Induction Curing of Cell Arrays for Uniform Adhesive Bondlines

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Solution Overview

Problem

Convection heating methods for curing adhesive bondlines in cell-based structural arrays result in uneven heating due to thermal gradients, leading to under-cure or over-cure conditions, which increase manufacturing time and costs, and can result in scrap or rework.

Innovation Solution

The use of tooling blocks with embedded magnetic susceptors that are inductively heated by an electromagnetic field produced by an induction coil powered by a high-frequency AC source, ensuring uniform and controlled heating across the array, including interior and exterior cells, and allowing for targeted heating to avoid overheating of thermally sensitive components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If convection heating is used to cure adhesive bondlines, then the adhesive can be cured, but uneven heating occurs due to thermal gradients causing under-cure or over-cure conditions

Engineering Contradiction:

Improveuniformity of adhesive cureVSAvoidtemperature distribution uniformity

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The patent replaces the convection-based heating system with an induction heating system that uses electromagnetic fields to directly heat susceptors embedded in tooling blocks. This substitution eliminates the thermal gradient problems inherent in convection heating, as the electromagnetic field penetrates uniformly through the tooling blocks and cells, providing consistent heating throughout the adhesive bondlines regardless of position in the array.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic susceptors as intermediary elements that convert electromagnetic energy into heat locally within the tooling blocks. These susceptors act as mediators between the electromagnetic field source and the adhesive bondlines, enabling controlled and uniform heat transfer to the adhesive without the thermal gradient issues of direct convection heating.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If convection heating is used, then adhesive curing can be achieved, but manufacturing time increases due to extended cure cycles needed to address uneven heating

Engineering Contradiction:

Improvecure cycle timeVSAvoidadhesive cure uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

By replacing convection heating with induction heating, the system achieves both uniform temperature distribution and reduced cure cycle time. The direct electromagnetic heating of susceptors eliminates the need for extended cure cycles required by convection systems to compensate for uneven heating, thereby simultaneously improving productivity and manufacturing precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The induction heating system provides continuous and uniform heating action throughout the cure cycle, eliminating the intermittent or extended heating periods required by convection systems. This continuous useful action ensures uniform adhesive cure while reducing overall manufacturing time.

Inventive Principle:

Principle #20Continuity of useful action

3Use of energy by moving object

If convection heating is used, then adhesive bondlines can be cured, but energy consumption increases and cost rises due to extended manufacturing time and potential scrap/rework

Engineering Contradiction:

Improveenergy efficiency of curing processVSAvoidadhesive cure quality

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The induction heating system replaces energy-intensive convection heating with a more efficient electromagnetic heating mechanism. The susceptors convert electromagnetic energy directly into heat with high efficiency, reducing overall energy consumption while delivering uniform adhesive cure quality that eliminates scrap and rework costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic susceptors perform self-heating when exposed to the electromagnetic field, converting electromagnetic energy directly into thermal energy without requiring external heating media. This self-service mechanism improves energy efficiency by eliminating heat transfer losses associated with convection systems while ensuring uniform adhesive cure.

Inventive Principle:

Principle #25Self-service

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 achieves rapid, uniform, and highly controllable heating, reducing the risk of under-cure or over-cure, consuming less energy, and preventing overheating, while being easily scalable and cost-effective compared to convection heating.

Implementation Method 1

inductively heated by an electromagnetic field produced by an induction coil powered by a high-frequency AC source

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Induction heating of the tooling blocks is achieved by subjecting the susceptors to an electromagnetic field produced by an induction coil

Methodology Applied

Scientific EffectInduction heating: Induction Heating

Data Source

PatentUS11858219B2Induction curing of cell-based structural arrays

Publication Date: 2024.01.02 THE BOEING CO

AI summary

Adhesive bondlines in a cell-based structural array are thermally cured using tooling blocks inserted into the cells. The tooling blocks have embedded susceptors that are inductively heated by an alternating electromagnetic field generated by an electromagnet.