End Mill Corner Relief Geometry for Smoother Radius Transitions

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Solution Overview

Problem

End mills with convex radial relief surfaces face challenges in aligning with corner radius surfaces, leading to discontinuities and reduced tool life and surface finish, especially when machining difficult materials at high speeds.

Innovation Solution

The design of end mills with convex radial relief surfaces and circular arc profiles, where the corner relief surface is tangentially connected to the convex radial relief surface at the cutting edge, reducing the radial length between the radial tangent point and the end mill to minimize alignment issues and enhance surface finish.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a convex radial relief surface is used on the end mill, then the tool life and surface finish are improved, but the alignment with corner radius surfaces becomes problematic causing discontinuities

Engineering Contradiction:
Improvetool lifeVSAvoidalignment between radial relief surface and corner radius surface
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies curvature by transitioning from a flat or concave radial relief surface to a convex radial relief surface. This convex curvature allows the surface to better conform to the workpiece geometry and eliminates the alignment discontinuities that occur with flat or concave surfaces when connected to corner radius surfaces, thereby improving both tool life and manufacturing precision.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameter of the radial relief surface from flat or concave to convex. This parameter change fundamentally alters how the surface interacts with the workpiece and corner radius surfaces, eliminating the harmful discontinuities and improving the overall performance of the end mill.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the radial length between the radial tangent point and the end mill is reduced, then the alignment and surface finish are improved, but the manufacturing complexity increases

Engineering Contradiction:
ImprovealignmentVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The convex curved profile of the radial relief surface naturally achieves the required alignment precision by conforming to the workpiece geometry. While the curved profile requires precise manufacturing, the overall design simplifies the alignment process compared to trying to achieve perfect alignment with flat or concave surfaces, and the manufacturing complexity is offset by the elimination of additional corrective steps.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP3194101B1End mill with convex radial relief surface and corner having circular arc profile
Publication Date: 2023.07.26 ISCAR LTD
  • EP3194101B1 patent drawingFigure 1A~1B
  • EP3194101B1 patent drawingFigure 2A~3B
  • EP3194101B1 patent drawingFigure 4A~4B

AI summary

An end mill includes a tooth having a convex radial relief surface, a corner with a circular arc profile, a rake surface and a corner relief surface. The corner relief surface extends rearward of a radial tangent plane defined in relation to the circular arc profile.