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The secret of Swiss watch durability and beauty

How can a thin coating start your day accurately?

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Swiss watches enjoy centuries of reputation as the most beautiful and accurate of devices. But resting on laurels would let them fall behind the competition. So, the industry has embraced special coatings to add attractiveness while reducing wear and preserving accuracy.

By Erik Sherman

Tick Tock

Few luxuries embrace the confounding combination of beauty and function of a Swiss wristwatch. Most personal adornments with equivalent style, design, and value are jewelry kept under lock and key other than on the rare special occasion.

Swiss watches are used more frequently owing to their ultimately utilitarian nature. Aside from beauty, they must exhibit a precision and accuracy of engineering and manufacturing that is startling when contemplated.

The Contrôle Officiel Suisse des Chronomètres, or COSC, is the official Swiss organization that certifies the precision of between 1.6 million and 1.8 million watches and clocks a year. The COSC applies demanding tests to evaluate products in the light of the ISO 3159 international standard for mechanical wristwatches and its own specifications, when no such standard exists. Such an attention to such detail is nothing new — for nearly 500 years, Switzerland and its watchmaking industry have been serious about accuracy. The best mechanical timepieces will gain or lose only a second a day. For a certified quartz watch, the daily accuracy is within a small fraction of a percent.

Whether certified or not and quartz- or spring-driven, Swiss watches all must battle an inherent problem: the potentially hundreds of parts involved in a watch. The outside must be striking while resisting corrosion. Inside, parts must also be durable and resist friction and wear to provide accurate time over years and even decades of use.

Manufacturers use the most advanced engineering and production techniques and strategies available. One significant set of technologies is coatings a hundredth the thickness of a human hair. For decades, companies like Oerlikon have provided technologies that allow manufacturers to enhance the look of exterior parts, adding colors in-fashion such as deep black, anthracite, gold, chocolate brown, and bronze surfaces for beauty. The coatings also bring abrasion- and scratch-resistance to housing, helping them retain their luster while lasting longer.

More recently, the use of coatings has extended to the gears, rotor, escapement, escape wheel, and other parts of the movement. No matter how well designed and made, moving parts will undergo wear. “So long as uncoated elements show no signs of abrasion, timekeeping accuracy should remain,” says Beat Weber, Oerlikon Balzers Segment Manager in High End Deco. “But as soon as the tiny interior parts inside a watch show wear, their functionality is affected.”

Amorphous carbon coatings cover and protect the watch parts from wear and corrosion, helping to preserve their accuracy. The coatings also reduce the amount of lubricant needed and ensure a less frequent maintenance schedule.

In some watch designs, a cutaway case design visually exposes a segment of the movement to the watch owner. A coating provides those parts with the additional durability needed for accuracy and operation while also making them visually attractive to pair with the aesthetics of the watch’s design.

Coatings also play an important role for the manufacturing equipment that make watch parts. “After only 10 to 20 operating cycles, drills with a diameter of as little as 0.2 mm will become worn,” Weber says. “Coatings can prolong the service life of the same tool by a factor of up to 50.”

That is why more and more watch makers decide to coat their watch parts and tools. Oerlikon is an influential force in that industry, responsible for some of the most innovative technologies, products, and services.

 

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