for the low cost pursue, some small manufacturers print the black stamps on the bearing to identify models and manufacturers, with some very simple equipments, electro etching solutions, and very simple templates. Because of the low cost, it is used by some inferior products.

Formal manufacturers use laser engraving.the stamps are deep, have significant dents with hand touch, good-looking, with no breakpoints, and are never disappeared. this obviously improves the bearing grade.

Performance and wider range of temperature than iron cage. in the

Underground its anti-static performance is also better. to get

Safety certificate for coal mining products must use nylon

Cage bearing.

the material of nylon cage must be pure and has enough

Toughness and strength, because the cage will get very soft if

It is made of bad material or mixed material, thus to make no

Anti-stuck performance within the bearing.