A tyre is an assembly of numerous components that are built up on a drum and then cured in a press under heat and pressure. Heat facilitates a polymerization reaction that cross-links rubber monomers to create long elastic molecules. These polymers create the elastic quality that permits the tyre to be compressed in the area where the tyre contacts the road surface and spring back to its original shape under high frequency cycles.Raw materials
The main raw materials of a tyre are natural rubber, synthetic rubber, carbon black and oil. The share of rubber compounds in the total weight of a tyre is more than 80%. The rest consists of various kinds of reinforcing materials. Approximately half of the rubber is natural rubber from a rubber tree. Rubber trees are grown in the tropics, in countries like Malaysia, India and Indonesia. Most of the synthetic, oil-based rubbers come from European manufacturers. Approximately one-third of the compound consists of filler substances. The most important of these is carbon black which makes the tyres black in colour. Important filler is oil which is used as a plasticiser in the compound. Furthermore, hardening or vulcanising agents, various booster chemicals and protective agents are used in the rubber compounds. Our manufacturing facility is divided into five main departments that perform the following respective functions –
Compounding & Mixing
- Compounding & Mixing
- Component preparation
- Tyre building
- Final finish & Inspection
In the mixing stage, the raw materials are mixed together and heated at a temperature of approximately 120 degrees Celsius.
The consistency of the rubber compounds used in different parts of a tyre varies, and the consistency also varies depending on the intended use and model of the tyre. The rubber compound used in a summer tyre for a passenger car is different from that of a winter tyre, and there are very few similarities between the rubber compound of a bicycle tyre and that of a forestry tyre. Developing and adjusting the recipes is an important part of the tyre development work. Component manufacturing
The compounds are used in rubberising various components, such as steel cord, Bead wire, Tread, Side wall etc. A tyre is manufactured from 10–30 different components. Steel cord
Steel wire cord quality is based on tensile strength, elongation, and stiffness. It is manufactured from steel rod with high carbon content; and while the steel wires used have different configurations, all are brass-coated strands twisted together into cords. If the wire is used in a multi-ply tire rather than a belted tire, the fatigue performance will be important. If used in belted tires, then stiffness is of primary concern. Since the steel wire is brass coated, storage conditions are important to maintain the steel wire to rubber bonding properties. Therefore, the steel wires are also kept in a temperature and humidity controlled room once they arrive at the factory. Belt and Ply Calendering
To produce fabric or steel belts, the fabric or steel cord must go through a calendering process—an operation in which the rubber compound is pressed on and into cords. Because the bonding of fabric to rubber or steel to rubber is critical to performance, the calendering process is an important step.
The calender is a heavy-duty machine equipped with three or more chrome-plated steel rolls which revolve in opposite directions. The roller temperature is controlled via steam and water. In this process, the rubber compound is applied to the cords.