Coated Cutting Tool Structure for Adhesion and Impact Relaxation
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Solution Overview
Problem
Existing coated tools for cutting processes face challenges in achieving optimal adhesion between the base member and coating layer, as well as sufficient impact relaxation, which affects their durability and performance during machining operations.
Innovation Solution
A coated tool design featuring a base member with a hard phase of tungsten carbide and a binder phase of cobalt or nickel, along with island portions, and a coating layer comprising a titanium compound and aluminum oxide layers with strategically placed voids, enhancing bondability and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer is formed on the base member to improve adhesion and impact relaxation, then the durability and performance are enhanced, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
The coating layer is divided into multiple functional layers (titanium compound layer and aluminum oxide layer) with distinct roles, where the titanium compound layer provides adhesion and the aluminum oxide layer provides impact relaxation. This segmentation allows each layer to be optimized for its specific function while working together to enhance overall durability.
Solution Approach 2:
The aluminum oxide layer is designed with a porous structure containing multiple voids that provide impact relaxation functionality. These voids act as energy absorption zones during cutting operations, reducing the transmission of impact forces to the base member while maintaining the protective function of the coating layer.
2Strength
If island portions with high binder phase content are scattered on the base member surface to improve adhesion, then the bond strength increases, but the manufacturing precision requirements increase
Solution Approach 1:
The base member surface is designed with island portions that have locally high binder phase content (70 area % or more) scattered across the surface. Each island portion acts as a localized adhesion enhancement zone with equivalent circle diameter of 10 μm or more. This local quality approach concentrates adhesion functionality in specific regions rather than requiring uniform high adhesion across the entire surface, thereby reducing manufacturing precision requirements while maintaining strong overall adhesion.
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 improves adhesion and impact resistance, leading to increased durability and performance by maintaining strength while absorbing cutting loads effectively.
Implementation Method 1
a plurality of voids are formed at an interface between the titanium compound layer and the aluminum oxide layer, and an impact relaxation effect may be obtained by these plurality of voids
Implementation Method 2
adhesion between a base member and a coating layer may be increased by providing an island portion structure in which a plurality of binder-phase-aggregated portions, obtained by aggregating cobalt (Co) and nickel (Ni) as binder phases, are scattered on the surface of the base member
Data Source
AI summary
A coated tool may include a base member including a first surface, and a coating layer located on the first surface. On the first surface, scattered island portions may include 70 area % or more of a binder phase and have an equivalent circle diameter of 10 μm or more. The coating layer may include a first layer including a titanium compound and located on the first surface, and a second layer including aluminum oxide and located on and in contact with the first layer. The coating layer may include a plurality of voids. An average value of widths of the voids in the direction along the boundary may be less than an average value of distances between the voids adjacent to each other.