Golf is one of the most popular sports in the world.Â Over 850 million golf balls are manufactured and shipped annually and bring in about $550 million in annual sales.Â Golf balls made today are constructed of two or three parts.
Â A two-piece golf ball is made of plastic and rubber and is most commonly used by the casual golfer. These types of balls make up 70 percent of the golf ball production and last longer that the three-piece ball used by professional golfers.Â The three-piece golf ball is constructed of a plastic cover, windings of rubber thread and a solid core or a core containing gel or a liquid of sugar and water.Â The dimple pattern on the surface of the ball determines flight performance.
Â The Dimples of the Golf Ball
There are three common dimple patterns for golf balls: the icosahedral, the dodecahedral, and the octahedral.Â The icosahedral pattern has 20 identical triangular faces; the dodecahedral 12 identical faces in the shape of pentagons; and the octahedral eight-sided triangular faces.Â Some balls have 500 dimples based on the icosahedral pattern.
Â In general, the more dimples a golf ball has, the better it flies so long as the dimples are about .38cm (.15 inch) in diameter.Â The depth and size of the dimples are other factors in the performance of the golf ball. Shallow dimples generate more spin which increases lift and allows the ball to stay in the air longer and roll less.Â In contrast, deeper dimples generate less spin, have decreased lift, less air time and increased roll.Â Small dimples usually give the golf ball a lower trajectory with good control in wind while small large dimples give a longer flight time with higher trajectory.
Â Technology has advanced to the point that allows manufacturers to custom-fit golf balls for weather conditions, a playerâ€™s particular game and specific course conditions. Golf balls are separated into four basic performance categories: control and maneuverability; distance and durability; slow club-head speed; and distance and control. Within these four categories there are over 80 different balls of varying design and construction materials.
Â The History of Golf Balls
Â The first golf ball similar to todayâ€™s, was first used some time in the 1400s. Dutchmen stuffed feathers into a 3.75cm (1.5 inch) leather pouch. It was called a feathery and was made by stitching together a round pod made from strips of horse or bull hide softened into leather. The pod was turned inside out and a small opening left into which chicken or goose feathers were stuffed to retain the spherical shape. The opening was stitched closed, the ball dried and then hammered into a round shape. To complete the process, the ball was rubbed with oil and chalk. This version of golf balls lasted about 450 years.
Â Around 1850, the feathery was replaced with a ball made out of a natural gum, called gutta-percha, found in Southeast Asia.Â This ball, developed in Italy, was manufactured by heating a slice of resin rope that had been pre-mixed with a stabilizer. Heating made the slice pliable and allowed the maker to shape it into a sphere. The ball was rounder and smoother than the feathery ball, but had poorer flight performance. However, the ball was much cheaper to make, thus it affordable for the working class.Â This version of the golf ball remained popular until around 1910.
Â The gutty ball, as this version was called, went through several transformations during its heyday. Ballmakers discovered a ball with a rough surface was more aerodynamic so they used a knife to cut grooves in the balls to simulate the stitching of the feathery and pounded the ball with a chisel-faced hammer to produce bruises and nicks on the surface of the gutty ball. Â Ballmakers also experimented with adding other materials into the pure gutta percha before shaping the ball, but though the balls were more durable, they couldnâ€™t produce distance.
Â By the late 1870s, machined iron molds with regular patterns inscribed on their insides were developed to make golf balls. The brambleberry design with raised dimples was one of the most popular. These particular molds created a regular pattern over the surface, thus eliminating the need for hand hammering. From this ball, the aerodynamic design progressed further as did the rate of manufacturing.
Â Spalding produced the first American-made golf ball in 1895.Â By the early twentieth century B.F. Goodrich invented a lighter ball that was made from tightly wound rubber thread.Â In 1908, Spalding introduced the recessed dimpled golf ball which proved to be a huge success.Â It dominated the market by 1930 and the spherical dimple became the standard. Over the years, the dimples evolved to include the elliptical and truncated cone dimples.
Â The Construction of the Golf Ball
Â A two-piece golf ball consists of a solid rubber core with an ionomer resin, a durable thermoplastic, cover.Â The rubber is a hard block that is heated and pressed to form a sphere.Â The three-piece ball has a smaller solid rubber or liquid-filled center with rubber thread wound around it, and an ionomer or balata rubber cover.
Â During the 1970s, a petroleum-based polymer called polybutadiene was introduced to the interior of the golf ball. The material produced a ball that was too soft and had more bounce, so Spalding continued their research and eventually determined zinc would strengthen the material. The reinforced polybutadiene quickly became widely used by other manufacturers.
Â The Manufacturing Process of Golf Balls
Â Two-piece golf balls are easier to make than three-piece balls. Three-piece balls can require over 80 different manufacturing steps, 32 inspections and take up to 30 days to make one ball. Two-piece balls can be produced in one day and require only about half the steps as the three-piece balls.
Â In the center of the two-piece ball is a molded core comprised of a blend of several ingredients which are chemically reactive to give a rubber-type compound. A small core of about 3.75cm (1.5 inch) is formed after heat and pressure is applied.
Â To form the cover and dimples on a two-piece golf ball, injection or compression molding is used. When injection molding is used, molten thermoplastic is injected into the dimpled cavity surrounding the core which is centered within a mold cavity with pins. Â The heat and pressure cause the material of the cover to flow and join with the center and form the dimpled shape and size of the finished ball. As the plastic cools, it hardens and the pins retract. The finished ball is then removed.
Â When compression molding used, the cover is injection molded into two hollow hemispheres.Â These two molds are then positioned around the core, heated and then pressed together using a mold which fuses the cover to the core and forms the dimples.Â This is the process used for three-piece golf balls because the flowing hot plastic in the injection molding would cause breaks in the rubber threads of the balls.
Â Once the molding process is complete, the rough spots and the seam on the cover are removed and two coats of paint applied. Each ball sits on two posts that spin so the automatically controlled spray guns apply the paint uniformly.Â The ball is stamped with the logo and the last step is to apply a clear coat for scuff resistance and high sheen.
Â The entire manufacturing process is monitored by computers and in addition, the three-piece balls are x-rayed to ensure the centers are perfectly round.Â Compression ratings are used to measure the compression balls, though the ratings have no meaning for the two-piece golf balls.Â The two-piece are measured by a coefficiency rating, a ratio of initial speed to return speed after the ball strikes a metal plate. The procedure measures the restitution coefficiency.
Â Mechanical testing is used to verify the ballâ€™s performance meets the standards of the United States Golf Association. Some manufacturers use wind tunnels to test wind resistance and lift.Â Other special machines such as the True Temper Mechanical Golfer, also called the Iron Bryron can be fitted for any club and set up at different swing speeds.Â Normal testing has the Iron Byron configured using a 5-iron, 9-iron and a driver.Â The Ball Launcher machine provides the capability to propel balls through the air at any spin rate, velocity and launch angle.
Â The data from these machines can be measured and analyzed including the carry distance, roll distance, total distance, statistical accuracy area and the apogee angle which indicates the height of the trajectory reached by the ball.
Â Further technology will no doubt improve the performance of the golf ball even more and golfers across the globe will continue to have the best golf balls available for their games.
The copyright of the article â€œHow Golf Balls are Madeâ€ is owned by Cheryl Weldon and permission to republish in print or online must be granted by the author in writing.