Asymmetrical Razor Blade Coating Reduces Cutting Force
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Solution Overview
Problem
Conventional razor cartridges with symmetrical blade shapes face limitations in reducing cutting force and minimizing skin irritation during shaving, as they do not effectively manage the asymmetrical demands of cutting hair and interacting with the skin surface.
Innovation Solution
A razor cartridge with an asymmetrical blade shape, featuring a substrate and coating layer configuration where the blade angle between the skin surface and the bisector of the edge portion is greater than the efficient angle, reducing cutting force and minimizing skin irritation by optimizing the facets and angles of the cutting edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a symmetrical blade shape is used, then the manufacturing process is simple, but the cutting force cannot be effectively reduced and skin irritation is not minimized
Solution Approach 1:
The blade is designed with an asymmetrical cross-sectional shape where the first thickness (from skin-facing side) differs from the second thickness (from opposite side). This asymmetry allows the blade to differentiate between cutting function and skin interaction function, reducing skin irritation while maintaining cutting effectiveness. The asymmetrical design creates an efficient angle less than 10 degrees that minimizes harmful effects on skin.
Solution Approach 2:
Different regions of the blade are given different thickness properties to perform different functions. The first thickness region (facing skin) is optimized for minimizing skin irritation, while the second thickness region (opposite side) provides structural support and cutting capability. This local differentiation of properties resolves the contradiction between manufacturing simplicity and skin irritation reduction.
2Ease of operation
If the blade angle is increased to reduce cutting force, then shaving comfort improves, but the blade may not effectively interact with the skin surface
Solution Approach 1:
The blade angle is precisely controlled within a specific range (greater than efficient angle but less than or equal to 22 degrees) to simultaneously achieve reduced cutting force and effective skin interaction. The coating layer thickness parameters (first thickness and second thickness) are also optimized within specific ranges to balance shaving comfort and skin interaction reliability.
Solution Approach 2:
The blade design incorporates dynamic angle relationships where the blade angle varies relative to the skin surface during shaving. The asymmetrical thickness distribution creates different effective angles for cutting versus skin interaction, allowing the blade to adapt its functional characteristics based on the operational phase.
3Strength
If the coating layer thickness is increased to enhance durability, then blade strength improves, but the asymmetrical shape complexity increases
Solution Approach 1:
The coating layer is applied with different thicknesses at different locations: the first thickness on the skin-facing side and the second thickness on the opposite side. This localized thickness variation provides enhanced durability where needed while maintaining overall shape control. The asymmetrical thickness distribution is precisely managed to balance durability enhancement with shape complexity management.
Solution Approach 2:
The blade comprises a substrate with a coating layer formed thereon, creating a composite structure. The coating layer materials and thicknesses are optimized to provide enhanced durability and strength while the asymmetrical thickness distribution manages the complexity of the overall blade shape.
Data Source
AI summary
A razor cartridge is proposed. The razor cartridge may include at least one blade having an edge portion and a cutting edge formed at the tip of the edge portion. The at least one blade may include a substrate comprising a substrate tip and a coating layer formed on the substrate to form the cutting edge. The coating layer may include a first facet extending toward one side from a final edge forming a tip of the cutting edge, to face a skin surface during shaving and a second facet extending toward the other side from the final edge to opposite to the first facet. A blade angle between the skin surface and a line passing through a bisector of the edge portion may be greater than an efficient angle between the skin surface and a line passing through a bisector of the final tip.