Cermet Cutting Insert Stress Zoning for Wear and Edge Sharpness
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Solution Overview
Problem
Current cutting inserts made of cermet materials face challenges in achieving optimal fracture resistance, wear resistance, and maintaining sharp cutting edges due to uneven compressive residual stress distribution and degranulation issues in hard phases.
Innovation Solution
A cutting insert design featuring a base member with a hard phase containing titanium carbonitride and a binding phase of cobalt and nickel, where the compressive residual stress of the second hard phase on the second surface is less than on the first surface, promoting degranulation and enhancing wear resistance and cutting edge sharpness, while the binding phase with varying tungsten content improves fracture resistance and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If compressive residual stress is applied uniformly to hard phases in cermet cutting inserts, then wear resistance is improved, but degranulation of hard phases occurs leading to reduced cutting edge sharpness
Solution Approach 1:
The patent applies different compressive residual stress levels to different surfaces of the cutting insert. The first surface (rake face) has higher compressive residual stress in hard phases to improve wear resistance, while the second surface (flank face) has lower compressive residual stress to prevent degranulation and maintain cutting edge sharpness. This local differentiation resolves the contradiction between wear resistance and cutting edge integrity.
2Strength
If shot peening or wet blast process is applied to increase compressive residual stress, then fracture resistance is improved, but uneven stress distribution occurs across different surfaces
Solution Approach 1:
The patent creates non-uniform compressive residual stress distribution by applying different surface treatments or processing conditions to different surfaces. The first surface receives treatment that generates higher compressive stress, while the second surface receives treatment that generates lower compressive stress, achieving local optimization for different functional requirements.
Solution Approach 2:
The cutting insert is divided into different surface zones (first surface and second surface) with distinct compressive residual stress characteristics. This segmentation allows each surface to be optimized independently for its specific function, resolving the contradiction between fracture resistance and stress distribution uniformity.
3Strength
If hard phase degranulation is suppressed through high compressive stress, then wear resistance improves, but cutting edge sharpness deteriorates
Solution Approach 1:
The patent applies high compressive residual stress to the first surface (rake face) where wear resistance is critical, while maintaining lower compressive residual stress on the second surface (flank face) where cutting edge sharpness is paramount. This localized stress differentiation allows simultaneous optimization of both wear resistance and cutting edge 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 design results in improved wear resistance, fracture resistance, and sharper cutting edges, with reduced degranulation and crater wear, leading to enhanced cutting performance and smoother surface finishes.
Implementation Method 1
A compressive residual stress of the second hard phase in the second surface is less than a compressive residual stress of the second hard phase in the first surface
Implementation Method 2
the binding phase with varying tungsten content improves fracture resistance and heat dissipation
Data Source
AI summary
A cutting insert may include a base member. The base member may include a first surface, a second surface adjacent to the first surface, and a first cutting edge located in at least a part of a first ridge line which the first surface intersects with the second surface. The base member may include a hard phase containing a titanium carbonitride, and a binding phase containing at least one of cobalt and nickel. The hard phase may include a first hard phase observed on a higher angle side, and a second hard phase observed on a lower angle side in a comparison of (422) plane peak in an X-ray diffraction analysis. A compressive residual stress of the second hard phase in the second surface may be less than a compressive residual stress of the second hard phase in the first surface.