Outlet Guide Vane Assembly Using a Reduced-Size Vacuum Sheet
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Solution Overview
Problem
The existing method for assembling outlet guide vanes in aircraft turbofan engines is prone to geometric and mechanical defects due to the fragility of hermetic bags, which can tear or perforate, leading to inconsistencies in resin sealing and heating, resulting in increased manufacturing time and costs.
Innovation Solution
A reduced-size vacuum sheet is used, with a bead of sealant applied to the body to delimit the vacuum space, reducing the risk of sheet damage and allowing for more controlled heating, and a tooling system can automate the process for improved reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hermetic bag is used to enclose the body and cover during vacuumising and heating, then the resin seal quality is improved by preventing porosity, but the bag can be perforated or torn by sharp edges, leading to assembly defects
Solution Approach 1:
The hermetic bag is replaced by a rigid frame structure with multiple separate sealing zones. The frame divides the enclosure space into distinct sections, each sealed independently, preventing a single tear from compromising the entire assembly. Sharp edges are covered by protective elements integrated into the frame segments.
Solution Approach 2:
A rigid frame structure acts as an intermediary between the resin seal and the vacuumising/heating environment. This frame provides mechanical protection against sharp edges while maintaining the necessary vacuum seal, eliminating the fragility issue of flexible bags without compromising seal quality.
2Manufacturing precision
If a hermetic bag is used to enclose the assembly, then vacuumising prevents porosity in the resin seal, but the bag creates folds that induce turbulence in autoclave gas flow, causing non-uniform heating
Solution Approach 1:
The rigid frame structure segments the gas flow path into controlled channels, preventing turbulence-inducing folds. The segmented design allows uniform gas distribution across the autoclave while maintaining the vacuum seal necessary for porosity-free resin curing.
Solution Approach 2:
The flexible hermetic bag is replaced with a rigid frame structure that eliminates folds and turbulence. The frame maintains the necessary sealing function through rigid contact surfaces rather than flexible membranes, ensuring uniform heat and gas flow distribution during autoclave processing.
3Ease of manufacture
If a hermetic bag is used for vacuumising and heating, then the assembly process is standardized, but the bag is a single-use consumable that cannot be repaired, increasing manufacturing time and cost
Solution Approach 1:
The disposable hermetic bag is replaced with a durable, reusable rigid frame structure. The frame can be disassembled, cleaned, and reused across multiple production cycles, eliminating the time and cost associated with disposing and replacing single-use bags while maintaining process standardization through consistent framing geometry.
Solution Approach 2:
Instead of discarding the entire hermetic bag after one use, the rigid frame structure is recovered and reused. Only the consumable sealing elements (gaskets or seals) are replaced, significantly reducing material waste and assembly preparation time while maintaining the standardized process benefits.
4Manufacturing precision
If the body and cover are placed in a hermetic bag, then vacuum pressure can be applied to press the cover against the body for optimal resin seal thickness, but the bag placement is long and delicate, increasing assembly time
Solution Approach 1:
The rigid frame structure is pre-assembled with the body and cover positioned in their correct orientations before vacuumising. This preliminary positioning eliminates the delicate and time-consuming bag placement step, as the frame itself provides the structural framework that holds components in place during the vacuum and heating process.
Solution Approach 2:
The flexible mechanical system of bag placement and sealing is replaced with a rigid mechanical framing system. The frame provides structural support and positioning without requiring delicate manual manipulation, significantly reducing assembly time while maintaining precise seal thickness control through the rigid geometry.
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 enhances assembly reliability by minimizing vacuum loss and geometric defects, reduces manufacturing time and costs, and allows for more efficient use of autoclave space, while ensuring uniform heating and improved reproducibility.
Implementation Method 1
a step of placing a sheet against the front side of the vane; an operation of vacuumising a space included between the cover and the front side
Implementation Method 2
a heating operation capable of polymerising the resin and thus attaching the cover to the body of the vane
Data Source
AI summary
A method for assembling a body and a cover of a vane by polymerisation of a resin. The covens positioned on a junction face of the body covered with this resin. A sheet is placed against a pressure side of the vane, formed by an outer face of the cover and an outer face of the body, so as to define a space sealed with a bead of mastic sealant. The bead of mastic sealant is deposited on the outer face of the body, around the junction face of this body. The space between the sheet and the pressure side of the vane is placed under vacuum during a heating operation of the vane in an autoclave, in order to press the cover against the body of the vane.