Concave Major Cutting Edge Insert for Lower Chip Thickness

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Solution Overview

Problem

Conventional cutting inserts experience high chip thickness, heat generation, and a risk of fracture due to the 45° or 90° major cutting edge angle, leading to increased impact and reduced durability during milling processes.

Innovation Solution

A cutting insert with a polygonal upper and lower surface, featuring a major cutting edge with a downwardly dented concave shape, including a curvilinear section and straight sections, and varying rake surfaces to manage chip flow and reduce cutting edge angle, enhancing strength and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a cutting edge angle of 45° or 90° is used for the major cutting edge, then the cutting insert can effectively cut the workpiece, but chip thickness increases leading to large impact on the cutting edge

Engineering Contradiction:
Improvecutting effectivenessVSAvoidcutting edge strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The cutting edge is designed with non-uniform thickness distribution, creating different local properties along its length. The thicker portions provide strength while thinner portions reduce chip thickness and impact, allowing each section to optimize for its specific function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the geometric parameters of the cutting edge by introducing a concave curvature profile. This modifies the cutting edge angle dynamically along the length of the cutting edge, transitioning from standard angles to variable angles that reduce chip thickness while maintaining cutting effectiveness.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If a cutting edge angle of 45° or 90° is used for the major cutting edge, then the cutting process can proceed, but large amount of heat is generated during cutting

Engineering Contradiction:
Improvecutting process continuityVSAvoidheat generation
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

By changing the cutting edge geometry to a concave profile with variable thickness, the invention modifies the cutting parameters dynamically. This reduces chip thickness and consequently lowers the heat generated during cutting, while maintaining continuous cutting process capability.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If a cutting edge angle of 45° or 90° is used for the major cutting edge, then the cutting insert can cut the workpiece, but there is a large risk of fracture in the major cutting edge

Engineering Contradiction:
Improvecutting capabilityVSAvoidcutting edge reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The cutting edge features non-uniform thickness distribution with thicker sections providing structural strength and thinner sections reducing chip thickness. This local quality variation ensures that the cutting edge has sufficient strength to prevent fracture while maintaining cutting capability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The concave curvature design creates a cushioning effect by gradually reducing chip thickness along the cutting edge. This beforehand cushioning prevents sudden impact loads that could cause fracture, allowing the cutting edge to withstand cutting forces more reliably.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Productivity

If the cutting edge is curved downward in a side view, then chip thickness increases, but the invention modifies this by creating a concave shape with varying thickness

Engineering Contradiction:
Improvecutting edge geometryVSAvoidchip thickness control
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The cutting edge employs local quality variation with different thickness sections. The thinner portions effectively control chip thickness to prevent excessive impact, while the overall concave geometry maintains the desired cutting edge profile for productive cutting.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3072618B1Cutting insert, cutting tool and method for producing a cut article
Publication Date: 2021.09.29 KYOCERA CORP
  • EP3072618B1 patent drawingFigure 1
  • EP3072618B1 patent drawingFigure 2
  • EP3072618B1 patent drawingFigure 3

AI summary

A cutting insert (1) according to an embodiment has a lower surface (2), an upper surface (3), a side surface (4) disposed between the lower surface (2) and the upper surface (3), a pair of corner cutting edges (5) located along an intersection of the upper surface (3) and the side surface (4), and a major cutting edge (6) located between the pair of corner cutting edges (5). The major cutting edge (6) has a downwardly dented curvilinear part (61) and a pair of straight parts (62) respectively extending from the curvilinear part (61) toward the pair of corner cutting edges (5) in a side view. A portion (6p) of the curvilinear part (61) located lowermost is close to one corner cutting edge (5b) in the side view.