in American. The hot-press technology is restricted into the producing disk-like Si3N4 blank balls, and the blank balls must be cut to square shape using diamond saw blade, then grinded to near spherical polyhedron, and then processed to G16 ceramic balls by rough grinding, fine grinding and finishing. Si3N4 is superhard and wear-resistant, so it can only be cut and grinded by a few grinding materials such as diamond etc. It can be imagined that the cost of producing Si3N4 balls from hot-pressed Si3N4 is so high that it can not be accepted in many applications.
In 1980s, gas pressure sintering (GPS) and hot isostatic pressing(HIP) have been successfully applied in the producing of ceramics. Si3N4 biscuit is molded to spherical shape before sintering, this can overcome a series of shortcomings of hot-pressed Si3N4, the cost falls down a lot, ceramic ball bearings have been widely used in the electrical main arbor, and the application expands gradually to high-speed and high-precision fields such as the main arbor of machine tool and dental drill etc. However, the ceramic ball blank is not completely spherical shape, normally near spherical shape with an annulus or similar sphere with a flat head, the processing cost is still high.
The ceramic balls we provided use superfine high-pure home-made Si3N4 powders, the uniformly mixed powders are molded to near net size, and then sintered by GPS-HIP, the produced ceramic balls have excellent material performance and good spherical shape, this highly reduces the processing cost and shortens the processing periods from formerly several hundreds of hours to current several tens of hours, furthermore, our factory have explored a complete set of technology of processing ceramic balls, established a complete production line, and now we can provide large batches of kinds of gauges of G5 ceramic balls, and some gauges can be processed to G3.
