Diamond-Coated Tool Surface Texture for Anti-Welding Cutting

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Solution Overview

Problem

There is a need for a diamond-coated tool with enhanced welding resistance and extended tool life, particularly in cutting machining of aluminum alloys, as existing tools often suffer from welding and wear issues.

Innovation Solution

A diamond-coated tool is developed with a diamond layer having a skewness Ssk greater than 0, surface roughness Ra of 0.5 μm or less, a high ratio of sp3 carbon to sp2 carbon, and increased oxygen content, formed using chemical vapor deposition and oxygen ion etching, which improves oxidation, welding, and wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a diamond layer is formed by conventional CVD method, then the tool has basic cutting capability, but the tool suffers from welding and wear issues reducing tool life

Engineering Contradiction:

Improvewelding resistanceVSAvoidtool life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies oxygen ion etching to change the surface parameters of the diamond layer, specifically achieving a positive skewness (Ssk > 0) and controlled roughness (Ra ≤ 0.5 μm). This parameter modification creates a surface texture that prevents welding adhesion while maintaining the diamond's inherent hardness, thereby improving both welding resistance and extending tool life in aluminum alloy cutting applications

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a specific local surface quality on the diamond layer through oxygen ion etching, producing a unique texture pattern with positive skewness. This localized surface characteristic (rather than changing the bulk diamond properties) provides anti-welding performance at the tool-workpiece interface while preserving the overall structural integrity and cutting functionality of the tool

Inventive Principle:

Principle #3Local quality

2Reliability

If the diamond layer surface is made smoother, then welding resistance improves, but the surface may lack adequate texture for optimal performance

Engineering Contradiction:

Improvewelding resistanceVSAvoidsurface texture control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent precisely controls two critical surface parameters through oxygen ion etching: roughness (Ra ≤ 0.5 μm) and skewness (Ssk > 0). By independently optimizing these parameters, the invention achieves a surface that is smooth enough to prevent welding adhesion while maintaining an appropriate texture pattern that enhances overall tool performance in cutting aluminum alloys

Inventive Principle:

Principle #35Parameter changes

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 tool exhibits improved welding resistance, extended tool life, and enhanced surface quality, particularly in cutting machining of aluminum alloys, due to the specific surface texture and chemical composition of the diamond layer.

Implementation Method 1

forming a diamond layer on the base material by a chemical vapor deposition method

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 2

subjecting the diamond layer to oxygen ion etching to obtain a diamond-coated tool

Methodology Applied

Scientific EffectIon etching: Ion Beam

Data Source

PatentUS20230249262A1Diamond-coated tool and method for manufacturing the same

Publication Date: 2023.08.10 SUMITOMO ELECTRIC HARDMETAL CORP

AI summary

The diamond-coated tool includes a base material and a diamond layer disposed on the base material, wherein the skewness Ssk defined in ISO25178 of the diamond layer is more than 0.