Uneven-Edge End Mill Geometry for Chatter Suppression
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Solution Overview
Problem
Existing end mills with variable-lead arrangements, where cutting edges have different helix angles, complicate tool design and may not effectively prevent chatter vibration, leading to interference issues and restricted cutting velocities.
Innovation Solution
An end mill design with peripheral cutting edges having equal helix angles, where at least one edge is partially uneven with a nicked or roughing portion, allowing for varying lengths and positions of the uneven edge to alter cutting force magnitude and reduce resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If variable-lead arrangement with different helix angles is used, then chatter vibration is suppressed, but tool design becomes complicated and tooth interference occurs
Solution Approach 1:
Instead of varying the helix angle across different cutting edges (global variation), the invention applies local modification by adding uneven edge portions (nicked or roughing portions) to specific cutting edges. This local quality change alters the cutting force characteristics without changing the overall helix angle configuration, thereby suppressing chatter vibration while maintaining simple tool design with equal helix angles for all peripheral cutting edges
2Reliability
If variable-lead arrangement with different helix angles is used, then chatter vibration is suppressed, but cutting velocity is restricted
Solution Approach 1:
The uneven edge portions are applied locally to specific cutting edges rather than varying the helix angle globally. This local modification allows the end mill to maintain a consistent helix angle configuration that supports higher cutting velocities, while the localized uneven portions create sufficient variation in cutting force magnitude to suppress chatter vibration
3Device complexity
If equal helix angles are used for all peripheral cutting edges, then tool design is simplified, but chatter vibration cannot be effectively suppressed
Solution Approach 1:
The invention maintains the simplicity of equal helix angles for all peripheral cutting edges (global uniformity) while introducing local uneven edge portions on specific cutting edges. This combination of global simplicity and local variation achieves chatter vibration suppression without complicating the overall tool design
Solution Approach 2:
Instead of changing the helix angle parameter across different cutting edges, the invention changes the local geometry parameter by adding uneven edge portions (nicked or roughing portions) to specific cutting edges. This parameter change in local edge geometry creates variation in cutting force magnitude while maintaining the simple equal-helix-angle configuration
Data Source
AI summary
An end mill includes a plurality of peripheral cutting edges have respective helix angles which are equal to each other and which range from 0° to 5°. Each of the plurality of peripheral cutting edges is defined by one of four types of teeth A-D consisting of (a) teeth A-C each defining a partially-uneven cutting edge that includes an uneven edge portion consisting of a nicked portion or a roughing portion and (b) a tooth D that does not define the uneven edge portion. The peripheral cutting edges are defined by at least two of the four types of teeth A-D, such that each adjacent pair of the peripheral cutting edges adjacent to each other are defined by the teeth that are different in type from each other.