cBN Tool Joining Strength via Recessed Anchor Interface

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Solution Overview

Problem

The existing cBN sintered body tools face issues with insufficient adhesion between the cBN sintered body and the tool base material, leading to the cBN sintered body falling during high-stress applications, despite improvements in hardness, toughness, and thermal conductivity.

Innovation Solution

A cBN sintered body tool is developed with a joining layer containing Ti, Zr, Cu, Ag, and Ni, and the surface of the cBN sintered body is treated to create a recess, increasing the contact area and enhancing the anchor effect, thereby improving the joining strength between the cBN sintered body and the tool base material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cBN sintered body is improved in hardness, toughness, and thermal conductivity by increasing cBN particle content, then the performance of the cBN sintered body is improved, but the adhesion between the cBN sintered body and the tool base material becomes insufficient

Engineering Contradiction:
Improvehardness and toughness of cBN sintered bodyVSAvoidadhesion between cBN sintered body and tool base material
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention divides the joining interface into multiple functional layers: a joining layer containing Ti, Zr, Cu, Ag, and Ni; and a surface treatment layer creating recesses on the cBN sintered body. This segmentation allows each layer to perform its specific function - the joining layer provides chemical bonding while the recesses provide mechanical interlocking, thereby resolving the adhesion problem without compromising the high cBN content and performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The joining layer acts as an intermediary between the cBN sintered body and the tool base material. It contains specific elements (Ti, Zr, Cu, Ag, Ni) that facilitate bonding to both materials. The surface treatment creating recesses further enhances this intermediary function by increasing the contact area and providing mechanical anchoring, thus resolving the adhesion insufficiency while maintaining the high-performance cBN structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the cBN sintered body is designed for high performance with high purity cBN particles at high concentration, then wear resistance is improved, but the joining force between the cBN sintered body and the tool base material becomes insufficient

Engineering Contradiction:
Improvewear resistance of cBN sintered bodyVSAvoidjoining force between cBN sintered body and tool base material
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The invention applies local quality by treating only the surface region of the cBN sintered body to create recesses, while maintaining the high purity and high concentration of cBN particles in the bulk structure. This localized surface treatment enhances joining force without affecting the overall wear resistance provided by the high-performance cBN structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The surface treatment creates a three-dimensional recess structure on the otherwise flat surface of the cBN sintered body. This dimensional change increases the contact area and provides mechanical interlocking in the vertical dimension, thereby enhancing joining force without compromising the wear resistance of the high-performance cBN structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the joining layer composition is revised to improve adhesion, then the joining force is improved, but the structure becomes more complex

Engineering Contradiction:
Improveadhesion of joining layerVSAvoidcomposition complexity of joining layer
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention optimizes the composition parameters of the joining layer by selecting specific elements (Ti, Zr, Cu, Ag, Ni) within defined concentration ranges. This parameter-based approach systematically improves adhesion while controlling complexity, as the composition can be adjusted within established boundaries rather than requiring entirely new material systems.

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 enhanced joining strength allows the cBN sintered body tool to withstand severe conditions, reducing the likelihood of falling and improving its durability and performance in machining and plastic working applications.

Implementation Method 1

a joining layer containing Ti, Zr, Cu, Ag, and Ni... enhancing the anchor effect, thereby improving the joining strength between the cBN sintered body and the tool base material

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2835195B1Sintered cubic boron nitride tool
Publication Date: 2020.11.18 SUMITOMO ELECTRIC HARDMETAL CORP
  • EP2835195B1 patent drawingFigure 1(a)~2
  • EP2835195B1 patent drawingFigure 3~4(b)
  • EP2835195B1 patent drawing

AI summary

A cubic boron nitride sintered body tool (1) of the present invention, in which a cubic boron nitride sintered body (2) is joined to a tool base material (4) via a joining layer (3), has the following feature. The cubic boron nitride sintered body (2) contains cubic boron nitride particles by not less than 30 volume % and not more than 95 volume %, and a binder phase (6) by not less than 5 volume % and not more than 70 volume %. In at least one cross sectional surface of the cubic boron nitride sintered body tool (1) taken along a plane perpendicular to a joining surface having the largest area in joining surfaces between the cubic boron nitride sintered body (2) and the joining layer (3), a point C and a point D are assumed to represent points away by 1/4 of the length of a line segment connecting a point A and a point B shown in a figure. A value obtained when an area of a region surrounded by a line segment connecting the point C and the point D, the first cubic boron nitride particle (7), the second cubic boron nitride particle (8), and the binder phase (6) is divided by the length of the line segment connecting the point A and point B to each other is not less than 0.14 µm and not more than 0.6 µm.