As the advancement of technology advancements, it will require higher on the precision of large scale bearings, and the tolerance level also reaches P4 and P5. Large bearings are normally manufactured by using CNC Lathes and Grinding Tools. Because of the limitations of the grinding process the efficiency and price are low.
Through the study and application of superhard cutting instruments pcbn turning inserts
in a variety of cold process, turning process can be used to replace grinding. This article will describe the process of hard turning bearings rings, and the surface roughness will reach Ra0.4~0.8 and will satisfy the specifications for the bearing.
For hard turning bearings the initials of the cbn insert
CBN Insert is one of the most effective materials to machine ferrous metals. It has high hardness and wear resistance. It it is second to diamond tools. It has good performance when machining high hardness materials.
CBN Insert is stable and is high temperature hard. When the temperature rises it will cause the material to soften. This is beneficial to the cutting process.
CBN Insert has high antioxidant capacity and does not react with iron-based materials at the temperature 1200~1300 ?,however it is likely to undergo hydrolysis around 1000 ? If you are using solid cbn insert or machine bearings, it is necessary to use dry cutting techniques.
CBN Insert is low in Coefficient of friction, and will not quickly make the chipping layer. It also enhances the surface quality and finish of the piece.
CBN materials for hard-turning bearings
To reduce the time required to make large-scale bearings machined, we employ solid cbn inserts to improve efficiency and cut the cutting processes. The most widely used cbn component is the BN-S20 solid CBN insert.
The BN-S20 is part of solid cbn insert, and the hardness is about HRC951000. They use ceramic as their binder, which can ensure the highest wear resistance and chemical resistance at high temperatures.
For instance grinding wind power bearings of diameter 1900mm, thickness 130mm If you use a grinding process the time for grinding is around 18 hours. if use turning instead of grinding it will take about 4.5h. The roughness may reach Ra0.3um. Turning can have a processing efficiency about four times that of grinding. And all the costs are only 20.
Benefits of inserts made by CBN with hard-turning bearings
(1) Efficiency increased by several times,
(2) It can be used for bulk orders, and is durable.
(3) Reduce the impact of pollution In comparison to grinding processes chips are easy to recycled. Turning process doesn't require cutting fluid.
CBN cutting tools and CNC Lathe can be used to turn the bearings that are hard turning. This can increase the efficiency of work and decrease tool costs. As the technology develops in the cutting tools industry many bearings makers use cbn insert instead of grinding process.