Sintered Cubic Boron Nitride Tool Edge Geometry
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Solution Overview
Problem
Conventional sintered cubic boron nitride tools experience chipping and crater wear during high-efficiency and high-load cutting machining due to insufficient blade edge strength and thermal conductivity, leading to reduced tool lifetime.
Innovation Solution
A sintered cubic boron nitride tool with optimized surface structures, including a round honing surface with increased cubic boron nitride content for thermal load and a chamfer honing surface with more binder phase to prevent chip welding, along with a specific ratio of cubic boron nitride to binder phase, and a coating film for enhanced wear resistance and oxidation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sintered cubic boron nitride tool uses a conventional blade edge structure with radius of curvature 5-30 μm, then the tool can be manufactured with standard processes, but the blade edge strength is insufficient leading to chipping under high-load cutting conditions
Solution Approach 1:
The patent applies local quality by creating distinct surface structures at different locations of the blade edge. The round honing surface with radius of curvature 10-50 μm provides enhanced strength at the critical edge portion, while the chamfer honing surface with specific binder phase distribution (LCC/LCB ratio 0.6-1.4) provides localized wear resistance. This localized optimization of surface morphology and composition resolves the contradiction between standard manufacturing and improved blade edge strength.
Solution Approach 2:
The patent changes key parameters of the blade edge structure: increasing the radius of curvature from the conventional 5-30 μm range to 10-50 μm for the round honing surface, and controlling the binder phase distribution through the LCC/LCB ratio parameter (0.6-1.4). These parameter changes enhance blade edge strength and thermal conductivity while maintaining manufacturability, thereby resolving the contradiction between strength and reliability.
2Temperature
If the sintered cubic boron nitride tool increases cubic boron nitride content to improve thermal conductivity and hardness, then thermal load resistance improves, but chip welding and crater wear increase due to insufficient binder phase
Solution Approach 1:
The patent applies local quality by creating distinct surface structures at different locations of the blade edge. The round honing surface with radius of curvature 10-50 μm provides enhanced strength at the critical edge portion, while the chamfer honing surface with specific binder phase distribution (LCC/LCB ratio 0.6-1.4) provides localized wear resistance. This localized optimization of surface morphology and composition resolves the contradiction between standard manufacturing and improved blade edge strength.
Solution Approach 2:
The patent changes key parameters of the blade edge structure: increasing the radius of curvature from the conventional 5-30 μm range to 10-50 μm for the round honing surface, and controlling the binder phase distribution through the LCC/LCB ratio parameter (0.6-1.4). These parameter changes enhance blade edge strength and thermal conductivity while maintaining manufacturability, thereby resolving the contradiction between strength and reliability.
3Strength
If the sintered cubic boron nitride tool uses a larger radius of curvature at the blade edge (10-50 μm), then blade edge strength and thermal conductivity improve, but manufacturing precision and surface finish become more difficult to control
Solution Approach 1:
The patent applies segmentation by dividing the blade edge surface into two distinct functional zones: the round honing surface and the chamfer honing surface. Each zone is controlled independently with specific geometric parameters (radius of curvature 10-50 μm for round, LCC/LCB ratio 0.6-1.4 for chamfer). This segmentation allows precise control of surface structure in each zone, resolving the contradiction between improved strength and manufacturing precision.
4Object-generated harmful factors
If the sintered cubic boron nitride tool increases binder phase content to prevent chip welding, then adhesion resistance improves, but thermal conductivity and hardness decrease due to reduced cubic boron nitride content
Solution Approach 1:
The patent applies local quality by creating distinct surface structures at different locations of the blade edge. The round honing surface with radius of curvature 10-50 μm provides enhanced strength at the critical edge portion, while the chamfer honing surface with specific binder phase distribution (LCC/LCB ratio 0.6-1.4) provides localized wear resistance. This localized optimization of surface morphology and composition resolves the contradiction between standard manufacturing and improved blade edge strength.
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 achieves stable machining under high-load and high-efficiency conditions, significantly extending tool lifetime and improving machining efficiency and cost-effectiveness.
Implementation Method 1
it is preferred to increase an amount of the cubic boron nitride which shows high hardness and high thermal conductivity
Data Source
AI summary
A sintered cubic boron nitride tool can perform stable machining without causing any defect for a long lifetime even under a high-load cutting condition and a high-efficiency cutting condition. The sintered cubic boron nitride tool is such that: assuming a reference length longer than five times an average particle size of cubic boron nitride is S, when a total length of profile curves of cubic boron nitride included in the reference length S of the chamfer honing surface is LCC, when a total length of profile curves of the binder phase included in the reference length S of the chamfer honing surface is LCB, and a ratio of LCC to LCB is PC(PC=LCC/LCB), and when a total length of profile curves of cubic boron nitride included in the reference length S of the round honing surface is LRC, a total length of profile curves of the binder phase included in the reference length S of the round honing surface is LRB, and a ratio of LRC to LRB is PR(PR=LRC/LRB), then, a ratio of PR to PC (PR/PC) satisfies the relation of 1.2≦PR/PC≦8.0.