Bearings, as one of the most important components, are widely used various industries. With the rasing needs, it required higher and higher on the bearing performance. Especially for the bearings after heat treatment, the hardness will be much higher, it will be more difficult to machine, it usually has the following problems with traditional cutting tools machining bearings:
(1) The hardness of the bearings after heat treatment will be above HRC45, some will reach HRC60, traditional cutting tools will wear rapidly, which will affect the production efficiency.
(2) Some bearings working surface will exist interrupt turning condition, for example, it has inner bore or keyway or oil hole, traditional cutting tools will be easily chipping when meet interrupt turning condition, which make the cutting tools cost high.
(3) Large scale bearings, such as wind power bearings, has high hardness after heat treatment, and have large deformation, require high on the cutting tools’ abrasive resistance and the impact resistance.
 
Bearing steel GCr15 is one type common materials for bearings, the hardness will be about above HRC50, the hardness is too high to machine, In current times, the manufacturers choose tungsten carbide insert for turning instead of grinding machine bearings, however it needs change the insert frequently, which will affect the processing efficiency. Later, with the appearance of the ceramic insert and PCBN insert, hard turning process become easily.
The hardness and abrasive resistance of the ceramic insert both are higher than tungsten carbide, but because of brittleness, it will be easily chipping when the working allowance is large or exist interrupt turning condition, so ceramic insert will be not used as wide as cbn inserts.

PCBN Insert is the most suitable cutting tools for turning bearing instead of grinding, especially BN-S20,BN-S200,BN-H11 PCBN Grade are widely used. For different machining condition, we can choose different cbn grade, BN-H11 PCBN Insert and BN-S200 solid cbn insert can be used for continuous turning process, BN-S20 can be used for any probess (solid cbn insert, roughing process)

The following is some practical application of Halnn PCBN insert hard turning bearings:
(1) BN-S200 solid cbn insert finish turning bearings

About Insert		About Component
Insert Model	SNGN120712	Component	Slewing bearing
Tool Holder	CSDNN	Mateirals	42CrMo
Previous process	Grinding process	Hardness	HRC47-55
Cutting Condition		Image
Vc（m/min）	100-150
Fr（mm/r）	0.15-0.7
ap（mm）	1-4
Machining Effect: With same precision, the efficiency with BN-S20 solid cbn insertis about 4 times of grinding process, and the costs on the Electricity, manpower and Material supplies only occupy 20% of ginding process, and the tools can be used with a long time, lower costs.

（2）BN-H11 PCBN Insert finish turning bearings

About the cutting tools		About the Component
Insert Model	DNGA150408	Component	Metallurgical Bearings
Previous Cutting tools	Some PCBN Insert	Materials	GCr15
Cutting Condition		Image
Vc（m/min）	60-250
Fr（mm/r）	0.05-0.35
ap（mm）	≤1
Machining Effect: With same cutting condition, the tool life of PCBN Insert is much higher than international pcbn insert, the tool costs on each component will be lower, the roughness can reach about Ra0.8