Technological advances in materials and aerodynamics now allow the manufacturer to custom-fit a golf ball for a players’ particular game, for weather conditions, and even for specific course conditions. Golf balls can be separated into four basic performance categories: distance and durability; control and maneuverability; distance and control; and slow clubhead speed. Within these categories, there are more than 80 different balls of varying construction materials and design.
Today, the golf ball market is worth around $550 million in annual sales, with over 850 million golf balls being manufactured and shipped every year. A two-piece ball is made of rubber and plastic and is mostly used by the casual golfer. These balls last a lot longer than the three-piece balls the pros use and hence make up 70% of all golf ball production.
Shallow dimples generate more spin on a golf ball than deep dimples, which increases lift and causes the ball to rise and stay in the air longer and roll less. Deep dimples generate less spin on a golf ball than shallow dimples, which decrease lift and causes the ball to stay on a low trajectory, with less air time and greater role.
The United States Golf Association (USGA) has established rules for the ball in regard to maximum weight, minimum size, spherical symmetry, initial velocity, and overall distance. The weight of the ball must not be greater than 1.62 oz (45.93 g) and must be spherically symmetrical. These rules are updated every year.
The most common dimple patterns are icosahedral, the dodecahedral, and the octahedral. Some balls are based on the icosahedral with 500 dimples. As a general rule, the more dimples a ball has the better it flies, provided those dimples are about 0.15 in (0.38 cm) in diameter.
Currently, there are around 850 models of balls that conform to these standards. Recently, balls that are about 2% larger than ordinary balls have been introduced that still conform to USGA rules. These balls have softer cores and thicker, harder covers, which leads to a straighter, longer shot.
Carry distance is the distance a golf ball travels in the air and is measured using a grid system with markers in the landing zone. Total distance is the distance a golf ball travels in the air plus the roll distance.
The statistical accuracy area (SAA) or dispersion area is used as a measure of a golf ball’s accuracy. For a given ball, the SAA value is based on the deviations of the ball’s performance in the directions of carrying and left/right of the centerline. These deviations are used to calculate an equivalent elliptical landing area.
Three-piece golf balls are more difficult to make and can require more than 80 different manufacturing steps and 32 inspections, taking up to 30 days to make one ball. Two-piece balls require about half of these steps and can be produced in as little as one day.
Another machine called the Ball Launcher provides the capability to propel balls through the air at any velocity, spin rate, and launch angle. Using both types of equipment, performance data associated with the flight of a golf ball can be measured and analyzed.
Mechanical testing is also used to verify that the ball’s performance meets the USGA’s standards. For normal testing, the Iron Byron is configured using a driver, 5 iron, and 9 iron.
1 The center of the two-piece ball is a molded core. It is a blend of several different ingredients, all of which are chemically reactive to give a rubber type compound. After heat and pressure are applied, a core of about 1.5 inches (3.75 cm) is formed.
Forming the cover and dimples
2 Injection molding or compression molding is used to form the cover and dimples on a two-piece ball using a two-piece mold. Heat and pressure cause the cover material to flow to join with the center forming the dimpled shape and size of the finished ball.
3 With compression molding, the cover is the first injection molded into two hollow hemispheres. These are positioned around the core, heated and then pressed together, using a mold which fuses the cover to the core and also forms the dimples. Three-piece balls are all compression molded since the hot plastic flowing through would distort and probably cause breaks in the rubber threads.
Polishing, painting, and final coating
Two coats of paint are applied to the ball. Each ball sits on two posts, which spins so that the paint is applied uniformly. Next, the ball is stamped with the logo.
Drying and packaging
5 After the paint is applied, the balls are loaded into containers and placed in large dryers. After drying, the balls are ready for packaging in boxes and other containers.
Compression ratings are also used to measure compression-molded, wound golf balls. Instead, these balls are measured by a coefficiency rating, which is the ratio of initial speed to return speed after the ball has struck a metal plate.