Composite Aircraft Panel Lay-Up Over Unsupported Stringer Slots
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Solution Overview
Problem
The conventional manufacturing process of aircraft panels using composite materials is complex and time-consuming due to the need for reaction mandrels and auxiliary supports, which increase lead time and recurrent costs while introducing variability and potential errors.
Innovation Solution
A method for automatic lay-up of composite materials directly over integrated components like stringers or frames without internal support, using optimized tow tension and reduced compaction pressure from the AFP machine to ensure accurate placement and adhesion, eliminating the need for reaction mandrels and other auxiliary tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reaction mandrels and auxiliary supports are used during AFP machine operation, then the pressure application and tow deposition are supported, but the manufacturing process complexity increases and lead time extends
Solution Approach 1:
The patent removes reaction mandrels and auxiliary supports from the manufacturing process. The AFP machine is designed to operate directly over unsupported slots in the tooling, eliminating the need for these auxiliary components while maintaining the ability to apply necessary pressure and deposit tow accurately.
Solution Approach 2:
The tooling design allows the AFP machine to self-support during operation by depositing tow directly over unsupported slots without requiring external reaction mandrels. The system becomes self-sufficient, with the AFP machine's own capabilities sufficient to maintain pressure and trajectory without additional support structures.
2Stress or pressure
If reaction mandrels are used to compensate for AFP machine pressure, then pressure control is maintained, but the lead time increases due to extraction and positioning operations
Solution Approach 1:
The patent eliminates reaction mandrels from the process sequence. The AFP machine operates directly over unsupported slots without requiring mandrel insertion, extraction, or repositioning operations, thereby removing the time consumption associated with these auxiliary operations while maintaining pressure control through the AFP machine's own capabilities.
3Manufacturing precision
If auxiliary mandrels are used for vacuum bag positioning, then positioning accuracy is ensured, but the process variability and potential errors increase
Solution Approach 1:
The patent removes auxiliary mandrels from the vacuum bag positioning process. The tooling design incorporates features that directly enable accurate vacuum bag positioning without auxiliary supports, eliminating the variability and errors associated with multiple auxiliary component handle and coordination operations.
4Device complexity
If tow deposition is performed over unsupported slots without auxiliary support, then the manufacturing process is simplified, but the tow placement accuracy may be compromised
Solution Approach 1:
The patent adjusts key parameters including increased tow tension and reduced compaction pressure during deposition over unsupported slots. These parameter modifications enable the AFP machine to maintain accurate tow placement and adhesion without auxiliary support structures, balancing simplicity with precision.
Solution Approach 2:
The patent implements real-time feedback control during tow deposition over unsupported slots, dynamically adjusting tow tension and compaction pressure to maintain desired tow trajectory and position, ensuring placement accuracy without auxiliary support.
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 simplifies the workflow, reduces lead time and costs, enhances flexibility, and maintains product quality by allowing vacuum bag positioning before or after skin lay-up, while ensuring proper tow trajectory and position without additional support.
Implementation Method 1
adjusting the force applied to the tow with the AFP machine during deposition over the unsupported slot to compensate the lack of auxiliary support tools. In a preferred example, the step of adjusting the force applied to the tow comprises reducing a compaction pressure applied to the tow with the AFP machine while increasing the tow tension during deposition over the unsupported slot
Data Source
AI summary
In a method for manufacturing an aircraft panel that has a composite skin with integrated components (stringers/frames) having unsupported slots, a male tool with the integrated component is obtained. The composite skin is laid up directly over the unsupported slots of the integrated component with an automated fiber placement, AFP machine that provides tow deposition The integrated components lack auxiliary support tools. A force applied to the tow with the AFP machine is adjusted during deposition over the unsupported slots to compensate the lack of auxiliary support tools.