cBN Sintered Material Bonding for Chipping-Resistant Cutting Tools
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Solution Overview
Problem
High-cubic boron nitride sintered materials used in cutting tools experience premature chipping due to weak binding forces between particles, leading to reduced tool lifetime and increased costs.
Innovation Solution
A cubic boron nitride sintered material with a bonding material containing aluminum and cobalt, where an aluminum layer is formed between cBN particles to enhance binding force, reducing thermal shrinkage and chipping, and prolonging tool lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the content ratio of cubic boron nitride particles is increased to achieve high hardness and wear resistance, then the cutting tool's ability to resist wear improves, but the binding force between particles becomes weak leading to unexpected chipping
Solution Approach 1:
The patent uses a composite bonding material consisting of Co-Al intermetallic compound and aluminum compound. This composite approach combines the strong binding capability of Co-Al intermetallic compound with the adhesion enhancement from aluminum compound, creating a bonding material that can firmly hold cBN particles together while preventing particle dropout and chipping, thus resolving the contradiction between wear resistance and chip resistance
Solution Approach 2:
The patent changes the chemical composition parameters of the bonding material by specifying it contains Co-Al intermetallic compound and aluminum compound with specific ratios. This parameter optimization ensures the bonding material has both strong binding force to prevent particle dropout and good adhesion to prevent chipping, while maintaining the high cBN content for wear resistance
2Strength
If the content ratio of cubic boron nitride particles is increased to achieve high hardness, then the cutting tool's hardness improves, but the binding force between particles becomes weak leading to reduced tool lifetime
Solution Approach 1:
The patent employs a composite bonding material of Co-Al intermetallic compound and aluminum compound that provides strong binding force to hold together the high content of hard cBN particles. This composite structure ensures that the tool maintains its hardness from the high cBN content while the strong binding material prevents particle dropout, thereby extending tool lifetime
Solution Approach 2:
The aluminum compound in the bonding material acts as an intermediary that enhances adhesion between cBN particles and the bonding material matrix. This intermediary role of aluminum ensures that the hard cBN particles remain firmly bound, preventing premature tool failure and extending tool lifetime while maintaining the desired hardness
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 solution significantly enhances the binding force between cBN particles, reducing particle dropout and thermal cracking, thereby extending the cutting tool's lifetime and improving stability against chipping.
Implementation Method 1
the bonding material contains an aluminum compound... an aluminum layer is formed between cBN particles to enhance binding force
Implementation Method 2
contains cobalt as a constituent element... reducing thermal shrinkage and chipping
Data Source
AI summary
The cubic boron nitride sintered material is a cubic boron nitride sintered material comprising: cubic boron nitride particles in an amount of 70 vol % or more and less than 100 vol %, and a bonding material, wherein the bonding material includes an aluminum compound, and includes cobalt as a constituent element; the cubic boron nitride sintered material has a first region in which a space between adjacent cubic boron nitride particles is 0.1 nm or more and 10 nm or less; and when the first region is analyzed by using an energy dispersive X-ray analyzer equipped with a transmission electron microscope, the atom % of aluminum in the first region is 0.1 or more.