Surface-Coated Cutting Tool With Alumina-Titanium Layering

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Solution Overview

Problem

Existing surface-coated cutting tools face challenges with deposition resistance, as they are either rough on the cutting edge portion or have insufficient deposition resistance, leading to suboptimal performance during cutting operations.

Innovation Solution

A surface-coated cutting tool with a multilayer structure coating, including an inner aluminum oxide layer and an outer layer with multiple titanium-containing layers, featuring voids at the interface between the inner and outer layers, which reduces stress and enhances deposition resistance while maintaining wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional coating is applied to improve wear resistance, then wear resistance is improved, but deposition resistance becomes insufficient

Engineering Contradiction:
Improvewear resistanceVSAvoiddeposition resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The coating is divided into multiple layers with different functions: an inner layer (including aluminum oxide) providing wear resistance and an outer multilayer structure providing deposition resistance. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between wear resistance and deposition resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coating uses composite material structure combining different materials (aluminum oxide, titanium-containing layers) with complementary properties. The inner layer uses aluminum oxide for wear resistance while the outer layer uses titanium-containing multilayer structure for deposition resistance, achieving both requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If surface finishing is performed to improve surface roughness, then surface smoothness is improved, but deposition resistance remains insufficient

Engineering Contradiction:
Improvesurface roughnessVSAvoiddeposition resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

Instead of relying solely on surface finishing to achieve deposition resistance, the invention uses a composite coating structure where the outer multilayer titanium-containing structure provides deposition resistance through its material composition and layered architecture, working in conjunction with the smoothed surface.

Inventive Principle:
Principle #40Composite materials

3Device complexity

If a single-layer coating is applied to simplify structure, then device complexity is reduced, but both wear resistance and deposition resistance cannot be optimized

Engineering Contradiction:
Improvecoating structureVSAvoidcutting performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The coating is segmented into functional layers: an inner layer for wear resistance and an outer multilayer structure for deposition resistance. This segmentation enables optimization of both wear resistance and deposition resistance simultaneously, resolving the contradiction between structural simplicity and performance optimization.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS10987738B2Surface-coated cutting tool
Publication Date: 2021.04.27 SUMITOMO ELECTRIC HARDMETAL CORP

AI summary

A surface-coated cutting tool includes a substrate and a coating that is disposed on the substrate and formed so as to cover at least a portion of a flank face, in which the coating includes an inner layer and an outer layer formed on the inner layer, the inner layer is formed of at least one layer and includes an aluminum oxide layer as a layer in contact with the outer layer, the outer layer has a multilayer structure that includes three or more layers stacked on top of one another, and each of the layers that constitute the multilayer structure contains titanium.