Cutting Insert Edge Geometry for Strength and Cutting Sharpness

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Solution Overview

Problem

Conventional cutting inserts face a challenge in achieving both high cutting performance and edge strength, as increasing the intersection angle of the main cutting edge enhances edge strength but may decrease cutting performance, while decreasing the angle improves cutting performance at the cost of edge strength.

Innovation Solution

A cutting insert design featuring a main cutting edge with a combination of first and second straight portions and a curved portion, where the intersection angles of these portions with respect to a reference side are different, allowing for adjustable shape and reduced stress concentration, thereby enhancing both cutting performance and edge strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the intersection angle of the main cutting edge is increased to enhance edge strength, then the edge strength is improved, but the cutting performance (sharpness) deteriorates

Engineering Contradiction:
Improveedge strengthVSAvoidcutting performance
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The main cutting edge is divided into multiple segments: a first straight portion adjacent to the reference side, a second straight portion at a distance from the first straight portion, and a curved portion connecting them. Each segment has a different intersection angle with the reference side, allowing the first segment to provide edge strength while the second segment maintains cutting sharpness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the main cutting edge are given different local geometric properties. The first straight portion has a larger intersection angle for edge strength, while the second straight portion has a smaller intersection angle for cutting performance. This local differentiation resolves the contradiction between overall edge strength and local cutting sharpness.

Inventive Principle:
Principle #3Local quality

2Productivity

If the intersection angle is decreased to improve cutting performance, then the cutting performance is improved, but the edge strength deteriorates

Engineering Contradiction:
Improvecutting performanceVSAvoidedge strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The main cutting edge is segmented into portions with different intersection angles. The second straight portion has a smaller intersection angle optimized for cutting performance, while the first straight portion compensates with a larger intersection angle to maintain overall edge strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cutting edge features local geometric variation where the second straight portion has optimized sharpness for cutting performance, while the first straight portion provides structural strength. This local quality differentiation allows simultaneous optimization of both cutting performance and edge strength.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4101567A1Cutting insert and cutting tool
Publication Date: 2022.12.14 SUMITOMO ELECTRIC HARDMETAL CORP
  • EP4101567A1 patent drawingFigure 1~2
  • EP4101567A1 patent drawingFigure 3~4
  • EP4101567A1 patent drawingFigure 5~6

AI summary

A cutting insert includes a main body including a first face, a second face, and a third face. The second face is continuous with the first face and extends in a direction intersecting the first face. The third face is continuous with the first face and the second face. The first face has a fixing hole formed therein. The second face includes a rake face. Among the outer-peripheral sides of the second face, the boundary portion with the first face is a main cutting edge. When viewed from the side where the first face is disposed, the main cutting edge includes a first straight portion, a second straight portion, and a curved portion. The first straight portion is located adjacent to a reference side. The second straight portion is arranged at a distance from the first straight portion. The curved portion connects the first straight portion and the second straight portion. A first intersection angle of the first straight portion with respect to the reference side is larger than a second intersection angle of the second straight portion with respect to the reference side.