Rotary Cutting Tool Body With Elliptical Stress Relief Grooves

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Solution Overview

Problem

Rotary cutting tools experience high stress concentration at the transition between the tangentially facing bottom surface and the internal wall in the insert seats, leading to potential material failure and limiting design flexibility.

Innovation Solution

The tool body incorporates elliptically shaped stress relief grooves in the insert seats, which provide a larger radius of curvature at high-stress areas, reducing material thickness and allowing for more insert seats, smaller tool diameter, larger chip pockets, or better chip flute adaptation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional circular stress relief grooves are used, then the tool body structure is simple and easy to manufacture, but the stress concentration is not sufficiently reduced and material thickness must be maintained

Engineering Contradiction:
Improvestress concentration reductionVSAvoidgroove shape complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies curvature principle by transitioning from circular cross-sectional grooves to elliptical cross-sectional grooves. The elliptical shape provides optimized curvature distribution with larger radius of curvature at critical stress areas, effectively reducing stress concentration while maintaining manufacturability through standard machining operations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the stress relief groove from a circular cross-section to an elliptical cross-section. This parameter change allows optimization of the radius of curvature at specific locations along the groove, enabling better stress distribution without fundamentally changing the groove formation process.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If material thickness is reduced to allow more insert seats, then tool diameter can be reduced, but stress concentration increases and reliability decreases

Engineering Contradiction:
Improvenumber of insert seatsVSAvoidtool body reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By implementing elliptical stress relief grooves with optimized curvature, the patent enables reduced material thickness while maintaining adequate stress distribution. The larger radius of curvature at critical points prevents stress concentration even with thinner material, allowing increased insert seat capacity without compromising reliability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If conventional stress relief grooves are used, then manufacturing is straightforward, but design flexibility for chip pockets and chip flutes is limited

Engineering Contradiction:
Improvedesign flexibilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The elliptical cross-sectional shape modifies the stress relief groove parameters to provide enhanced design flexibility. This parameter change enables better adaptation of chip pockets and chip flutes while maintaining compatibility with standard machining processes, achieving improved versatility without excessive manufacturing complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4624080A1Tool body of a rotary cutting tool and rotary cutting tool comprising such a tool body
Publication Date: 2025.10.01 SANDVIK COROMANT
  • EP4624080A1 patent drawingFigure 1
  • EP4624080A1 patent drawingFigure 2~3
  • EP4624080A1 patent drawingFigure 4~5

AI summary

A tool body (2) of a rotary cutting tool comprising at least one insert seat (10) provided in the tool body at a transition between a front face (2c) and a peripheral surface (2d) of the tool body (2), wherein said at least one insert seat (10) comprises: - a tangentially facing bottom surface (12) and an internal wall (14) that extends transversely to the bottom surface (12); and - a stress relief groove (20) forming a transition between the bottom surface (12) and the internal wall (14) and having a, first end (20a) ending in the front face or peripheral surface of the tool body. Said stress relief groove comprises a stress relief surface (22) that has an elliptical cross-sectional shape and that extends from said first end (20a) of the stress relief groove along at least a part of the length of the stress relief groove.