Polymeric Razor Blade Manufacturing with Sub-Micron Edge Precision
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Solution Overview
Problem
Existing methods for manufacturing razor blades from polymeric materials fail to achieve a cutting edge tip radius of less than 1 μm due to high viscosity issues and subsequent flashing, leading to variability in edge quality and sharpness, limiting the ability to create non-linear edges and integrated assemblies.
Innovation Solution
A method involving a base structure of a first polymeric material, pressing a cutting edge template into it, removing the template to form a cavity, filling with a second precursor material, curing, and separating to produce cutting edge structures with tip radii less than 1 μm, using materials like PMMA or PDMS and precursor materials with viscosities less than 10000 centiPoise, and curing via heat or light to avoid flashing and achieve precise edge profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If melt flow processing techniques are used to inject molten polymer into a mold cavity, then the process can form cutting edge structures, but the high viscosity of the polymer prevents full penetration into sub-micro-meter dimensioned spaces required for razor blade edges
Solution Approach 1:
The patent changes the physical state of the polymer from molten (high temperature) to a lower viscosity state that can be injected at room temperature or with minimal heating, enabling penetration into sub-micro-meter spaces without causing flashing
Solution Approach 2:
The patent prepares the polymer material in advance by reducing its viscosity through chemical modification or selective heating before injection, ensuring it can flow into the finest mold cavities without requiring excessive injection pressure that would cause flashing
2Manufacturing precision
If injection pressure is increased to improve penetration into sub-micro-meter dimensioned spaces, then the polymer can reach the cutting edge spaces, but the polymer penetrates between the mating surfaces of the mold tool causing flashing
Solution Approach 1:
The patent modifies the viscosity parameter of the polymer to achieve an optimal range that allows flow into sub-micro-meter spaces at moderate injection pressures, preventing the polymer from forcing its way between mold surfaces and causing flashing
Solution Approach 2:
The patent uses a master blade with a precisely formed cutting edge to create a negative mold cavity, which then serves as a template for forming multiple replicated blades with identical precise geometry, ensuring consistent sub-micro-meter tip radii without requiring high injection pressures
3Ease of manufacture
If the polymeric material is heated above the glass transition temperature to decrease viscosity, then the material becomes more fluid for injection, but cooling causes shrinkage and rounding of the edge
Solution Approach 1:
The patent changes the thermal processing parameters by minimizing the temperature increase above glass transition and reducing the time at high temperature, thereby limiting thermal expansion and subsequent shrinkage upon cooling, which preserves the sharpness of the cutting edge
Solution Approach 2:
The patent prepares the mold cavity with the exact final dimensions desired, including the precise cutting edge geometry, so that when the polymer is injected and cured, it replicates this geometry without requiring significant thermal expansion or contraction that would alter the edge sharpness
4Productivity
If traditional metal blades are used with proven economical processes, then high volume production at high speed is achieved, but the material cost is higher and blade shapes are limited to straight edges with triangular or wedge profiles
Solution Approach 1:
The patent uses a master blade template to create a negative mold cavity that can be used to replicate multiple blade shapes, including non-linear and complex profiles that would be difficult or impossible to produce with traditional grinding processes, while maintaining high production volumes
Solution Approach 2:
The patent creates a universal mold-making process that can produce various blade shapes and profiles from a single mold cavity, enabling the same manufacturing system to produce different blade types (straight, curved, serrated, etc.) without requiring separate specialized processes for each shape
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 enables the production of razor blades with precise, sharp cutting edges and non-linear profiles, reducing variability and enabling the use of lower-cost materials while maintaining sharpness and cost-effectiveness, comparable to traditional metal blades.
Implementation Method 1
curing the second material, the curing comprising polymerization or cross-linking of the second material via exposure to UV light or heat
Implementation Method 2
after filling the cavity, the fluid polymeric material needs to be cooled to achieve a solid state, which causes shrinkage of the blade shape and rounding of the edge
Data Source
AI summary
A functional polymeric cutting edge structure and methods for manufacturing cutting edge structures using polymeric materials are provided. A razor blade for use in a razor cartridge or a blade box for assembly in a razor cartridge frame may be formed using the present invention.