TYRE MANUFACTURING PROCESSES AT

PRESENTED BYTHOMAS MATHEW(1021110436)

INTRODUCTIONTyres are the only point of contact of the vehicle with the road. The intentions of the driver are finally executed by the tyres only, hence the quality and design of the tyres is important.

Function of tyres :• Steering• Carrying a load• Cushioning, rolling• Transmitting drive and• Long lasting life.

COMPANY PROFILE

Apollo Tyres Ltd, with its corporate headquarters in Gurgaon, India, is in the business of manufacture and sale of tyres since its inception in 1972. Over the years, the company has grown manifold, establishing its footprint across the globe.

The company has manufacturing presence in Asia, Europe and Africa, with 8 modern tyre facilities and exports to over 100 countries. Powered by its key brands — Apollo and Vredestein, the company offers a comprehensive product portfolio spread across passenger car, light truck, truck-bus, off highway and bicycle tyres, retreading material and retreaded tyres.

COMPONENTS OF A TYRE

• Inner liner• Body ply• Side walls• Beads• Apex• Belt package • Tread • Cushion gum

COMPONENTS OF A TYRE

Inner Liner It is an extruded halobutyl rubber sheet

compounded with additives that result in low air permeability. The inner liner assures that the tire will hold high-pressure air inside, without the air gradually diffusing through the rubber structure.

Body Ply The body ply is a calendared sheet (two or more

sheets are rolled together such that mechanically they are bonded) consisting of consecutive layers of rubber and reinforcing fabric.

COMPONENTS OF A TYRESidewalls

Sidewalls are non-reinforced extruded profiles with additives to give the sides of the tire good abrasion resistance and environmental resistance. Additives used in sidewall compounds include antioxidants and antiozonants to protect the tyre from decomposition.

Beads Beads are bands of high tensile-strength steel wire

encased in a rubber compound. Bead wire is coated with special alloys of bronze or brass. Coatings protect the steel from corrosion. Copper in the alloy and sulphur in the rubber cross-link to produce copper sulphide, which improves bonding of the bead to the rubber. Beads are inflexible and inelastic, and provide the mechanical strength to fit the tyre to the wheel.

COMPONENTS OF A TYREApex

The apex is a triangular extruded profile that mates against the bead. The apex provides a cushion between the rigid bead and the flexible inner liner and body ply assembly. It is alternatively called as "filler" in literature and industry.

Belt Package Belts are calendared sheets consisting of a layer of

rubber, a layer of closely spaced steel cords, and a second layer of rubber. The steel cords are oriented radially in radial tire construction, and at opposing angles in bias tire construction. Belts give the tyre strength and dent resistance while allowing it to remain flexible. Passenger tires are usually made with two or three belts.

COMPONENTS OF A TYRETread

The tread is a thick extruded profile that surrounds the tire carcass and this is the layer which comes directly in contact with the road. Tread compounds include additives to impart wear resistance and traction in addition to environmental resistance. Tread compound development is an exercise in compromise, as hard compounds have long wear characteristics but poor traction whereas soft compounds have good traction but poor wear characteristics.

Cushion Gum Many higher-performing tyres include an extruded

component between the belt package and the tread to isolate the tread from mechanical wear from the steel belts.

TYRE MANUFACTURING PROCESSES

COMPOUNDING AND BANBURY MIXING

A Banbury mixer combines rubber stock, carbon black and other chemical ingredients to create a homogeneous rubber material. Time, heat and raw materials are factors utilized to engineer material composition. The ingredients are generally provided to the plant in pre-weighed packages or are prepared and weighed by the Banbury operator from bulk quantities.

Measured ingredients are placed onto a conveyor system, and the Banbury is charged to initiate the mixing process. Hundreds of components are combined to form rubber utilized for tyre manufacturing. The components include compounds which act as accelerators, anti-oxidants, anti-ozonants, extenders, vulcanizers, pigments, plasticizers, reinforcing agents and resins. Most constituents are unregulated and may not have had extensive toxicological evaluations.

MILLINGShaping of rubber begins in

the milling process. At the completion of the Banbury mixing cycle, rubber is placed onto a drop mill. The milling process shapes the rubber into flat, long strips by forcing it through two set rolls rotating in different directions at different speeds.

Mill operators are generally concerned with safety hazards associated with the open operation of the turning rolls. Older mills usually had trip wires or bars which could be pulled by the operator if he or she is got caught in the mills.

CALENDERING

The calender operation continues to shape rubber. The calender machine consists of one or more (often four) rolls, through which the rubber sheets are forced. The calender machine has the following functions: • To prepare compounded rubber as a uniform sheet of definite thickness and width • To place a thin coat of rubber on a fabric (“coating” or “skimming”) • To force rubber into the interstices of fabric by friction (“frictioning”)

The rubber sheets coming off the calender are wound on drums, called “shells,” with fabric spacers, called “liners,” to prevent sticking.

EXTRUSION

The extruder is often referred to as a “tuber” because it creates tube-like rubber components.

The extruder functions by forcing rubber through dies of appropriate shape. The extruder consists of a screw, barrel or cylinder, head and die. A core or spider is used to form the hollow inside of tubing. The extruder makes the large, flat section of tyre treads.

COMPONENT ASSEMBLY AND BUILDING

The tyre assembly machine consists of a rotating drum, on which the components are assembled, and feeding devices to supply the tyre builder with the components to assemble ( The components of a tyre include beads, plies, side walls and treads. After the components are assembled, the tyre is often referred to as a “green tyre”.

Tyre builders and other workers in this area of the process are exposed to a number of repetitive motion operations. Builders utilize solvents, such as hexane, which allow the tread and plies of rubber to adhere. Exposure to the solvents is an area of concern. After being assembled, the green tyre is sprayed with a solvent- or water-based material to keep it away from adhering to the curing mould. These solvents potentially expose the spray operator, material handler and curing press operator.

CURING AND VULCANIZINGCuring press operators place green tyres into the curing press or onto press loading equipment. An impressive degree of automation was observed at Apollo tyres Kalamassery.The press utilizes steam to heat or cure the green tyre. Rubber curing or vulcanization transforms the tacky and pliable material to a non-tacky, less pliable, long-lasting state.

FINISHING AND INSPECTIONFollowing curing, finishing operations and inspection remain to be performed before the tyre is stored or shipped. The finishing operation trims flash or excess rubber from the tyre. Additionally, excess layers of rubber may need to be ground from the side walls or raised lettering on the tyre.

One of the major health hazards that workers are exposed to while handling a cured tyre is repetitive motion. The tyre finishing or grinding operations typically expose workers to cured rubber dust or particulate. This contributes to respiratory illness in workers in the finishing area. In addition, a potential exists for solvent exposure from the protective paint which is often used to protect the side-wall or tyre lettering. After finishing, the tyre is ready to be stored in a warehouse or shipped from the plant.

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