The manufacturing process of wrist watches

Quartz digital watches with LED displays are widely used in this days. The assembly of such watches must be performed carefully and methodically, the most essential aspects of the manufacturing process are in the manufacture of the components.

Quartz

 The heart of a quartz watch is a little sliver of quartz. This synthetically produced quartz is cut by the manufacturer of the quartz  with a diamond saw and shipped to the watchmaker to make it usable. To make the quartz workable some critical process are to follow.

For the first time  the natural  Quartz loaded into a giant kettle or autoclave.  Hanging from the top of the autoclave are seeds or tiny particles of quartz. In the assembly of watches, the entire set of crystal and microchips are  set onto a circuit board. A battery is also installed in it and it generates electricity for the quartz crystal and supplies the power for the LED display.

An alkaline material is pumped into the bottom of the autoclave. The autoclave is heated to a temperature of roughly 750 degrees Fahrenheit (400 degrees Celsius). The natural quartz dissolves in the hot alkaline liquid, evaporates, and deposits itself on the seeds. As it deposits itself, it follows the pattern of the crystalline structure of the seeds. Almost 75 days later, the chamber can be opened, and the newly grown quartz crystals can be removed and cut into the correct proportions. Different angles and thicknesses in the cutting process lead to predictable rates of oscillation. The desired rate of fluctuation for quartz which are used in wristwatches is 100,000 mega Hertz or 100,000 oscillations per second.

To make the quartz most effective, the piece of quartz needs to be sealed in a vacuum chamber of one sort or another. Most commonly, the quartz is placed into a sort of capsule, with wires attached to both ends so that the capsule can be soldered or otherwise connected to a circuit board.

The microchip

The electronic leads generated by a battery through the quartz goes to a microchip. Microchip manufacturing, like the quartz, is also carried out by the supplier to the watch manufacturer. An extremely extensive and complex process, making microchips involves chemical and x-ray printing of a microscopic electronic circuit onto a tiny piece of silicon dioxide.

The fluctuation rate of perhaps 100,000 vibrations/second is reduced to 1 or 60 or some other more manageable number of oscillations. The new pattern of fluctuation is then sent to another microchip that works as a "counter-decoder-driver." This chip will actually count the oscillations that it receives. If there are sixty oscillations per second, the chip will change the reading on an LED every second. After 3,600 oscillations (60 x 60), the counter will instruct the LED to change the reading for minutes. And, after 60 x 60 x 60 oscillations (216,000), the counter will change the hour reading.

Assembly

The entire set of crystal and microchips is set onto a circuit board. The board incorporates a space to hold the battery that supplies electricity to the quartz crystal and supplies the power for the LED display. Generally, the space for the battery is on the outside of the surface facing the back of the case.  

The mechanism for setting the watch is then connected. This mechanism involves two pins that extend beyond the case of the watch. A pin lets the counter circuit know which reading to reset—seconds, minutes, or hours. The other pin is pushed a number of times to bring the display to the desired reading. The entire circuit board, along with a battery, is then closed into a case, Finally a wrist strap is attached.



Source of this article is http://www.madehow.com/Volume-1/Watch.html