The so-called hard cutting gear refers to the precision cutting process of hardened steel gears with a hardness greater than 50HRC using ceramic or superhard CBN tools. Compared with grinding, hard cutting has good processing flexibility, economy and environmental performance, so it has attracted the attention of the gear industry.
In the process of hard cutting gears, due to the high cutting force and high cutting temperature, the requirements for cutting tools are high, such as high heat resistance and wear resistance. Ceramic tools and CBN tools have good heat resistance and wear resistance, and can be processed at high cutting speed and low feed rate. However, due to their high brittleness, they can only be processed with a small margin of cutting depth. Otherwise, chipping will occur.
Ceramic tools are suitable for processing gears between HRC45-55. For gears with a hardness above HRC58, it is more suitable to choose CBN tools. CBN tools are currently the hardest tools for processing ferrous materials, and can process workpieces with a hardness between HRC45-79. As a pioneer in the localization of superhard cutting tools, Halnn has focused on the research and development of CBN cutting tools and high-grade diamonds for brittle and hard materials in the early stage, and has deep knowledge in hard cutting gears, especially the application of BN-H10 brand , making hard cutting technology develop rapidly in the gear industry.
The BN-H10 grade belongs to the composite CBN tool, and only one cutting edge can be used. However, when cutting gears in a hard state, its excellent wear resistance and heat resistance are unmatched by other companies' multi-edged CBN tools.
At the same time, on the basis of ensuring the dimensional accuracy and surface quality of the gears to reach Ra0.8, the production efficiency is greatly improved and the production cost is reduced.
Take the hard cutting gear as an example: material: 20CrMnTi; hardness: HRC58-62, processing conditions: continuous cutting conditions, required surface finish: Ra0.8, blade model: BN-H10 CNGA120408, cutting parameters: Vc=180m/ min; ap=0.2mm; Fr=0.1mm/r, processing method: dry cutting
Compared with a certain brand of CBN inserts (as follows): Under the same cutting parameters, the tool life of Halnn CBN tool BN-H10 is 1.33 times that of a certain brand of CBN tool.
Tool material | Cutting speed | Tool life | Surface finish |
Halnn BN-H10 grade | 180m/min | 800 pieces/blade↑ | Ra0.8 |
Other brand CBN | 180m/min | 600 pieces/blade | Ra0.8 |
BN-H10 Grade composite CBN cutters generally use dry cutting without adding cutting fluid when cutting gears in a hard state, but sometimes water-based cutting fluid can also be used when there are special requirements for the machining accuracy, surface quality, and tool life of the workpiece. Continuous and uniform cooling method to avoid micro-cracks in the insert.