A peek inside Callaway’s factory reveals the complex anatomy of high-end golf balls

CUT OPEN a golf ball made before the dawn of the 21st century, and there’s a good chance you’ll find a messy tangle of tightly-wound rubber bands hugging a hard rubber core. That springy mass compresses when a club smacks the ball and rebounds as it launches into the air. Modern versions function around the same basic principle, but they rely on a fully solid core made of carefully engineered rubber compounds wrapped in meticulously measured layers of thermoplastic and urethane. Put together, those layers determine how the ball will act as it comes off the club face. 

Take, for example, Callaway’s Chrome Soft line of balls: The spheres promise relatively low spin and high speed off the driver and irons, which helps with distance without sacrificing control on wedge shots around the green. As the Callaway has churned out these high-end balls from its Chicopee, Mass., factory, it’s become one of the fastest growing golf ball manufacturers in the world. There, we got a look at the elaborate chemistry and engineering that goes into those little orbs before we buy them and shank them into the water hazard.

↑ The process starts with a proprietary mixture of synthetic rubber and other powdered compounds that funnel into the three-story-high gravity-fed mixer. Engineers keep meticulous tabs on the process, which applies heat and pressure to the materials, combining them into a firm rubbery mass. 

↑ As a uniform substance, the material drops onto large metal rollers that cool it and create a sheet. A worker then cuts the flattened substrate by hand. From here, the pieces go to storage, while small samples head to Callaway’s on-site lab, where techs test the batch’s compression, among other key variables. 

↑ Callaway cures and dries the sheets in a climate-controlled room that’s cooler than the rest of the factory and has very low humidity. Every batch is carefully labeled with its manufacturing details and chemical properties. The material is also color-coded according to what ball it’s bound for. The blue, for example, ends up in the Chrome Soft X LS balls. These promise extra-low spin, which translates into faster speeds off the club face and more distance.

↑ Once the sheets have cured and dried, the shaping process begins. Cut into strips and warmed up to become malleable, the material enters a machine similar to the Play-Doh extruder you had as a kid—only this dough is very hot, and a spinning blade chops part of it off multiple times per second. The resulting small logs are called preforms, and Callaway workers regularly weigh them to ensure that the extruder is outputting the correct amount of material to create a ball’s core.

↑ Preforms go into a molding press, which heats them up and applies up to 2,000 pounds of pressure. As they shape into identical spheres, the temperature and squeeze cause a chemical reaction that locks in the cores’ performance characteristics. This gray material ends up in the Chrome Soft X balls, which are geared toward advanced players with faster swings, who want less spin off the driver but more on iron shots for extra control. From here, the orbs enter a grinding process, which perfects their size and creates a slightly rough texture that helps the outer layers adhere. 

↑ Each golf ball has at least one level of mantle, a thermoplastic layer that sits between the core and the cover. Inside an injection molding machine, the cores sit on pins, which allows the apparatus to surround them with one or two mantle layers. The balls then once again parade back into the grinder for sizing and textural adjustments.

↑ The balls go through another injection molding process to get a golf ball’s signature dimpled urethane cover. After this step, Callaway employs a secretive three-dimensional X-ray process to inspect the inside of every ball without cutting it open. This ensures the center of gravity exists in its actual center; if it’s off even a little bit, odd or unpredictable flight paths will result.

↑ A large rotating canister full of ceramic pebbles acts like a rock tumbler to remove any excess material from the outsides of the balls. They’ll spend several minutes getting banged around before they head onto a conveyor belt for a wash and a rinse on their way to the printer. Fresh out of the tumbler, the balls look like the finished product, but they don’t feel like it: The matte exterior lacks the familiar glossy polish.

↑ Before getting emblazoned with their logos, the balls pass through one more round of quality control. A machine rotates each one in front of a six-camera array and a ring of LEDs. This setup can spot any flaws on the surface—such as cuts, nicks, or scuffs—that the smoothing and washing process can sometimes leave behind. If the system detects an abnormality, a human inspector steps in. 

↑ Each Callaway line has its own specific branding that’s applied to the nearly finished balls. A flexible rubber blob picks up the ink and stamps it precisely onto each near-complete sphere. Some will simply showcase the Callaway logo along with a number and model name, while others, like the Chrome Soft Triple Track pictured above, have more complex markings like lines for guiding putts. 

↑ With the printing applied, each ball gets a coat of clear primer to protect the surface and the ink, as well as a final polish coat that delivers the familiar glossy surface. To ensure even coverage, the balls spin at high-speeds atop three-tined forks, which allows spray guns to apply the coatings from above and below.

↑ With the polish applied, the balls are finished. They’re inspected again to protect against inconsistencies and then packaged into dozens and sent out to stores and pro shops around the world. The finished ERC Soft balls pictured here include a compound in the cover called an impact modifier; developed by materials company Dow, the sheathing maintains the ball’s soft feel while making the outer cover more durable against scuffs and cuts. 

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