Composite Cutting Element for Electric Shaver Wear Reduction
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Solution Overview
Problem
Stainless steel cutting elements in electric shavers suffer from unbalanced hardness with the shaver cap lamellae, leading to excessive wear and corrosion, especially in additive shavers where moisture exposure increases these issues.
Innovation Solution
A cutting element made from stainless steel with a hardened surface layer, featuring a composite cutting end face with a hardened peripheral edge and normal stainless steel areas, optimizing the hardness balance to reduce wear on both the blade and cap, while maintaining corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cutting element is made with high hardness throughout, then wear resistance of the cutting edge is improved, but wear of the shaver cap increases
Solution Approach 1:
The cutting element features a composite end face with a hardened peripheral edge (hardness 600-1800 HV1) surrounding a softer central area (hardness 150-600 HV1). This local differentiation allows the hardened edge to resist wear during cutting while the softer central area reduces impact on the shaver cap, resolving the contradiction between cutting edge durability and cap wear.
2Strength
If stainless steel is hardened by conventional heat treatment, then wear resistance is improved, but corrosion resistance deteriorates
Solution Approach 1:
The invention applies hardening treatment only to the peripheral edge of the cutting end face, leaving the central area in its original corrosion-resistant stainless steel state. This localized approach maintains overall corrosion resistance while providing wear resistance where most needed at the cutting edge.
Solution Approach 2:
The cutting end face is constructed as a composite structure combining hardened steel material at the periphery with softer, more corrosion-resistant stainless steel in the center. This composite approach allows simultaneous optimization of wear resistance and corrosion resistance in different zones.
3Strength
If the entire cutting end face is made of hardened steel, then cutting sharpness is maintained, but the hardness balance with shaver cap is unbalanced
Solution Approach 1:
The peripheral edge of the cutting end face is hardened to maintain cutting sharpness and edge integrity, while the central area remains softer to balance the overall hardness relationship with the shaver cap. This local differentiation creates an optimized hardness gradient that satisfies both cutting performance and cap compatibility requirements.
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 solution effectively reduces wear on the shaver cap and maintains the cutting edge's sharpness, extending the lifespan of both the cutting element and shaver cap by adjusting the geometric distribution of hardened and less hard stainless steel surfaces, and can be manufactured using various stainless steel types, including softer steels, enhancing manufacturing flexibility.
Implementation Method 1
it has been proposed to provide the cutting elements and/or the shaver cap lamellae with a hardened surface layer, for instance obtained by plasma nitriding
Implementation Method 2
whereby the cutting end face (11) of the element comprises a surface layer of hardened steel
Data Source
AI summary
The invention relates to a cutting element (10), such as used in an electric shaver. The cutting element is made from stainless steel with a hardened surface layer (14) over at least part of its surface, and is characterized, in that the cutting end face (11) of the element comprises a, surface layer of hardened steel at least over its cutting edge (12), the rest of the end face comprising the stainless steel. The cutting element has self-sharpening and wear adjustable characteristics. The invention also relates to a method for producing the cutting element, and to an electric shaver comprising at least one cutting element according to the invention.