Rotary Cutting Insert Geometry for Lower Resistance and Heat

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Solution Overview

Problem

Rotary cutting tools face challenges in extending the life of cutting inserts due to high cutting resistance and heat generation, which leads to premature wear and breakage of cutting edges.

Innovation Solution

The cutting insert design features a unique configuration with curved sub-cutting edge portions and a specific angle arrangement between seating surfaces, reducing cutting edge angles and enhancing stability, while the outer circumferential surface includes a flat third seating surface for secure fixation, thereby distributing cutting loads effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If conventional cutting edge designs are used, then initial cutting performance is adequate, but cutting resistance increases and heat generation occurs leading to premature wear and breakage

Engineering Contradiction:

Improvecutting insert lifeVSAvoidcutting resistance and heat generation

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The cutting insert employs curved sub-cutting edge portions instead of straight lines. When viewed from the first surface toward the second surface, each sub-cutting edge portion has a curved shape that reduces the cutting edge angle compared to conventional straight designs. This curvature allows the cutting edge to gradually engage the workpiece, reducing shock loads and heat generation, thereby extending cutting insert life while lowering cutting resistance.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The cutting insert features different geometric configurations at different locations: main cutting edge portions for primary material removal and curved sub-cutting edge portions for finishing and reduced resistance. The outer circumferential surface includes a flat third seating surface at a specific angle to distribute loads. This local differentiation optimizes performance at each zone, reducing overall cutting resistance and heat while extending service life.

Inventive Principle:

Principle #3Local quality

2Duration of action of moving object

If cutting edge angles are reduced to lower cutting resistance, then cutting insert life extends, but cutting edge strength may be compromised

Engineering Contradiction:

Improvecutting insert lifeVSAvoidcutting edge strength

Core Design Contradiction:

Duration of action of moving objectVSStrength

Solution Approach 1:

The cutting edge is segmented into main cutting edge portions and sub-cutting edge portions with different functions. The main cutting edge portions handle primary material removal with higher strength requirements, while the sub-cutting edge portions with curved geometry provide finishing cuts at reduced angles. This segmentation allows the insert to benefit from both low cutting resistance (via curved sub-edges) and sufficient strength (via main cutting edges) simultaneously, extending life without compromising strength.

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If curved sub-cutting edge portions are implemented, then cutting resistance reduces and heat generation minimizes, but manufacturing complexity increases

Engineering Contradiction:

Improvecutting resistance and heat generationVSAvoidcutting insert manufacturing

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The curved sub-cutting edge portions are designed with standardized curvature radii that can be efficiently manufactured using conventional CNC machining or molding processes. The curvature is optimized to reduce cutting resistance and heat generation while maintaining manufacturability through standard toolpaths and manufacturing methods, balancing performance improvement with ease of production.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Stability of the object's composition

If multiple seating surfaces with specific angles are used, then load distribution improves and stability increases, but device complexity increases

Engineering Contradiction:

Improvecutting insert stabilityVSAvoidseating surface configuration

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The cutting insert incorporates a flat third seating surface on the outer circumferential surface at a specific angle (5° to 15°) relative to the first seating surface. This localized angular feature optimizes load distribution and stability without requiring complex multi-axis configurations. The simple angular relationship between seating surfaces achieves enhanced stability while maintaining ease of manufacturing and assembly, avoiding excessive device complexity.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12064821B2Cutting insert for rotary cutting tool, and rotary cutting tool

Publication Date: 2024.08.20 SUMITOMO ELECTRIC HARDMETAL CORP

AI summary

A cutting insert for a rotary cutting tool has a second surface that includes a second seating surface having a shape of a flat surface. The first cutting edge has a first main cutting edge portion and a first sub cutting edge portion. The second cutting edge has a second main cutting edge portion and a second sub cutting edge portion. When viewed in a direction from the first surface toward the second surface, at least a portion of the second sub cutting edge portion is located outside the first main cutting edge portion, and at least a portion of the first sub cutting edge portion is located outside the second main cutting edge portion. When viewed in the direction from the first surface toward the second surface, each of the first sub cutting edge portion and the second sub cutting edge portion has a shape of a curved line.