Spiral Rotary Cutting Edge Geometry for Lower Cutting Resistance
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Solution Overview
Problem
Existing rotary tools face challenges in reducing cutting resistance while maintaining the integrity of the cutting edge, as narrowing the pitch of the waveform-shaped cutting edge can lead to stress concentration and potential damage due to reduced radius of curvature of the ridge portions.
Innovation Solution
A rotary tool design featuring a spiral cutting edge with convex and concave curved sections, where the radius of curvature of the convex sections is greater than that of the concave sections, reducing cutting resistance and alleviating stress concentration by positioning the sections in a manner that suppresses chatter vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the pitch of the waveform-shaped cutting edge is narrowed to reduce cutting resistance, then cutting resistance is reduced, but the radius of curvature of the ridge portion is reduced causing stress concentration and potential cutting edge damage
Solution Approach 1:
The cutting edge is designed with different radius of curvature in different regions: the first region (apex) has a larger radius of curvature to reduce stress concentration and prevent damage, while the second region has a smaller radius of curvature to achieve narrower pitch and reduced cutting resistance. This local differentiation of geometric parameters allows simultaneous optimization of both strength and cutting performance.
Solution Approach 2:
The invention changes the geometric parameters of the cutting edge by introducing a dual-radius curvature design. The radius of curvature is varied along the cutting edge profile, with R1 for the first region and R2 for the second region, where R1 > R2. This parameter variation enables the cutting edge to achieve both structural integrity and reduced cutting resistance.
2Productivity
If the radius of curvature of the ridge portion is reduced to achieve narrower pitch, then pitch is narrowed, but stress is concentrated at the apex of the ridge portion during cutting and the cutting edge may be damaged
Solution Approach 1:
Different regions of the cutting edge are assigned different radius of curvature values to fulfill different functional requirements. The first region with larger radius R1 provides structural reliability and stress distribution, while the second region with smaller radius R2 achieves the desired narrow pitch for improved productivity.
Solution Approach 2:
The cutting edge profile is segmented into two distinct regions with different geometric characteristics. The first region (apex area) and second region (side area) are treated as separate functional zones, each optimized for its specific role in the cutting process.
Data Source
AI summary
A rotary tool of the present aspect has a body and a cutting edge positioned on the outer periphery of the body. The cutting edge has a first section and a second section when viewed on an imaginary plane defined by cutting a rotational trajectory of the rotary tool on a plane including a rotational axis. The first section has a first region and a second region. A first radius of curvature of the first region is greater than a second radius of curvature of the second region in at least one of a plurality of the first sections.