In the previous blog, we gave a brief introduction to the components of a tire. In this blog, we will give you a brief introduction to the process of car tire manufacturing. A good tire supplier will always use good natural rubber or synthetic rubber during the manufacturing process. Apart from the rubber, other materials are also used. Another primary ingredient is carbon black which is a fine soft powder, created from crude oil or natural gas when burnt. Along with Sulfur other chemicals are used in tires too. Some of the chemicals, are first mixed with rubber and then heated. This produce specific tire characteristics such as high friction (but low mileage) for heavy-duty tires or high mileage (but lower friction) for a passenger car tire. So, lets take a look at it, in details.
Blend
The first step for manufacturing a tire is to mix the raw materials to form the rubber compound. At most, 30 ingredients are used for a tire’s rubber blend. The ingredient proportions depend on what type of tire is being manufactured. It’s composed of several types of rubber, fillers, and other ingredients which are then mixed in giant blenders known as Banbury mixers. These create a black gummy compound that’ll be sent on for milling.
Mill
When sent in for mill, each mix is then milled with additional heating to soften the batch and mix the chemicals. The batch goes through a mixer again, where more chemicals are added for formation. This is known as the final mix. During these steps, heat and friction are applied to the batch to soften the rubber and evenly distribute the chemicals.
After the mixing is over and the rubber has cooled, it goes through a powerful rolling mill where the rubber is cut into strips that will form the basic structure of your tire. During the milling stage, all the other elements of the tire are also prepared, some of which are then further coated in another type of rubber. Each strip is called a ply of the tire.
Build
The tire itself is constructed, from the inside out. When the beads of a tire are made, wire bundles are wrapped on a wire wrapping machine. The bundles are then formed into rings, and the rings are covered with rubber. The rubber of the tire tread and sidewall are manufactured separately with the help of an extruder. The sidewall rubber is covered with a protective plastic sheet and rolled. Tread rubber is sliced into several strips. They are then loaded into large, flat metal cases. Then all these components are placed in a tire-building machine that ensures every part is in its precise location. This results in what looks like a finished product. This is known as a green tire.
Cure
The green tire is pressed with the help of a large mold, compressing all of the parts of the tire together and giving the tire its final shape. After curing is complete, the tire is removed from the mold for cooling and then tested thoroughly. Each tire is inspected for flaws such as bubbles in the rubber of the tread, sidewall, and interior of the tire. Then, the tire is placed on a test wheel, inflated, and spun. Sensors in the test wheel measure the balance of the tire and determine whether the tire will run in a straight line or not.
As the design and assembly of a modern tire are highly advanced, rarely is one rejected. Once the tire has been inspected and runs on the test wheel, it is passed on to a good tire supplier.
