Cartier ID One - Cartier's take on the future of mechanical watchmakingDate: Mar 07, 2010,10:25 AM - (view entire thread)
Cartier's take on the future of mechanical watchmaking - the Cartier ID One
by Su JiaXian
© March 2010
(This is the first part of a series examining the Cartier ID One.)
The ID One boasts three advantages:
1. No regulation
2. No lubrication
3. Escapement with one second daily deviation for the life of the movement, regardless of mainspring state of wind
One of the most vital processes in watchmaking is regulation. And as technology developed regulation got simpler but watchmakers still have to do it. All mechanical watches need regulation, at the point of assembly as well as later during their life.
Regulation refers to several procedures that adjust the various parts of the escapement. One of them is poising the balance. Because of the imprecision of CNC machining, the resulting balance wheel is not perfect, hence the need for poising.
That is achieved via adjusting weights on the balance, with screws being the most common though the weights can be circular like on Patek’s Gyromax or any other shape.
Poising can also be done by removing metal from the underside of the balance. Most modern watches have smooth Glucydur balance wheels with no screws. This is possible because the material is so hard that once it has been poised by removing material it no longer needs adjustment.
Poising gives the balance, well, balance, meaning that weight is distributed evenly on all points of the wheel. So when the balance wheel oscillates its does so in a consistent manner because of the uniform weight around the rim.
Adjustments can also be made to the hairspring. One way to do that is to move the regulator index. The regulator index can take several forms, the most famous of which is the swan neck regulator. A swan neck allows the watchmaker to move the index by turning a screw that sits perpendicular to the index, which allows for more precise adjustments to the index than if the index were adjusted directly.
Adjusting the index moves the curb pins, in between which the coil of the outermost hairspring runs. That changes the effect length of the balance spring, in other words the length that expands and contracts with the movement of the balance wheel. This is the finest form of hairspring adjustment that is often done when a watch is returned for minor adjustments.
Additionally, there are other more complex types of hairspring adjustment. They include moving the collet, which is the point on the balance wheel to which the innermost point of the hairspring, or moving the stud (to which the outer end of the hairspring is attached).
Eliminating the complexities of regulation would be a great convenience to watchmakers. The presumed benefit to the consumer on the other hand would be getting rid of the need to return a watch for regulation.
One of the great goals of watchmaking in recent years has been to reduce or eliminate lubrication. Omega started the trend with the co-axial escapement it purchased from Daniels which in theory does not need lubrication but which was lubricated in early specimens though I’m unsure if that’s true in the current movements.
Lubrication is a bugbear for several reasons. During assembly there are often a multitude of oils that are used for different parts, depending on the wear and tear, size and materials used in the particular spot. A single movement can have up to several dozen types of lubricants used.
Later on lubricants eventually dry up, though modern synthetic lubricants are supposed to last for several years and still retain their viscosity. When lubrication dries up, and mixes with debris that can emerge from the wear of metal parts, it can then act as a sandpaper of sorts on the movement components.
To address those perennial issues, Cartier turned to materials never used before in watchmaking.
Carbon crystal was selected for the balance wheel, anchor and escape wheel. It is a type of artificial diamond and consequently is hard and light. Importantly it has a low coefficient of friction meaning it needs no lubrication. Carbon crystal is also insensitive to temperature changes and magnetism.
Another quality of carbon crystal is that it can be etched very precisely, to the micron, which means that all components are perfectly shaped after fabrication. Hence the balance wheel, bearing the Cartier logo of course, needs no poising.
The carbon crystal balance wheel of the ID One
A conventional screwed balance
Similarly, the anchor needs no adjustment as well. The anchor is a single piece of carbon crystal, unlike traditional anchors which have pallet jewels attached with shellac to the steel portion of the anchor. Usually pallet stones have to be adjusted so that they engage the escape wheel correctly; the one piece carbon crystal anchor does away with that.
Escape wheel and one-piece anchor in carbon crystal compared with a traditional escape wheel and pallet with red rubies
For the hairspring Cartier selected a material known as Zerodur, a zero expansion glass ceramic. Developed by Schott AG, a German glassmaker that also makes the glass in Zeiss lenses (both companies are owned by the Carl Zeiss Foundation), in 1968, Zerodur comprises tiny crystals suspended in glass. When heated, the micro-crystals contract while the glass expands. So the proportion of glass and crystals are optimised so much so it has nearly zero thermal expansion.
A conventional hairspring
And not only is the Zerodur hairspring impervious to temperature changes, it is also extremely lightweight. Cartier experimented with various hairspring shapes before settling on one that expands and contracts in a regular fashion with minimal variation across positions.
The Zerodur hairspring
Both the Zerodur and carbon crystal components of the ID One are manufactured by CSEM (Swiss Center for Electronics and Microtechnology) in Neuchâtel. Cartier, however, has a patent pending on the manufacturing process for the Zerodur hairspring.
Like the escapement, carbon crystal is also used for the wheels of the gear train, leaving them free of lubrication. On the other hand, all pivots in the gear train, like those in the escapement, are in titanium, which is not only non-magnetic but also more elastic than steel. This allows the pivots to withstand shocks without breaking.
Titanium pivots are highlighted in black
While the use of carbon crystal and Zerodur ensure that regulation is not necessary, Cartier took additional steps to ensure that the long term performance of the movement remains optimal.
The escapement, comprising the escape wheel, anchor, balance and hairspring, is housed inside a carbon crystal cage which sits on silent blocks which are dampers that absorb shock. Both the upper and lower platforms of the cage are supported by silent blocks made of titanium and rubber.
Profile of the silent block
This shock resistance is most important for the balance wheel and staff, which sit on a small pivot relative to the balance wheel diameter, leaving it vulnerable to sharp knocks that can damage the balance. The Incabloc or KIF shock protection (tiny gold-coloured brackets over the pivot jewel on the balance cock) commonly seen are to protect the balance.
The rest of the movement is largely conventional in construction and materials, steel for wheels and brass for the baseplate, except for the fact that those parts are treated with ADLC – amorphous diamond-like coating. Cartier previously used ADLC treatment for the case of the Santos 100 launched last year. Though scratch-resistant, the use of ADLC on the Santos was mostly cosmetic. In contrast the use of ADLC in the ID One is functional – it gives the movement parts a low coefficient of friction so no lubrication is necessary.
All the effort translates into some interesting results. Compared to a regular automatic movement, the ID One enjoys extremely minimal chronometric error throughout its entire power reserve. Its greatest deviation is +1 second. In contrast, the comparison movement, the JLC designed Cartier 8000 MC, suffers an increasing as the power reserve diminishes. This of course is a typical problem with mechanical watches – falling amplitude as the mainspring unwinds due to the lessening torque from the mainspring.
On average the ID One gains 0.8 seconds a day. In comparison, a quartz wristwatch 0.5 seconds a day, while a regular anchor escapement wristwatch gains about 2.3 seconds a day.
Those are laboratory results but they are promising. Intuitively, the solutions offered by the ID One make sense. So is this the future of watchmaking at Cartier or anywhere else? That idea and others will be explored in further articles.
Copyright March 2010 - Su JiaXian & PuristSPro.com - all rights reserved
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