Diamond-Coated Cemented Carbide Cutting Tool with Etched Protrusions
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Solution Overview
Problem
Conventional diamond-coated cutting tools exhibit insufficient edge tip strength and chipping/peeling resistance during high-speed cutting of difficult-to-cut materials like CFRP, leading to a short service life due to inadequate adhesion between the diamond film and the tool body.
Innovation Solution
A diamond-coated cutting tool with a tool body made of tungsten carbide-based cemented carbide containing TaC and NbC, where the Co binder is strategically removed and repositioned through acid and electrolytic etching to form protrusions that enhance adhesion, with a diamond film coating that bites into these protrusions for improved bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cobalt is removed from the surface of the cemented carbide tool body to improve adhesion between the diamond film and tool body, then adhesion is improved, but edge tip strength decreases leading to chipping and peeling
Solution Approach 1:
The invention applies different Co content levels to different regions of the tool body: the surface region (0-5μm depth) has reduced Co content (0-3 mass%) to improve diamond film adhesion, while the edge tip region maintains higher Co content (3-15 mass%) to ensure sufficient strength and resistance to chipping. This spatial variation in composition resolves the contradiction between adhesion and strength.
Solution Approach 2:
The tool body is segmented into distinct regions with different compositional characteristics: a surface layer with low Co content for adhesion, and an edge tip region with higher Co content for strength. This segmentation allows each region to optimize its local properties without compromising the other.
2Productivity
If the diamond film is made thinner to maintain sharpness for high-speed cutting, then cutting performance is improved, but peeling resistance decreases
Solution Approach 1:
The diamond film thickness is optimized differently for different regions: the edge tip region maintains a thinner film (3-10μm) to preserve sharpness and cutting performance, while other regions can have thicker films for enhanced peeling resistance. The improved adhesion at the interface enables this differential thickness distribution.
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 adhesion between the diamond film and the tool body, resulting in improved edge tip strength and wear resistance, extending the tool's service life and maintaining performance during high-speed cutting operations.
Implementation Method 1
the surface of the cemented-carbide tool body is subjected to chemical etching so that Co is removed from a surface of the cemented-carbide tool body
Implementation Method 2
the surface of the cemented-carbide tool body is subjected to the electrolytic etching so as to have concave and convex surfaces
Implementation Method 3
a diamond film is deposited
Implementation Method 4
a diamond film is deposited
Data Source
AI summary
A cutting tool made of diamond-coated cemented carbide includes: a tool body made of tungsten carbide-based cemented carbide including: 3 to 15 mass % of Co; at least one of TaC and NbC of which a total amount is 0.1 to 3.0 mass %; and a balance including WC; and a diamond film coating the tool body, the tool body has a plurality of protrusions on a surface of the tool body, an upper portion of each of the protrusions is made of the at least one of TaC and NbC, and a lower portion of each of the protrusions is made of WC and Co, the lower portion being under the upper portion.