Composite Tape Layup on Flexible Facesheets for Curved Part Curing
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Solution Overview
Problem
Existing composite part manufacturing methods face inefficiencies with automated fiber placement (AFP) and automated tape laying (ATL) processes, particularly for curved surfaces, due to high costs, material waste, and thermal expansion issues, as well as challenges in co-curing or co-molding composite components without fasteners.
Innovation Solution
A method and system using an ATL machine to lay composite material on a flexible facesheet, employing magnets for temporary holding and an impermeable membrane for pressure application, combined with joule heating and vacuum pressure to cure the composite parts on a curved tooling surface, allowing for efficient transfer and fusion without thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If automated fiber placement (AFP) processes are used to manufacture composite parts on curved tooling surfaces, then the process can accommodate gentle compound curves with flexibility, but the programming and manipulation of the AFP head reduces manufacturing speed and increases cost
Solution Approach 1:
The patent divides the composite part manufacturing process into two independent stages: (1) flat layup of composite tapes using ATL process, and (2) transfer to curved tooling for curing. This segmentation allows each stage to use the most appropriate process - ATL for efficient flat layup and autoclave curing for curved surface accommodation - thereby resolving the contradiction between adaptability to curves and manufacturing speed.
Solution Approach 2:
The patent performs the composite tape layup on a flat surface beforehand using the efficient ATL process, then transfers the completed flat composite structure to the curved tooling surface for curing. This preliminary action on a flat surface avoids the speed limitations of programming AFP heads for curved surfaces, while still achieving the desired curved final shape.
2Productivity
If automated tape laying (ATL) processes are used for large flat parts, then the process is more efficient and uses less expensive materials, but the process is not compatible with curved contours
Solution Approach 1:
The patent separates the layup process (performed flat using efficient ATL) from the forming process (performed on curved tooling during curing). This allows ATL to be used for its strength - efficient flat layup - while the curved contour adaptation is achieved through the transfer and curing stage, not the layup stage.
Solution Approach 2:
The patent adds a temporal and spatial dimension to the process by performing layup in one dimension (flat plane) and then transforming to another dimension (curved surface) during the curing stage. This dimensional transition allows ATL to be used for efficient layup while still achieving curved final parts.
3Manufacturing precision
If the mold or tooling is heated during curing or fusing of the composite part, then the composite material can be consolidated, but thermal expansion of the mold or tooling may result in an incorrectly sized composite part
Solution Approach 1:
The patent applies heating locally to the composite part and tooling surface only where needed for curing, rather than heating the entire autoclave and all tooling. This localized heating minimizes thermal expansion of the tooling while still achieving the necessary curing temperature for the composite material.
Solution Approach 2:
The patent pre-heats the tooling surface and composite part before placing them in the autoclave, then uses the autoclave's compression and steam pressure to complete the curing process without requiring extensive heating of the entire system. This preliminary heating action reduces the need for subsequent high-temperature heating that would cause tooling thermal expansion.
4Weight of moving object
If co-curing or co-molding of composite components is performed to integrate parts without fasteners, then the overall weight and cost can be reduced, but the process requires multiple complex tooling or mold components to provide sufficient pressure
Solution Approach 1:
The patent combines multiple composite components (skin and substructures) into a single integrated structure through co-curing in one autoclave cycle. This merging eliminates the need for separate fastening operations and reduces overall weight, while the tooling complexity is managed by using a single integrated tooling system rather than multiple separate tooling components.
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
Enables cost-effective and precise manufacturing of composite parts with curved surfaces by reducing material waste, minimizing thermal expansion, and integrating substructures without fasteners, thus improving efficiency and accuracy.
Implementation Method 1
heating the facesheet with the skin to a cure temperature
Implementation Method 2
providing consolidation pressure to the thermoplastic composite part when a pressure differential is applied to the impermeable membrane
Implementation Method 3
one or more conductive wires providing current to heat the facesheet
Implementation Method 4
Transform Electrical Energy to Thermal Energy
Data Source
Figure 1~2
Figure 3~4
Figure 5a
AI summary
Disclosed is a method and system for manufacturing a composite part by laying up courses of composite tape, for example using an automated tape layup (ATL) machine onto a conductive flexible facesheet (12) laid flat on a flat surface, and then transferring the facesheet with the composite material thereon to a curved tooling surface (24) for attachment of substructures (36) and curing into the composite part. The method may also include applying insulation (26, 28) below the facesheet and above the composite material, then heating the conductive facesheet to cure the composite tape and fuse the composite tape to the substructures without heating the tooling surface or any other items used to compress and cure the composite material into the composite part. Heating of the facesheet may be performed using joule heat provided by a single turn transformer inducing current to a plurality of conductive wires (44) attached at opposing ends to the facesheet.