Multilayer Coated Cutting Tool for Chipping-Resistant Machining

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Solution Overview

Problem

Existing surface-coated cutting tools face issues with chipping and detachment of coating films due to brittleness and low adhesion between layers, leading to reduced tool life, especially when cutting high-temperature materials like stainless steel or difficult-to-cut materials.

Innovation Solution

A surface-coated cutting tool with a configuration that includes an intermediate layer between alternating layers and an adhesion layer between the base material and the first alternating layer, utilizing specific thickness ratios and compositions of A, B, C, and D layers to enhance chipping resistance and wear resistance, and employing physical vapor deposition methods like cathode arc ion plating for coating formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If multiple alternating layers are created to improve chipping resistance, then chipping resistance is improved, but the number of layers increases making manufacturing more complex

Engineering Contradiction:
Improvechipping resistanceVSAvoidcoating structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The coating is segmented into two main alternating layer groups (first and second alternating layers) that can be formed using standardized deposition cycles. This segmentation approach achieves chipping resistance through controlled layering while maintaining manufacturing feasibility by using repeatable processing patterns rather than arbitrary multi-layer configurations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention controls the thickness, composition, and sequence of layers by adjusting deposition parameters such as sputtering power, gas flow rates, and deposition time. By changing these parameters, the complex multi-layer structure can be precisely controlled and reproduced, reducing manufacturing complexity despite the increased number of layers.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If cutting speed is increased to improve productivity, then productivity is improved, but tool edge temperature increases reducing tool life

Engineering Contradiction:
Improvecutting speedVSAvoidtool life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The composite coating structure with alternating layers of different materials (nitrides, carbonitrides, and other compounds) provides enhanced thermal stability and heat resistance. This allows the tool to maintain higher operating temperatures during high-speed cutting without degrading, thereby extending tool life even when cutting speed is increased for improved productivity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The coating layers are designed with specific thicknesses and compositions to provide thermal cushioning before the heat reaches the tool edge. The alternating layers create a thermal barrier that protects the underlying tool material from excessive temperature buildup, allowing sustained high-speed operation without premature tool failure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 chipping resistance and wear resistance, maintaining excellent cutting edge quality and extending tool life by preventing coating film detachment and oxidation, even under severe cutting conditions.

Implementation Method 1

employing physical vapor deposition methods like cathode arc ion plating for coating formation

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

employing physical vapor deposition methods like cathode arc ion plating for coating formation

Methodology Applied
Scientific EffectCathode arc ion plating: Cathodic Arc Deposition

Data Source

PatentEP3808477B1Surface-coated cutting tool and process for producing same
Publication Date: 2022.11.30 SUMITOMO ELECTRIC HARDMETAL CORP
  • EP3808477B1 patent drawingFigure 1~2
  • EP3808477B1 patent drawingFigure 3~4

AI summary

A surface-coated cutting tool includes a base material and a coating film provided on a surface of the base material, wherein the coating film includes a first alternating layer provided on the base material and a second alternating layer provided on the first alternating layer, the first alternating layer includes A and B layers, the second alternating layer includes C and D layers, one or a plurality of the A layers and one or a plurality of the B layers are layered alternately, one or a plurality of the C layers and one or a plurality of the D layers are layered alternately, each of the one or plurality of the A layers is composed of a nitride or carbonitride of AlaCrbM1(1-a-b), each of the one or plurality of the B layers is composed of a nitride or carbonitride of AlcTidM2(1-c-d), each of the one or plurality of the C layers is composed of a nitride or carbonitride of TieSifM3(1-e-f), and each of the one or plurality of the D layers is composed of a nitride or carbonitride of TigSihM4(1-g-h).