Stages involved in the production of a tyre
A tyre is the only source of contact between the vehicle and the road. Different types of tyres are manufactured for different types of vehicles and road condition. The tyre industry today is making a lot of technological advancements and introducing the concept of futuristic tyres. From the time tyre came into existence, its manufacturing process kept changing from time to time. If we look at a simple car-tyre today, it goes through a lot of stages during production. Let’s see all the stages of Tyre Production.
A tyre is round and it is black. However, if you examined all the manufacturing stages you would realize what a complex product lies beneath its plain exterior. In actual fact, leaving the natural and synthetic rubbers aside, more than 200 different materials are combined to manufacture the tyre that we know so well. There is carbon black, silicon and sulphur, plasticizers and vulcanizing agents. There are also cores, a lot of cores, which in fact can be either steel or fabrics such as polyester and Kevlar. These different raw materials are used to produce a wide variety of components – flat or profile products, steel core or fabric plies and also bead wire. These components give the tyre its elastic properties, ensure its resistance to wear and tear, provide adhesion and determine its service life.
It all begins on the tyre building drum which is a rotating cylinder with a flexible centre so that its edges can be brought closer to each other. A thin and a perfectly airtight sheet of synthetic rubber must first be laid down on the drum. This will act as an inner tube inside the finished tyre.
The second layer is called the casing ply because it contains the framework of parallel fabric cord which we call the casing. This assembly is the vital substructure and consequently a key component in the radial tyre. Set tightly against strips of profiled rubber, are two high resistance steel wire hoops, which are known as the bead wires. They hold the tyre firmly on its rim. The casing ply is then folded up over the bean wires to hold them securely in place. Other components are added with the same degree of accuracy. Some tyres have dozens of them. If we take a look at the sidewalls, they are made of rubber both flexible and tough to protect the tyre from side impact. Then by inflating the central part of the drum, its edges are brought closer to each other. Now the tyre is shaped.
The reinforcing tread plies providing directional stability and mechanical resistance have yet to be added. Fine but highly resistant steel cord strengthens these plies. Being laid crosswise to the casing ply it forms a shape retaining triangles. Now it’s time to lay down the tread rubber. It is this part of the tyre which will have a tread pattern and will be in contact with the road surface.
The unfinished tyre is then put into the curing mould, which has all the tyre markings and the tread pattern. A curing bladder filled with hot pressurized water forces the rubber back into the mould cavity. The hot water and steam around the mould start the Curing Process. This curing or vulcanization chemically bonds the rubber compounds to the steel and fabric cord reinforcement components. During this chemical reaction, the tyre goes from plastic to an elastic state. Sometime later, the transformation is complete and the tyre emerges from its metal shell. The tyre has been given its final features and finished the shape.