Vacuum Debulking Tool for Consistent Composite Bondlines

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Solution Overview

Problem

Inconsistent bonded joints in composite structures, such as aircraft components, often result in rework requirements, which can ground aircraft and cause delays due to issues like voids, porosity, and thickness variations, leading to reduced availability and increased costs.

Innovation Solution

A method and apparatus using a vacuum debulking tool that positions a patch relative to a composite workpiece, applies a vacuum to remove air and gases, and cures adhesive to achieve a desired thickness, thereby forming a consistent bonded joint without removing the composite parts from the aircraft.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional bonding methods are used to join composite structures, then the bonding process can be completed, but inconsistent bondlines with voids, porosity, and thickness variations occur, requiring rework

Engineering Contradiction:

Improvebondline consistencyVSAvoidbonded joint quality

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent uses a bladder filled with fluid (hydraulic or pneumatic system) to apply uniform pressure to the adhesive layer during curing. This fluid pressure system ensures consistent thickness and eliminates voids and porosity by evenly distributing force across the bondline, resolving the contradiction between manufacturing precision and reliability.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent controls and maintains specific parameters during the bonding process, including adhesive thickness, pressure, and temperature. By precisely controlling these parameters through the bladder system and curing conditions, consistent bondlines are achieved without defects, improving both manufacturing precision and bonded joint quality.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If rework is performed on composite structures with inconsistencies, then the bonded joints can be corrected, but aircraft downtime increases and availability decreases

Engineering Contradiction:

Improvebonded joint qualityVSAvoidaircraft downtime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary pressure using the bladder system before the adhesive fully cures, ensuring proper bonding and eliminating the need for subsequent rework. This preliminary action prevents inconsistencies from developing in the first place, maintaining reliability while avoiding time loss from rework operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The bonding process maintains continuous pressure and curing conditions throughout the entire adhesive set time, ensuring consistent bondline formation without interruption. This continuous process eliminates the need for stopping and restarting operations during rework, reducing aircraft downtime while ensuring joint quality.

Inventive Principle:

Principle #20Continuity of useful action

3Ease of manufacture

If adhesive is applied between workpieces without controlled pressure, then the bonding process is simple, but voids and porosity occur in the bondline

Engineering Contradiction:

Improvebonding process simplicityVSAvoidbondline thickness uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs a bladder with fluid pressure to automatically apply uniform compression to the adhesive layer. This pneumatic/hydraulic system maintains consistent pressure throughout the bonding process, ensuring uniform thickness and eliminating voids while keeping the operation simple and automated.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The bladder system automatically adjusts and maintains the required pressure during adhesive curing without continuous manual intervention. The system self-regulates to ensure proper bondline thickness and eliminate defects, maintaining manufacturing precision while simplifying the manufacturing process through automation.

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 approach allows for efficient rework of composite structures in situ, reducing downtime, maintaining mechanical properties, and ensuring consistent bondlines with reduced porosity and voids, thus enhancing the reliability and service life of the bonded joints.

Implementation Method 1

A vacuum is applied to the first workpiece and a portion of the second workpiece

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

adhesive having a desired thickness is positioned between the first workpiece and the second workpiece. The adhesive positioned between the first workpiece and the second workpiece is cured

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentUS10173371B1System and method for forming a bonded joint

Publication Date: 2019.01.08 THE BOEING CO

AI summary

A method and apparatus for forming a bonded joint on a composite structure is presented. An apparatus carrying a first workpiece is positioned relative to a second workpiece. A vacuum is applied to the first workpiece and a portion of the second workpiece. A bladder on a first surface of a housing of the apparatus is deflated. Deflating the bladder positions the first workpiece such that adhesive having a desired thickness is positioned between the first workpiece and the second workpiece. The adhesive positioned between the first workpiece and the second workpiece is cured.