Cutting Insert Flank Geometry for Chip Abrasion Prevention

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Solution Overview

Problem

Conventional cutting inserts with negative-type configurations face challenges in preventing chip abrasion and damage to the rake face, especially when the radial rake angle is set to a negative value to maintain a large gap between the flank and rotational trajectory.

Innovation Solution

The cutting insert design features a recessed first minor cutting edge flank towards the center, allowing a sufficient gap between the flank and rotational trajectory without requiring a negative radial rake angle, thus preventing chip abrasion and damage to the rake face.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the radial rake angle is set to a negative value to maintain a large gap between the flank and rotational trajectory, then the gap between the flank and rotational trajectory is improved, but the space above the rake face is narrowed and chip discharge becomes difficult

Engineering Contradiction:
Improvegap between flank and rotational trajectoryVSAvoidchip discharge efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The side face is divided into multiple flanks (first flank, second flank, third flank) with different clearance angles. The first flank has a clearance angle of 0°, the second flank has a positive clearance angle, and the third flank has a clearance angle of 0°. This segmentation allows each flank to serve different functions: the first flank maintains gap distance, the second flank provides clearance, and the third flank maintains structural integrity, thereby resolving the contradiction between maintaining gap and ensuring chip discharge.

Inventive Principle:
Principle #1Segmentation

2Duration of action of moving object

If the cutting insert is used with reversed top and bottom to extend usage, then the number of uses is improved, but the rake face may be damaged by chip abrasion

Engineering Contradiction:
Improvenumber of usesVSAvoidchip abrasion to rake face
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The first minor cutting edge flank is recessed toward the center of the cutting insert before use. This preliminary geometric configuration creates sufficient gap between the flank and rotational trajectory without requiring negative radial rake angle, preventing chips from contacting and abrading the rake face during operation, thus protecting the rake face while allowing reversible use.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the first minor cutting edge flank is recessed toward the center, then the gap between flank and rotational trajectory is improved, but the structural strength may be reduced

Engineering Contradiction:
Improvegap between flank and rotational trajectoryVSAvoidstructural strength of cutting insert
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

Different regions of the side face are given different clearance angles to optimize local functions. The first flank (0° clearance) and third flank (0° clearance) provide structural support and gap maintenance, while the second flank (positive clearance) provides chip clearance. This local differentiation of geometric properties allows the recessed first minor cutting edge flank to maintain gap without compromising overall structural strength.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3702079B1Cutting insert
Publication Date: 2025.04.30 TUNGALOY CORP
  • EP3702079B1 patent drawingFigure 1
  • EP3702079B1 patent drawingFigure 2
  • EP3702079B1 patent drawingFigure 3~4

AI summary

A cutting insert (10) has a cutting edge (21, 22, 23, 24, 25) formed on part of an intersecting ridge line portion of an upper face (20) or a lower face (30) and a side face (40). The cutting edge includes a major cutting edge (23, 24, 25), a minor cutting edge (21), and a connecting cutting edge (22) that connects the major cutting edge and the minor cutting edge. A minor cutting edge flank (44, 45) that is part of the side face and that corresponds to the minor cutting edge includes a first minor cutting edge flank (44) that connects to the minor cutting edge and that has a clearance angle of 0°, and a second minor cutting edge flank (45) that connects to the first minor cutting edge flank and that has a clearance angle of a negative value. A connecting cutting edge flank (41, 42) that is part of the side face and that corresponds to the connecting cutting edge includes a first connecting cutting edge flank (41) that connects to the connecting cutting edge and that has a clearance angle of 0° or greater, and a second connecting cutting edge flank (42) that connects to the first connecting cutting edge flank and has a clearance angle that is greater than the clearance angle of the first connecting cutting edge flank.