Diamond-Coated Cutting Edge Geometry for Smooth Chip Ejection

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Solution Overview

Problem

Diamond-coated cutting tools have a short tool lifetime due to inefficient chip ejection, leading to damage and reduced performance.

Innovation Solution

A cutting tool design featuring a substrate with a diamond layer that includes a rake face and a flank, where the rake face has protrusions with inclined and curvature portions, allowing for improved chip ejection and reduced tool damage, achieved through a manufacturing process involving ion beam removal of the diamond layer without turning the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a conventional diamond-coated cutting tool is used, then the cutting edge can maintain sharpness, but chip ejection is inefficient leading to short tool lifetime

Engineering Contradiction:

Improvetool lifetimeVSAvoidchip ejection inefficiency

Core Design Contradiction:

Duration of action of moving objectVSObject-generated harmful factors

Solution Approach 1:

The rake face is segmented into multiple protrusions with inclined portions, creating a stepped structure that facilitates progressive chip ejection. This segmentation transforms the continuous rake face into discrete functional zones that actively promote chip removal at different stages of the cutting process.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces a third dimension to the rake face by creating protrusions with inclined portions that extend outward from the substrate surface. This dimensional addition creates a three-dimensional chip ejection path, allowing chips to be lifted and removed more effectively from the cutting zone.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If the diamond layer is removed by conventional methods involving substrate turning, then the diamond layer can be precisely shaped, but the manufacturing process becomes complex and time-consuming

Engineering Contradiction:

Improvediamond layer shape precisionVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of turning the substrate to shape the diamond layer, the invention inverts the approach by removing the diamond layer while keeping the substrate stationary. This is achieved through ion beam irradiation from multiple directions, eliminating the need for complex substrate turning mechanisms.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The mechanical substrate turning process is replaced with ion beam irradiation. The ion beam provides precise material removal through a non-mechanical process, substituting mechanical motion with a controlled energy field that can selectively remove diamond material without moving the substrate.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Shape

If the rake face is made smooth for sharp cutting, then cutting edge sharpness is maintained, but chip ejection becomes difficult causing tool damage

Engineering Contradiction:

Improvecutting edge sharpnessVSAvoidtool damage from poor chip ejection

Core Design Contradiction:

ShapeVSObject-generated harmful factors

Solution Approach 1:

The rake face is designed with local quality variations through protrusions and inclined portions. Different regions of the rake face have different geometries: the cutting edge maintains sharpness while the inclined portions provide chip ejection pathways. This local differentiation allows simultaneous optimization of both cutting sharpness and chip removal.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The inclined portions of the protrusions feature curved surfaces that guide chips smoothly away from the cutting zone. The curvature of these surfaces facilitates chip flow and prevents chip accumulation, reducing the risk of tool damage while maintaining cutting effectiveness.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design enhances chip ejection, reduces tool damage, and extends tool lifetime by allowing chips to smoothly pass over the inclined portions of the rake face, with the angle of chip ejection being parallel to the inclined portion, and maintaining sharpness with a controlled radius of curvature.

Implementation Method 1

a part of each of the plurality of protrusions is removed by emission of ion beams from upper left in a direction inclined with respect to top surface

Methodology Applied

Scientific EffectIon beam: Ion Beam

Data Source

PatentUS11554421B2Cutting tool and method of manufacturing the same

Publication Date: 2023.01.17 SUMITOMO ELECTRIC HARDMETAL CORP

AI summary

A cutting tool includes a substrate and a diamond layer that covers the substrate. The diamond layer includes a rake face and a flank continuous to the rake face. A ridgeline between the rake face and the flank forms a cutting edge. The substrate includes a top surface opposed to the rake face. When viewed in a direction perpendicular to the top surface, the rake face includes a plurality of protrusions. In a cross-section perpendicular to a direction of extension of the cutting edge, each of the plurality of protrusions includes an inclined portion and a curvature portion continuous to the inclined portion. In the cross-section, a height of the inclined portion in the direction perpendicular to the top surface increases as a distance from the cutting edge increases.