Rolex is known for its reticence and reluctance to disclose information, earning it the nickname "oyster." The company's headquarters and manufacturing sites, in particular, remain largely shrouded in mystery. Kronos Germany editor-in-chief Rüdiger Bucher, who was granted permission to visit the Swiss headquarters and manufacturing site for the first time in about 10 years, takes us inside the hidden world of this crowned watch kingdom.
Read from the first part
http://www.webchronos.net/features/44587/
Translation by Akiko Ichikawa
Schön-Boulle – Dial and ceramic bezel manufacturing and gem setting
The dial is completed after going through approximately 60 manufacturing steps.
The Schönbourg site, inaugurated in 2000 and expanded in 2002, is located 7 kilometers from the central headquarters, but is also in the canton of Geneva. It is here that dials are manufactured. Gemstone setting is also carried out. Recently, the company has also begun producing ceramic Cerachrom bezels.
Dials are generally made of two materials: brass for dials without gemstones and gold for dials with gemstones. Mother-of-pearl, malachite, and meteorite are also used as exceptions. Dials can be crafted in a variety of colors using three methods: lacquer, electroplating (which involves immersing the dial in a solution to form a thin metal film), and PVD (which involves vapor-depositing a surface layer under vacuum). It takes approximately 60 steps to complete a single dial. Finally, the process of adding text and other details to the dial begins. The scales and text are printed using a stamping method known as octopus printing, and the applied hour markers and crown mark are applied as separately manufactured three-dimensional parts. These three-dimensional parts are also manufactured in-house and are individually hand-attached to the dial.
The Schöne-Bourg site covers an area of 73,000 square meters. While smaller than Rolex's other locations, much of it was impressive, just as it was in the central location and Plan-les-Ouates. It also houses the automated control systems warehouse (although it's significantly smaller than the previous two), several basement floors, quality control and laboratories throughout, and an in-house gemological department where diamonds, rubies, sapphires, and emeralds are quality-checked.
Rolex first introduced a ceramic bezel on the GMT-Master II in 2005, featuring gold numerals on a black ceramic background. In 2013, the first blue-and-black Cerachrom bezel was introduced. Currently, bezels are available in over 20 color variations. These bezels are made with a high-tech ceramic called Cerachrom, which Rolex calls Cerachrom. Instead of the traditional aluminum oxide (for red) or zirconium oxide (for colors other than red), the bezel is blended with pigments and binders. The resulting mixture is then poured into molds designed to create the numerals and dots, then baked in an oven for several days. The oven temperature is gradually increased, first to remove the binder at around 700°C, and finally to 1600°C, where it hardens and develops a deep color. Next, the fired ceramic ring is ground with a diamond disc to remove burrs from the edges and inside, smoothing the surface, then sandblasted all over, and coated with gold or platinum using PVD to fill in the recesses of the numbers and dots. Finally, the PVD coating is removed from the rest of the surface, polishing it to reveal the numbers and dots clearly.
The ceramic ring is extremely hard, scratch-resistant, and UV-resistant. What's surprising is that this high-tech ceramic is also quite flexible, otherwise it wouldn't be possible to press it onto a metal ring.
