Variable Relief Angle End Mill for Chatter Suppression
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Solution Overview
Problem
Existing end mills experience chatter vibrations during cutting processes, leading to surface roughness deterioration and reduced thickness precision, particularly in thin-wall machining, due to excessive cutting resistance caused by uniform relief angles.
Innovation Solution
The end mill features a columnar tool body with first and second outer peripheral cutting edges, where the relief angle of the first edge increases and the second edge decreases along the axial direction, respectively, to manage cutting resistance and suppress chatter vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relief angles are reduced to facilitate contact between relief faces and machined surface, then process damping effect is obtained to suppress resonant harmonic vibrations, but cutting resistance increases causing forced chatter vibrations and reduced machining precision
Solution Approach 1:
The invention applies different relief angle characteristics to different outer peripheral cutting edges. Specifically, some cutting edges have relief angles that increase in the axial direction while others have relief angles that decrease, creating local variations in contact characteristics with the machined surface. This allows each cutting edge to contribute differently to process damping while maintaining acceptable cutting resistance levels.
Solution Approach 2:
The invention introduces asymmetry in the relief angle configuration by making relief angles unequal among different outer peripheral cutting edges. This asymmetric arrangement prevents uniform pressing forces that would cause forced chatter vibrations, while still providing sufficient process damping to suppress resonant harmonic vibrations through the varied contact characteristics.
2Reliability
If relief angles are reduced to suppress chatter vibrations, then contact between relief faces and machined surface increases, but cutting resistance increases causing the standing wall to become curved
Solution Approach 1:
Different outer peripheral cutting edges are assigned different relief angle variations (increasing, decreasing, or constant) to create localized differences in pressing force distribution. This prevents uniform excessive pressing that would cause the standing wall to curve, while still maintaining sufficient contact for vibration suppression.
Solution Approach 2:
The asymmetric arrangement of relief angles among cutting edges creates non-uniform contact forces that avoid concentrated pressing on any single area of the standing wall. This distributes the mechanical load more evenly, preventing the standing wall from becoming curved while still achieving chatter vibration suppression.
3Reliability
If relief angles are made unequal to suppress chatter vibrations, then resonant harmonic vibrations are reduced, but device complexity increases
Solution Approach 1:
The invention implements local quality by assigning different relief angle characteristics to specific cutting edges based on their positions. This creates a systematic but not overly complex configuration where each cutting edge has a defined relief angle pattern (increasing, decreasing, or constant) that contributes to vibration suppression without requiring complex control mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces excessive cutting resistance, preventing forced chatter vibrations and maintaining cutting process precision and efficiency, even in thin-wall machining scenarios.
Implementation Method 1
obtaining a process damping effect owing to the contact by the relief faces
Data Source
AI summary
An end mill includes: a columnar tool body that rotates about a center axis; and outer peripheral cutting edges on an outer peripheral surface of the tool body, the outer peripheral cutting edges including a first outer peripheral cutting edge and a second outer peripheral cutting edge. A relief angle θ of the first outer peripheral cutting edge changes to increase in an axial direction of the tool body from a bottom face that is one end of the tool body. A relief angle θ of the second outer peripheral cutting edge changes to decrease in the axial direction from the bottom face.