Silicon Razor Blade Etching and Coating for Edge Strength

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Solution Overview

Problem

Current methods for manufacturing razor blades from metallic materials result in variability in edge sharpness and strength, leading to inconsistent shaving experiences and higher production costs, with a desire for a lower cost method that can produce blades with increased edge strength and reduced edge quality variability.

Innovation Solution

The method involves using a mono-crystalline silicon wafer with specific crystal orientations, etching techniques to form razor blades with precise angles, and applying hard and soft coatings to achieve ultra-fine cutting edges with reduced edge radius, allowing for the production of razor blades with improved strength and consistency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If metallic sheet material is used for razor blade manufacturing with heat treatment and quenching, then high volume production at high speed is achieved, but edge quality variability increases and edge strength decreases

Engineering Contradiction:

Improveproduction speedVSAvoidedge sharpness consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention changes the material parameter from metallic sheet to silicon wafer with specific crystallographic orientation ({100} surface). This fundamental material parameter change enables the formation of blades with ultra-fine edge radii (20-100 nanometers) through etching processes, achieving superior edge sharpness consistency while maintaining high production capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the thermal-mechanical process (heat treatment and quenching) with a chemical etching process. The silicon wafer is etched to expose {111} planes that naturally form the blade edge geometry, eliminating the need for high-temperature furnaces and quenching operations. This substitution achieves both high precision edge formation and high production speed

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If metallic sheet material is used for razor blade manufacturing, then proven economical process is achieved, but edge strength is reduced requiring higher trimming force

Engineering Contradiction:

Improveprocess economyVSAvoidblade edge strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The invention creates a composite structure by depositing hard coating materials (such as diamond-like carbon, silicon nitride, or titanium nitride) and soft coating materials (such as PTFE) onto the silicon blade edge. This composite structure combines the ultra-sharp silicon edge with coatings that enhance strength, reduce friction, and prevent corrosion, resulting in blades that require lower trimming force while maintaining economical production

Inventive Principle:

Principle #40Composite materials

3Productivity

If conventional metallic blade manufacturing is used, then high volume production is achieved, but material cost is higher

Engineering Contradiction:

Improvehigh volume productionVSAvoidmaterial cost

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The invention utilizes silicon wafers, which are significantly lower cost than stainless steel sheet material. The silicon blades are designed as disposable components that are mass-produced from standard silicon wafers using semiconductor industry etching techniques. This approach leverages the low cost of silicon and high-volume wafer fabrication capabilities to reduce material costs while maintaining high productivity

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 approach results in razor blades with enhanced edge strength, reduced surface roughness, and improved shaving comfort by providing a more consistent and sharper cutting edge, while also potentially utilizing lower-cost silicon materials.

Implementation Method 1

The wafer undergoes etching to expose an {111} plane and a second plane to provide a blade edge

Methodology Applied

Scientific EffectEtching:

Implementation Method 2

A hard coating is applied on the blade edge providing a radius of curvature of the blade edge between about 20 nanometers and about 100 nanometers after deposition of the hard coating

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 3

A soft coating is then applied on the blade edge. The soft coating can comprise polytetrafluoroethylene

Methodology Applied

Scientific EffectCoating: Coatings

Data Source

PatentEP3158113B1Methods of manufacturing silicon blades for shaving razors

Publication Date: 2022.03.30 THE GILLETTE CO

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AI summary

Methods are provided for the manufacture of razor blades from silicon material. In some implementations, the method includes aligning a mono-crystalline silicon wafer comprising a {100} surface at an angle where {111} planes intersect the {100} surface parallel and perpendicular to the wafer; etching the mono-crystalline silicon wafer to expose an {111} plane and a second plane to provide a blade edge having between about a 20 degree included blade angle and about a 35 degree included blade angle; applying a hard coating on the blade edge; providing a radius of curvature of the blade edge between about 20 nanometers and about 100 nanometers after deposition of the hard coating; applying a soft coating on the blade edge; and removing the razor blade from the mono-crystalline silicon wafer.