Mechanical Watch Design Technology
Mechanical Watch Design Technology Developed over Seven Decades
ORIENT, one of several Epson watch brands, boasts a history dating back 70 years. ORIENT watches have embodied numerous technological innovations over the decades. Read on to learn about the evolution of Epson's mechanical watch design technology.
ORIENT Watch Designs refined over seventy years
The first ORIENT model was designed back in 1950 and was named the NEW ORIENT. The following year marked the debut of the original ORIENT STAR, a mechanical watch with a small movement. The movement is the heart of a mechanical watch, a small engine packed with technology. Its main component is a mainspring, which serves as the power source, and various gears that transmit and adjust the generated energy.
In 1955, the company announced the design of the T-type center-second movement, in which the center wheel and the fourth wheel are overlaid. The mainspring in the T-type movement was made of a stronger material called Nivaflex. Nivaflex, a type of stainless alloy made primarily of cobalt, molybdenum, and beryllium, has non-magnetic and highly elastic properties.
Then, in 1958, the company designed what it called the N-type movement. In 1961, ORIENT released an N-type self-winding movement that had a ratchet-type self-winding mechanism. There are various types of self-winding mechanism, each distinguished by the mechanism used, one example being a center rotor. The ratchet type was adopted for the ORIENT and ORIENT STAR lines. It was around this time that the first watches with water resistance specifications were designed.
Cal. 46 series movement in production for half a century
Designed in 1971, Cal. 46 series movements were both smaller in diameter and thinner than
L-type movements. The adoption of a magic lever in the self-winding mechanism also provided high winding
efficiency. The 46 series movements have an orthodox mechanism that lends exceptional versatility. These
movements are found in a wide range of ORIENT and ORIENT STAR watches and have been practically synonymous
with the brand for 40 years.
In the 90s, mechanical watches made a comeback, rekindling technological development work on mechanical movements. Two of the developments to come out of this were a power reserve indicator and a retrograde movement.
Cal. 46 series movement
Power reserve indicator
A power reserve indicator is a mechanism that is designed to show at a glance how many more hours a watch can run on the remaining energy stored by the mainspring. Engineers at the time studied literature coming out of Switzerland, a country renowned for watchmaking, and worked for about two years to develop the technology that became a power reserve indicator, in 1996. Power reserve indicators are now a standard feature on ORIENT STAR watches.
Unlike the second hand and other hands that move in one direction, the hand in a retrograde display, which indicates the day of the week, reverses.
Changing the direction of movement of the power obtained from the mainspring required a new mechanism. Engineers created such a mechanism by redesigning a cam. In a retrograde display, the instant Sunday (SU) turns to Monday (MO) at midnight, the hand suddenly reverses direction, like a windshield wiper.
Main plate standardized to improve production efficiency
We have continued to manufacture 46 series movements because of their exceptional versatility, but accommodating a large number of different models required designing many new parts. This included the main plate, which serves as a base upon which all other parts of a movement are mounted, and the bridges, parts that hold the gears and base plate together. The manufacturing process became complicated as a result.
Therefore, around 2012, we began design work on a new movement, the 46-F6. The aim was to create a standard base plate and bridges that could accommodate all models. Using rolls of sheet metal several millimeters thick allowed us to easily fabricate the base plates in a continuous process. Producing models with the 46-F6 movement, some with and some without a power reserve indicator mechanism, was a challenge that took significant engineering skills to solve.
It wasn't just about technology. We needed to continue manufacturing existing products in parallel with development efforts, so we had to meticulously analyze production and sales in advance to ensure that there would be no parts shortages even when the production line was stopped for research purposes. Within two years, we overcame these challenges and began manufacturing watches equipped with the new movements.
Developed in 2017, the 46-F7 movement improved on the accuracy of the 46-F6, with a daily rate of +15 to -5 seconds compared to a daily rate of +25 to -15 seconds. Later, the power reserve was increased from 40 hours to 50 hours.
There was also a technological innovation in decoration. A new method of embellishing the movements with decorative patterns was adopted. Instead of using rubber whetstones, patterns are engraved using cutters that Epson developed for other products. Patterns are sharper and cutters require less frequent replacement, further improving production efficiency.
Epson MEMS processing technology used on the new 46-F8 movement
Mechanical watches are made up of more than 100 parts including the movement. The part of the movement that determines the accuracy is called the escapement. The escapement consists of an escape wheel, anchor, and balance wheel. The escape wheel transmits energy to the balance wheel. It plays an important role in that it produces a tick and keeps accurate time while releasing the energy of the mainspring little by little.
In developing the 46-F8 movement used in ORIENT STAR watches, we overhauled the design of the escape wheel. Whereas traditional escape wheels are made of metal, the 46-F8 escape wheel is made of silicon. The use of silicon reduced the weight by about one-third. The lighter escape wheel allows the energy of the mainspring to be used more effectively, and the silicon is more resistant to friction and wear. In addition, the MEMS processing technology developed by Epson's semiconductor division and R&D organizations increased the processing accuracy from 1/100 mm in the case of metal to 1/1000 mm in the case of silicon.
On the other hand, silicon is susceptible to chipping. These problems were solved with a new surface coating structure and by redesigning the configuration of things such as the assembly of the escape wheel and shaft. Innovations like these extended the drive time of the F8 to 70 hours, or 20 hours longer than that of the 46-F7. Increasing the durability of the escape wheel also further stabilized driving.
The 46-F8 movement was successfully developed by taking manufacturing technology that Epson developed over many years and combining it with time-honored processes that have relied on outstanding craftsmanship. As a result, we have made great strides toward enabling us to volume-produce products of exceptional quality.