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A watch ahead of its time

News International-French

1 Jul 2019

The Carrera Calibre Heuer 02T Tourbillon Nanograph represents a very discrete revolution in watchmaking, at the atomic scale of graphene molecules. This timepiece brings the art of watchmaking into the twenty-first century, where scientific innovation meets the watchmaker tradition of passing knowledge down from master to apprentice.

A watch ahead of its time ©TAG Heuer

A watch ahead of its time ©TAG Heuer

At the SIHH (Salon Internationale de la Haute Horlogerie) watch fair in Geneva, TAG Heuer unveiled its latest cutting-edge innovation for the watchmaking sector: a patented spiral hairspring made of carbon composite. The new hairspring finds its place as a core component of the Heuer 02T in-house movement, with a tourbillon regulator.

Performance and precision
Guy Sémon, CEO of the TAG Heuer Institute, who, along with his engineering team, is behind the innovation to improve the performance and precision of mechanical watches, said:

Guy Sémon, CEO of the TAG Heuer Institute

“It took years to perfect this world first. This carbon-composite spiral is a first step towards new improvements under development, which will be perfected in our laboratories.”

This new approach to watchmaking could definitely change things over the coming years. With the new timepiece, TAG Heuer is ushering in the next generation of tourbillon watches. The in-house movement for the new model includes a spiral hairspring made not of silicon, but of carbon composite, based on natural-gas-derived carbon.

The atomic-scale research described by Guy Sémon is quite visionary. This new type of hairspring is gravity and impact resistant, non-magnetic, and perfectly invulnerable to temperature variations. It guarantees optimum precision for these watches, which have been officially chronometer certified.

Next-generation hairsprings
Considered as a core component of the mechanical watch, the hairspring is the most difficult part to produce, because its infinitesimal tolerances have a direct, immediate effect on the precision of the timepiece. A team of mathematicians, physicists and chemists working at the TAG Heuer Institute developed the new hairspring. The carbon-composite spiral not only disrupts traditional watchmaking knowhow, but also improves the performance of watches equipped with the brand’s chronometer certified movement. The Carrera Calibre Heuer 02T Tourbillon Nanograph model is the first timepiece to be fitted with the innovative hairspring.

A watchmaker manipulating the carbon composite hairspring ©TAG Heuer

A watchmaker manipulating the carbon composite hairspring ©TAG Heuer

How it is made:
Guy Sémon, CEO of the TAG Heuer Institute explained how the TAG Heuer hairspring is made.

Guy Sémon, CEO of the TAG Heuer Institute
"TAG Heuer is the largest producer of tourbillons in Switzerland. Furthermore, 100% of these watches are certified chronometers. Having developed the new carbon-composite hairspring, it seemed the Carrera Calibre Heuer 02T Tourbillon was a suitable vehicle for demonstrating this technology. It is important to consider the relationship between the balance wheel and the hairspring. Consideration has to be given to both stiffness and inertia. With regards to the spiral (hairspring), there are two existing technologies Elinvar, a steel alloy from 1930s, and silicium (silicon).

When using Elinvar, it is difficult to improve the accuracy of this type of hairspring because it needs to be attached to the balance wheel axis using a hand fitted collet. This is a very tricky operation and, therefore, it proves difficult to improve accuracy using this approach. The position of the hairspring and gravity also influence precision.

Silicium hairsprings are nice because they prove convenient to use. They are made using technology from the electronic industry and produced in large, clean rooms. They are made using a complex chemical process. The spiral is costlier but, more importantly, it is also very fragile.

Four years ago I began a search to find a superior material for hairsprings. I sought to create a new material which was very smooth and flexible, like a polymer material, but keeping the features of metal. To achieve this goal, I created a composite of two forms of an element (allotropy)."

TAG Heuer | TAG Heuer Carrera Calibre Heuer 02T Tourbillon Nanograph

The hairspring fabrication process in video

"Carbon is a very common element. On one side it is a very poor material, like graphite, an amorphous material. On the other side you have diamond, very hard and strong. However, when you look inside both of these materials they are the same, carbon atoms. The difference is the arrangement of the elements. On one hand you have an amorphous structure and on the other hand a crystalline arrangement. Carbon nanotubes have very interesting properties, but when we change the scale from micro to macro, we lose its benefits.

Our hairspring is made with a new material with new properties. The main property relates to Young’s modulus, the elastic modulus. The Young’s modulus for our material is 25 GPa, while for steel it is 200 GPa, meaning our material is much more elastic."

Carbon+ 150 system by CVD Equipment Corporation, USA

The Carbon+ 150 system, which operated operated in La Chaux-de-Fonds, has been configured with TAG Heuer specifications.
 

"We made various calculations using computer simulation in order to identify the optimum geometry and period for the spiral. After making these calculations, we transferred the design of the spiral to a silicon wafer. This was not because it was silicon, but because it was very flat and very clean. Using a special, metallic pen filled with an ink rich in iron atoms, we drew the spiral on the wafer. This proves a very precise method, 100 times more accurate than the tolerances typical of silicon engraving."

The design of the spiral is tranferred to the silicon wafer ©TAG Heuer

The design of the spiral is tranferred to the silicon wafer ©TAG Heuer

"The spiral is now marked on the wafer. It is very small, we can actually place 330 spirals on one wafer. The wafer is then placed in a large machine, we have two. It was engineered by us and made in the US. The machines are the only ones in existence and are exclusive to the TAG Heuer Institute.

After placing the wafers in the machine, we create a chemical reaction at 950°C in an atmosphere free of oxygen. We have to extract the oxygen from the machine because it is very explosive. We introduce two gases, hydrogen and ethylene, the latter is very rich in carbon atoms. The process breaks the ethylene molecules to produce three carbon atoms. These atoms are free, very excited and they are attracted to iron atoms, the carbon atoms grow upon the iron atoms, forming smooth tubes called carbon nanotubes."

The ethylene molecules are breaked and its carbon atoms settle on the wafer ©TAG Heuer

The ethylene molecules are breaked and its carbon atoms settle on the wafer ©TAG Heuer

"After two hours, you have nanotubes forming a spiral. However, they have no mechanical properties. If you put your finger on the spiral and scratch it, the spiral is destroyed. Therefore, we have to create a second chemical reaction. Here we put carbon atoms between the nanotubes. This is what makes it a composite."

The wafer is extrated once the nanotubes growing process and the carbon infiltration are finished ©TAG Heuer

The wafer is extrated once the nanotubes growing process and the carbon infiltration are finished ©TAG Heuer
 

Watchmaker can collect the non-magnetic, strong, chemical neutral, and flat carbon hairspings ©TAG Heuer

Watchmaker can collect the non-magnetic, strong, chemical neutral, and flat carbon hairspings ©TAG Heuer

"The resultant material is non-magnetic, strong, chemical neutral, flat, which is helpful for a watchmaker, and the collet is already attached to the hairspring, simplifying production and enhancing accuracy.

Normally in watchmaking when we adjust the frequency of the balance, we add masselottes to the balance wheel or use a raquette (index adjuster). With silicon it is not possible to use a raquette, however, with a carbon-composite hairspring, it is."

The final part
The carbon-composite material used to make the hairspring have an hexagonal structure. This hexagonal pattern is echoed in the overall design of the Carrera Calibre Heuer 02T Tourbillon Nanograph and reproduced on the black PVD-treated oscillating weight, which is visible through the sapphire crystal case back. A bright lime green enhances some of the watch parts, like the tourbillon’s aluminium bridge and the lettering on the cage. The balance wheel is highlighted with white-gold inserts, while the Super-LumiNova coated markings are perfectly readable, both day and night.

The watch is available – and not just as a limited series – for a price of about 23,000 euros.

The hexagonal pattern is echoed in the overall design of the Carrera Calibre Heuer 02T Tourbillon Nanograph ©TAG Heuer

The hexagonal pattern is echoed in the overall design of the Carrera Calibre Heuer 02T Tourbillon Nanograph ©TAG Heuer

The hexagonal pattern is echoed in the overall design of the Carrera Calibre Heuer 02T Tourbillon Nanograph ©TAG Heuer


This article and interview have been extrated from the JEC Composites Magazine N°129 (July/August).
Editorial changes from the following sources have been issued: - calibre11.com, The Inside Story of TAG Heuer’s Carbon Hairspring - worldtempus.com, TAG Heuer invente le spiral en carbone - escapementmagazine.com, Guy Sémon, CEO of the TAG Heuer Institute - worldtempus.com, Conversation avec les atomes : le nouveau balancier en composite de carbone - journal.hautehorlogerie.org, Un labo hors normes chez TAG Heuer