CVD-Coated Cutting Tool Peening With Tungsten Carbide Beads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Coated cutting tools face challenges in maintaining wear resistance during metal cutting, particularly in intermittent applications, as existing dry blasting methods do not effectively enhance the performance of coated cutting tools with cemented carbide substrates.
Innovation Solution
The use of spherical crystalline tungsten carbide beads for shot peening, with specific density, hardness, and size characteristics, applied to the rake face and cutting edge of coated cutting tools, followed by shot blasting, to alter residual stresses and improve wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dry blasting methods are used on coated cutting tools, then the process is simple and quick, but the wear resistance of the tool is not effectively enhanced
Solution Approach 1:
The invention changes the material parameter of the blasting media from conventional materials to crystalline tungsten carbide, which has significantly higher density and hardness. This parameter change enables the blasting media to effectively enhance wear resistance of the coated cutting tool while maintaining process simplicity
Solution Approach 2:
The invention uses composite structure consisting of crystalline tungsten carbide particles embedded in a binding agent matrix. This composite material combines the high hardness of WC with the cohesive properties of the binding agent, enabling effective stress transfer to the coating while maintaining media integrity during blasting
2Duration of action of stationary object
If shot peening is applied to increase wear resistance, then the tool lifetime is extended, but the risk of damaging the cutting edge increases with inappropriate media size
Solution Approach 1:
The invention optimizes the size parameter of the blasting media to a specific range (40-120 μm) that balances energy transfer efficiency with cutting edge protection. This size optimization ensures sufficient impact energy to enhance wear resistance while preventing excessive force that could damage the cutting edge
Solution Approach 2:
The invention applies shot peening selectively to specific surfaces (rake face and/or flank face) rather than the entire tool, concentrating the beneficial stress effects on areas subject to wear while preserving the integrity of critical features like the cutting edge
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
This method significantly extends the lifetime of coated cutting tools by effectively transferring energy to the TiCN and α-Al2O3 layers, enhancing their resistance to wear and maintaining tool performance without chipping, as demonstrated by prolonged tool life in cutting tests.
Implementation Method 1
The method comprises a step of subjecting at least a part of the cutting tool to a shot peening treatment using a peening media. The peening media comprise beads of crystallin tungsten carbide
Implementation Method 2
The unexpected response in the coated cutting tool from the shot peening with crystallin tungsten carbide is believed to be due to the unique combination of a very high density and a very high stiffness of the tungsten carbide material
Implementation Method 3
dry blasting or shot peening of coated cutting tools are known in the art to increase the performance of the tool by impacting the residual stress in the coating and the substrate
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention relates to a coated cutting tool. The cutting tool is CVD coated and the substrate is made of cemented carbide. The CVD coating comprises an inner layer of TiN and a subsequent layer of TiCN and a layer of Al2O3. The coated cutting tool is subjected to a shot peening process using a granular media comprising beads of crystallin tungsten carbide. The present invention also relates to a method of shot peening coated cutting tools with beads of crystallin tungsten carbide.