The drill bearing is special for dental dentists. The inner and outer rings of the drill bearings produced by Shanghai Fangji are made of refined stainless steel (9gr18); the balls are made of refined stainless steel (9gr18) or non-metallic super hard ceramic (Si3N4), which have good wear resistance; the cages are made of polyimide or 80-120 pieces of phenolic cloth Glulam with high strength, low wear resistance and self-lubricating properties; the air pressure of the drill bearings is 200-250kpa Under pressure, the rotational speed can reach 350000-400000 rpm. Under normal service conditions, the working life of drill bearing is more than 6 months.