Football is the most popular sport on the planet. In 2006 FIFA reported that there were 265 million players registered to one of its member associations, and this doesn’t include the countless players who have the occasional kick around at the park. Around 40 million footballs are sold each year around the world, making the football industry big business. Football technology has progressed significantly in recent years, this blog post explores the manufacturing techniques which are used to make one of those 40 million balls.
Stitched Leather Footballs
The modern football was made possible thanks to the invention of vulcanised rubber by Charles Goodyear in the 1800s. Vulcanisation makes rubber stretchy and durable, allowing it to be used as the inflatable bladder in the centre of a football. The inflatable bladder dramatically improved the bounce of the ball. The outer panels of the ball were made of leather which was tanned to improve durability. The thickness of the panels was difficult to control as leather is a natural material. The panels were also cut by hand (until the early 1900s at least), leading to inconsistencies in shape. There were two main problems with leather footballs. The leather panels stretched over time, causing the ball to lose its shape, and the leather also absorbed water. A football which is soaked in water is heavy, making it uncomfortable and sometimes painful to kick and header.
Figure 1 Leather football used in the 1936 Olympics
Stitched Synthetic Footballs
The introduction of synthetic leather in the 1960s enabled manufacturers to more easily control the panel construction of balls. The most common structure was the 32 panel ball based around a truncated icosahedron, consisting of 12 regular pentagons and 20 regular hexagons.
Figure 2 Truncated icosahedron; 32 panel football
The mathematically ordered shape created a ball which was rounder than ever before and also consistently round, without the bulges and deformities which plagued early footballs. The balls consist of synthetic panels and a latex or butyl bladder. To control the panels shape carefully, each one is die cut (using a very accurate metal tool) from a sheet of material and holes are pre-punched into each one to make stitching easier.
The manufacture of synthetic balls is labour intensive. It takes an experienced stitcher around 3 hours to stitch a ball together, with up to 15 minutes taken to stitch the last seam together.
The introduction of synthetic materials meant that footballs absorbed much less water than leather balls. Consequently, the mass and playing characteristics of the ball wouldn’t noticeably change in the wet (making them much better in British weather). The synthetic panels also stretched much less than leather, meaning synthetic balls also retained their shape much longer than leather balls.
Thermally Bonded Footballs: The Modern Ball
Figure 3 Thermal bonding of panels
‘Thermally bonded’ footballs are different from their stitched counterparts in the way the panels are attached together. All of the panels are arranged inside a mould with adhesive applied to the edges of each panel. The mould is then heated and pressurised, gluing all the panels together into a sphere. This process is much less labour intensive than stitching the panels together. The first thermally bonded football was used in the 2004 European Championship.
Since then, many other changes have occurred as a direct result of thermal bonding. Panel design has changed significantly as the number of panels used to make a ball can be dramatically reduced (the Jabulani – used in the 2010 World Cup – has only 8 panels) because straight edges (to stitch along) are no longer needed, much more exotic curved panels can be used. In the latest ball designs, surface texture has been added to the panel surface to try and improve the aerodynamic performance of the ball. This has come about after lots of controversy surrounding the behaviour of the latest balls used in the world cup.
A further development of the modern ball is the addition of a fabric carcass. This forms an intermediate layer between the panels and the bladder. The aim of which is to improve the consistency of the balls behaviour during impact.
Figure 4 Fabric carcass surrounding bladder
Recent developments in ball manufacture have given freedom to designers to make the product look more attractive whilst still aiming to improve performance. Footballs can now be made more spherical with better shape retention and water resistance than ever before.
The Football of the Future: Where next?
With all the recent developments made in ‘football’ technology, where do we head next in search of the perfect football? Judging by the well-publicised criticism of recent balls, I am certain the aerodynamic performance of footballs will be looked into in greater depth. The other hot topic that could influence the football of the future is goal line technology. It remains to be seen if this can be successfully incorporated into a ball which is suitable for the professional game.
Figure 5 CAIROS Goal line technology inside a ball
I’m sure a new material or manufacturing process will come along at some point that will once again change the way footballs are made. But where do we stop?