Radius End Mill with Segmented Flank Width for Chatter Reduction
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Solution Overview
Problem
Radius end mills face challenges with chatter vibrations and surface roughness due to uniform flank widths of end cutting edges, leading to potential damage and inadequate finishing quality, especially in high-accuracy applications like plastic molding.
Innovation Solution
The end cutting edge is divided into inner peripheral side and outer peripheral side end cutting edges in the radial direction, with coupled second surfaces forming a continuous surface near the central axis, increasing the cross-sectional area and uniformity of bending resistance, and featuring a constant curvature radius for the radius end cutting edge to reduce contact with the work material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the end cutting edge has uniform flank width, then the structure is simple and easy to manufacture, but the bending resistance is insufficient leading to edge damage and chatter vibrations
Solution Approach 1:
The end cutting edge is divided into multiple segments along the radial direction, with each segment having a different flank width. The inner peripheral side has a larger flank width while the outer peripheral side has a smaller flank width, creating a gradient structure that optimizes bending resistance distribution without requiring complete structural redesign
Solution Approach 2:
Different portions of the end cutting edge are given different flank widths according to their specific functional requirements. The inner peripheral side with larger flank width provides enhanced bending resistance where needed, while the outer peripheral side maintains adequate performance with reduced material, achieving local optimization of the cutting edge structure
2Productivity
If the feed speed is increased to improve machining efficiency, then productivity increases, but chatter vibrations occur and surface roughness deteriorates
Solution Approach 1:
The flank width parameter of the end cutting edge is changed along the radial direction, creating a variable cross-sectional area that optimizes the stiffness-to-weight ratio. This parameter variation enhances the tool's resistance to chatter vibrations, enabling higher feed speeds to be used without sacrificing surface roughness quality
3Stability of the object's composition
If the curvature radius of the radius end cutting edge is increased to smooth the cutting edge, then chatter vibrations are reduced, but the contact area with work material increases leading to higher cutting load
Solution Approach 1:
The curvature radius of the radius end cutting edge is set to a specific range (0.01 to 0.3 times the cutting diameter) to achieve optimal balance. This local optimization of the curvature parameter provides sufficient smoothness to reduce chatter vibrations while controlling the contact area to maintain acceptable cutting load levels
Data Source
Figure 1~2
Figure 3(a)~3(b)
Figure 3(c)~4
AI summary
[Problem] To ensure obtaining highly accurate finishing surface roughness on a work material simultaneous with ensuring highly efficient cutting work. [Solution] The present invention includes a plurality of end cutting edges 3 arrayed around a central axis O and a plurality of arc-shaped radius end cutting edges 6 continuous with the end cutting edges 3 on an outer peripheral side in a radial direction. The end cutting edge 3 is divided into an inner peripheral side end cutting edge 4 and an outer peripheral side end cutting edge 5 in a radial direction. A lowest point Pb of the radius end cutting edge 6 during cutting is positioned in a section from a boundary P2 between the outer peripheral side end cutting edge 5 and the radius end cutting edge 6 to a boundary P4 between the radius end cutting edge 6 and the peripheral cutting edge 7. Second surfaces 40 of the plurality of inner peripheral side end cutting edges 4 are coupled at a part close to the central axis O. A region of coupled second surfaces 40 is continuous from a region including the central axis O to outer peripheral sides of respective inner peripheral side end cutting edges 4 in a radial direction in a strip shape. A width of the strip-shaped region gradually enlarges from the central axis O side to an outer peripheral side in a radial direction.