Partial Sealing of Anodic Films for Thermal Stress Resistance

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Solution Overview

Problem

Fully sealed anodic films tend to craze or crack under thermal stress during manufacturing processes due to differential thermal expansion with the metal substrate, while unsealed films are vulnerable to staining and cosmetic damage.

Innovation Solution

A partial sealing process is applied to anodic films, where the outermost pores are sealed to resist contamination and remain unsealed to provide strain tolerance, allowing for thermally compliant processing without cosmetic damage, followed by full sealing post-manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the anodic film is fully sealed, then the film resists contamination and staining, but the film becomes susceptible to cracking under thermal stress

Engineering Contradiction:

Improveresistance to contamination and stainingVSAvoidresistance to thermal cracking

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The anodic film is segmented into two distinct regions: a sealed outer region (first section) that resists contamination, and an unsealed inner region (second section) that provides strain tolerance. This segmentation allows each region to fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the anodic film are given different sealing properties: the outer region is sealed to provide cosmetic protection and contamination resistance, while the inner region remains unsealed to maintain flexibility and strain tolerance during thermal processing.

Inventive Principle:

Principle #3Local quality

2Strength

If the anodic film remains unsealed, then the film maintains strain tolerance for thermal processing, but the film becomes vulnerable to staining and cosmetic damage

Engineering Contradiction:

Improvestrain tolerance during thermal processingVSAvoidvulnerability to staining and cosmetic damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The anodic film is divided into sealed and unsealed regions, allowing the inner region to remain flexible and strain-tolerant while the outer region provides cosmetic protection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The inner region of the anodic film maintains an unsealed state to provide strain tolerance during thermal processing, while only the outer region is sealed to prevent staining, thus locally optimizing properties for different functional requirements.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If a sealing process is applied to protect the anodic film surface, then cosmetic appearance is improved, but the film becomes prone to crazing and cracking

Engineering Contradiction:

Improvecosmetic appearance and protection from stainingVSAvoidstructural integrity under thermal stress

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The sealing process is applied selectively to only the outer region of the anodic film, leaving the inner region unsealed. This segmentation ensures that cosmetic protection is provided where needed while structural integrity is maintained through the flexible unsealed interior.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sealing treatment is localized to the outer section of the anodic film, providing cosmetic quality and stain resistance at the surface, while the inner section remains unsealed to maintain structural flexibility and prevent cracking during thermal processing.

Inventive Principle:

Principle #3Local quality

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 anodic films remain crack-free and cosmetically appealing during manufacturing processes, suitable for consumer products, offering durability and aesthetic appeal while maintaining strain tolerance and corrosion resistance.

Implementation Method 1

an outermost one micrometer of the anodic film is characterized as having a nickel concentration of at least 20 weight %

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

the anodic films are treated with a partial sealing process that seals the outermost portions of the pores

Methodology Applied

Scientific EffectHydrothermal sealing:

Implementation Method 3

differential thermal expansion between the anodic film and underlying metal substrate

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10443145B2Protecting anodized surfaces during manufacturing processes

Publication Date: 2019.10.15 APPLE INC

AI summary

Treatments for anodic coatings that provide improved resistance to staining and cracking during various manufacturing processes are described. According to some embodiments, the methods include placing the anodic coatings in partially sealed states by sealing only the outermost portions of the anodic coatings, which protect the outer surfaces of the anodic coatings from contamination and staining. Inner portions of the anodic coatings are left unsealed, thereby making the anodic coatings more compliant and resistant to cracking when exposed to manufacturing processes, even those that involve exposure to high temperatures or high mechanical stress. Subsequent to the processing, another sealing process can be implemented to fully seal the anodic coatings so that they provide good corrosion and wear resistance.