Hard turning bearing ring technology:
a. Finish turning the base level end , the base level end will be less than 0.005mm after finish turning ,then turning the outer diameter of the shaft washer;
b. Turn to another face for turning
c. Step1:Turning the upper end surface (inside the channel);
Step2: Convert the workpiece plate, then turning the upper end surface.（outside the channel）
d. Hard turning the spherical channel, the channel bottom range will less than 0.005mm after hard turning ,the channel surface roughness will be Ra0.3μm
e. Finish turning inner diameter of the shaft washer.
With above technology, the wall thickness difference of the push ball bearing ring will less than 0.01mm,which is more than the precision value of P5 grade bearing .
Case 1：Hard turning wind power bearing ring.
Machining Targets: Variable pitch bearing ring for 1.5MW wind power machine sets.
Machine: CNC Lathe
Cutting Inserts Grade: Halnn BN-S20 Solid cbn insert
Workpiece Dimension: Outer diameter φ1900mm，Thickness 130mm，
Roughness after finish turning：The channel bottom range of double peach channel after finish turning all less than 0.005mm, and the channel surface roughness will reach Ra0.3μm.
Case 2: Turning the bevel of the Precision angular contact bearing ring
Machining Targets: Precision angular contact bearing
Cutting Inserts Grade: Halnn superhard BN-H20 PCBN Inserts
Inserts Lifetime: Machining about 1000 sets /cutting edge; smooth finish≤Ra0.4
Advantages of hard turning the bearing ring
1. High working efficiency
For example, like variable pitch bearing ring which is used for machining wind power 1.5MW machining sets in bearing industry.If grinding machining all the allowance after queching, the grinding time is above 18h, but use the turning instead of grinding process ，just need 4.5h .At the same machining precision, the turning machining efficiency is 4 times than grinding machining.
2. Low cost
For example, like turning the 1900 variable pitch bearing ring, use Halnn superhard BN-S20 solid CBN inserts can finish turning more than 30 piece bearing ring.
3. Reduce pollution
Compared with the grinding iron grain with the turning iron scraps, it will be more convenient to deal with the iron scraps, and the irons scraps cost lower as resource, also reduce the pollution.
Conclusion : When turning the large-scare and high-precision bearings, using hard turning technology (used turning instead of grinding process) has become a trend in bearing industry .This technology has high machining efficiency, low cost..BN-H20 PCBN Inserts enter into the market, the smooth finish and reliability which use turning instead of grinding process become better ,and the inserts cost become lower .