Patent Application
20170305131
The present disclosure relates generally to composite layering processes utilizing automation, and more specifically to use of film adhesives having visual target references included within composite layers to compensate for fabrication deviations due to tolerance buildups.
Modern aircraft construction has become more efficient and cost-effective, in part because composite layered structures are now commonly used in commercial airliners. Composite structures are both stronger and lighter in weight than conventional aluminum structures previously employed in the manufacture of airliners.
One issue with composites, however, has involved the use of automation in fabricating core-stiffened composite structures, such as and including those designed for use in exterior skins and control surfaces of aircraft. The designs and builds of such composites generally require layering of various prepreg composite fiber materials for achieving satisfactory final composite structures. Those skilled in the art may appreciate that dimensional deviations of parts from their design parameters occur during fabrication, and are particularly associated with processes involving relatively thick honeycomb cores. Such deviations, primarily involving the cores per se, can result from even simple factors such as variations of temperature and humidity.
In a first form of the disclosed embodiments, a core-stiffened composite product has an interior core and layers of composite laminates sandwiched together about the core. The core-stiffened composite product includes at least one layer of adhesive film containing a visual target spatially scanned by an automated tracking system to produce a dimensionally corrected reference volume to collate successive layers of film as applied to the interior core. The visual target is positioned to assure an as-designed alignment of each applied layer of laminate onto the core to minimize cumulative tolerance build-ups during a laminate layering process. At least the one layer of adhesive film remains within the completed composite product.
In a second form of the disclosed embodiments, an aircraft component has an interior core and layers of composite laminates sandwiched together about the core. The aircraft component includes at least one layer of adhesive film containing a visual target spatially scanned by an automated tracking system to produce a dimensionally corrected reference volume to collate successive layers of film as applied to the interior core. The visual target is positioned to assure an as-designed alignment of each applied layer of laminate onto the core to minimize cumulative tolerance build-ups during a laminate layering process. At least the one layer of the adhesive film remains within the completed aircraft component.
In a third form of the disclosed embodiments, a process of manufacturing a lightweight aircraft core-stiffened composite product, containing an interior core and layers of laminates sandwiched about the core, includes steps of placing a first prepreg laminate layer on a work surface of a composite layup tool. Next, a first adhesive layer is placed over the first prepreg laminate, and a core is then placed over the first laminate. A second adhesive layer is applied over the core, the second adhesive layer containing a visual laser target. An optical scanner is then used to track the visual target to generate a spatial reference for accurate positioning of a second prepreg laminate layer. Finally, the second prepreg laminate layer is applied over the second adhesive layer in accordance with a dimensionally corrected reference volume generated by the optical scanner.
All features, aspects, functions, and advantages disclosed herein can be achieved independently in various embodiments or may be combined in yet other embodiments, the details of which may be better appreciated with reference to the following description and drawings.
It should be understood that referenced drawings are not necessarily to scale, and that disclosed embodiments are illustrated only schematically. Aspects of the disclosed embodiments may be combined with or substituted by one another, and within various systems and environments that are neither shown nor described herein. As such, it should be understood that the following detailed description is merely exemplary, and not intended to be limiting in either application or use.
The following detailed description is intended to provide both apparatus and methods for carrying out the disclosure. Actual scope of the disclosure is as defined by the appended claims.
In
Referring now also to
In the manufacture of aircraft components, special care may be required to properly align successive layers of core and composite materials. This initiative can be particularly challenging when the core is substantially thicker than the layers to which the core is bonded. For example, if critical dimensions are not appropriately accounted for, the core geometry can be altered by automated mechanisms utilized to place successive layers.
For this purpose, and to the extent that the core may have a thickness of about one order of magnitude greater (e.g. 5 to 15 times) than the thickness of any attached composite layer, this disclosure utilizes a layer of adhesive film containing visual tracking targets which may be scanned by an implement capable of reading positions within the thousands of an inch, such as an optical scanner in a spatial tracking system to be described.
Referring now also to
Referring now to
For purposes of this disclosure, the definition of the point cloud 32 includes data points representing an “as designed” volume of the core-stiffened composite product 10, which may be digitally represented by a shape, contour, and/or geometry of the intended final composite product 10 (
Finally, referring now back to
Alternatively, the immediate disclosure may encompass fabrication of room temperature materials and prepreg laminate layers that do not require the described autoclave curing.
A process of making at least a portion 10A or 10B of the composite product 10 includes placing a first composite laminate 14 on a surface 13 of a layup tool 11; applying a first adhesive film layer over the laminate 14; applying a core 12 over the first adhesive film layer; applying a second layer of adhesive film 20 containing a visual target over the core 12; using an automated tracking system 26 to scan the visual target to generate spatial references in a point cloud 32 for accurate positioning of a second laminate layer 16; and placing the second laminate over the second layer of adhesive film 20 in accordance with scan-generated reference targets 22. The autoclave 40 is used in a final operation to cure the portion 10A or 10B.
As noted, dimensional accuracy of the “as built” core-stiffened composite product 10 is better assured via use of the automated tracking system 26, which spatially monitors the visual targets 22, and makes real time comparisons with “as designed” parameters of the point cloud 32. The “as designed” parameters thus constitute a predetermined frame of reference by which an “as-built” product 10 may be accurately replicated. For this purpose, the point cloud 32 provides an as-designed dimensionally corrected reference volume for comparison. As a result, any error data that is read by the scanner 24 with respect to any “as-built” work in process may be compared in real time against predetermined “as designed” parameters. Resulting positional corrections, as made by the tracking system 26 for example, will assure accurate collation; i.e. precision in placement and alignment, of the applied layers of laminates on and/or about the interior core 12. In summary, the point cloud 32 provides an effective reference tool for minimizing cumulative tolerance build-ups that may occur during a laminate layering process.
Finally, a specific sequence of steps, identified by boxes 100 through 112 of the flowchart of
Step 100: Store “as-designed” data in computer 30 to generate the point cloud 32;
Step 102: Place laminate 14 on the layup tool 11;
Step 104: Apply adhesive film 18 on the laminate 14;
Step 106: Apply the core 12 to the adhesive film layer 18;
Step 108: Apply adhesive film 20 (which contains visual targets 22) to the core 12;
Step 110: Operate the scanner 24 to utilize point cloud 32 to accurately position laminate 16 on the adhesive film layer 20; and
Step 112: Use the autoclave 40 to cure the collated laminates 14, 16, the film 18, 20, and the core 12.
The disclosed core-stiffened product 10 and process for making may have other variations and alternative constructions neither described nor suggested herein. For example, although described only in terms of a few layers, the composite product may have a large plurality of layers sandwiched about the core, including Kevlar and other substantial and/or protective materials. Moreover, other configurations and/or other components may be utilized with such composite products, and in potentially in other environments, including space flight. Further, although the disclosure presents structures in only the shapes and sizes depicted, numerous variations of the disclosed structures may be envisioned for use in the manufacture of alternative embodiments.
