Cutting Insert Curved Edge Design for Chip Discharge

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Solution Overview

Problem

Conventional cutting inserts face challenges in achieving high efficiency with large axial depth of cut and feed due to insufficient chip discharge performance and potential strength issues when increasing cutting edge angles or insert size.

Innovation Solution

A cutting insert design featuring a central axis with a through hole, a polygonal upper and lower surface, and a cutting edge with varying angles and a curved intersection, along with a land and rake surface configuration to enhance strength and chip discharge, allowing for efficient cutting without excessive size increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the depth of cut is increased, then the productivity is improved, but the size of the cutting insert must be excessively increased and chip discharge performance becomes insufficient

Engineering Contradiction:
Improvedepth of cutVSAvoidsize of cutting insert
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The invention applies curvature to the cutting edge by forming a curved portion with a specific radius of curvature (R1) between the end of the major cutting edge and the start of the flat cutting edge. This curved geometry allows the cutting insert to achieve large depth of cut without requiring excessive size increase, as the curved profile optimizes the cutting path and chip flow characteristics.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the cutting edge by defining specific angle ranges (alpha1 for the major cutting edge portion, alpha2 for the flat cutting edge portion) and a specific radius of curvature (R1). These parameter optimizations enable the cutting insert to maintain effective cutting performance at large depth of cut without excessive size increase.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the depth of cut is increased, then the productivity is improved, but the chip discharge performance becomes insufficient

Engineering Contradiction:
Improvedepth of cutVSAvoidchip discharge performance
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The curved portion of the cutting edge with radius of curvature R1 facilitates improved chip discharge by creating a more favorable chip flow path. The curvature helps chips evacuate more efficiently from the cutting zone even when the depth of cut is large, preventing chip congestion and maintaining consistent cutting performance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

By optimizing the angle parameters (alpha1, alpha2) and the radius of curvature (R1), the invention creates geometric conditions that promote effective chip discharge. The specific parameter ranges ensure that chips are efficiently evacuated during deep cutting operations without compromising productivity.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If the cutting edge angle is increased, then the chip discharge performance is improved, but the strength of the cutting insert may be insufficient

Engineering Contradiction:
Improvechip discharge performanceVSAvoidstrength of cutting insert
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The invention applies different cutting edge angles to different portions of the cutting edge. The major cutting edge portion has angle alpha1, the flat cutting edge portion has angle alpha2, and the curved portion connects them smoothly. This local differentiation allows each section to be optimized for its specific function while maintaining overall insert strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The curved portion with radius of curvature R1 provides a smooth transition between the major and flat cutting edge portions, avoiding abrupt angle changes that could create stress concentration points. This curved geometry maintains structural integrity while enabling effective chip discharge.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Length of moving object

If the size of the cutting insert is increased, then the depth of cut capability is improved, but the chip discharge performance becomes insufficient

Engineering Contradiction:
Improvesize of cutting insertVSAvoidchip discharge performance
Core Design Contradiction:
Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The invention optimizes the geometric parameters (alpha1, alpha2, and R1) to achieve effective chip discharge without requiring excessive insert size. The specific parameter ranges enable the cutting insert to maintain compact dimensions while still providing large depth of cut capability and good chip evacuation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2926932B1Cutting insert, cutting tool, and cut workpiece manufacturing method
Publication Date: 2019.01.16 KYOCERA CORP
  • EP2926932B1 patent drawingFigure 1
  • EP2926932B1 patent drawingFigure 2
  • EP2926932B1 patent drawingFigure 3

AI summary

A cutting insert according to an embodiment of the present invention has an upper surface, a lower surface, a side surface connected to each of the upper surface and the lower surface, and a cutting edge having sequentially a corner cutting edge, a first straight cutting edge, a second straight cutting edge, and a third straight cutting edge, which are located along an intersection of the upper surface and the side surface and intersect one another at an obtuse angle. The upper surface has a first inclined surface extending along the first straight cutting edge, a second inclined surface extending along the second straight cutting edge, and a third inclined surface extending along the third straight cutting edge. An inclination angle of the second inclined surface with respect to the lower surface is larger than an inclination angle of each of the first inclined surface and the third inclined surface with respect to the lower surface.