Not one but two watchmakers came to Baselworld this year with new gear trains. Despite approaching the subject from different angles, they have the common denominator of using DRIE or UV LIGA technology. Breitling chose silicon for its wheels so as to reduce energy loss. Lang & Heyne, like Piaget, went for nothing less than gold. All these initiatives point to the high level of fundamental research going on inside watch R&D labs, as all three explore new possibilities on an atomic scale. Until now, silicon was used mainly to produce components for the movement’s regulating organ. As for gold, it had to be machined.
Breitling’s silicon wheels are one of five technical breakthroughs presented this spring, all of which are part of an experimental project designed to significantly improve the performance of the in-house B01 mechanical chronograph, introduced in 2009. “The next stage, after launching a perfectly solid and reliable movement, was to boost its performance,” explains Breitling vice president Jean-Paul Girardin. “To achieve this, we set up a research division whose role is to explore every possible means of optimisation and to be a test bench for innovative solutions. The brief for this gear train was to reduce the weight of the wheels so it would use less energy. By choosing silicon, we cut weight by half.”
The wheels in question are made by Sigatec, a specialist manufacturer. They are driven onto a non-treated steel arbor using an assembly technique that was developed in-house by Breitling. Trials showed that this interaction between steel and silicon means the teeth on the wheels must be precisely formed. The wheels must also be perfectly aligned to prevent the silicon, a very hard material, from cutting into the metal. “This is a first in watchmaking,” says Jean-Paul Girardin. “This new feature, combined with the other innovations of a ceramic baseplate and bridges, silicon escapement, variable-inertia balance, and elastic toothing for the wheels that transmit power from the base movement to the chronograph, increases power reserve by 45%, from 70 hours to 100 hours, without any modification to the barrel. This configuration guarantees performance that will pass COSC tests right off the bat.”
Breitling is to produce 100 of these calibres, which it will fit inside the Superocean Heritage Chronoworks. Girardin confirms that “production costs are still high, but results are on-target: shock and ageing tests have shown resistance is equal to that of traditional constructions.”
Lang & Heyne chose to use gold, but in a different way. Patek Philippe, Kari Voutilainen and De Bethune have all incorporated gold wheels into certain movements, but these are the exception, never the rule. Possibly because even hardened gold will ultimately lose its shape, due to its natural ductility. “Sooner or later, the forces at work in any watch mechanism will cause gold to bend out of shape,” explains Denis Flageollet, co-founder and master watchmaker at De Bethune, which has since shelved plans for gold wheels. Marco Lang, master watchmaker at the head of the small Saxon firm, has found a way round the problem by replacing traditional machining techniques with material growth technology. “We use an alloy supplied by a German manufacturer, a 14k pink gold, not any kind of special alloy,” he explains. “The wheels are made using LIGA, an electrochemical material growth process. We already incorporated this type of wheel into a small calibre back in 2009. Now we are able to equip our larger movements. These gold wheels improve performance and are ultimately more resistant than brass wheels, having a hardness of 260 Vickers versus 185 Vickers.”
In January this year, Piaget quietly introduced two gold wheels in its new Emperador XL 700P with quartz regulator. Manufactured by Mimotec, sister company to Sigatec, they are made from 24k gold with a hardness of 220 Vickers. “We spent five years developing the right manufacturing process and finding the most suitable alloy,” comments Mimotec founder and CEO Hubert Lorenz. “The biggest challenge was adapting the shape of the moulds to the chemical properties of the gold bath.” In Fine Watchmaking, no component is too small to warrant innovation.