Surface-Coated cBN Sintered Material for Burr-Suppressing Cutting
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Solution Overview
Problem
In precision machining using High-cBN sintered materials, the generation of burrs on the finished surface of work materials is a common issue, leading to decreased precision and increased production costs due to the need for post-treatment processes like polishing.
Innovation Solution
A surface-coated cBN sintered material with a specific composition and structure, including a cBN sintered material with a high volume percentage of cBN particles and a binder containing Al and Cr, coated with a layer A composed of Al x1 Cr y1 M z1 C a1 N b1 O c1, where M includes Ti, V, Nb, and Si, and a thickness of 0.5 to 10 µm, which improves wear resistance and suppresses burr generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a High-cBN sintered material with high cBN particle content (≥85% by volume) is used to improve wear resistance, then wear resistance is enhanced, but burr generation on the finished surface increases
Solution Approach 1:
The coating is divided into multiple layers with different functions: layer A (AlCrMxCaNbOc) provides oxidation resistance and burr suppression, while layer B (TiAlMzN) provides wear resistance. This segmentation allows each layer to address specific problems without compromising the other.
Solution Approach 2:
The invention uses composite coating structures combining different material systems (AlCrMxCaNbOc and TiAlMzN) to achieve both burr suppression and wear resistance simultaneously, resolving the contradiction between surface finish quality and wear resistance.
2Temperature
If a Low-cBN sintered material with low cBN particle content is used to improve heat resistance, then heat resistance is enhanced, but wear resistance decreases
Solution Approach 1:
The coating applies different material properties to different regions: the AlCrMxCaNbOc layer addresses oxidation and heat resistance at the cutting edge, while the TiAlMzN layer addresses wear resistance on the flank face, allowing the substrate to maintain optimized cBN content for its specific function.
3Manufacturing precision
If a conventional coating is applied to suppress burr generation, then surface finish quality improves, but coating peeling occurs due to insufficient adhesion
Solution Approach 1:
The invention optimizes the chemical composition parameters of layer A (AlCrMxCaNbOc) to achieve both burr suppression capability and strong adhesion to the cBN sintered material substrate, preventing peeling while maintaining surface finish quality.
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 surface-coated cBN sintered material effectively reduces burr formation by enhancing wear resistance on the flank face and maintaining cutting performance, thereby minimizing the need for post-treatment processes and lowering production costs.
Implementation Method 1
the coating contains a layer A in contact with the cBN sintered material, and the layer A is constituted of Al x1 Cr y1 M z1 C a1 N b1 O c1
Data Source
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AI summary
The surface-coated cBN sintered material of the present invention includes a cBN sintered material, and a coating covering the surface of the cBN sintered material. The cBN sintered material contains cBN particles and a binder. A proportion of the cBN particles in the cBN sintered material is exceeding 80% by volume and less than or equal to 98% by volume, the binder contains a first compound including at least one element of Al and Cr and at least one element selected from the group consisting of N, B and O. The coating contains a layer A in contact with the cBN sintered material. The layer A is constituted of Alx1Cry1Mz1Ca1Nb1Oc1 (provided that M is greater than or equal to one kind of Ti, V, Nb and Si, and 0.25 ≤ x1 ≤ 0.75, 0.25 ≤ y1 ≤ 0.75, 0 ≤ z1 ≤ 0.5, x1 + y1 + z1 = 1, 0 ≤ a1 ≤ 0.5, 0.5 ≤ b1 ≤1, 0 ≤ c1 ≤ 0.1, and a1 + b1 + c1 = 1 are satisfied).