Al2O3-Coated Cutting Tool Interface for Heavy Intermittent Cutting
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Solution Overview
Problem
Coated tools, particularly those with Al2O3 layers, face challenges in fracture resistance during heavy intermittent cutting processes, where the coating layer is prone to chipping and peeling due to large impacts.
Innovation Solution
A coated tool design featuring a base with a coating layer comprising an intermediate Ti layer and an Al2O3 layer, where the Al2O3 layer is in contact with the intermediate layer further away from the base. The intermediate layer includes a plurality of first protrusions with an average distance of 70-120 nm, enhancing adhesion and fracture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protrusions are densely arranged to improve adhesion properties, then adhesion between coating layers is enhanced, but film forming properties deteriorate due to poor shape characteristics
Solution Approach 1:
The patent changes the geometric parameters of protrusions by specifying that the tip angle α must be 90° or more (preferably 100°-170°) and the height h must be 5-50 nm. These parameter changes optimize both adhesion properties and film forming properties, resolving the contradiction between dense arrangement for adhesion and shape quality for manufacturing.
Solution Approach 2:
The patent applies local quality by creating protrusions with specific local geometric characteristics (tip angle ≥90°, height 5-50 nm) at the interface between intermediate layer and Al2O3 layer. This localized structural optimization ensures excellent film forming properties in the coating region while maintaining adhesion through controlled density (10²-10⁴ protrusions/mm²).
2Ease of manufacture
If protrusions are arranged at a distance of 140 nm or more to improve film forming properties, then film forming characteristics are enhanced, but adhesion properties become insufficient due to reduced number of protrusions
Solution Approach 1:
The patent optimizes the density parameter by specifying 10²-10⁴ protrusions/mm², which corresponds to appropriate spacing. This parameter change ensures that protrusions are neither too dense (which would harm film forming) nor too sparse (which would harm adhesion), thus resolving the contradiction between film forming properties and adhesion properties.
Solution Approach 2:
The patent creates a composite structure at the interface between intermediate layer and Al2O3 layer, combining protrusions with optimized geometry (tip angle ≥90°, height 5-50 nm) and optimized density (10²-10⁴ protrusions/mm²). This composite approach at the interface region simultaneously achieves excellent film forming properties and adhesion properties.
Data Source
AI summary
A coated tool in the present disclosure includes a base and a coating layer located on a surface of the base. The coating layer includes an intermediate layer including Ti, and an Al2O3 layer. The Al2O3 layer is located in contact with the intermediate layer at a position further away from the base than the intermediate layer. The intermediate layer includes a plurality of first protrusions protruding toward the Al2O3 layer. An average distance between the plurality of first protrusions is 70-120 nm. A cutting tool in the present disclosure includes a holder which is extended from a first end toward a second end and includes a pocket on a side of the first end, and the coated tool located in the pocket.