End Mill Core Thinning Geometry for Drilling and Face Milling
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Solution Overview
Problem
Existing end mills are not suitable for drilling operations due to the lack of cutting edges near the center, leading to unreliable chip removal and compromised quality in both face milling and drilling.
Innovation Solution
The end mill features a cutting area with at least two geometrically different point thinnings, with the first point thinning having an angle of 30° to 45° and the second point thinning having an angle of 35° to 50°, allowing for improved drilling capabilities while maintaining face milling quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If point thinning is increased to improve drilling capability, then drilling performance is improved, but tooth thickness and stability are reduced
Solution Approach 1:
The patent applies local quality by implementing different point thinning angles at different locations around the cutting edges. Specifically, first point thinnings have an angle of 30°-45° while second point thinnings have an angle of 35°-50°. This localized differentiation allows certain areas to have greater chip removal capability (improving drilling) while other areas maintain sufficient tooth thickness (preserving stability and rigidity).
Solution Approach 2:
The patent segments the point thinning geometry into distinct first and second point thinnings with different angular characteristics. This segmentation allows the end mill to have varied thinning profiles around its circumference, enabling it to perform both drilling operations (requiring aggressive chip removal) and face milling operations (requiring stable, rigid cutting edges) effectively.
2Adaptability or versatility
If uniform point thinning is applied to enable drilling, then drilling is possible, but face milling quality deteriorates due to reduced rigidity
Solution Approach 1:
By applying different point thinning angles (30°-45° for first point thinnings, 35°-50° for second point thinnings) at different locations, the patent ensures that not all cutting edges are equally thinned. This localized quality control allows the end mill to maintain sufficient rigidity in certain areas for high-quality face milling while providing adequate chip removal capability in other areas for effective drilling operations.
Solution Approach 2:
The patent introduces asymmetry by deliberately creating non-uniform point thinning distribution around the cutting edges. Instead of applying identical thinning to all locations, the varied angular characteristics of first and second point thinnings create an asymmetric geometry that balances the competing demands of drilling versatility and face milling precision.
Data Source
Figure 1~2
Figure 3
Figure 4-1~4-2
AI summary
The end mill, preferably made of solid carbide, provides a fastening section and a cutting area. The cutting area is formed by a core and at least two cutting edges arranged around the core, extending helically around a rotational axis of the end mill, each of which has a circumferential main cutting edge and a secondary cutting edge on an end face of the cutting area. On the end face of the cutting area, at least one first point thinning of the core is provided between (first) two adjacent cutting edges and at least one second point thinning is provided between two (other or second) adjacent cutting edges. The end mill is further characterized in that the first point thinning is geometrically designed differently than the second point thinning.Furthermore, the first point thinning should have a (point thinning) angle of 30° to 45°, and the second point thinning a (point thinning) angle of 35° to 50° (always relative to a (e.g., frontal) normal plane to the rotation axis of the end mill). Furthermore, the first point thinning should have a (point thinning) opening angle of 30° to 50°, and the second point thinning a (point thinning) opening angle of 40° to 60° (always the opening angle is the angle between the flanks of the point thinning in a plan view of the end mill face).