The birthplace of Gorilla Glass resides in a small town in Kentucky's Bluegrass region. Find out how the glass was originally developed, and how it ended up on 4.5 billion devices worldwide.

Image: Mark Cornelison

The rolling green hills of central Kentucky are dotted with the occasional historical site such as Shaker Village and Abraham Lincoln's childhood home, not to mention bourbon distilleries and Thoroughbred horse farms so impressive that the barns are larger than most antebellum mansions.

In the midst of these picturesque locations is another significant place: the Corning factory in Harrodsburg, Ky. This is the birthplace of Gorilla Glass and where it's still produced to this day.

Just a mile past a full-sized replica of Fort Harrod sits the 360,000-square-foot Corning plant that opened in 1952 on 43 acres. It's one of the the biggest employers in this tiny town of 8,377 residents, with each of the approximately 400 employees logging an average of 14 years of service. Among Corning's worldwide employee tally of 40,000 employees is a sole employee with 52 years of service, and this employee is at the Harrodsburg plant. That kind of dedication is rare in the tech industry, where moving to a new job is an expected part of the career ladder.

Corning, which was founded in Corning, N.Y. in 1851, has manufacturing facilities around the globe, but Harrodsburg is the company's oldest operating plant. Harrodsburg's facility has focused on just a few products and continually innovates to make them better. It developed Gorilla Glass 5, which debuted earlier this year, and the plant also makes Willow Glass, an ultra-thin, bendable glass that can be spooled like a giant roll of paper towels.

Corning had sales of $9.8 billion in 2015. Companywide, Corning spends about 10% of its revenue each year on research and development. "It's why we've survived as long as we have, and we'll continue to survive," said Pat Carrothers, Corning's Harrodsburg plant manager.

The Harrodsburg plant originally produced glass pressings for various military, academic, consumer, and scientific applications. It segued in the mid-1980s into developing glass substrates for the LCD market. And in 2006, everything changed when Apple came calling, and the Harrodsburg plant was the first to make Gorilla Glass. As demand increased, the Harrodsburg plant couldn't produce all the Gorilla Glass needed, so now other Corning plants manufacture some of the necessary materials.

SEE: Gorilla Glass 5 will protect phones and tablets from 80% of drops (TechRepublic)

"In 2006, we were approached by Apple to produce a cover material. They were basically using plastic at the time. The thing of it is, they're under a tight schedule," said Joe Dunning, supervisor of corporate communications for Corning.

"Being the world leader in glass ceramics and things like that, we get approached by them [Apple] to see if we can come up with a solution. The caveat is we've got six months. Not only do we have to invent the solution, use our material expertise, but we have to process it and get it through development and manufacturing. It was because of the deep knowledge of glass that we had with our experts at Sullivan Park along with the expertise with the manufacturing process with the folks that we have here that we were able to meet that extremely tight deadline and produce the first version of Gorilla Glass all within six months," Dunning explained. Sullivan Park Research is in Corning, N.Y. and is the company's largest R&D facility.

Carrothers said, "We were always monkeying with the molecular structure of glass to start with. So we took that concept and basically used a new glass recipe and developed Gorilla Glass."

Gorilla Glass was used on the first Apple iPhone in 2007. Although many of their customers now require nondisclosure agreements from Corning before they use Gorilla Glass on their mobile devices, Corning does say that the super strong glass is on 4.5 billion devices worldwide from 40 different major brands. Customers that they can mention include Motorola, HTC, Samsung, and Huawei. The full list of customers is on Corning's site.

An HTC spokesperson said the reason they use Gorilla Glass is because, "Build quality is extremely important to HTC and our customers, and for this reason the HTC 10 was mercilessly engineered to handle everyday knocks, bumps, and scratches, including over 10,000 drop, bend, scratch, and corrosion tests. Our decision to use Gorilla Glass on the display is a key component of this strong build quality."

Inside the factory

The plant itself is nondescript, sitting in a mostly residential neighborhood in Harrodsburg. But inside, it's as if Willy Wonka's chocolate factory has come to life, but with glass instead of delicious candy being produced. On the ground floor, a plethora of workers bustle about, carting giant rolls of Willow Glass, and moving vast sheets of Gorilla Glass. In another area on the ground floor, trucks dump off the raw materials used to make the glass.

SEE: Photo gallery of the Corning plant (TechRepublic)

Upstairs, in the melting area, there's a large brick box that is a glass melting tank. The area feels like Phoenix in the summer, as the air is extremely hot, despite insulation surrounding the melting tank. An orange glow is visible through a small window in the tank as sand and other materials are melted into liquid at upward of 2,300 degrees Fahrenheit. Impurities are removed before the liquid is cooled and fed into an isopipe that is similar to a rain gutter and delivers the liquid glass to the next step in the process. Employees sit in the central control room next door to monitor production.

SEE: How tough is the new Gorilla Glass 5? (CNET)

"This is where fusion happens. This is the magic of what Corning does in this room," Carrothers said. The glass being produced is in sheets 5 ft. wide and .7mm thick. The largest sheet of glass that Corning can make is called Gen 10, and it's 10 ft. x 10 ft., but they don't make that size in Harrodsburg. The maximum size in Harrodsburg is called Gen 7.5, and it's 2200mm x 1950 mm, which is about 7.2 ft. x 6.4 ft.

"Gen 10 can't be shipped--it's too large. Those plants are co-located with the client," he said, adding that the Corning plant in Hefei, China is one such facility.

When the glass is fused and cooled, it is scored and broken into smaller sheets by a robot. The plant produces tons of glass each day, Carrothers said, declining to specify the precise amount for competitive reasons. Most of the product is shipped to Asia, where customers manufacture mobile devices, he said.

The future of Gorilla Glass

The Harrodsburg plant has been working at full capacity for 64 years, and there's no end in sight, as the demand for mobile devices, and ever-stronger glass, continues. The newest Gorilla Glass, version 5, can withstand 80% of drops from shoulder height. Gorilla Glass is also being tested for vehicles, for use both inside the car and for windshields, since it's stronger and lighter than traditional glass and optics are better for heads-up displays, Carrothers said.

Gorilla Glass is already used on the BMW i8 and the Ford GT.

"On the Ford vehicle, it's the windshield, the back window, and the panel on the inside. It can be used anywhere there is glass on a car. Basically think of the interior of the car as being a smartphone. Because that's about the way it's going," he said.

The top 3 takeaways for TechRepublic readers

Gorilla Glass was originally developed at Corning's Harrodsburg, Ky. plant in 2006, and debuted on the first Apple iPhone in 2007. The Harrodsburg plant is Corning's oldest operating plant, and it still manufactures Gorilla Glass. Gorilla Glass is on 4.5 billion devices worldwide and is now being used on automobiles including the Ford GT and the BMW i8.

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