Soluble Coating for Honeycomb Surface Texturing

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Solution Overview

Problem

Conventional methods for preparing honeycomb structures for heat shields, such as using chemical etching or mechanical sanding, often result in incomplete surface preparation due to inaccessibility of cell walls, leading to poor adhesion between the honeycomb structure and AVCOAT insulation, causing mechanical property degradation and potential failure.

Innovation Solution

A method involving the application of a soluble coating on the pins or mandrels to create a leachable surface, which is then washed off to expose a textured bonding surface, enhancing adhesion with AVCOAT insulation by reacting with the resin matrix or chemical coupling agents to provide dangling functional groups for improved bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If chemical etching or mechanical sanding is used to prepare honeycomb cell walls, then surface roughness is improved, but adhesion quality deteriorates due to inaccessibility of cell walls

Engineering Contradiction:

Improvesurface roughnessVSAvoidadhesion quality

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

A soluble coating is applied to the pins before forming the honeycomb structure, creating a textured surface on the cell walls in advance. This preliminary texturing ensures that when AVCOAT insulation is later applied, it bonds effectively to the roughened surface despite the inaccessibility of the cell walls to conventional sanding or etching processes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The soluble coating acts as an intermediary substance that is applied to the pins, transferred to the cell wall surfaces, and then removed to create the desired rough texture. This intermediary approach allows surface preparation in locations that are otherwise inaccessible to direct mechanical or chemical treatment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If pins are coated with release agent for easy removal, then ease of manufacture is improved, but surface contamination occurs interfering with adhesion

Engineering Contradiction:

Improvepin removal easeVSAvoidadhesion quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The harmful release agent contamination is extracted and replaced with a soluble coating that serves the dual purpose of facilitating pin removal and creating surface texture. The soluble coating is subsequently removed through washing, leaving only the desired rough texture without contamination.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The chemical composition of the pin coating is changed from a permanent release agent to a soluble coating that can be easily washed away. This parameter change in the coating's solubility allows it to be removed after serving its temporary purpose of facilitating pin removal and creating surface texture.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If nylon peel-plies are integrated during manufacturing to create rough texture, then adhesion is improved, but ease of operation deteriorates due to difficulty of removal from tight spaces

Engineering Contradiction:

Improveadhesion qualityVSAvoidpeel-ly removal ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The mechanical peel-plies are replaced with a soluble coating system that uses chemical dissolution instead of mechanical peeling. The soluble coating is applied to the pins, transferred to the cell walls, and then removed by washing with water or solvent, eliminating the need for difficult mechanical removal from tight honeycomb spaces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

A hydraulic or liquid-based removal method is used instead of mechanical peeling. The soluble coating is removed by circulating water or solvent through the honeycomb structure, allowing easy removal of the coating material from tight spaces without requiring physical access for peeling operations.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 ensures robust bonding between the honeycomb structure and AVCOAT insulation, enhancing mechanical properties and preventing material degradation or failure by creating a textured surface that is difficult to achieve with conventional surface preparation techniques.

Implementation Method 1

reacting with the resin matrix or chemical coupling agents to provide dangling functional groups for improved bonding

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

application of a soluble coating on the pins or mandrels to create a leachable surface, which is then washed off

Methodology Applied

Scientific EffectDissolution: Solvation

Data Source

PatentUS8323549B2Techniques for forming temporary protective coatings and bondable surfaces

Publication Date: 2012.12.04 TEXTRON SYSTEMS CORP

AI summary

A method for forming temporary protective coatings and bondable surfaces is disclosed. In the method, a soluble layer is disposed on a material surface, such as the interior surfaces of cell walls of a web material. The soluble material is then removed or leached from the web material to form and expose a roughly textured, bondable surface for bonding with another material, such as AVCOAT insulation. Use of the soluble layer, therefore, enhances the bondability of any surface that requires good adhesion, such as where the surface is difficult to reach for conventional surface preparation techniques.