Analysis of Minimum Cutting Speed in Velocity Effect Sensitive Area of Ball End Mill

To effectively evaluate the performance of the milling cutters, the relationship between the main movement and the feed movement is analyzed, and the speed proportional function model is established. The analysis shows that the cutting performance of the ball end mill is poor within the range of less than 25°, which is the sensitive area of velocity effect. while the milling performance of the torus cutter without the velocity effect sensitive area is better than the ball end mill. Based on the geometry contact relations, the impact of feed direction on the minimum cutting speed in the contact area is respectively analyzed for the ball end mill, and the mathematical model for the ball end mill is presented between the minimum cutting speed point and some machining parameters, such as cutters, the surface slope, the cutting depth, the feed direction. Based on the math model, it can be determined whether the minimum cutting speed point is within the velocity effect sensitive area of the ball end mill. The experimental results show that when the velocity effect sensitive area of the ball end mill is involved in the milling area, a vibration perpendicular to the feed direction is generated on the cutting path, and an optimal feed direction interval exists in the vertical upward direction. The torus cutter milling performance is significantly better than the ball end mill, and the feed direction has little influence on the milling effect.