In 1991 Swedish legend Bjorn Borg made a dramatic return to the tennis circuit with a wild card entry into the first round of the Monte Carlo Masters.
Eyebrows were raised as he strode onto court sporting the same wooden Donnay racket he’d used in his heyday, keen to prove that it could still cut it against the modern graphite design wielded by his opponent Jordi Arrese.
He failed, losing in straight sets and only helping to demonstrate how much stronger, more powerful and playable modern rackets had become.
These days, racket design has only become more important as advanced materials offer players the blend of strength, comfort, flexibility and feel that are needed to compete at the highest level.
But have you ever wondered how those rackets are made? Well you’re in the right place…
What are tennis rackets made from?
Before we get into the actual manufacturing process, it’s useful to understand what material rackets are made from.
Most modern rackets are made from different types and grades of graphite.
Graphite is essentially a crystalline form of carbon. The exact structure and formation of those carbon fibres will determine the characteristics and performance of the material. For example, Wilson uses a braided graphite which they claim makes for a stronger construction that absorbs harsh vibrations.
Occasionally metals such as copper, titanium, or tungsten are also woven in.
As you’ll see below, during the manufacturing process, those sheets of carbon fibres are layered up to add different properties to different parts of the frame.
The Manufacturing Process
There are obviously subtle differences in how rackets are produced depending on the manufacturer. Yonex may take a slightly different approach to Head and Babolat to Wilson but in general the process takes some very familiar steps.
Of course, nothing gets done without a thorough design process. Expert designers set out to create a racket to specialise in power, control, spin or feel and decide how best to achieve the balance they’re looking for.
The shape of the frame is initially designed using 3D software, which is able to test how the frame will react to different forces and conditions.
But the racket’s geometry is also assessed by hand using a rapid prototyping machine, essentially 3D printing the design so it can be handled and inspected with the human eye.
Forming the Racket shape
As discussed above, most modern rackets are made from graphite, a form of carbon fibre.
The carbon fibre is a surprisingly soft, flexible material which comes in large rolls, stored at -15°C. They’re pre-impregnated with a plastic resin giving them the informal name ‘prepreg‘.
The first step to creating the rackets is to cut out sections of this prepreg and layer it up, adjusting the direction of the fibres in different areas to vary the strength and flexibility at individual parts of the frame.
When the layering is done, the material is rolled tightly around a steel bar to create a long flexible tube.
The tube is then pressed around a steel mould, forming the rough shape of a racket’s frame.
At this stage yet more pieces of prepreg material are layered on to specific areas of the frame, for example to strengthen the throat or add flex to different parts of the hoop.
Heating the Mould
With the shape of the racket formed, the mould is heated to 160 degrees to harden the materials and bond the layers of carbon fibre. At the same time a 10 bar pressure is applied inside the tube of the frame to push the fibres outwards and create the hollow interior, allowing it to feel lightweight.
Cleaning & Inspection
On removal from the oven the racket is cleaned and finely sanded, removing any debris and blemishes to create a completely smooth outer surface. The frame will also be inspected – not just by human eye but mechanically to check for any imperfections.
Drilling the Grommets
When the racket is set, sanded and cleaned it’s time to drill the holes for the grommets. A high precision carbide drill is used to make sure the holes are in the right place. Of course the number and placement of the grommets will depend on the string pattern of this specific frame.
Paint & Design
At this stage the racket is given its recognisable paint job, the brand’s colours and logos applied using a spray paint machine.
Handle Pallet and Grip
Finally, the handle pallet is attached, depending on the grip size of this particular frame. The racket is then placed in a machine which rotates it and applies the grip tape, wrapping it tightly around the handle. Sometimes this is finished by hand.
Of course if it’s to be sold pre-strung, the string will now need to be added but for more advanced rackets that’s usually the end of the manufacturing process.
What about Aluminium Frames?
Aluminium frames are less common these days as they don’t have the strength and superior playing characteristics of more advanced materials. However they are cheaper to produce, in part due to a simpler manufacturing process.
Raw aluminium is melted down and forced through a die into the shape of the racket. The grommet holes are then drilled and sanded at which point the frames are tempered.
Tempering involves heating the frame to a high temperature and then plunging it into water to rapidly cool. This strengthens the aluminium.
The frame is then strung and finished in much the same way as a graphite racket.
Stop Making That Awful Racket…
Hopefully this has given you a useful insight into how advanced tennis rackets are made. Something to consider next time you bemoan the price of the latest Wilson Pro Staff update.