At, production can only be superlative, as Philippe Bentele explained to delegates at the International Chronometry Conference, held in Montreux end September and hosted by the Société Suisse de Chronométrie. “ has been using the term ‘superlative’ to describe the precision of its watches since the late 1950s, when the brand made it a point of honour to manufacture chronometers whose precision was greater than standards of the day required. This was testified by the ‘Superlative Chronometer Officially Certified’ inscription on every chronometer dial.” Since 2015, has upped the ante and measured its watches’ reliability to even more draconian standards, having this year extended these criteria to its entire production. These requirements include a tolerance of -2/+2 seconds per day for all calibres.
It is, of course, one thing to impose such a standard and another to have the instruments with which to measure it. With this in mind, Rolex began by taking a closer look at how its watches are actually worn on a daily basis, then used these findings to draw up a testing protocol that exactly mirrors these real-life conditions. Following this, the brand set up its “Superlative Control”, a fully automated procedure within the production line that tests timekeeping precision, water-resistance, automatic winding and power reserve. This new facility is installed over 500 square metres on the lower ground floor of the production building, on the same level as and directly connected to the automated central stocking system. “This has the advantage that watches needn’t be taken out of the production circuit for testing. We are also ensured of stable conditions for the measuring instruments, and the system can operate round-the-clock,” adds Philippe Bentele.
The perfect match
For the first stage in this Superlative Control, the watches are fully wound, a task performed by six rotating heads turning on two axes to operate the automatic winding module in each watch. Two acoustic cells control the amplitude, beat error and proper functioning of the winding robot. The next stage verifies timekeeping precision. An exclusive read-off system takes a high-resolution image of each hand then analyses these images in three dimensions to determine the altitude of the said hands. Each image is linked to a universal reference time taken from a GPS time base. First the watches are rotated on a Cyclostock, a wheel that makes one revolution in six hours with cradles for the watches that also turn on themselves. They are then tested in seven static positions in conditions as near as possible to typical wearing conditions.
The next control examines water-resistance. After first checking air-tightness to prevent any risk of damage, the watches are immersed in tanks at the equivalent of 250 and 500 bar. After these 33 hours of testing, all that remains is to check power reserve. According to Philippe Bentele, “this fully automated installation is a means of controlling the entire production in perfectly reproducible and independent conditions. Advanced integration means this final control is part of assembly chain logistics, enabling optimal throughput time without any concession as to the representativeness of the different measures.” For Rolex, manufacturing parameters must exactly coincide with the perception each customer has of his or her watch.