Tennis Balls: their evolution and manufacture
In this article, we’ll analyze tennis balls, how they’ve evolved and how they are manufactured. Tennis balls have changed considerably since the early days of tennis.
How have tennis balls evolved?
Tennis first began in 1870, and back then, tennis balls were made out of leather and filled with rags or horse hair. Rubber balls, which are similar to the ones we see today, are produced in India. They quickly took over the sport.
Tennis balls were originally white or black, but then the International Tennis Federation (ITF) introduced the yellow balls in the 1970s. The reason for this change was because the color yellow was easier to see on television.
The tennis balls that we use in today’s games are made to meet specific requirements that the International Tennis Federation establishes. Thus, they must be of a standard size, composition, and color.
The size of the tennis balls must be between 6.54 and 6.85 millimeters, with a weight of between 56.0 and 59.4 grams. The only color allowed is yellow with white stripes, because it allows for better visualization of the ball.
As for the materials that are used, it must consist of two halves of rubber domes that are put together. Pressurized air is then introduced to allow the ball to ensure it bounces in the correct way. Once they inject the air into the tennis ball, they cover them with glue and add a layer of yellow felt.
The manufacturing process
Manufacturers heat the tennis balls to make the glue seal to hold the two halves together. There’s a basic step by step process for manufacturing these elements, they are:
- Mixing the rubber together.
- When this is ready, the mix is made into a ball. Each ball is of the same weight and made with the same precision.
- Then they are cut in half and hollowed.
- They are then smoothed out and fused together with the correct air pressure inside.
- During this process, specific controls are made concerning the air pressure inside, which is measured at two atmospheres.
- The ideal mix for the fabric is Nylon and prestressed felt.
- Lastly, when the ball has all of these characteristics, the logo is printed on its surface.
After the final step, the tennis balls are placed in a hermetically sealed plastic cylinder. The air pressure in this cylinder is also two atmospheres.
One professional tournament or nine games is the lifespan for a tennis ball. This is because of permanent deformation in the structure.