Polycrystalline Diamond Cutting Tool Without Sintering Aid

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Solution Overview

Problem

Conventional polycrystalline diamond cutting tools suffer from insufficient mechanical properties, uneven wear, and instability due to varying grain sizes and incomplete sintering, making them unsuitable for precision machining, while existing methods struggle to produce homogeneous diamonds of suitable size and reproducibility for cutting tools.

Innovation Solution

A cutting tool is developed using polycrystalline diamond with a mixed construction of fine-grained and coarse-grained diamond crystals, achieved by directly converting non-diamond carbon at ultra-high pressure and temperature without a sintering aid or catalyst, optimizing the microstructure for enhanced hardness and wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If monocrystalline diamond is used in cutting tools, then hardness and wear resistance are improved, but blade edge chipping and uneven wear occur due to cleavage property and direction-dependent hardness

Engineering Contradiction:
Improvehardness and wear resistanceVSAvoidblade edge stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent uses polycrystalline diamond with uniform grain size distribution to create a homogeneous material structure. This eliminates the directional dependence and cleavage properties of monocrystalline diamond, providing uniform hardness and wear resistance in all directions while preventing blade edge chipping and uneven wear.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The patent changes the grain size parameter of diamond to approximately 10 micrometers, which is optimized to balance hardness, wear resistance, and resistance to blade edge chipping. This specific grain size parameter resolves the contradiction by providing sufficient hardness while preventing the cleavage and uneven wear issues of monocrystalline diamond.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If polycrystalline diamond with sintering aid or binding agent is used, then manufacturing is simplified, but manufacturing precision deteriorates due to blade edge unevenness and surface irregularities

Engineering Contradiction:
Improvesintering process feasibilityVSAvoidblade edge precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent extracts and removes the sintering aid or binding agent from the polycrystalline diamond composition. By using pure diamond powder without additives, the patent eliminates the source of blade edge unevenness and surface irregularities, achieving precision machining capability while maintaining manufacturability through direct sintering of pure diamond particles.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses pure diamond powder with uniform grain size distribution without sintering aids or binding agents. This homogeneous composition eliminates the heterogeneity introduced by additives, resulting in a uniform blade edge and precise cutting surface that enables precision machining.

Inventive Principle:
Principle #33Homogeneity

3Ease of manufacture

If polycrystalline diamond with varying grain sizes is used, then manufacturing is easier, but reliability deteriorates due to incomplete sintering and insufficient mechanical properties

Engineering Contradiction:
Improvesintering process flexibilityVSAvoidmechanical property consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the grain size parameter to a specific uniform distribution centered at approximately 10 micrometers. This controlled parameter change ensures complete sintering and consistent mechanical properties while maintaining ease of manufacture through standardized diamond powder production processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses diamond powder with uniform grain size distribution to create a homogeneous starting material. This homogeneity ensures complete and uniform sintering throughout the polycrystalline diamond body, resulting in consistent mechanical properties and reliable performance.

Inventive Principle:
Principle #33Homogeneity

4Adaptability or versatility

If naturally produced polycrystalline diamond is used, then availability is improved, but reliability deteriorates due to material quality defects and considerable variation

Engineering Contradiction:
Improveavailability for tool applicationsVSAvoidmaterial quality consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the diamond material into controlled artificial polycrystalline structures with uniform grain size. This artificial segmentation replaces the unpredictable natural structure, providing consistent material quality and reliable performance while maintaining availability through controlled synthesis processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent produces artificial polycrystalline diamond with uniform grain size distribution and consistent composition. This homogeneity eliminates the material quality defects and considerable variation found in naturally produced polycrystalline diamond, providing reliable and repeatable performance for precision machining applications.

Inventive Principle:
Principle #33Homogeneity

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 resulting cutting tool exhibits significantly improved wear resistance, reduced uneven wear, and extended lifespan, with a life twice that of conventional tools, and precise machining capabilities for challenging materials like aluminum alloys and glass.

Implementation Method 1

directly converting non-diamond carbon at ultra-high pressure and temperature without a sintering aid or catalyst

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

direct conversion and sintering at an ultra high pressure and an ultra high temperature without a catalyst or a solvent

Methodology Applied
Scientific EffectHigh-pressure high-temperature conversion: Pressure Increase

Implementation Method 3

sintering the diamond at an ultra high pressure and an ultra high temperature without a catalyst or a solvent

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP2127789B1Cutting tool
Publication Date: 2013.04.03 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

One object of the present invention is to provide a cutting tool excellent in strength and wear resistance. The cutting tool has a cutting blade formed using a highly hard diamond polycrystalline body made substantially only of diamond and produced by directly converting a raw material composition including a non-diamond type carbon material into diamond and sintering the diamond at an ultra high pressure and an ultra high temperature without adding a sintering aid or a catalyst, the polycrystalline body having a mixed construction including fine-grained diamond crystals with a maximum grain size of less than or equal to 100 nm and an average grain size of less than or equal to 50 nm and plate-like or particulate coarse-grained diamond crystals with a minimum grain size of greater than or equal to 50 nm and a maximum grain size of less than or equal to 10000 nm.