Vitrified CBN grinding tools have the advantages of good thermal stability and good wear resistance, and are not easy to react with iron group elements and are suitable for machining steel parts with high hardness and toughness. The automobile industry is the main application field of vitrified CBN grinding wheels, especially as the key parts of the engine camshaft and crankshaft processing, the machining quality of camshaft and crankshaft directly affects the dynamic characteristics of the engine. However, due to the large machining margin and difficult grinding, the requirement for grinding precision is very high, and the processing difficulty is relatively large, the performance of ordinary corundum abrasive grinding wheel is difficult to meet the requirements of efficient machining, the durability and service life of ordinary corundum are low, and need frequent dressing or replacement, resulting in large corundum grinding waste, causing great pollution to the environment. The hardness of CBN is more than 2 times that of corundum; CBN grinding wheel can meet a high-performance grinding tool with high speed, high efficiency, high precision, and low grinding cost, which reduces the problem of environmental pollution at the same time.
For imported CNC camshaft grinder, in the case of the same workpiece, the life of vitrified CBN grinding wheel is 40-50 times longer than that of ordinary vitrified corundum grinding wheel, and the raw material consumption for one piece of CBN grinding wheel is 1/50 of that of corundum grinding wheel. The production efficiency of using CBN grinding wheel is 30% higher than that of corundum grinding wheel.
Figure 1 Comparison of life and raw material consumption for machining camshaft between vitrified CBN grinding wheel and corundum grinding wheel
In the aspect of crankshaft machining, in the comparison of machining crankshaft and main shaft with vitrified CBN grinding wheel and vitrified bond corundum grinding wheel, the life of high speed vitrified CBN grinding wheel is 15 times longer than that of ordinary vitrified corundum grinding wheel. The raw material consumption for one piece of CBN grinding wheel is 1/59 of that of corundum grinding wheel. Due to the high durability of vitrified CBN grinding wheel, the use of CBN grinding wheel can greatly reduce the dressing times of grinding wheel, and the pollution caused by grinding wheel in the dressing process will be minimized.
Compared with the traditional corundum grinding wheel, the vitrified CBN grinding wheel shortens the production cycle, reduces the production cost and improves the production efficiency. CBN vitrified bond grinding wheel will instead of corundum grinding wheel, which is the development direction of modern grinding tools.
Figure 2 Comparison of life and raw material consumption for machining crankshaft between vitrified CBN grinding wheel and corundum grinding wheel
CBN is one of the superhard materials with superior performances, such as high hardness, high thermal stability, low affinity with C and suitable for processing ferrous metals. The speed of vitrified grinding wheel made of CBN is generally up to 120m/s, and a large margin of rough and fine grinding is completed at one time. Because the grinding workpiece surface is in a state of compressive stress, the service life of the workpiece can be increased by 20%, and the comprehensive grinding cost can be reduced by more than 10%. The CBN grinding wheel grinding tool has achieved great use value. Vitrified CBN grinding wheel is a high-performance grinding tool with high efficiency, high precision, low grinding cost and low environmental pollution, which realizes the sustainable development, coordination and optimization of economy, society and environment, making industrial processing more efficient and simpler and achieving the goal of green machining.