Tire Manufacturing Process, Raw Materials, Production

Tire is a great combination of several materials to make our day to day life easier. The tire's job is to create a safe and more effective connection between the road and the vehicle. Rubber (natural and synthetic), carbon black, and sulphur are some raw materials used in tire production. In this tutorial, we will learn the manufacturing process, raw materials, and production of tires.


Written by: Chamidhu Lakpriya, (undergraduate), Manufacturing Engineering, University of Peradeniya,


  1. What is a tire?
  2. What is the history of the tire?
  3. What are the row material of the tire?
  4. What is the process of manufacturing tire?
  5. How they are check the quality of the tire?


What is a tire?

Tire is the great combination of several materials to easier our day today life. The tire's job is to create a safe and more effective connection between the road and the vehicle. At present, there are two types of tires in market. They are tire with inner tube and tubeless tires. Tire making isn't just a process of mixing rubber and other chemicals to convert into tire shaped object. It is a process must take place in such a way as to obtain the special properties that tire should possess.

A fully made and finished tire

History of the tire

In 19th century, before 1839, many inventors tried to develop tires but because of the elasticity of rubber it failed. In 1839, The vulcanization method of rubber was introduced in 1839 by an American inventor named Charles Goodyear, as a result of research with rubber since 1830. This process increases the strength and durability of rubber more than it had.

After introducing vulcanization, the demand for rubber has increased. As a result of it the pneumatic tire with inner tube was developed in 1845 by Scottish inventor, Robert Thomson. Since then, under the guidance of inventors and chemists, the tire manufacturing process has improved to where it is today.



Raw materials of the tire

  • Rubber (Natural and Synthetic)
  • Carbon black
  • Metal
  • Textile
  • Sulphur
  • Other materials


Rubber

Rubber is the main raw material of manufacturing rubber. Due to the properties such as strong and tough, iit exhibits a great resistance to abrasion, tearing and cutting over a wide range of temperature, hardness and strength. They can be used as natural rubber and synthetic rubber. Natural rubber is a substance made from the rubber latex of the rubber plant. Synthetic rubber is produced in laboratories.


Carbon black

Carbon black is a material produced by the semi - combustion of petroleum, coal or natural gas. They are black in color and cause the tire to darken. The excess heat generated by the tread and belt area is conducted away from it, cause of that excess heat can damage the parts.


Metal

The metal reinforced plies are made of metal and rubber. That can limit the deformation of the tier and can withstand under loades.


Textile

The body ply layer of the tire is made of a combination of textile and rubber. This layer with a network of a textile gives structural strength to the tire also that has a flexibility but has an elasticity.


Sulphur

Sulphur is added for vulcanize the tire.




Manufacturing process of tires

Process flow chart of the tire manufacturing

The tire manufacturing process is almost entirely mechanical. The tire called green tire just before the vulcanization is made up of a combination of separate layers of rubber.


The raw materials that natural rubber, synthetic rubber, carbon black, sulfur and other chemicals are mixed for form the rubber compound by gigantic mixers. Each of ingredient percentage of the mixture is determined by computer system.


After that, in 2nd step the mixture is stirred again and heat is added to the mixture for soften. In 3rd step additional chemicals which are accelerators, anti-oxidants, antiozonant, extenders and plasticizers are added to the mixture to make the final mixture and then pass back into the mixer. The quality of the final mix is depending on how soft it and how far it is distributed of the chemicals in the mix.


Then, the final mixture is distributed to several processes to form the various layers needed to make the tire. In each case the result is a gummy rubber machinery convert into flat long strips to further needing.


Several layers must be produced to make the tire.

  • Body ply layer
  • Steel belt layer
  • Inner liner layer
  • Tread and sidewall layer
  • Beads
Section of the tire

Body ply layer

The cloth - like fabric is rolled into a machinery. That machine contains big rollers to apply rubber mixture to both side of the fabric. Cotton treads are than laid on this layer to produce body play layer.


Steel belt layer

It consists of a layer of steel closely lined on a layer of rubber as shown in following figure.

Steel belt layer

Inner line layer

It is made of a layer of mechanically integrated Halo butyl rubber with additives that cause low air permeability.


Tread and sidewall layer

While mixture father mixes and heat it goes through the machine called an extruder and formed into die-a shaped orifices.


Beads

High tensile strength steels are blended into band-shape by wire wrapping machine and covered with rubber mixture.

In this step, a separate rubber layers as described above are assembled by a rotating which is a rotation cylinder with flexible center so that it's edges can be brought closer to each other.


First, the inner line layer laid down on the drum. After that, the body ply layer must second be laid down on the drum. Then, the tow beads are attached to each side of the body ply layer with bead holder. The length should be in middle of the beads are determined by the type of the tire.


Then, the body ply layer sections located on either side of the beads are folded over the beads to hold on. After that, the sidewall layers are added to either side of drum by inflating the central part of the drum. Each edges of the drum are brought closer to each other to get the shape of the tire.


After that, the two of steel belt layers are laid down on the shaped tire. These plies in the steel belt layer being laid crosswise to the each other. It forms triangles-shaped. Finally, the tread layer is placed on the steel belt layer. Then the unfinished tire is removed from the drum. This tire is specially named as a 'green tire'.


In the next step, the green tire is put into the curing mold. In there, all the tread patterns and marking can be marked on the tire. In the curing mold, a curing bladder is filled with hot water with pressure that forces the rubber back into the mold cavity. The hot water and steam around the mold start the vulcanization process with temperature about 1800C. After Sometime, when the curing process is completed, the finished tire is removed from the curing mold.




How to check quality of the tire?

Quality testing is done in two ways, one way is testing all the manufactured tiers and the other one is using only a few tires.

  • All the manufactured tires are sent through an X-ray machine to identify defects. Also, if a defect can be identified the tire is reassemble and the fault is identified.
  • Another way, take the few tires from the finished products and sliced them to see if there are any defects in the inner layers or air bubbles between the layers.





Who are the leading tire manufactures in the world

In 1845, Scottish inventor named Robert Thomson discovered a rubber tire. After that, the tire manufacturing industry expanded rapidly. By now, Lot of manufacturers are coming in to the industry with their modern technologies. Below are some of those manufacturers.

  • Bridgestone
  • Michelin
  • Goodyear
  • Sumitomo
  • Pirelli
  • Hankook
  • Yokohama
  • Maxxis
  • Toyo Tires
  • Ceat