stored in cage pallet after properly identifying with tags in earmarked areas in the Raw Material Stores. They are transported with forklifts.
b) The greige fabric is unloaded from the truck with the help of forklift and stored in storage racks.
D. RAW MATERIALS INSPECTION :
Every lot of rubber, fabric, wire, oils, pigments & other chemicals received needs some form of inspection for its quality level & degree of uniformity before it is prepared for use in tyres. The inspection may be visual or it may include physical and chemical tests.
MIXINGA.INTRODUCTION :
Rubbers go through a number of processing steps in their transformation from raw rubber to finished products. The first of these is mixing, which involves the incorporation and distribution of various compounding ingredients to the rubber. This is done with predetermined amounts, usually in a high shear Banbury mixer which is in combination with a two roll mill and batch off system. The mixture of rubber & the ingredients is commonly known as compound.
Depending upon the use, the major compounds of radial tyres are:I. Inner liner.
II. Body ply skim/squeegees.III. Cap ply skim.IV. Belt skim/Belt edge filler/Belt edge wrap.V. Bead insulation.
VI. Bead filler.VII. Rim strip.
VIII. Wing tip.IX. Shoulder pad.X. Tread cushion.
XI. Sidewall.XII. Tread cap.
XIII. Tread base.
COMMON MIXING METHODS :
1. Master batch : The rubber, some chemicals (excluding vulcanizing agent & accelerators) oil & carbon black are added to the mixing. Chamber according to normal sequence & mixed until thoroughly dispersed. That batch is dumped & allowed to cool. It is called master batch or non productive stock.
2. Final mixing : A portion of the master batch is loaded into mixer alongwith curing ingredients such as vulcanizing agent and
accelators which make up the finished batch. Batch is discharged after getting the desired dispersion/ temperature. This is called productive stock/final batch.
3. Re mill mixing : sometimes one intermediate stage or remill stage is given for some compounds to improve dispersion of compounding ingredients & reduce the viscosity of master batch before mixing final compound. This is called as ‘Repass batch’.
B. EQUIPMENTS DETAILS :
1. Auto stock loader :
which is a device for loading the compound sheet mechanically.
2. Weighing conveyor :
It is a conveyor with a scale in between auto stock loader & banbury feed conveyors to weigh compound sheets/rubber bales.
3. Loading conveyor : It is semi – automatic feeding system to feed weighted compound/rubber/pigments.
4. Auto oil charging system :
The process oil from the day tanks automatically weighed and collected in the hold charge tank and upon call, transferred through injection pumps into the mixer.
5. Auto carbon charging system.
It is pneumatic conveying & handling system for carbon blacks based on low viseosity dense phase with timed line air injector. The carbon black bags are silted automatically and the black is conveyed & stored in bulk storage silos then black is transferred to day bins as required. The carbon black is fed from the day bins containing desired carbon black into a surge hopper. The surge hopper is equipped with both a full feed compartment. The weighed carbon is transferred to a lower hopper and into the mixer.
6. F-270 Banbury :
It is an internal mixer and the mixing is taking place inside a closed chamber. It consists of two horizontal rotors with 4 protrusions known as ‘wings’. There is an opening at the top for feeding rubber and ingridents & at the bottom for discharge.
It is fitted with a pneumatically operated ram to ensure that rubber and powder are in contact. Rotor design is such that the material being mixed in constantly displaced like cross blending done in an open mill. The chamber sides, rotors & drop door are cooled to maintain highest level of shear during the mixing process.
7. Dump mill :
Mixed compound from banbury is dumped to the two roll mill.
8. Sheeting mill :
Compound from dump mill is transferred to sheeting mill through inter mill conveyor. This mill is provided with notched knife assembly to make indentation of desired width for use in cold feed extruded as strips.
9. Batch off unit :
The batch off unit consist of the following:
a. Take off conveyor section which includes the driven taken off conveyor belt. It is designed to reciece the rubber slab/sheets coming from the batch off mill & to convey it to the dip tank.
The take off conveyor is provided with an impression type printer to imprint figures on rubber sheet.
b. Dip tank for cooling & for applying anti tack medium such a soap on rubber sheet.
c. Cooling festoon rack, provided with a chain conveyor, fized suspension bar and number of cooling ventilation. Main functions are :1) To cool the compound.2) To dry the dip slurry.
d. Wig – wag stacking unit for discharging the rubber as an endless strip.
e. Packer/Stracker :The sheet are uniformly laid and packed on storage skid.
C. STORAGE & HANDLING
The compound ‘Master/Repass/Final batches are stored in skids and transported to earmarked area by pallet trucks/jacks. The final batch compounds are identified with colour crayon strips for ‘FIFO’ system at the user section and with an identification tag. These batches can be used for further processing only after its release by laboratory after their testing.
D. SEQUENCE OF OPERATIONS
a. CHEMICAL COMPOUNDING
SI.no Step Pupose Remarks1. check the
weighing balance for no zero error and cross check with standard weight
To get weightment as per spec.
Inferior compound as well as tyres. More rework on compound or may be scrapped due to scorch compound.
2. Display specs card for weighment
-DO- -DO-
3. weigh each chemical cal as per the spec. card in the serial order as given in the spec card.
To get weightment as per specs and avoid wrong weightment.
-DO-
4. keep the weighed chemical bags on pre identified chemical trolley.
Correct chemicals usage in respective comound,
Inferior compound as well as poor performance of tyres.
b. MIXING
SI.no Step Purpose Remark1. Display mixing
specicfiations card & follow specs.
Mixing is to be done as per specifications.
Off specs. Batches.
2. clean dump mill & sheeting mill.
To avoid compound mix up and foreign
Off specs batches & compound may be scrapped/downgraded.
matter contamination
3. check TCU temp.
Uniform compound mixing. No scattering on mill, compound stuck on drop door.
Poor dispersion of ingredients.
4. select the correct recipe from the computer & mix the batches in remote mode.
To avoid man to man variations and consinstency in batches.
under/over mixing in batches.
5. Do two skid blending during repass & final.
Minimise batch to batch variation.
Off specs batches, more variations in process & inferior product performance.
6. Check the polymer weighing balancing for no zero error & cross check with standard weight.
To ensure correct weighment as per specs.
Off specs batches, compound may be scrapped/downgraded.
7. Apply wheel code marking for all compound.
Identifaction of batches
Change of wrong compound usage.
8. Counter check actual dump temperature from recorder & verify with set temperature.
To check abnormality in mixing.
Under/over mixing of batches.
9. Check compound sheet
Cool down the sheets and easy
-Uneven temperature rise during next
gauge, width & loop lenth as per specs.
loading through banbury hopper door.
mixing.-compound become scorch.-more loading time.
10. Send first batch sample to Lab
To check material added as per specifications.
-more off specs. Batches & compound may be scrapped/downgraded.
11. Give cut on dump mill & use of blender bar at sheeting mill
Uniformity in compound.
Poor dispersion of ingridents &inferior product performance.
12. Regulate sheeting mill speed.
To get continous rubber sheet & uniform loop length.
Improper cooling & lay down on skid.
13. Laydown the compound in auto mode.
Better cooling of compound.
High laydown temperature.
14. Put identifaction tag and sampling from the middle of the batches.
Identifaction of batches
Chance of wrong compound usage.
E. DO’s & DON’Ts IN MIXING
DO’s Communicate to miliman as well as laydown man about
compound change. Stack maximum 4 batches on a skid. Keep the compound skids at its earmarked area. Use disposed compounds as per technical disposition. Identify left over path skid with crayon marking & tags. Consume part skids during next mixing.
Calibration checks for weighing scale of chemicals, rubber, carbon & oil.
Do not use any non-conforming raw material/compound. Do not load batch if ‘stop’ signal received from millman. Do not allow compound sheets to touch the ground. Do not compound from memory. Do not dilute soap solution in the dip tank with water.
4- ROLL CALANDER
A. INTRODUCTION :
The calander machine is the most important machine for the tyre industry. Generally, a calander is described to have ‘two’ or more rolls revolcing in opposite direction so that a mass of masticated or plastic rubber compound fed between them will be squeezed out in sheet form. Calanders are used in rubber industry primarly to produce-a) Rubber compound sheets of various thickness.
b) Coating textiles or other supporting material with thin rubber film.
c) Fractioning of chafer fabrics with rubber compounds.
B. DETAILS OF EQUIPMENT :
1. 4-roll calander : Size/type : Drilled rolls of 72X28” (LXD) inclined Z-calander Manufacturer : Farrel,USA. Roll speed max. : 26.8 rpm. Roll crown : 1st & 4th 0.007” dia. 2nd & 3rd straight. Heating/cooling : water (TCU) Medium.Roll adjustment : motorized for nip adjustment with roll bending.
During the calandering process, rolling bank is formed in the roll nip of 1 & 2 and in between 3 & 4. The rubber compound is heavily compressed when being conveyed through the roll gap.
2. Accessories of 4-roll calendar train. Dual let off. Hydraulically operated splice press. Accumulator feed roll stand. 120 meter accumulator. Drying drums. Tension stand. First dancer. Second dancer. Fabric cooling drums. Pick breaker.
Bleeder cord creel. Printer. 60 meter wind up accumulator. Wind up feed roll stand with nip roll. Dual wind up with nip roll. Dual wind ups with liner let off.
C. STORAGE & HANDLING :
a) Dipped fabric is unloaded from storage rack by hoist/forklift.b) Compound issued in skid are brought by pallet trucks/forklifts.c) Cakendered fabric is unloaded from wind up to store in storage
racks using hoist.
D. SEQUENCE OF OPERATIONS .
SI.no. Step Purpose Remarks1. Set TCU
temperature for 4-rolls as per specs.
To get proper coating
cols calendaring, scorch compound, generation of fabric scrap, non uniform gauge.
2. Set drying can temperature.
To remove moisture from cord and proper coating.
determination of cord properties. Tyre may be scrapped and tyre may fail in service.
3. Set splice temperature as per specs.
to get good splicing between the roll.
splice may get open during calendaring as well as fabric scrap generation.
4. Cooling can water circulation temp/pressure.
cool down the fabric to room temperature.
deterioration of tack and chance of air entrapment in building.
5. Operation of centre guides/web master edge expander in auto mode.
Ro get correct cord distribution & improper fabric width.
cutter jamming at bias cutter & scrap generation. Poor product performance.
6. Display specifications & follow set up specifications.
calendering is to be done as per specs.
off material generation.
7. Two skid blending.
Compound Uniformity
variation of compound properties & poor performance of product.
8. Break down & warm up of compound.
maintain compound plasticity to get smooth calendring
cold calendring/gauge variation.
9. Use blender bar. Compound Uniformity
variation of compound properties & poor performance of product.
10. Set pre & post calendar tension as per specs.
proper coating 7 cord distribution.
loose coating and fabric scrap generation.
11. Use blister breaker
No air entrapment & proper cord distribution.
“
12. Use perforator. Help to remove air from in between plies.
ply blow & tyre may be scrapped
13. Use bleeder yarn as per specs.
identification & remove air from in between plies.
no traceability & ply blow defects in cured tyre.
14. set proper code marking.
identification & proper material
no traceability & improper material
usage usage15. set calendar fabric
gauge, check and record in control chart.
to maintain uniform gauge
Lower gauge: less compound between ply layer results lower adhension & premature failure of tyre.Higher gauge: material loss & premature failure due to excess amount of rubber in the components & subsequent poor heat dissipation.
16. Check balance of coating.
balanced coating, cord embedded properly in rubber.
adhesion failure due to low film gauge cord chafing & heat generation in service.
E. DO’s & DON’Ts FOR 4-ROLL CALANDER.
DO’s Use only lab okayed / disposed dip rolls & compounds. Ensure cleaning of mill area, calander roll area & free from
fpreign matter. Follow FIFO for dip rolls & compounds. Identify defective portion of calander wind up. When unit stop exceeding 10 min, sheet out stock from mills &
calander nip. On restarting, start with fresh stock only. Initiate gauge chanfe with code change just when splice enters
the cakander or next fabric code is started. Keep left over compounds / sheeted out compound with proper
identification. Follow stock change procedure.
Use’pick breaker’ only on radial fabric.
DON’Ts Do not use dip roll with open/torn packing without technology
disposition. Do not expose opened dip rolls for more than one hour. Do not over lad compounds in mill & calander nips. Do not use overadge dipped roll & compounds without
techonolgy disposition. Don’t turn calander without metal detector. Don’t use ‘pricker’ roll for chafer & bfreaker fabric.
DUPLEX HEAD EXTRUDER
1. INTRODUCTION
Extrusion is the Process of Forcing the Rubber Material through a Die to get a definite continous shape. The machine used for purpose is known as Extruder. The Rubber Components is a Passanger Car/LCV/Radial Tyres need to Processed with Leaser heat and to have Homogenity, cold feed Extruders are Preferred. The Extryder in our Plant is
“200 X 150 DUPLEX HEAD COLD FEED EXTRUDER”
The Duplex Head Cold Feed Extruder is for the Co-Extrusion of two Compounds.The Profiles that are Extruded in the above Extruder are
A) Tread for Passanger Car Radial/ LCV – Tread Cap Wing TipB) Sidewall for Passanger Car Radial/ LCV/ Truck – Sidewall Rim
StripC) Filler for LCV/Truck RadialD) Shoulder Pad for Truck Radial E) Chafer Pad for Truck Radial
2. DETAILS OF EQUIPMENT
A. DUPLEX HEAD EXTRUDER – MAKE KRUPP(GERMANY)
1) Screw Diameter - 200 mm (FOR CAP)/150 mm (FOR BASE)
2) Type - Cold Feed3) Barrel - Pin Type ( 64 – Pin & 108 – Pin for 150
With Deeding Device & Metal Detector4) Cushion Calander Size – 16” X 42” (Roll Dia. X Roll Width)5) Cushion Calender Feed –Through 90mm Cold Feed Extruder6) Cooling Line Length - 90 Meters (Approx.)7) Cooling Type - Water Spray Cooling8) Operating Line Speed - 3 Mpm to 30 Mpm
Output of 200mm Extruder - 3200 Kgs/HrOutput of 150mm Extruder - 1800 Kgs/HrNo.of TUC’s -9-no’s Total (1-Barrel Inlet, 2- Barrel/1-Screw Each & 1-Head)
B. THE EXTRUDER LINE :
o Take Off & Shrinkage Conveyoro Exhaust System Over The Conveyor
Code Marker Mounted Over The Shrinkage Conveyor Conveyor To And From Cushion Calander
Cushion Calander With Drive Conveyor To And From Continous Weighing Scale Continous Weighing Scale Conveyor Before Cooling Line Strip Market Mounted Over Above Conveyor Inclined Conveyor Color Drying System (Electric Heater System) Cooling Line-4 No’s Decline Conveyor Skiver Water Blow Off Separating Conveyor Drying Fan & Set Of Blower Nozzle Roller Conveyor Check weigher Out of Tolerance Marker End Cementer Exhauster System For End Cementer Fire Extinguisher Booking Conveyor Safety Rope Dual Cassette Wind Up System
3. STORAGE AND HANDLING OF COMPONENTS
COMPONENTS STORED IN TRANSPORTED BY
compound with perforation
skids lifted & pulled by pallet trucks.
tread leaf truck pulled by two truckssidewall cassettes on wheels
with 1050mm diameter.
pulled by two trucks
I.T filler/shoulder leaf truck pulled by two trucks
pad/chafer pad.
4. SEQUENCE OF OPERATION
STEP PURPOSE REMARK1. Set barrel/screw/head
TCU Temp as per spec. for both extruders.
for uniform profile & to avoid cold extrusion
cold extrusion will lead to poor tread adhesion & hence processing problem.
2. Set cushion calendar TCU as per the spec.
for avoiding cold cushion & uniform gauge.
the temperature increase shat the all be as per the PLC setting to avoid damage to calendar.
3. Set barrel/screw/head TCU Temp as per spec. for both cushion calendar extruder.
for uniform feeding & to avoid cold extrusion
cold cushion will lead to poor tack & hence processing problem in building.
4. Take out required perform/insert/die cassette from pre-heating chamber & fix on to the head.
pre-heating will give uniform profiles immediately. Cleaning will ensure die cut/fm etc.
this will give good consolidation of dual compound profiles at the junction like cap-wing tip in tead & SW-rim strip in sidewall.
5. Clean and cushion calendar.
for avoiding contamination & compound mix up.
-DO-
6. Open water spray in cooling
for effective cooling of trade & sidewall.
poor water quality will lead to poor adhesion of tread belt adhesion and future failure in field.
7. Clean code printer/stripe market unit & fix the require letters/colour print.
for uniform stripe mark & identification.
for avoiding wrong tread usage & wrong moulding in curing.
8. Check the continous to ensure uniform zero error can be
weighing scale accuracy with standard weight at four corners/centre and record in control chart.
measurement of weight. detected & corrected immediately.
9. Clean the sticher disc.
to avoid air under cushion & wrinkled cushion application.
this will reduce cured tyre defects & failures in field.
10.Clean leaf trucks and keep atleast 3-no’s ready before the extrusion start up.
to avoid contamination & undue delay in production.
this will improve adhesion & hence tyre service.
11. Bring the lab OK compounds as per the tech.spec & feed through the metal detectors
to ensure right compound usage
wrong compound usage leads to service failures & less mileage.
12. Select the recipe on the PLC as per the schedule
for correct item extrusion.
-
13. Set the cushion calendar nip as per the spec & measure the gauge and record in control charet.
for ensuring right gauge low gauges will affect tyre performance & higher gauges will lead to excess compound usage.
14. Measure the dimension of the extrudate before cooling & record in control chart.
for ensuring the dimensions as per the spec.
component consistency will improve the tire uniformity, quality and reduce tyre defects.
15. Measure all booking dimension like overall width, hump, width, tread length, cushion width etc. & record in control chart.
-DO- control chart recording will help in process improvement & hence productivity.
5. DO’s
1) Use Compounds having OK Lab Approval & Record in Compound Usage Register
2) Use Only Clean Leaf Trucks for Booking3) Identify the Left Ovcr Comopund with the Tag/Crayon.4) Identify the Rejected Treas & Sidewalls With the Tag & Stack
Seprately on Skid and Record the Rejection Details in the Register
5) Follow the Compound Disposition Procedures.6) Clean the Die & Cassette Assembly immediately after the
Extrusion.7) Ensure the correct Width & Cushion Centering in Treads.8) Ensure Proper Code/Line Printing on Tread9) Check for any Wing Tip/Tread Sepration-If any Stop the
Extrusion, Clean the Die & Start Again.10Ensure Proper Chilled Water Temp. & Pressure11 ) Ensure Correct Skiving Before Booking12 ) Book The ‘OK treads Straight On the Leaf Trucks With Out
Touching Each Other13 ) Identify the Leaf Truck With Right Tag & Enter the Details
On the Register14 ) Ensure Uniform Cement Application
6. DON’Ts
1) Don’t use the Compounds with out Identification & Lab Approval.
2) Don’t Mix Two Different Compound During Size Change3) Don’t Book Tread & SW Which are Out Of spce.4) Don’t Book Tread With Cushion Side Facing Down.5) Don’t Book Treads Of Different. Code in the Same Leaf Truck6) Don’t Keep the Die & Perform Outside Oven7) Don’t Allow the Treads to Touch Each Other While Booking.8) Don’t Book Treads Without Line/Code Mark Identification.
9) Don’t Store Different Rejected Tread & Sidewall in the Same Skid.
Don’t Book Treads without End CementDon’t Let the Compound of Component to Fall On the Floor
5. ROLL CALANDER
A. INTRODUCTION :
As the name indicates the equipments consists of three rolls place vertically one above the other the requirements of a calender is described to be “two or more” rolls rotating in opposite directions so that a mass of masticated or plastic rubber compound fed between them will be squeezed into sheet form by the rolling action of definite thickness and width. Three roll calander will have drive for the middle roll and the top & bottom rolls are driven through gears either to have even speed or friction speed between the rolls as required. This calander is squeegee/chafer)
B. DETALIS OF EQUIPMENT :
1. 3 ROLL CALANDER
General specification :
Calander roll dimension 20” dia X 48” face width (508mm X 1219.2mm)Surface speed min 3 mpm; max. 30 mpmFriction ratio between rolls 1:1:1 even speedOperating Nip range 0.2mm min; 3.0mm max.
Nip adjustment range 0.2 mm min; 2.0mm max.Working width 20 mm min; 750mm max.Rate of adj. for nip Fast: 3mm/min.
Roll ends nip can be adjusted either individually or together. This mechanism ensures correct and uniform squeegee gauges. Squeegee width can be adjusted manually or through motor.
2. : CALANDER FEED EXTRUDERS
Two number of cold feed extruders are provided for compound feeding into the calendar nip.
90mm extruder for split squeegee ( top nip ) 120 mm extruder for wide squeegee ( bottom nip )
3. CALANDER LINE :
3.1 COOLING DRUMS :
Six numbers two tries cooling drums (hard chrome plated) of diameter 500mm and width.800 mm are placed with mono flow rotary joint for effective cooling of the squeegee.
3.2 DUAL LET OFF CHAFER ASSEMBLY CONVEYOR:
Dual let off chafer assembly is mounted over 800 mm width conveyor with compete centering devices for positioning chafer (cross woven fabric ) with respect to drum squeegee split squeegee assembly.
3.3 DUAL CASSETTE WIND UP:
It has dual wind up station for cassette winding of the assembly. It is provided with three position photo eyes to control the speed of wind up and maintain a loop. An edge guiding system is provided for positioning the assembly centrally into the liner the cassette diameter is 1050 mm.
3.4 TRANSFER CONVEYORS:
This conveyor is in two parts to facilitate transfer of material from one cassette to the other automatically. The second conveyor will have movements to receive material from first transfer conveyor & drop it to second wind up. Conveyor width is 800 mm.
C.STORAGE & HANDLING OF COMPONENTS
COMPONENTS STORED IN TRANSPORTED BYCompound strips. Skids Pulled by two trucksChafer strips. 7”/9” polypropylene
liners stored in mobile pin trolleys.
Pulled by two trucks/ manual
Drum squeegee assembly
Cassettes on wheels with 1050mm diameter.
Pulled by two trucks
D. SEQUENZE OF SET UP OPERATION :
SI.no Step Purpose Remark1. Set TCU
temperatures for 120 mm & 90 mm CFE
for uniform flow of rubber to the head and for
to avoid high extrudate temperature,
as per spec. continous feeding to the calendar with required temperature.
scorching and non uniform calendered gauge.
2. Set TCU temperature for calendered rolls.
to get proper film gauge and width.
to avoid cold calendaring, scorch compd, non uniform gauge and blister from rubber film.
3. Check cooling drums water circulation temperature/pressure.
to cool down the squeegee to room temperature.
to avoid deterioration of tacj and blooming.
4. Displaay specification and follow set up specification.
calendaring to be done as required by spec.
incorrect and non uniformity gauge lead to anomalies like frequent tube puncture, poor balance/uniformity and high rolling resistance.
5. check, measure centered placement of split squeegee and chafer placement with correct overlap.
to have consistency in the placement of components in a tyre.
to avoid anomalies like poor balancing and uniformity yield. Field performance will also be consistent.
6. a) Check & record TCU temperature of calendar and cold feed extruder.
b) Check & record squeegee gauge,
To ensure uniform surface temperature and refer/analyse for trouble shooting.to ensure constituent
to get the trend and take preventive steps.
to get the trend and take
width, chafer width and overall assembly width, chafer overlap.
component and refer/analyse for trouble shootings.
preventive steps.
7. check for component centered winding into the cassette.
To ensure proper centering of component on the tyre building drum.
to get better uniformity balance and to avoid green waste and cured tyre anomalies.
8. Put proper identification tag.
identification of components.
to avoid wrong material usage.
E. DO’s AND DON’T’Ts FOR 3-ROLL CALANDER :
DO’S :
Use only lab ‘okayed’ compounded strips for cold feed extruders.
Cleaning of extruder area, calendar roll/line area, including left over compounds from previous run.
Follow first in first out for the compound strips. Identify each cassette with proper tag with a duplicate tag on
FIFO board. Keep the fillied cassette in the respective identified area. For unit stoppage of more than 20 minutes, remove the
compound from the calendar nip. identified the removed stock.
For extruder unit stoppage of more than 20 minutes, push out to be taken.
Identify the push out stock. Close/adjust the nip gauge with the compound in the
calendar nip.
DON’Ts
Do not run the extruder idle. Do not load the calander nip with excess compound. Do not suddenly heat or cool the calander rolls. Do not put the calander strip /stock and extruder push out
on the floor. Do not contaminate the calendar stock; liners & compound
with dirt; grease; oil; paint; water etc. Do not book squeegee with lumps and foreign matter. Do not run calendar at higher speed under no load
condition.
HIGH TABLE BIAS CUTTER
1) INTRODUCTION :
High Table Bias cutter is used for cutting plies of required smaller widths/angle from a Calandered Roll of continous length. The cut ply is wound on the cassette wind-up system after manual splicing.
2) DETAILS OF THE EQUIPMENT :
The high table bias cutter consists of the following.
1) Let-off units & festoon.2) Main conveyor table with cutter.3) Splicing table and chute assembly4) Wind up unit5) Control panel.
OTHER DETAILS OF THE EQUIPMENT :
Manufacturer : Devon Machines-MadrasMax. width of the calandered fabric : 1676 mm.Cutting angle Range(degrees) : 45-90Ply width range : 200-1400 mmAccuracy of cut :+1.5 mm at 1000mm cut width.No. of cuts :20-cuts per min. for 590 mm width. :9- cuts per min. for 2000 mm width.Table width : 1712 mmSurface Speed of the conveyor :64 mpm at 1000rpm of motor
3)STORAGE & HANDLING OF COMPONENTS
COMPONENTS STORED IN TRANSPORTED BYcalenderd fabric storage racks with
support on edges(at bias plant)
trolley pulled by tow worker
empty liners of calendered roll
A-frame trolley pulled by tow worker back to bias plant.
cut piles cassettes of dia.1050 pulled by tow truck or
mm hand
4)SEQUENCE OF OPRATION
SI.No Steps Purpose Remarks1. clean the
splicing table and conveyers before start up
to ensure no foreign matter contamination in the liners and fabric.
improved track retention and reduced ply separation in service.
2. load the fabric as per the spec.
to ensure production of right component.
avoids ply scrap & production delays
3. set the correct ply width & angle.
to avoid production of components with wrong dimensions.
less scrap & improved productivity
4. keep the wind up cassette ready
-do- for improved productivity
5. ensure the width consistency & record in control chart.
for consistency width of ply
improved uniformity
6. splice the cut ply as per the specification
improved uniformity
reduced scrap
7. observe for any anomalies during cutting, splicing and wind-up.
avoids difficulties in further processing.
reduced scrap
5) DO’s
1) Clean the conveyor and splice table before start up
2) Use only lab approved fabric on FIFO basis.3) Record the fabric used with production details in procedd
check register.4) Set the width and angle as per spec.5) Record the ply width measurement in SPC chart6) Splice the cut ply as per the spec.(3-cords max.)7) Identify the cut ply cassettes with Tag.8) If any problem in machine or material is noted immediately
report to the shift charge. Shift in charge has to personally see the problem before it is reported to the engineering or technology.
9) Defective material is to be immediately removed from the machine, hold it with a kold and technical is to be obtained for the same.
6) DON’T’s
1) Don’t use fabric without lab approval.2) Don’t start operation without cleaning the conveyor and
splice table.3) Don’t cut the calendered fabric with visual defects
lumps/cured bits/bare coats/loose coat.
BEAD APEXING
A.INTRODUCTION
Bead apexing machine consists of 2-1/2” cold feed extruder and filler assembly unit. The 2-1/2” cold feed extruder is used for preparing predermined profile of filler which in turn will be assembled with bead in the assembling unit. The fillering extrusion and assembly of filler with bead is called BEAD APEXING.
B. DETAILS OF EQUIPMENT :
a) 2-1/2” cold feed extruder Make : FAMM-INDIAScrew diameter : 60 mmNO OF TCU : 5 ZonesMax. screw speed : 60 RPMMax. line speed : 2-20 mpmMax. strip width required : 390 mm
b) Bead-filler assembly unit
C.STORAGE AND HANDLING OF COMPONENTS
COMPONENTS STORED IN TRANSPORTED BYFiller compound strips
Storage Bins Pulled by Two Trucks
Wound beads pinge tyre storage rings
pulled by two trucks/manually
Fillered Beads bead storage rings moved in pin type trolley
D. SEQUENCE OF OPERATION :
Sr.No Steps Purpose Remarks
1. Clean the conveyor & bead fillering assembly unit.
To avoid FM contamination
-
2. Clean the filler die before start-up.
For uniform flow of rubber & to get uniform filler profile.
Lesser waste & quick start-up.
3. Set TCU for cold feed extruders as per spec.
For uniform flow of rubber into head & consistent dimension.
To avoid high extrudate temperature scorching and waste generation.
4. Set the screw RPM & line speed as per spec.
To ensure uniform profile.
Higher line speed and RPM leads to compound scorch and less tack in filler.
5. Clean the fillered bead storage ring before start up.
To avoid FM/dust contamination in fillered bead.
Helps in tack retention & avoids turn up related defects.
6. measures and record filler height, width, TCU readings, feed compound used in process check register.
to have consistently in cpmponent quality and traceability for trouble shooting.
To get the trend and take precentive steps.
7. butt splice the filler after application on bead.
for improved uniformity in tyre and reduced air entrapment bead area.
Air entrapment leads to turn up separation in field & blow related defects in cured tyre.
8. store the for easy -
fillered beads in specified storage rings.
identifaction of components
E. DO’s AND DON’Ts FOR BEAD APEXING :
DO’s Ensure TCU remperature as per the specification. Clean the die and barrel before start up. Ensure proper die as per the specification. Ensure proper butt splicing. Ensure correct bead before filler application. Ensure uniform application of filler over bead. Clean the barrel & die after the production. Store the die in identified & pre heated oven. Collect the push out compound & identify with tag for
disposal. Keep the work area near extruder Clean from powder
dust.
DON’Ts
Don’t exceed TCU temperature spec. Don’t use compound with out lab approval. Don’t splice the filler with overlap. Don’t use the filler which are out of dimensional
tolerance. Don’t exceed the line speed beyond the spec. Don’t stretch the filler during application. Don’t use hand for cutting filler. Don’t use dirty/uncleaned bead storage trays.
STEELASTICA.INTRODUCTION
Steelastic unit is used for insulating the steel wires with rubber compound to a specified gauge and width. The Calendered steel strip is then cooled, cut at a specified angle, with and spliced to make steel belt. This belt is wound in dual cassette wind up station with or without edge filler applied through gum edger as necessary.
B. DETAILS OF EQUIPMENT :
1. Creel stand with spool let off tensioning device.2. De-humidifier for monitoring humidity and temperature
of the creel room.3. 90 mm cold feed extruder with screen changer
Make : Farrel U.K. Screw diameter : 90 mm TCU : 4 zonesMax. Screw Speed : 50 RPMMax. head pressure : 4000 psi
4. Cooling drums : 6-Numbers.5. Columbia bias cutter :
Make : Steelastic U.S.A.Belt angle range : 18 to 90Max. strip width : 152 mmMax. knife cut length : 390 mmMax. vaccum ram stroke : 838 mmConveyor belt width : 305 mmMax. line speed : 12 mpm
6. 40 mm cold feed extruder : for gum edge filler.(2 nos.) Make : Steelastic, U.S.A.
Screw diameter : 40 mm TCU : 3 Zones. Max. screw speed : 80 RPM Max. operating speed : 30 MPM Max. belt width : 300 mm
7. Dual cassette wind up system for passanger belt.
8. Surface roll wind up system for LCV belt.
C.STORAGE AND HANDLING OF COMPONENTS
COMPONENTS STORED IN TRANSPORTED BYSteel Wire Creel Room at
Controlled Temperature & Humidity
Moved to creel room by pallet trucks.
Belt Skim feed compound & edge filler feed compound strips
Storage Bins pulled by two trucks
Belts PP Liner cassette with Diameter of
pallet trucks
D. SEQUENCEOF OPERATION :
Sr. No Steps Purpose Remarks1. check humidity
and of creel room temperature & record.
to ensure no rusting of steel wire and to avoid water droplets on steel wire.
proper coating will be ensure abd belt separation in service will be avoided by enhancing the
bonding with rubber compound.
2. display specification on follow set up spec.
steel calendring belt preparation to be done as per spec.
incorrect and non uniformity component will lead to belt separation in the field & cured tyre waste.
3. set TCU for cold feed extruders as per spec.
for uniform flow of rubber and for uniform compound coating of steel wire.
to avoid high extrudate temperature scorching an improper coating and her avoid steel cord waste.
4. clean insert and die before fixing into head.
to ensure no contamination and uniform coating with correct gauge.
to avoid improper coating and hence steel wire was and also to avoid belt separayion in field.
5. check cooling drum water circumulation pressure and temperature
to cool down to the belt to room temperature.
to avoid deterioration of tack and blooming.
6. measure and record with, gauge angle and plies.
to have consistency in components and refer analyse for trouble shooting.
to get the trend and take prevence steps.
7. put to identigy the to avoid wrong
identification tag.
components. material usage.
E. DO’s AND DON’Ts FOR STEELASTIC :
DO’s Ensure creel room temperature and relative humidity as
per the specification. Clean the die. Clean the die and insert before start up. Ensure head pressure as per the specification. Ensure splicing overlap. Ensure uniform belt width. Ensure correct edge gum. Ensure uniform edge gum application over the belt. Wind the belt in clean PP liner. Ensure centred belt winding. Keep the work area near extruder (3.5” and 1.5”). clean
frpm powder dust
DON’Ts Don’t exceed TCU temperature spec. Don’t exceed head pressure of 4000 PSI max. Don’t run the belt splice more than 0 mm.(Butt splice). Don’t run the belt with die cut or without wire coating. Don’t run the belt without adequate cooling on the drum. Don’t apply gum edge with exposed belt edges. Don’t wind the belts non symmetrically. Don’t wind the belts in dirty PP liner. Don’t allow the belt material to touch the floor at various
loops.
CAP PLY SLITTER
1) INTREODUCTION :
This equipment is used for slitting cap ply fabric into cap ply strips of required smaller widths. Cap piles are used to improve the belt integrity and reduce the belt separation.
2) DETAILS OF THE EQUIPMENTS :
Manufacturer : Tech Edge, DelhiFeed roll diameter & weight (max.) : 1000 mm /800 kg.Feed roll width (max.) : 915 mm.Wind up roll Diameter (max.) :900 mm.Wind up shell/liner width(max.) :250 mm.Wind up square shaft : 89 mm.Max. web correction for the let off : 100 mm.Line speed(max.) : 30 mpm
DESCRIPTION OF THE MACHINE :
a) FABRIC LET OFF :The fabric is let off from the roll by unwinding the liner and a constant feed is ensured by the loop system. The centering and constant tensioning of the cap ply is
achieved by mounting the cap ply roll on to a moving base and tensioning device which is controlled by an E&L hydraulic centring system.
b) SLITTING KNIFE :This consists of three knives which are fitted to a shaft whch is pneumatically operated. The distance between the knives can be independently adjusted depends on the width of the cap ply required. The slitted pieces are seprated by independently adjustable idle rollers vertically mounted.
c) TAKE AWAY CONVEYOR AND WIND UP STATION :The take away conveyor is 1 m wide and 6 m in length. This is driven by a DC motor. There are four station along with one set each of stand by wind ups for continuous winding of slit rolls.the wind up station can be lifted up for disengaging with the conveyor when the roll is full or can be brought down when empty. The liner tension from the liner let off in the wind can be adjusted by a particle brake. All wind ups are provided by air motors to ensure a positive and tight winding. The position of the wind ups can be adjusted with a hand wheel operated lead screw.
d) CONTROLS :
All the machine operations are PLC controlled.
3) STORAGE & HANDLING OF COMPONENTS
COMPONENTS STORED IN TRANSPORTED BYCap ply calendered roll
storage recks with support on edges.
Using hoist & chain.
Empty liners ofcalandered roll
platform troiely Pulled/pushed by Hand
Slitted rolls pin trolley Pulled/pushed by Hand
Empty liners of .slitted roll
pin trolley Pulled/pushed by Hand
4) SEQUENCE OF OPERATION
Sr. No Steps Purpose Remark1. clean the
equipmentto ensure no foreign matter contamination in the liners, cap ply and fabric.
improved tack retention and reduced belt separation in service
2. check all accessories functions & record in checks register.
for avoiding undue delay in production and for high machine reliability.
3. ensure right specification displayed on the board.
to avoid production of wrong components
lesser scrap & improved productivity.
4. check the calendered ply width, code, snd knife setting as per spec. and enter in register.
-do- for improved traceability and identification.
5. ensure the centering of the calendered ply
for consistent width of cap ply.
6 place the wound cap ply rolls on the pin type
for easy transportation & reduce scrap
trolley generation from fabric jamming.
5) DO’s a) All shit rolls are to be identified with a two or part tag.
One tag is to be placed along with the roll and the other one in the FIFO board. Collect the tag corresponding to the first roll produced from the FIFO board and the same roll is to be taken to the building machine. This is to ensure that the FIFO is being followed.
b) Identify each roll with Date/Shift, calendered part roll no. Operator etc. to have full tractability.
c) Keep all the items, viz., Calendered roll, cut ply rolls. Empty liner etc. in the respective earmarked area only.
d) When the machine is not running switch off the machine and accessories like fans, fights etc…
e) The storage area for the calendered roll and slit rolls shall be free from dust, moistures dripping water, steam leakage and direct sun light.
f) If any problem in the machine or material is noted immediately report to the shift in charge. Shift in charge has to personally see the problem see the problem before it is reported to the engineering or technology.
g) Defective material is to be immediately removed from the machine, hold it with a hold tag and technical is to be obtained for the same.
6) DON’Ts a) Do not keep the calendered rolls on the floor.b) Do not keep the fabric exprosed on the conveyor.
c) O not use the calendered fabric with lumps/cured bits/bare coats.
d) Do not book the fabric with foreign matter or any calendered defects.
RADIAL FIRST STAGE TYRE BUILDIN G
A) INTRODUCTION Radial tyres are manufactured in two stages. In the first stage the carcass is made which consist of inner liner, plies, beads, bead filler and sidewall. This machine is used for the manufacture of first stage carcass.
B) DETAILS OF EQUIPMENT
Make Continental FMF, Germany Model KM 92 Basic type (single plus Servicer KM 92 Bsic machine with 750 Type servicer ( two ply let off )
Cycle time Mono ply 32 sec Two ply 37 sec
Out put Mono ply 700 tyres. Two ply 580 tyres.
DESCREPTION OF THE MACHINE :
Basic machine consist of head stock which houses the drive unit, in board
bead setter and operator interface. Tail stock houses the out board Bead setter Spindle box houses the stitcher unit.
Carcass ply servicer Equipped with cassette unwiding station for plies and sidewall. to the cutting table. Rotary knife for cutting Innerliner. Hook knife for cutting plies. Cutting device for sidewall.
Controls PLC controlled Operator interface can store 100 tyre receipes. Displays error messages.
C) STORAGE AND HANDLING
The components used and their storage and handling are as follows.
Component Made at Stored in HandlingInner liner 3 roll cassettes on pulled with
(Drum squeegee/split squeegee/squeegee chafer assembly)
calendar wheelsa)1050 mm diab) 346 m lengthc) 310 no tyres
a tow truck and docked in the let off of first stage servicer.
Body plies High table bias cutter
cassettes on wheelsa)1050 mm diab) 346 m lengthc) 310 no tyres
pulled with a tow truck and docked in the let off of first stage servicer.
Fillered beads Bead winding and apexing machine platform trolleys.
profiled bead storage rings of FRP on
pulled with tow truck and kept near the machine
Sidewall Coldfeed duplex extruder
cassettes on wheelsa)1050 mm diab) 346 m lengthc) 310 no tyres
pulled with a tow truck and docked in the let off of first stage servicer.
STORAGE AND HANDLING OF CARCASS.The carcass is sent to second stage TBM through a conveyor for making it into a green tyre.
D) SEQUENCE OF OPERATION
In the beginning the cycle the building drum is in the collapsed conditioned and the bead setters are out.- The beads are manually inserted and automatically
centered.- The following operations then proceeds automatically- Application of inner liner. The innerliner is cut to length
automatically in the servicer by a rotary knife as per the data fed to the computer.
- Application of first ply. The ply is cut to length in the servicer by two hook knives.
- Application of second ply if any.- While piles are being applied, air is removed by a full
width spouge roller.- Expanding the drum and positioning the beads.- Turn up the piles/innerliner with turn up bladders.- Push can pushed the flared up plies to complete the run
up operation.- The sidewalls are automatically laid on, cut to length and
manually spliced. The sidewalls are tacked to the shoulder with a profile sticher while application. After the application of sidewall, the swan neck stichers do the ‘tuck in operation’ of sidewall and bottom stichers stitches from drum shoulder to center and consolidate the sidewall.
- Drum collapses to removed the finished carcass.- Apply builder number at the inboard sidewall splice
towards the mid sidewall area.- Keep the tyre on to conveyor which transport the carcass
to the second stage.
PRECAUTIONS TO BE TAKEN BEFORE STARTING THE PRODUCTION.
- Keep the area neat and clean.
- Keep the reqired tools viz. hand sticher, naphtha can, swab, measuring tape on the machine at the specified area.
- Check the guidelights are OK and as per specification.- Keep the relevant spec ready on the machine.
E) DO’s AND DON’Ts
DO’s- The minimum run out point of the drum shall be taken as
0 for spotting arrangement. This is to be set in the PLC.
- All materials (ply, drum squeegee assembly, sidewall) shall be applied at the axial guide light point.
- Filler splice shall be kept in the bead setter vector point which will be marked on the bead setters. This will be identified by uniformity group after bead setter vector analysis.
- Innerliner, plies beads and sidewalls- check for tags as per spec.
- If any cut pieces are there, the has to be in the identified bins.
- Finished carcass are to be kept vertically in the transfer conveyor.
DON’Ts- Do not book carcass with improper sidewall splice
(under splice or over splice)- Do not mix up fabric with compound.
RADIAL SECOND STAGE TBM
A) INTRODUCTION :
In the second stage of radial tyre building, the carcass is assembled with the belt and tread assembly to get the final green tyre. The shape of the green tyre is close to the final cured tyre to avoid distortion of the inextensible belt.
B) DETAILS OF THE EQUIPMENT :
Make - IRM HollandModel - VRP -148Productivity - 35 Seconds/tyre without cap ply -48 Seconds/tyre with cap Ply -45 Seconds/tyre with spiral wound cap stripsBead sizes -12-16”
C) DESCRIPTION OF THE MACHINE
1) B&T DRUM- The B&T building drum comprise of a double conical expansions core, which is fitted between the drum’s side flanges. The metallic flat rigid building deck is formed by aluminium segments number of which have been filled with magnets for steel cord breaker pick up. The segments are attached to pressure plates, which are in contact with expansion cone. Movement of the expansions cone by air pressure causes the segments to expand radially to a pre-set diameter. With the aid of rubber retraction rings the segments return to the rest position. The diameter of drum is adjustable by quickly exchangeable spacers to suit a specific tyre
specification. Also for each drum additional segments are availavle, to be mounted on the top of the standard segment, to increase the working range of the drum.
2) B&T MAIN FRAME :A drive motor located in the main frame achives tht rotation of the drum. An AC servo Geared Motor of 4.7KW and 120RPM drives the B&T drum.
3) CENTER BASE ASSEMBLY : This houses the T-ring guides.
4) T-RING : This also is radially expandable and collapsible ring to pick up the belt and tread assembly from B&T drum. This is mounted on to the centre base assembly and moves over a rail from B&T drum to carcass drum. The expansions and collapse is through a pneumatic cylinder. There is only one T-ring for the entire range of passanger car tyres with working a range of 465-720 mm. For getting the required T-ring diameters the shoes are to be changed with the specified one. The inward expansion of the T-ring is controlled with a capacitative switch to prevent crushing of belt and tread package. The traverse movement is through an AC Motor.
5) CARCASS DRUM : The carcass drum is having a conical bead locking system to ensure a positive bead lock. For different bead diameter, the carcass drums are to be changed.
6) STITCHER UNIT :This is a dynamic stiching arrangement; the sticher start stiching from the centerline of the type to the shoulder with dwell time at the tread shoulder. The template provided
governs the travel of the stitcher. The travel of the stitcher is through an AC Motor and activation is pneumatic.
7) SEVICER :1) BELT AND CAPPLY SERVICER – The belt and cap ply
servicers are kept behind the m/c in line with the B&T drum. For the belts edge of the belt is guided for centring the belts due on to B&T drum. Tip control ensures the correct placement of the first belt tip. Second belt does not have any tip control. The belts are pre-cut to the required length automatically. A book knife cuts the belts from centre to the sides. The cap ply is guided on both sides and this also is pre-cut to length using a rotary knife.
2) TREAD SERVICER: Tread servicer is kept behind the operator and application is from topside of the B&T drum. The tread is guided using ‘V’ groove at the centerline of the tread.
8) CONTROLS :All operations and PLC controlled and there is an interactive operator interface to programme various tyre size details.
9) FEATURES OF THE MACHINE :- Automatic belt servicer, pre-cut to length.- Automatic tread application.- Bladderless expansion.- Vector study and spotting arrangement.- PLC controlled.- First belt tip control.- Cap ply servicer.- Spiral wound cap strip applications.- Facility to store more these one no. of tyre menus.- Hook knife for belt cutting.- Rotary knife for cap ply.
D)STORAGE AND HANDLING :
Component Made at Stored in HandlingBelts steelastic Cassettes Pulled with a
tow truck and docked in the let off of second stage servicer.
Cap ply cap ply slitter drop in Cassettes
Pin type trolley
Tread dual extruder leaf trucks pulled with tow truck and stored near the machine.
E) STORAGE OF FINISHED GREEN TYRE :
Finished green shall be stored in a flat manner is the second stage green tyre trolley. The tyre shall rest with its shoulder area in the storage trolley. There will be three different types of storage trolleys, depending on the size of the storage trolleys. Orange Colour – For tyres from 12” to 14” bead. Green colour - For 15” tyres (195 mm section width and above) green colour – For 16” tyres.The tyres shall be stored flat, resting on the shoulder through out the circumference. Once the trolley is full, the trolley is identified with a production tag and moved to storage area after inspection.
F. SEQUENCE OF OPERATION :
In the beginning of the cycle the-B&T drum is in expanded condition.-T-RING is in middle of B&T drum and expansion drum.
Apply 1st belt; pre-cut to length to the B&T drum automatically; tip control place the tip in the correct poition.
Sopt to the 2nd belt spotting location automatically. Apply 2nd belt, pre-cut to length to the 1st belt automatically, No tip
control. Spot to cap ply spotting location automatically. Run on cap ply or cap strip. Cap ply is cut to length with a rotary
blade. The angle of cut to is 45. Spot to tread spotting location. Run to tread, Stitch splice manually. Active the T-ring to pick up the B&T assembly. Parallel to this above operation on the expander side, the
completed green tyre is unloaded automatically on to the unloading conveyor. This is than collected and kept in the storage trolley. Operator loads a new carcass at the bead jump set.
The respective splices are loaded as per FMVA position. Operator activated the bead holder expansion command. Both the beads of carcass are held by the expander and regulated
air is admitted into the carcass to inflate the carcass. Press the T ring actuation command from the expander side to
bring the T ring with B/T assembly over to the expander side. T ring moves over to expander and position centrally over the
expander drum. Carcass expands as bead holders moves inwards to stop at the
informing limit. Informing limit is genrally 70% of the bead jump set. Once the carcass is in contact with the inner diameter of the belt
and tread assembly, T ring collapses and releases the belt tread assembly to the expanded carcass and moves to home position.
Back sticher assembly moves forward and stitches the belt and tread package to the carcass.
Once stiching is over, the carcass drum deflates and moves outwards to release the tyre.
The finished green tyre is automatically unloaded on to the unloader conveyor.
G. PRECAUTION AND CHECLISTS.
STEP REASONKeep the area neat and clean To avoid the pick up of foreign
materials and dust contamination which leads scrap generation.
Check the respective spec is available in the machine.
To ensure and check the machine is set properly and the components used are the right ones.
Ensure all the production tools are available near the machine.
To prevent loss of time and avoid tearing of the ply etc.
Always keep the splices as per specification.
A heavy splice leads to a higher uniformity value and the extra material is a loss to the company.
Always keep the splice locations as per specification.
These splice location are designed to reduce the effect of machine and materials on uniformity parameters in the cured tyres. Any off situations from this lead to a higher uniformity rejects.
Ensure FIFO. FIFO ensures there is no overaged material.
Check the materials taken to the machine is as per spec.
To avoid the usage of wrong materials.
Keep the cut pieces of belts, cap ply etc. in the respective bins.
To avoid mix up of various compounds and fabric with compound.
Check the green tyre trolleys are cleaned and the colour code is matching with the tyre size.
To avoid the contamination with foreign matrials and to avoid deformation of the green tyre in storage.
For all the cpmonents check the level of A bloomed surface will have a low tack
tack and blooming or no tack at all. This leads to air entrapment in the tyre assembly. A bloomed surface can be identified by a dull colour or may have the colours of rainbow instead of a good black colour.
H.DO’s DON’Ts
a) If the material is found defective or there is a variation from the spec, immediately the machine is to be stopped and the same is to be in formed to the shift in charge. The material is to be held immediately and to be removed from the machine and disposition for the same has to be obtained from technology department.
b) The trolley for the second stage storage are to be cleaned every day.
c) All breakdowns must be personally seen by the shift in charge before it is reported to the engineering. Before the machine is accepted back for production ensure the machine is okay in all respect to produce a quality tyre and the area is cleaned.
d) Maintain the inventory and control of all production items like turn up bladder, turn down tool, bottom sticher tool, ply fingers, sticher tools etc. the responiblity of the approval of the items lies with Technology and Engineering. Once the items are approved the further control is the responsibility of production.
e) The production shift in charge has to check the availability of all components in the beginning of the shift and inform production planning accordingly to prevent the loss of production.
f) Green tyre inspector has to check at least five tyres per trolley and if two tyres are found defective, the trolley is to be inspected 100% and the defective tyres are to be removed. The disposition of tyres are to be taken from technology if the defect is major and minor ones can be repaired on the spot.
Immediate actions are to be taken to prevent the generation of such defective tyres.
g) All the trolleys are to be identified with tags mentioning the tyre size, date and shift of production, builder nos, etc. and the tags are to be signed by the shift in charge or green tyre inspector.
h) The tags in the second stage trolleys are to be collected by the curing supervisor and the details are to entered in the computer or in the register to have tracebility.
i) When more than one size is learning at a time the trolleys shall be identified with a big board.
j) Storage of more than one tyre code is not permitted in the same trolley.
k) Before the third tyre is made after a size change, the route, card/first tyre card is to be cleared by production along with tyre engineering.
l) Co-ordinate with tyre engineering for uniformity optimization programme.
m) In case of T speed rate and higher speed rated tyres, building has to be stopped after 20 tyres. Tyre engineering has to do the uniformity test and clear the cut section to proceed with the production. If any correction is required the same procedure may be repeated. Planning and engineering to ensure the mould is ready for curing along with building.
n) Identify the training needs of the builder to ensure a quality tyre is build and impart the same.
TYRE CURING AND FINAL FINISH
A. INTRODUCTION :
Curing is the operation of shapping and vulcanizing the plastic rubber compound by means of pressure and
temperature to elastic cured tyre. The green tyre applied with antisticking lube is cured in a press fitted with moulds in which a bladder shapes the tyre. Pressure is applied inside the bladder and is maintained, to keep the components in their desired location relative to the mould surface. It is applied both externally and internally to vulcanize the rubber compounds and achieve the required material properties. The designated cure cycle defines the pressure and temperature variation with the time. When the cure cycle is complete the bladder is deflated the moulds opened and cured tyre is ejected out.
The heat cycle during cure generates strains in the tyre materials. Not all these strains are relived when the tyre is ejected from the mould. Therefore, depending on the cord material used and the intended application tyres are subjected to post cure inflation pressure for a fix time. In case, passanger radial with polyster as cord material, there will not be any post cure inflation.
B. DETALIS OF EQUIPMENTS :
Radial curing consists of following stages :
a. GT preparation.b. Tyre curing.
a. GT PREPARATION Green tyres from tyre building are lubed on the inside and outside of the tyre in air automatic spray booth.
b. TYRE CURING -Chuck loader :
For radial tyres concentring loading is required. So chuck loaders are used which lifts the tyre, place it centrally on the bladder assembly and release the tyre only after the bladder is properly shaped.
C. STORAGE AND HANDLING :
Green tyres are stored in trollys with horizontal tray’s before and after lubing(20 tyres per trolley) and transported on wheels Manually.Tyres after curing are unloaded on to the rear side of the press, to the conveyor and are sent for trimming manually.Trimmed tyres are inspected on a rotating table with rollers/balls.Inspectd OK tyres are sent for uniformity machine to a conveyor if that size rim is in TUO. Oyher sizes tyres are sent to storage on platform trolleys. Any defects found are immediately entered into a computer and kept as designated area for repair/buffing. Uniformity OK tyres are sent to balancing machine through conveyors. TUO off tyres are kept at designated area for classification. TUO off tyres are kept at designated area for classification. Balance off tyres are kept at designated area for classification.
LCV RADIAL TYRES:
LCV tyres after curing is unloaded on the front side of pressed and loaded on the PCI units.LCV tyres after PCI are brought to trimming machine through platform trolleys and will go through in the same fashion as that of PCR tyres.
Step Purpose Remarkcheck green tyres, line, code, date and shift of
Line code for identification of green
Chance of wrong moulding in curing. Leads to scrap
extrusion
Builder nos
Defects like open sidewall. Open tread splice, FM, wrinkles, sidewall ending deformation etc.
Inside and outside lube applicationa) Set air pressure of gun
as per spec.b) Inside lubing from
bead to bead uniformity.
c) Ensure inner lube does not fall outside the tyre.
d) Ensure uniform outer lube.
tyres.
Date & shift of extrusion for traceability of extrudate.
Traceability of building m/c, date and shift of building
To avoid defective products & to prevent defects like T/F, bead cracks.
Uniform spray.Air bleeding between bladder and tyre.Also to prevent sticking of carcass to the bladder.
To prevent defect like F/M, light shoulder.
To bleed air between green tyre & mould and to facilitate easy flow of sidewall compound.
To prevent GT damage and deformation.
No traceabilty to follow up of any defective process/components.
To rectify defects & correct uniformity related problems.
Adds to rework. Poor appearance leading to scrap, service, return.
Non-uniform spray results in defects like S/F, F/C, LSW, F/M:
Leads to rework in tyres and hence poor appearance. Inner lube which falls on outside of tyre may block the micro vents in the moulds leading to productivity loss.Light sidewall, flow crack, light bead,leading to rework.Poor appearance may affect performance also.
May lead to defective products being cured. Less unigormity, off-centred loading leads to
e) Ensure green tyres are placed on GT trolley properly.
scrap, poor.
B) CURING :
SI.no Step Purpose Remarks1. Warm up:
If presses are not in operation for more than 45 minutes, platen to be warmed up by partially closing the press (1” opening) for a minimum period of 15 minutes.
to avoid heat loss and under cure problem.
may result in under cure of tyre in the tread portion leading to dirty moulds, productivity loss, poor appearance, fast wear of tyre in service.
2. To start up:a)with new bladders, continue shaping with shaping drain in/out for a minimum period of 3 minute.
b)with old bladders: If presses are idle for more than 5 mins, shape the bladder with continous drain until the bladder is too hot to touch.
Bladder is stiff in cold condition. To prevent undercure also.
Bladder is stiff in cold condition. To prevent undercure also
stiff bladder may result in air entrapment between GT & bladder resulting blows-scrap tyres. Premature failures of tyres may happen.
stiff bladder may result in air entrapment between GT & bladder resulting blows-scrap tyres. Premature failures of tyres may happen.
3. check the following before loading the GT.a) Correct green tyre
size/code is placed on the GT holder.
b) Check green tyres for obvious defects like open sidewall/ tread splice, wrinkles, high/low ending of sidewall.
c) Check for uniform inner/outer lube in tyre.
correct green tyre to be cured in the specified mould.
to prevent defective production.
inner lube in tyres bleed off air in-between tyre and bladder.
outer lube in tyre bleeds out
wrong moulding of the tyre leading to scrap.
add to rework and poor appearance in tyre.
inner lube in excess or in less quantity may lead to split fabric in tyres, poor uniformity and F/M defect.less outer lube may lead to F/C, LSW,
TYRE BALANCING TYRE BALACING AND UNIFORMITY
1) INTRODUCTION
A pneumatic tyre is a non-homogeneous composite structure made up of many components and is still built to a large degree by hand. Once it is cured a tyre has various non uniformities in it.
There are three types of non-uniformities in a tyre.
1. Dimension non-uniformity – Runout and wobble.2. Mass non-uniformity - static balancing.3. Stifness non-uniformity - force variations.
Dimensions variations are the radial run out and lateral run out. Radial runout is variation in the circularity of the tyre along the periphery. This is very important parameter since, in general, 1 mm runout creates the force variation of 18 daN. This is basically taken in the mould manufacturing stage. Lateral runout is also called wobble and is the runout along the sidewall. Lateral runout is measured on the tyre. This depend in addition to the mould manufactur, the building process also.
2) TYRE BALANCING
Tyre balancing is the process by which point in the tyre having the lowest weight is found out and marked. For any tyre the mass distribution along the circumference of the
tyre must be uniform. If this is not uniform the ride will be affected and leads to bumpy ride and steering wheel vibrations.
a) MACHINE DETAILS
Make : Avery SchenckModel : CAB 640Test rpm : 400 rpmRim size : 12”-16”Max. weight of test piece : 25 kgImbalance repeatability : +2 gmsAngle repeatability : +1Test time : 20 to 40 sec
The machine consists of a test spindle, motor, micro processor based measuring device and a maker unit.
1) Test spindle is the one on which the tyre to be tested is mounted. Depends on the bead diameter the chucks are to be changed. This is a dynamically balanced chuck assembly with practically zero imbalance value.
2) Motor is a DC servo motor with variable speed provision. The tese rpm is to be set as per the test requirement. There is another motor for auto indexing the tyre to the imbalance point without the help of operator.
3) Measurement device is a microprocessor based measuring device working on Wait Metric principle. The imbalanced picked up by the piezo electric sensor mounted on the spindle is convered in to a digital vales and displayed. The saqme unit is to be calibrated for various sizes of tyres and the calibrated vales can be stored in different types corresponding of each tyre. This unit is also use to locate the lowest imbalance point.
4) The marking unit is a pneumatically operated unit used to make the imbalance point towards the rim line area.
b) OPERATION
1. Select the require tyre type.2. Check the type is calibrated for that tyre size or not.3. Load the tyre to the collapsed chuck with serial side on
top an d with drum squeegee splice on the 0 of the chuck.
4. Press the start button to start the test.5. Once the test is over the chuck automatically index to
the low point of the marker to mark a yellow dot. In case of manual indexing, operator has to releasd the chuck brake, rotate the spindle till the arrows in the displays unit vanishes and xero is displaced then press the mark button to mark the tyre.
6. Collapse the chuck using the foot switch’7. Remove the tyre.
c) DO’s AND DON’Ts
1. Keep the chuck pallets at the respective areas only to avoid damage. Note that this is a dynamically balanced item and any damage to this will cause an erratic measurement of balance value.
2. Keep the area neat and clean. A dirty area will affect the aapearance of the tyre and cleaning a radial tyre is difficult.
3. Keep the tyres for OE and Replacment markets separately. All OE tyres are to be identified with OE stickers.
4. Keep the balancing off tyres serprately for NCMR classification.
5. In machines identified for radial tyres do not balance bias tyres.
TYRE UNIFORMITY The third tyre of non uniformity is the force varations generated by the variations in the stiffness of the structure at different parts of the tyre. These variations can not be measured until the tyre is inflated and loaded as in a vehicle. Mass imbalance and dimenstional variations can be measured in static conditions where as the force variations can be measured only in a dynamic conditions.
Basically a tyre can be thought of as a variable spring with a distribution of mass. The force variation originating at the tyre are comprised of variation of spring rate and variation of inertia. A pneumatic is an composite structure made of a large number of components made in different machines and assembled together to a large extent manually. The variation in stiffness is due to a the splices, difference in the gauges, epi variations, machine settings and to a good operator variations.
These force variations can be in the radial, lateral and the transverse directions. Three important force papmeters are measured in the uniformity machine. They are
a) RADIAL FORCE
Force response was based on the measuring of a tyre’s carcass stiffness, or the resistance to flexing while it is revolving under a load on a vehicle. Variation in force response were transmitted to the vehicles suspension system. In simple terms there is a variartion in spring rate throughout the periphery of the tyre.
A tyre’s carcass can be thought of as an infinite series of springs. Let us poition a spring at each from quadrant of tyre. If the spring are of same length and have the same spring constant, than the displacement, as the tyre is put into motion, would remain in a straight line.However, if at some location there was an extra spring, then there would be a subsequent wheel hop or axle displacement that would occur with each wheel revolution. All the springs are equal at all points except one location where there is an extra spring. The causes of varying spring rates can be attributed to minute variations in end count, fabric splices, tread splices, breaker splices, cord angles, cord states, etc.
b) LATERAL FORCES
When a loaded tyre revolves it develops a lateral force. This force varies around an average point. The average value of the lateral force is called lateral shift and the variation is called lateral force variation. Lateral shift variations will change significantly when the direction of rotation is changed. A positive lateral shift in the clockwise direction will become a negative lateral shift in the counter clockwise direction.
c) CONICITY
Conicity and ply steer are function of lateral force. This is a term derived by considering a tyre assumes the shape of a truncated double cone. Based on the geometry, such a configuration would
generate a force towars the apex of the cone regardless of which direction the cone is roated. Conicity can be thought of as a cause of vehicle pull. Vehicle pull refers to a condition where the driver must apply a constant tourque ro the steering wheel in order to maintain a straight line course with the vehicle.
So in the case of a perfect tyre the pull towards each side is balanced.
Off center belts have been determined as the main cause for large conicity values. A high conicity value can have such a large effect on vehicle pull, radial tyre are closely monitored for conicity.
UNIFORMITY MEASURMENT
To measure uniformity, the tyre is mounted on a precision steel rim, inflated and loaded against a large drum(road wheel). A device motor is connected to the axle of tyre drum and drives the tyre and drum at 60 RPM. The method of force response measurement involves loading the tyre and maintaining a fixed distance between the tyre and drum axle. The non-uniformities of the tyre create a wave form of force variations as the tyre rotates. Force variations in the radial and lateral directions are then measured using strain gauge transducers mounted on the axle supports. A brief description of the machine is as follows. The main part of machines are.
1) Feed conveyor – this is an driven roller conveyor which feed the tyre to the test station once one tyre test is completed. The gate at the end of the conveyor ensures only one tyre is fed to the test zone.
2) Test zone- the test zone consists of centring arms, spindle and chuck assembly and the high point marker. Centring arms, spindle and chuck assembly and the high point marker. Centring arms centres the tyre with the help of the
3) Drop conveyor –this is after the test station and is hinged on one side. This is a driven roller conveyor. This helps in accessing the test station easily for rim change, adaptor change etc.
4) Exit conveyor –this is a driven roller conveyor after the drop conveyor. This is provided with a gate to hold the tyre to mark with the bar marker on the bead, if bar marked is used.
5) Shoulder grinders – these are used to correct the radial force variations by selectively grinding the shoulder area at the high point and brinding the value down. There are two number of shoulder grinders, one for serial shoulder and for the non serial shoulder. As a thumb rule, removal of 0.025 mm of material will reduce radial composite force by about 1/2 kg.
6) Operators panel- All the control switches and most of the indicators are mounted on the control panel.
7) TQC 86- this is computer which controls all the test parameters and also displays the status of the test parameters and values: this uses TIGER software to do measuring, grading grinding and marking.
8) Main electrical panel – this houses all the electrical controls and the PLC. The PLC controls all the machine parameters such as loading the tyre, unloading the tyre and operate the bar markers.
WHAT CAN CAUSE HIGH UNIFORMITY
Anything that can cause a high build- up of stock (radial force), snacking of materials(lateral forece) or off centered components (conicity) can cause unacceptable uniformity values.
Some reason are as follows.
RADIAL FORCE
Humped pad or tread splice. Stretched pad or tread.
Splices not optimally spotted. Wide inner liner and fabric splices Lapped or open breaker splice. Uneven cords per inch. Uneven developed cords length (bead to bead distance)
caused by:-bead not concentric to carcass drum.-tight beads not fitting on bead ring-loose bead/turn ups
Carcass drum, transfer ring and breaker/tread assembly before carcass i completely formed.
Transfer ring dropping breaker/tread assembly before carcass is completely formed.
Storing green tyre vertically for long periods of time. Poor inside lubreications. Poor shaping. Warm tyres jammed together on converyor. Poor uniformity chuck lubrication. Low bead set pressure on uniformity measurements.
LATERAL FORCE
Trapped splices Snacked belts, pads, tread and edge strips. Carcass drum, transfer ring and breaker drum not square to
each other. Cooked in mould Cooked on post cure inflation Cheafer width variation and set variation Belt width variation and step of variation Poor ply, belt and tread tackiness Meas-aligned bead setters Loose ply turn up Incorrect green tyre diameter
Bad green tyre storage Sidewall ser variation Treads booked in bow shape from extruder.
CONICITY
OFF-Centred components.Transfer ring not centred over breaker/tread drum or carcass drum.Off gauge wedge strips or pads.Breaker band too wide or too narrowNarrow belt not propely centred on wide beltTread contour not symmetricOff centered building drumOff centered bead settersGreen tyre diameter too low.
TYRE TESTING
Tyre is one of the most versatile products and it is also one of the most abused products as it is being subjected to the worst of the operating conditions. The fact that the failures of tyres could prove fatal to human lives calls for highest of the quality requirement of the product.
Tyres are subjected to various kinds of tests and they can be tested in many ways too. One way is that they can be tested in actual running conditions. But the long time period required to get the results through this way makes it inefficacious and hence various drawbacks of testing on actual running conditions.
tyre testing can be mainly divided in two:
1) Destructive testing2) Non-destructive testing.
In the destructive kind of testing the tyre being subjected to the test will be destroyed beyond use.
Non-destructive tests include dimensional checks. Uniformity tests, static balance testing etc.
Destructive tests mainly include.
1) Indoor wheel endurance testing.2) Indoor wheel high speed testing.3) Indoor wheel bead endurance testing.4) Plunger testing.
Indoor wheel endurance tests are conducted on a machine called tyre testing machine, also called as pulley wheel machine. Apollo has got one of most sophisticated machines which was accqired from Akron standard USA.
1. Indoor wheel endurance testing:In this test tyre are made to run on a road wheel with varying percentage of rated loaded and recommended inflation pressure (the rated loaded is minimum load, the tyre shoul carrying without failing and it varies as per the requirement/kind of tyre). The test is divided in to two various step the tyre will be running with a constant speed (matching with normal vehicle speed) but the percentage loaded on tyre will be increasing in subsequent step and this will continue till the failures of the tyres. This test give us how much loaded tyre can withstabd, which can be clear indicatuion of the tyre endurance on actual running conditions.
2. Indoor wheel high speed testing:
The tests mainly used for tyres that are required to run at high speeds. So mainly passangers car /jeep tyres are the ones beinf tested.tn the tests the tyre is being tested in run on the road wheel with a particular percentage of the rated loaded under recommended inflation. The test is conducted in different steps in which the speed of the road wheel will be increase in subsequent step and the test will go on till the failure of the tyre. The test shows the maximum speed with which the tyre can run on actual road conditions.
3. Indoor wheel bead endurance test :Beads are the potion of the tyre holding tightly on to the rim and endurance and strength of this area is to be paramount importabce and this is been tested of a tyre on pulley wheel machine through bead endurance test.
The tyre to be tested will be buffed off bead portion inorder to facilitate the effective transferring of the complete leads on to the beads. The test is divided in to various steps in which loaded of tyre will be increasing in a step at a constant speed of the rpad wheel. The tyre will be inspected frequently for any defect at the bead area.
All these above test are carried out under maximin safety precautions as the busting of the tyre being tested could be fatal to the people around.
4. Plunger testing:This is another kind of destructive testing conducted on a breaking energy machine called plunger testing machine.
The tyre to be tested is mounted on the recommended rim with proper inflation pressure and then on to the machine. A needle of specified diameter also attached with the load cell will be
pierced through the crown of tyre in the direction perpendicular to the tread surface. The needle is advance either the tyre failed or can be stopped where the require plunger value is obtained. The loads exterted by the load on the tyre and the distance travelled by the needle are measured and from these values the plunger energy value can be calculated using a mathematically formula.
5. Tyre dimensions:
Tyre are also check for inflated dimensions.
The tyre to be checked is mounted on the recommended rim and inflated with recommended pressure. After keeping the tyre for required time to stabilize the growth, the dimensions are taken. Main parameters checked are:
Cuter diameter, section width, tread radius, tread arc width, tread width, non skid depth.
Then the obtain values will be compared with standards to ensure that the tyre is meeting the specified standars.
QUALITY SYSTEM IN MANUFACTURING
QUALITY SYSTEM IN MANUFACTURING
1. FIFO (FIRST IN FIRST OUT) :
Means material produce first must be use first. For almost the material min. & max. agenic is fixed and this agenic is based on the properties of the matrial.
Min. agenic : material should not be used before the specified period. Before ageing if the material is used, the component will not stabilize its properties, resulting in higher process defects and service failures.
Max. agenic : material should not be used after the specified period. After ageing limits if the material is used, than the component may loose its specific properties and hence may result in failures in process and service.
How to follow FIFO?
A)FIFO board system:- in our plant FIFO boards are displayed at Dip Unit 4-roll calener Dual extruder
The dept. which is producing the material must put all the tags duly filled at appropriate place on FIFO board and the duplicate tag on the material. Care should be taken that oldest material tag must be on the top and the latest one at the end. User department must refer the FIFO board and the material produce first must be used first. (if the material is within the specified age limit.)
B) Identifaction tags: tags must be dully filled furnishing all details by the producing dept. use dept. must refer the tag for date/shift of production, material produced first must be used first. E.g. cut ply rolls, bead, chafer & flipper.
FIFO should be follow for green tyres, which cab be ensured by proper storage, writing time of painting on GT’s checking for tread extrusion date etc.
C) Line marking: for banbury mixed batches (final), line marking of specified colours are marked over the top of the skid to identify the day of producyion. The earliest mixed batch should be taken for processing looking the coloured lines.
2. Specification Cards /Work Instuction.
Before starting the process, specification must be reffered and displayed. See that the specification issued is current & valid ie. It should have a controlled copy stamp. Operator should be fully aware of work procedures and work instructions.
Advantages:
1. Avoids production of wrong material.2. Productivity increased.3. Quality is maintained.4. Reduces scrap/ rework.5. Reduces mental tension & increases confidence.
3) Statistical Process Control (SPC)
Statistical process control is currently the most popular and effective quality activity in industry. It is tool for accessing the performance of process. SPC is an operator’s self control program which aims at preventing any non conforming product before being produced.
STATISTICS : statistics is a scientific method of collecting, classifying, presenting & interpreting numerical information.
PROCESS : a combination of machine, man, methods, material and environment, that produces a given result.
CONTROL : Means to make something behave, the way we want it to behave.
At the following areas SPC charts are displayed in our plant.
AREA PARAMETER1. Banbury Lay down temp.2. Dip Unit Dipped fabric width.3. 4-Roll Calender fabric gauge4. 3-Roll Calender Squeegee gauges & centring5. Duplex Extuder Tread length6. Bead Room Splice overlap & temp.7. High Table Bias cutter ply width8. Steelastic & Radial building Belt gauge & GT circumference9. Tyre Curing HPS, HW & PCI Pressure10.Final Finish Tyre balance & Uniformity.
SPC CHARTS : Median – Range (M-R charts), individual moving range (X-MR Charts), Average – Range charts (X-R chart) etc.
Median : The Mid value of the observations.
Range : Difference between the highest & lowest value.
Moving Range : Difference between two individual observations taken at consecutive shifts/day.
Control limits are calculated based on the observations for a period which indicate the process capability. Controls limits shall necessarily be within specification limits fixed by design department for a capable/ stable process. Attempts should be made to minimize the variation and achieve tighter control limits. This charts should be used for controlling process as well as for assessing the process capability.
4) Identification & Traceability.
All the material produced must be properly identified. Materials are identified using tags, marking, stamping etc. all detail must be filled up in the identification tags. Also all traceability systems like process records, tags, builder no. serial no. etc. should be properly followed. Inspector stamps (cured tyres) are also to be put wherever required.
Advantages :
1. Easy followed up FIFO2. Traceability become easier & faster.3. Usage of control material.4. Quality product.
5) Storage :
Specified areas earmarked for all the materials. Materials must be kept in a systematic way in that area. Sufficient ailse must be provided for easy material handling. Storage must be in such a way that FIFO is ensured.
Advantages:
1. Easy follow up of FIFO2. Mterials does not get damaged.3. Reduces workway/scrap.4. Productivity & Quality.
4 Handling of Non- Conforming Material :
Material may does not meet the soecification is known as non conferming material. Such material must be helped up using a hold tag and it should be removed to the held up area.
Held up material is disposed by the technical dept. depending on the deterioration of the material.
Material is disposed as a) Released as such b) disposed with downgradations/with some corrective action c) scrap.
Technical disposition must be strictky followed and at any cost it should not be used if the disposition is not given.
If the materoal is released as okay than such material must be kept in the earmarked area.
If the material is to be used after doing some corrective action, okay material must be keeping in the earmarked area and defective in held up,reworked area.
If the material is disposed as scrap, such material should be removed to the scrap area abd subsequently scrapped.
Note: Hold tag should have all relavent details.
5. Process Monitoring & Records :
After reffering the specification, machine IS is get accordingly. As soon as production of the material is started initial 5-10 samples must be checked such that the material produced is as per the specification. If found off then corrective action must be taken till the required material as per spec is obtained. Defective material must be removed. As soon as smooth functioning starts record the reading in the process check register as per the frequency.
Advantage :
1. Avoids production of wrong materials.2. Traceability becomes easier.3. Helps in corrective actions.4. Lesser Accidents.5. Higher employee morale.6. More time for improvement activities.
6) Inspecting And Testing :
Inspection and testing in all process stage is a vital Process control plan for Quality Assurance. Process monitoring by operation group, inspecyion of in-process products, testing of material by Lab. For conformance to specified parameters and release for next processing are essential elements of process control plan.
Inspector stamps ( cured tyres) and OK stamps by Lab. (RMS, Mixed Stock, Dipped & Calandered rolls etc.) are followed, wherever applicable. Each process group should ensure that they revice only OK matrial for their processing.
- Process Control Plan attached.
PROCESS CONTROL PLAN
PROCESS CONTROL PLAN
AREA MANUFACTURING RELEASE TEST (100%)
NON-RELEASE TEST (RANDOM)
RAW MATERIAL MIXING SAMPLE AUDITS
FABRIC DIPPING
FABRIC
PROCESS MONITORING &
-DO-
EVERY LOT SP.GR. & RAPID RHEO
CORD PHYSICALS
RHEO,M.S. M.V, PHYSICAL ETC.
H-ADHESSION, DIP PICK-UP
CALENDERING
CEMENT PREPARATION
EXTRUSION
STEEL CALENDERING
SQUEEGEE CALENDERING
PLY CUTTING
BEAD PREPARATION
TYRE BUILDING
TYRE CURING
FINSHIED PRODUCTS
-DO-
-DO-
-DO-
-DO-
-DO-
-DO-
-DO-
-DO-
-DO-
100% INSPECTION100% UNIFOMITY CHECKS 100% BALANCING
GAUGE, ELI, BALANCETS, VISCORCITY ADHESSION-
-
-
-
-
-
-
-
PHYSICAL &STRIP ADHESSION
MV,MS
BELT ADHESSION
MV,MS
PLY-MR & PHYSICALS
BELT ADHESSION MV,RHEO-
-
PRODUCT RELIABILITYTESTS (PULLEY WHEEL DIMESIONS, PLUNGER STRIP ADHESSION & CORD PROPERTIES)