Razor Blade Substrate Thickness and Coating Design
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Solution Overview
Problem
Existing razor blades with thin profiles and coatings achieve low cut forces for comfort but lack sufficient engagement and durability for extended shaving sessions or close shaves.
Innovation Solution
A razor blade design featuring a wide substrate profile, reduced telomer coating, and thicker DLC hard coatings, combined with a martensitic stainless steel substrate and chromium overcoat, to increase cutting force and hysteresis capture, resulting in a blade that engages and pulls hair rather than cutting cleanly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If thin substrate profiles and thinner hard coatings are used, then cutting forces are reduced and comfort is improved, but engagement and durability are insufficient for extended shaving sessions
Solution Approach 1:
The patent applies parameter changes by specifying precise substrate thickness measurements at multiple distances from the blade tip (greater than 2.30 μm at 4 μm distance, greater than 4.26 μm at 8 μm distance, greater than 7.93 μm at 16 μm distance) and controlling the tip radius (50-300 Angstroms). These parameter specifications optimize the balance between cutting force and engagement durability, allowing the blade to maintain sufficient thickness for durability while keeping the cutting edge sharp enough for effective cutting.
Solution Approach 2:
The patent employs composite materials through multiple coating layers including DLC (diamond-like carbon) hard coating, chromium overcoat, and telomer or PTFE outer layer. This composite structure provides both the durability needed for extended shaving sessions and the friction reduction necessary for comfort, resolving the contradiction between engagement strength and cutting smoothness.
2Strength
If thicker DLC hard coatings are applied, then strength and corrosion resistance are improved, but friction reduction capability may be compromised
Solution Approach 1:
The patent segments the coating structure into distinct functional layers: a DLC hard coating layer for strength and corrosion resistance, a chromium overcoat layer, and a separate telomer or PTFE outer layer specifically for friction reduction. This segmentation allows each layer to perform its specialized function without compromising the others, enabling both high strength and low friction simultaneously.
Solution Approach 2:
The multi-layer composite coating system combines materials with complementary properties: DLC provides hardness and corrosion resistance, chromium provides adhesion and additional protection, and telomer/PTFE provides low friction. The synergistic combination of these composite materials resolves the contradiction between strength and friction reduction.
3Object-affected harmful factors
If a continuous outer layer is applied, then friction reduction is maximized, but engagement with hair is reduced
Solution Approach 1:
The patent applies local quality by making the outer layer discontinuous rather than continuous. The telomer or PTFE outer layer is applied in a discontinuous manner, providing friction reduction in specific areas while leaving other areas exposed to maintain hair engagement. This localized application resolves the contradiction between friction reduction and engagement force.
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 novel blade design achieves higher cutting forces and extended shaving intervals by providing increased engagement and durability, maintaining comfort through controlled telomer application and reduced friction.
Implementation Method 1
Hard coatings such as diamond, amorphous diamond, diamond-like carbon-(DLC) material
Implementation Method 2
A telomer or Polytetrafluoroethylene (PTFE) outer layer can be used to provide friction reduction
Implementation Method 3
Interlayers of niobium or chromium containing materials can aid in improving the binding between the substrate, typically stainless steel, and hard carbon coatings, such as DLC
Data Source
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AI summary
A razor blade having a substrate with a cutting edge being defined by a sharpened tip. The substrate has a thickness of greater than about 2.30 micrometers measured at a distance of four micrometers from the blade tip, a thickness of greater than about 4.26 micrometers measured at a distance of eight micrometers from the blade tip, and greater than about 7.93 micrometers measured at a distance of sixteen micrometers from the blade tip. A hard coating joined to the substrate has a thickness of 700 Angstroms to about 3500 Angstroms. An outer layer joined to a coated substrate is discontinuous. The outer layer may be produced from a dispersion comprising about 0.03g/L or less of telomer or from about 0.5% solids or less of telomer by weight of composition. The novel razor blade cuts at less than 100% cutting efficiency using a single fiber cutting efficiency measure.