Razor Blade Manufacturing via Intergranular Cleavage
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Solution Overview
Problem
Existing manufacturing processes for razor blades face challenges in efficiently creating weakened areas, which limits the use of softer and thinner materials and requires additional steps like rolling or thermal energy, affecting the separation and attachment of razor blade components.
Innovation Solution
A method involving a progressive perforation tool to bend and flatten an elongated stainless steel strip, creating intergranular cleavage and grain boundary oxidation for fracture initiation sites, allowing for the separation and attachment of razor blades with a weakened portion without additional process steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rolling apparatus is used to create offset between blade portions, then weakened portion is formed, but additional process steps and device complexity increase
Solution Approach 1:
The patent combines the bending and flattening operations into a single integrated rolling apparatus that performs both functions simultaneously during one pass through the material, eliminating the need for separate rolling steps and reducing overall process complexity
Solution Approach 2:
The bending operation is performed preliminarily before the flattening operation, creating the offset that will become the weakened portion, and then the flattening operation completes the formation of the fracture initiation site in a predetermined sequence within the same apparatus
2Ease of manufacture
If laser thermal energy is used to create groove in strip, then weakened portion is formed, but energy consumption and process complexity increase
Solution Approach 1:
The patent replaces the thermal energy-based laser grooving process with a mechanical rolling apparatus that uses controlled bending and flattening forces to create the same weakened portion, substituting mechanical action for thermal energy and significantly reducing energy consumption
Solution Approach 2:
The patent changes the fundamental parameter used to create the weakened portion from thermal energy (laser) to mechanical stress (bending and flattening), achieving the same functional result through a different physical mechanism that is more energy-efficient
3Length of moving object
If strip thickness is reduced for thinner blades, then blade flexibility improves, but separation difficulty increases
Solution Approach 1:
The patent applies local quality by creating a concentrated weakened portion with fracture initiation sites at a specific location in the strip, while the rest of the blade maintains its required thickness and strength, allowing thin blades to be separated easily at the predetermined location without compromising overall blade integrity
Solution Approach 2:
The patent segments the blade into a body portion and a removable portion separated by a weakened portion, allowing the thinner blade material to be effectively divided into functional segments that can be easily separated at the weakened portion while maintaining adequate thickness in the cutting portions
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
Enables the use of softer and thinner blade materials, simplifies the manufacturing process, and facilitates the separation and attachment of razor blade components, improving the efficiency and effectiveness of razor blade production.
Implementation Method 1
The bending and the flattening operations cause intergranular cleavage at the irregularity
Implementation Method 2
the hardening process causes grain boundary oxidation in the vicinity of the cleaved (exposed) grain boundaries to create a fracture initiation site
Data Source
Figure 1~2
Figure 3~3A
Figure 4A~4B
AI summary
An elongated flat strip of stainless steel material for use in manufacturing razor blades is provided with an elongated weakened portion. A cutting edge is subsequently provided along one elongated edge of the strip. The weakened portion is between the cutting edge and an opposed edge. A blade portion is between the cutting edge and the weakened portion and a removable portion is between the weakened portion and the opposed edge. The weakened portion is provided by a) bending and flattening a portion of the strip in a progressive perforation tool to cause localized intergranular cleavage, and b) hardening the strip to oxidize the exposed (cleaved) grain boundaries.