Method for edge sealing a fiber-reinforced component

#The invention pertains to a method for edge sealing a fiber-reinforced component, particularly a connecting angle, wherein the component is formed with a carbon fiber-reinforced thermoplastic or duroplastic plastic material, particularly as a protection against contact corrosion in an interface area with metallic components.

#The invention furthermore pertains to a device for implementing the method, as well as to a fiber-reinforced component treated in accordance with said method.

#In modern aircraft construction, metallic materials are replaced with components of carbon fiber-reinforced plastics (CFRP), particularly for weight reasons. In the interface area between CFRP-components and metallic components, particularly components formed with aluminum alloys, contact corrosion may occur due to voltage differences between the different materials. For example, connecting angles (so-called “clips”) for connecting the skin to the frames of a primary structure of an aircraft fuselage are increasingly manufactured with carbon fiber-reinforced thermoplastic materials. They are manufactured from plate-shaped, carbon fiber-reinforced semifinished products in the so-called thermoplastic “punch forming process.” Excess material areas nowadays are usually removed from the blank in a milling process so as to realize a predefined contour of the CFRP-component. The thusly created milled component edges can be sealed, for example, with a synthetic enamel that is currently applied manually on each CFRP-component in order to avoid the above-described corrosion problems in the interface area with metallic components. Alternatively, any single-component or two-component synthetic resin system may also be used. However, the manual application of the edge seal is labor-intensive and therefore elaborate with respect to the manufacturing technology. In addition, the manual application of the edge seal does not provide a reliable consistency of the application results, particularly with respect to the material thickness and/or the coverage.

#In the drawings:

#FIG. 1. shows a perspective view of a CFRP-component in the form of a connecting angle, and

#FIG. 2. shows a schematic representation of a device.

#In the figures, identical constructive elements are respectively identified by the same reference symbols.

#FIG. 1 shows a perspective view of a connecting angle formed of a fiber-reinforced plastic material.

#An exemplary CFRP-component in the form of a connecting or support angle 2 features two contact surfaces 4, 6 that are connected to one another at an angle of 90°. The contact surface 4 contains four through-bores that are not identified by reference symbols. A CFRP-component may also be formed with a more complex geometric shape such as, for example, of at least two individual parts with a respectively simpler part geometry, wherein any component edges and joining surfaces—situated in the bonding area—are already closed and sealed by the adhesive material. The connecting angle 2 is preferably manufactured with a carbon fiber-reinforced thermoplastic plastic material such that it has a slight electric conductivity in the direction, in which the embedded reinforcing fibers or carbon fibers extend. Suitable plastic materials are, for example, polyether imide (PEI), polyetheretherketone (PEEK), polyethylene terephthalate (PET) or other mechanically and thermally durable thermoplastics. Alternatively, the connecting angle 2 may also be formed with duroplastic plastic materials such as, for example, an epoxy resin. The hatching in FIG. 1 indicates that both component edges 8, 10 are provided with a continuous edge seal 12 so as to prevent, in particular, undesirable electrochemical or galvanic contact corrosion processes due to metallic components that are in contact with this area and not illustrated in the drawing. The edge seal 12 is formed of a suitable sprayed-on thermoplastic powder that, after the spring process, is fused and compacted or cross-linked in a furnace or another heating device in order to form a smooth edge seal 12 that firmly adheres to the component edges 8, 10. The edge seal 12 may at least sectionally encompass the component edges 8, 10, i.e., it extends as far as into narrow edge regions 14, 16 that adjoin and extend parallel to the component edges and are indicated with broken lines. The width of the edge regions 14, 16 referred to the component edges 8, 10 may be as large as 10 mm. This makes it possible to prevent, for example, corrosion processes due to the formation of a crack within the edge seal 12 in a transition area between the component edges 8, 10 and the edge regions of the upper and lower component sides, i.e., particularly in the region of the smallest curvature radii of the connecting angle 2.