The advancement in technology makes it increasingly difficult to produce large-scale bearings with high precision. The tolerance levels have also reached P4 and even P5. Normally, large bearings use CNC Lathe and Grinding Tools as a result of the limitation of the grinding process, the efficiency is lower and the expense of the tool is excessive.
With the research and use of the superhard cutting tools full cbn inserts in a variety of cold processes, turning can be used to replace grinding. This article will demonstrate how to turn the hard bearing rings. The roughness of the surface can exceed Ra0.40.8 and satisfy the requirements of the bearing.
For hard turning bearings, the initials of the cbn insert
CBN Insert is one of the most efficient materials used to machine ferrous metals. It has high hardness as well as wear resistance. It it is second to diamond tools. CBN Insert is capable of cutting materials that have high hardness.
CBN Insert is stable and has high temperature red hardness. If the temperature increases, the materials will soften. This is beneficial to the process of cutting.
CBN Insert is very antioxidant and won’t react with iron at temperatures that are higher than 1200-1300?. However, it is able to undergo hydrolysis at 1000?. When we are using full cbn inserts machine bearings, we must use dry cutting methods.
CBN Insert is low in Co-efficient of friction and won’t readily form the chipping layer. It can also improve the quality of the surface and finish of the piece.
CBN materials used for bearings with hard turning
To speed up the time needed to machine large-scale bearings, we utilize solid cbn Insert to increase the efficiency and cut the cutting processes. The most popular cbn material is the BN-S20 solid CBN insert.
BN-S20 belong to full cbn inserts, the hardness is around HRC951000 and it uses ceramic as the binder, which can make sure the superior wear resistance and the highest chemical resistance at high temperatures.
To machine, for instance, wind power bearings of diameter 1900mm and thickness 130mm it takes about 18h. If you choose to use grinding, it will take about 4 hours. If you choose to use turning instead it will take about 4.5h. And the roughness can reach Ra0.3um,the processing efficiency of turning is approximately 4 times the grinding efficiency. The cost of all this is only have 20% percent.
The benefits of inserts made from cbn hard turning bearings
(1) Efficiency increased by several times,
(2) It is suitable for mass order and has a long life span.
(3) Reducing the amount of pollution When compared to grinding chips can be easily removed. Turning doesn’t need cutting fluid.
Conclusion
CBN cutting tools and CNC Lathe can be used to turn bearings by hard turning. This will increase the efficiency of the work process and lower the cost of tools. As the industry develops, more bearings manufacturers are using cbn insert instead of grinding.
