Cutting Tool Coating with Localized Cr Content for Wear and Fracture Resistance
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Solution Overview
Problem
Cutting tools with high TiAlN film ratios for the cutting edge suffer from insufficient chipping protection and rapid wear, leading to unstable tool life.
Innovation Solution
A cutting tool with a coating layer composed of Cr a (C 1-x N x ) where M is at least one element selected from Ti, Al, Si, W, Mo, Ta, Hf, Nb, Zr, and Y, with a Cr content ratio greater for the cutting edge than the flank face, enhancing fracture and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the coating layer for the cutting edge has a high TiAlN film ratio (high Ti content), then wear resistance is improved, but fracture resistance decreases leading to chipping
Solution Approach 1:
The patent applies different Cr content ratios to different regions of the coating layer: the cutting edge region has a higher Cr content ratio (0.1-0.5) for fracture resistance, while the flank face region has a lower Cr content ratio (0.01-0.1) for wear resistance. This local differentiation resolves the contradiction by optimizing each region's composition for its specific functional requirements.
Solution Approach 2:
The patent creates a composite coating layer structure with Cr a M 1-a (C 1-x N x ) where Cr provides fracture resistance and M (Ti, Al, Si, W, Mo, Ta, Hf, Nb, Zr, Y) provides wear resistance. The combination of multiple elements in specific proportions creates a composite material that simultaneously achieves both fracture resistance and wear resistance.
2Reliability
If the coating layer has high Cr content for fracture resistance, then chipping is prevented, but workpiece adhesion increases
Solution Approach 1:
The patent uses local quality by applying high Cr content (0.1-0.5) specifically to the cutting edge region where fracture resistance is critical, while maintaining low Cr content (0.01-0.1) on the flank face region where adhesion resistance is more important. This spatial differentiation allows the system to achieve fracture resistance without suffering from increased adhesion.
Solution Approach 2:
The patent changes the Cr content ratio parameter across different regions of the coating layer. By varying this composition parameter from 0.01-0.1 on the flank face to 0.1-0.5 at the cutting edge, the patent optimizes both fracture resistance and adhesion resistance simultaneously.
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 configuration prevents workpiece adhesion, increases fracture resistance, and extends tool life by improving wear resistance and preventing chipping at the cutting edge.
Implementation Method 1
A physical vapor deposition such as an ion plating or a sputtering is used as an example of a method of forming the coating layer
Implementation Method 2
A physical vapor deposition such as an ion plating or a sputtering is used as an example of a method of forming the coating layer
Implementation Method 3
A physical vapor deposition such as an ion plating or a sputtering is used as an example of a method of forming the coating layer
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3(a)~3(b)
AI summary
[Object] To provide a cutting tool having good chipping resistance and good wear resistance. [Solution] Provided is a cutting tool 1 including a base body 2 whose surface is coated with a coating layer 6 made of CraM1-a(C1-xNx) (here, M is at least one element selected from Ti, Al, Si, W, Mo, Ta, Hf, Nb, Zr, and Y, 0.01 ≤ a ≤ 0.4, and 0 ≤ x ≤ 1), a cutting edge 5 is formed on an intersection ridgeline between a rake face 3 and a flank face 4, and the coating layer 6 for the cutting edge 5 has a Cr content ratio greater than a Cr content ratio of the coating layer 6 for the flank face 4.