Asymmetric Multi-Bevel Cutting Blade for Razor Durability
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Solution Overview
Problem
Conventional razor blades face a trade-off between sharpness and durability, requiring high cutting force that leads to discomfort and wear, despite hard coatings, due to their symmetric design and limited mechanical strength.
Innovation Solution
A cutting blade with an asymmetric cross-sectional shape featuring a primary bevel with a greater wedge angle than the secondary bevel, and a tertiary bevel with an even larger wedge angle, combined with a thin secondary bevel for low cutting force and enhanced mechanical stability, utilizing hard coatings for increased durability and reduced friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cutting edge is made sharper to improve cutting performance, then the cutting force is reduced, but the mechanical strength and durability of the blade decrease
Solution Approach 1:
The cutting blade is segmented into three distinct bevels (primary, secondary, and tertiary) with different wedge angles. The primary bevel (θ1 = 40-60°) provides mechanical strength, the secondary bevel (θ2 = 10-20°) provides sharp cutting edge, and the tertiary bevel (θ3 = 60-80°) provides structural support. This segmentation allows each region to optimize for its specific function, resolving the contradiction between sharpness and strength.
Solution Approach 2:
The blade employs an asymmetric cross-sectional design where the second face has a complex multi-bevel structure while the first face has a simpler single bevel. This asymmetry allows the cutting edge to be sharply defined on one side while maintaining structural integrity through the asymmetric distribution of material and stress paths.
2Reliability
If hard coating is applied to increase durability, then the edge holding property is improved, but the blade friction increases
Solution Approach 1:
Different regions of the blade are assigned different qualities: the cutting edge region receives hard coating (diamond, DLC, nitrides, carbides, or oxides) for durability and edge holding, while the clearance face and other non-cutting regions maintain lower friction properties. This local differentiation resolves the contradiction by applying friction-reducing properties only where needed for cutting performance.
3Ease of operation
If the wedge angle is reduced to lower cutting force, then cutting comfort is improved, but the mechanical strength of the blade decreases
Solution Approach 1:
The blade profile is segmented into multiple bevels with different wedge angles optimized for different functions. The secondary bevel with θ2 = 10-20° provides the low cutting force needed for comfort, while the primary bevel (θ1 = 40-60°) and tertiary bevel (θ3 = 60-80°) provide the mechanical strength needed to support the thin cutting edge.
Data Source
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AI summary
The present invention relates to a cutting blade (1) having an asymmetric cross-sectional shape with a first face (2), a second face (3) opposed to the first face and different from the first face as well as a cutting edge wherein the first face comprises a surface and the second face comprises a primary bevel (5), a secondary bevel (6) and a tertiary bevel (7) with a first wedge angle (θ1) between the surface on the first face and the primary bevel, a second wedge angle (θ2) between the surface on the first face and the secondary bevel and a third wedge angle (θ3) between the surface on the first face and the tertiary bevel. Moreover, the present invention relates to a hair removal device comprising this cutting blade.