In recent years, "new materials" have become widespread in the watch market. The use of unconventional materials for the exterior and movement of watches has brought about major changes not only in terms of design, such as shape and color, but also in terms of performance. Issue 112 of Chronos Japan featured an article on these "new materials" titled "New Materials That Have Changed Watches," and we are republishing it on webChronos. This time, we will focus on the LIGA process, which has enabled the production of precision, three-dimensionally shaped parts and significantly evolved the movement.
Photographs by Takeshi Hoshi (estrellas)
Masamasa Hirota (this magazine): Interview and writing
Text by Masayuki Hirota (Chronos-Japan)
Edited by Hiroyuki Suzuki
[Article published in the July 2024 issue of Kronos Japan]
The LIGA process improves the performance of mechanical watches
There are two factors that have greatly improved the performance of mechanical watches. One is the silicon used in the escapement, as mentioned above. The other is functional parts manufactured using the LIGA process. While not as obvious as silicon, the LIGA process, which can create elastic metal parts, is now being used even in core movements.
The evolution of the movement with the adoption of the LIGA process
Previously, the only methods for manufacturing mechanical watch parts were forging or cutting. Since the late 1970s, wire electrical discharge machining has been added to these methods, allowing watchmakers to obtain parts with a level of precision that was previously unimaginable.
This core movement features gears manufactured using the LIGA process, significantly improving performance. While the basic design is based on the Cal. 324 SC, precision and ease of maintenance have been further improved. Rotor noise is also extremely low. Automatic winding. 30 jewels. 28,800 vph. Power reserve: maximum approximately 45 hours, minimum approximately 35 hours.
The latest addition to this category is the LIGA process. This process does not involve forging or cutting, but rather involves creating parts by layering plating. Like silicon, it can produce precision parts, but it differs in that it is easier to create three-dimensional shapes. Another major benefit is that the manufacturing process is not patented, making it easier to adopt. There is also an unexpected benefit. An engineer at one manufacturer confided to me, "People would complain about silicon, but no consumers have complained about a nickel-phosphorus alloy escapement made with LIGA." In other words, it is more easily accepted by consumers who have an aversion to silicon.
LIGA's strength in being able to reproduce three-dimensional shapes is utilized in gears and pinions with spring properties at their tips. By giving the gears themselves spring properties, springs to regulate their movement are no longer necessary. As a result, not only is the need for troublesome spring adjustment eliminated, but the oscillation angle of the balance wheel and other parameters can also be more easily adjusted to the design values. In other words, it becomes easier to reduce variations in performance.
Breitling's masterpiece movement also now uses LIGA gears in its chronograph mechanism. Since the regulating spring is no longer necessary, the amplitude remains almost constant even when the chronograph is running. Automatic winding. 47 jewels. 28,800 vph. Power reserve approximately 70 hours.
It was Jean-Marc Wiederrecht, founder of Agenau, who popularized the LIGA process in the watch industry. He began using elastic parts made with the LIGA process to stabilize the behavior of retrograde movements. He later came up with the idea of making the gear itself elastic by splitting the tips of the teeth, and popularized this idea along with the LIGA process in the watch industry.
Initially, LIGA was only adopted by small, ambitious workshops such as Agenau and La Fabrique du Temps. It was the latter that was the first to use a LIGA escapement in the micro-rotor automatic watch it developed in collaboration with Laurent Ferrier. Enrico Barbasini, who was involved in the design at the time, said, "The LIGA process made it possible to create a precision escapement. What's more, the material was a nickel-phosphorus alloy, which was lighter than steel." The classic natural escapement would not have been revived without new technology.
Parts made using the LIGA process are now also found in movements made by major manufacturers. Rolex, Breitling, and Hublot are using it in chronographs to improve performance. Because the gears themselves are elastic, these movements have less balance wheel swing-out, and even with a horizontal clutch, the hands are less likely to jump when starting a chronograph.
This automatic movement features a micro-rotor and a highly efficient natural escapement. The escape wheel is molded using LIGA, resulting in an extremely precise part. The pallet fork is made of lightweight silicon, increasing the oscillation angle. Automatic winding. 35 jewels. 21,600 vph. Power reserve of approximately 72 hours.
Additionally, brands such as Jaeger-LeCoultre and Patek Philippe have stabilized the movement of the second hand by adding LIGA gears to their gear trains. Furthermore, Patek Philippe has simplified the mechanism of its Travel Time by using LIGA parts in its Advanced Research. Incidentally, this is also one of the compliant mechanisms mentioned above, but it is made of pure metal parts. Watchmakers who don't like silicon will undoubtedly use the LIGA process to create compliant mechanisms in the future.
The UNICO features a robust flyback mechanism. The first model, the HUB1242, and its successor, the HUB1280, use LIGA gears for the chronograph intermediate wheel. Their elasticity makes it less likely for the hands to jump when the chronograph is in operation. Automatic winding. 43 jewels. 28,800 vph. Power reserve of approximately 72 hours.
