Coated Cemented Carbide Cutting Edge With Low-Oxygen Surface
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Solution Overview
Problem
Cutting tools face issues with coating peeling due to lack of adhesion between the coating and the base material, leading to reduced tool life, and there is a need for both coated and non-coated tools with extended lifespan.
Innovation Solution
A cutting tool with a base material of cemented carbide or cermet, having controlled oxygen concentration and strain, and a coating composed of specific elements, manufactured through alternate wet and dry grinding processes to prevent oxygen ingress and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating is formed on the base material to improve wear resistance, then the hardness and wear resistance are improved, but the coating may peel off due to lack of adhesion between the coating and base material
Solution Approach 1:
The patent applies parameter changes by precisely controlling the oxygen concentration in the base material (less than or equal to 1 at.% at 0.4 μm depth) to optimize coating adhesion. This chemical parameter control ensures proper bonding between the coating and base material while maintaining the hardness and wear resistance benefits of the coating
Solution Approach 2:
The patent applies local quality by creating a specific oxygen concentration gradient within the base material. The oxygen concentration is controlled at different depths (less than or equal to 1 at.% at 0.4 μm, less than or equal to 10 at.% at 0.2 μm), creating localized chemical environments that optimize both coating adhesion at the interface and overall material performance
2Productivity
If wet grinding is used to machine the base material precursor, then the manufacturing process is efficient, but oxygen enters the base material causing reduced fracture resistance and coating adhesion
Solution Approach 1:
The patent applies segmentation by dividing the continuous wet grinding process into alternating wet and dry grinding steps. This segmented approach allows the process to benefit from wet grinding efficiency while periodically removing oxygen through dry grinding steps, thereby maintaining fracture resistance
Solution Approach 2:
The patent applies periodic action by alternately repeating wet grinding and dry grinding processes. This periodic alternation enables efficient material removal during wet grinding phases while oxygen removal during dry grinding phases, creating a cyclical process that maintains both productivity and material integrity
3Ease of manufacture
If high oxygen concentration is present in the base material, then the material is easier to machine, but the fracture resistance and coating adhesion are reduced
Solution Approach 1:
The patent applies preliminary action by controlling the oxygen concentration during the base material formation process itself. By ensuring low oxygen concentration (less than or equal to 1 at.% at 0.4 μm depth) before coating application, the patent prevents oxygen-related adhesion problems from developing, rather than attempting to correct them afterward
Data Source
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AI summary
A cutting tool includes a base material. The base material is a cemented carbide or a cermet. A surface of the base material includes a rake face, a flank face, and a cutting edge face connecting the rake face to the flank face. The base material has an oxygen concentration of less than or equal to 1 at.% at a depth position of 0.4 µm from the cutting edge face.