Why exactly is sapphire glass so ''expensive''?
At present, in the meter world, as long as the price is relatively high, such as more than 20,000,30,000 meter, whether mechanical or quartz meter, or produced in Japan, Germany or Switzerland.
With 99.9% of the watches, sapphire crystal is used as a mirror material.In other words, sapphire glass is the boss.However, part of the table price is only thousands of yuan, will also use sapphire crystal mirror, which depends on whether the pursuit of the table factory focus on the mirror material, this kind of table (quartz, mechanical) will often be the words Sapphire printed on the surface plate.
Thus, sapphire crystal glass mirror is becoming the standard of a good-quality watch.
Compared to our common ore glass mirror, the sapphire crystal surface hardness of 9 (Mo Shi hardness), while the ore glass is only 6,
It is easy to be cut by daily glass, sand particles (containing quartz, hardness of 7) or other metals.But the sapphire crystal is only cut by diamonds (Mosh hardness 10),
Therefore, since the 1980s, it has gradually become a quasi-equipment for medium and advanced watches.
Because its production cost is quite high, so it is very rare in the low-end brands of watches.
Early acrylic glass and common ore glass, sapphire crystal was aluminum and alumina (Aluminium oxide). After the addition of different additives, after a high temperature of 1400 degrees of high temperature heating and crystallization formation, it became a cylinder. After initial size cutting, after surface polishing, it became the mirror used on the wrist watch.
However, because the hardness of the sapphire crystal is too high, the surface of the diamond particles of the abrasive is needed to polish the surface, and the life of the abrasive is not long, which is the factor of the high price of the sapphire crystal mirror.
At present, many advanced watches, in order to pursue the retro appearance, that is, the former arc design used by the acrylic glass, so the special curved sapphire crystal mirror;
Nonetheless, if there is such a meter of friends at hand, usually should be particularly careful, do not always wave, because hit a piece, the cost of a mirror costs thousands or even tens of thousands of yuan.
On account of The factory cannot use mold making (like acrylic glass), but use 4-5 times thicker than the general sapphire crystal mirror, and then start grinding, that is, the factory must grind more than 70 or 80% of the raw materials, to get the perfect arc mirror, but also cannot affect the reading of the plate pointer, so the production technology is certainly much higher than the plane sapphire crystal mirror; therefore, the high price is also from this reason.
Sapphire has a Mosh hardness of 9, second only to diamond.The resistivity at 25℃ is 1 × 1011 Ω cm, electrical insulation.In addition, sapphire also has good optical permeability, thermal conductivity and excellent mechanical properties, mainly used in the fields of wear-resistant original, window materials and electronic devices.
So do you know anything about it?
Sapphire glass selling expensive is not a false name oh