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Effect Of Cutting Parameters On Cutting Force Of Bearing Steel For Precision Hardening Turning


Effect of cutting parameters bearing on cutting force of bearing steel for precision hardening turning

Various suitable hard turning tools (diamond tools, CBN tools, ceramic tools and coated cemented carbide tools, etc.) realize the hard turning of hardened steel (hardness 45 ~ 68 HRC). However, diamond tools and iron-based materials will react Effect chemically at high temperature, so they are generally not used to cut bearing steel materials;

Ceramic and cemented carbide tools often show weak cutting performance when cutting hardened steel workpieces with hardness greater than 50 HRC. Therefore, the suitable tool material for hard turning of Effect bearing steel is all kinds of CBN tools.

Although grinding can produce good surface accuracy at a relatively high feed rate, with a lower cutting depth and feed rate (compared with grinding) without coolant, conventional hard turning can also reduce the processing time by up to 60%, significantly improve the material removal rate, and the machined surface accuracy is equivalent to or even better than grinding.

In addition, multi-step hard turning operation only needs a single setting, while grinding needs multiple settings, which also helps to achieve high Effect precision through hard turning.

Cutting parameters are important factors affecting cutting force. Improper selection of cutting parameters will produce high cutting force, affect the surface machining accuracy, and be unfavorable to the tool and the whole process. The cutting conditions of fine hard turning are very different from the turning of conventional materials, and the cutting force needs to be deeply studied.

A large number of studies at home and abroad show that in hard turning finishing (the cutting depth is generally less than the tip arc radius / head radius), the cutting depth resistance (radial component) is much greater than the cutting force in the other two directions, which is different from the traditional cutting process, the radial force is only 0.3 ~ 0.5 times of the main cutting force.

Therefore, the radial force in the process of hard turning can not be ignored in similar machining systems with static and dynamic Effect characteristics. Alexandre compared different cutting tools (ceramic tools and PCBN tools with different CBN content) when cutting bearing steel.

It was found that among the cutting forces in three directions, the cutting depth resistance was large, followed by the main cutting force and feed resistance. Many researchers have found that under the condition of low-speed turning, high cutting force will appear in the process of hard turning due to low temperature and the formation of chip build-up (bue).

It may be that the high cutting temperature produced by high-speed cutting causes the thermal softening of workpiece materials, so the cutting force will decrease with the increase of cutting speed. The cutting force increases with the increase of feed rate, cutting depth and cutter head radius, and the cutting depth has a great influence on the cutting force, followed by the feed rate, and the cutting speed has little influence.

A large number of researchers are committed to predicting the cutting force during hard turning through empirical formula calculation, Effect theoretical model establishment and finite element simulation, in order to realize the precision hard turning technology of bearing steel.

In practice, the response is the optimal selection of cutting parameters (cutting speed, feed rate, cutting depth / back draft).

Effect Of Cutting Parameters On Cutting Force Of Bearing Steel For Precision Hardening Turning

1) Selection of cutting speed

For different cutting tools and workpiece materials, the selection of cutting speed is different. In the process of hard turning, the workpiece hardness is large. Appropriately increasing the cutting speed is Effect conducive to increase the softening effect of workpiece material and reduce the cutting force.

However, when the cutting speed is too high, the larger cutting Effect temperature will aggravate the tool wear and reduce the machining quality. When the cutting force decreases due to heating softening, the cutting speed will reach the critical range.

Therefore, it will be more energy-saving to adopt medium cutting depth and relatively low and appropriate cutting speed within the selected parameter range, such as cutting speed of 200 ~ 250 m / min.

2) Selection of feed rate

Excessive feed rate will cause cutting vibration and affect the machining surface quality. Therefore, a smaller feed rate should be selected, such as 0.06 ~ 0.09 mm / R at low speed and no more than 0.15 mm / R at high speed.

3) Selection of cutting depth

The cutting depth is generally 0.10 ~ 0.25 mm. The cutting depth has a great impact on the cutting force. If the cutting force is too large, it will increase the machining deformation and affect the machining accuracy.