Coated Cutting Tool Edge Recession Resistance

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Solution Overview

Problem

Conventional cutting tools experience wear and chipping issues, leading to shifts in machining dimensions and reduced processing efficiency due to edge recession, necessitating frequent edge corrections.

Innovation Solution

A coated cutting tool with a cemented carbide substrate and a multilayer film structure formed by chemical vapor deposition, comprising a lower film of alternately laminated TiN and TiCN layers and an upper aluminum oxide film, providing enhanced wear and chipping resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional coating structures are used, then basic wear protection is provided, but edge recession due to wear and chipping occurs

Engineering Contradiction:
Improveedge stabilityVSAvoidtool life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The coating is divided into multiple functional layers with distinct thicknesses and compositions. The lower film (2-15 μm) provides strong adhesion to the substrate, the intermediate film (0.5-2.0 μm) offers transition and stress relief, and the upper film (1-5 μm) provides wear and chipping resistance. This segmented structure prevents edge recession and extends tool life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite coating structures combining different materials (TiN, TiCN, Al2O3, TiAlN) with complementary properties. TiN and TiCN layers provide hardness and adhesion, while Al2O3 layers provide chemical inertness and wear resistance. The composite structure achieves superior edge stability and extended tool life compared to single-material coatings.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If frequent edge corrections are performed, then machining dimension precision is maintained, but processing efficiency decreases

Engineering Contradiction:
Improvemachining dimension precisionVSAvoidprocessing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The multi-layer coating structure is designed in advance to prevent edge recession and maintain cutting edge geometry throughout the tool's service life. The optimized layer thicknesses and material combinations provide long-lasting protection, eliminating the need for frequent edge corrections and maintaining machining precision over extended periods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention optimizes specific parameters including lower film thickness (2-15 μm), intermediate film thickness (0.5-2.0 μm), and upper film thickness (1-5 μm). These parameter optimizations ensure the coating maintains its protective function throughout the tool life, reducing the frequency of edge corrections needed to maintain machining dimension precision.

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 coated cutting tool effectively reduces edge recession, minimizing machining dimension changes and reducing the need for edge corrections, thereby improving processing productivity and tool longevity.

Implementation Method 1

a lower film having an average film thickness of 2 to 15 μm formed on the surface of the substrate, and an upper film having an average film thickness of 1 to 10 μm formed on a surface of the lower film on a side opposite to a surface in contact with the substrate, the lower film has an alternately laminated film in which a TiN film having an average film thickness of 10 to 300 nm and a TiCN film having an average film thickness of 0.1 to 0.5 μm are alternately laminated

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 2

the upper film has an aluminum oxide film

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentEP2700460B1Coated cutting tool
Publication Date: 2018.11.07 TUNGALOY CORP

AI summary

An object of the present invention is to provide a coated cutting tool, in which recession of a position of a cutting edge of the tool due to wear or chipping is unlikely to occur, and excellent in wear resistance and chipping resistance. The coated cutting tool of the present invention comprises a cemented carbide substrate and a film formed on a surface of the substrate by a chemical vapor deposition method, wherein an average film thickness of the film is 3 to 20 µm, the film comprises a lower film having an average film thickness of 2 to 15 µm formed on the surface of the substrate, and an upper film having an average film thickness of 1 to 10 µm formed on a surface of the lower film on a side opposite to a surface in contact with the substrate, the lower film has an alternately laminated film in which a TiN film having an average film thickness of 10 to 300 nm and a TiCN film having an average film thickness of 0.1 to 0.5 µm are alternately laminated, and the upper film has an aluminum oxide film.