Bonded Nutplate Heating Fixture for Fast Adhesive Cure
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Solution Overview
Problem
The long curing time of adhesives used in bonded hardware, such as nutplates, in the aerospace industry poses a challenge as it negatively impacts aircraft availability and safety, especially when supplemental heating is considered in environments with flammable materials.
Innovation Solution
A rapid cure system that applies localized heating through the body of the nutplate and into the adhesive bondline, using a nutplate engagement fixture with a rigid and elastomeric tube structure, and a temperature sensor retention fixture to control and monitor the heating process, ensuring efficient heat transfer and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If supplemental heating is applied to accelerate adhesive curing, then curing time is reduced, but the risk of damage to surrounding structure and safety hazards increase due to excessive temperature exposure in environments with flammable materials
Solution Approach 1:
The heating system applies heat locally and selectively to the bonded hardware area through controlled heat delivery mechanisms, concentrating thermal energy only where needed for curing while maintaining lower temperatures in surrounding areas to prevent damage and eliminate safety hazards in flammable environments
Solution Approach 2:
The system incorporates temperature monitoring and control mechanisms that provide feedback to regulate heating intensity, ensuring the adhesive receives sufficient heat for curing while preventing excessive temperature exposure that could damage surrounding structures or create safety hazards
2Strength
If approved repair adhesives are used with standard curing specifications, then adhesive strength requirements are met, but system availability decreases due to lengthy cure times
Solution Approach 1:
The system changes the temperature parameter during the curing process, applying elevated localized heat to accelerate the chemical reaction of the adhesive while maintaining control to achieve the desired strength properties, thereby reducing cure time from 24 hours to a much shorter duration and improving system availability
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 solution significantly reduces the nutplate bonding time, increases aircraft production rates, and enhances the consistency and performance of adhesive bonds while minimizing the risk of damage to surrounding structures and ensuring safety in flammable environments.
Implementation Method 1
a heater operable to deliver heat to the bonding surface of the nutplate
Implementation Method 2
a temperature sensor operable to measure the temperature at the bonding surface of the nutplate
Data Source
AI summary
Systems for positioning and bonding a nutplate to a substrate having an aperture include a nutplate engagement fixture and a temperature sensor retention fixture. The nutplate engagement fixture includes a rigid tube and an elastomeric tube engaged with the rigid tube, the elastomeric tube having an elongated tube sized to provide a friction fit with the aperture and retain the elastomeric tube within the aperture. The rigid tube is operable to engage the nutplate at one end and the elastomeric tube is configured to anchor the nutplate engagement fixture at the aperture and secure the nutplate in contact with the substrate. The temperature sensor retention fixture includes a fixture body sized and configured to engage with the nutplate and at least one passageway within the fixture body sized and configured to allow a temperature sensor to be inserted or embedded therein with an end proximal a surface of the nutplate.