Patent Application
20240017504
This application claims the benefit of the European patent application No. 22382677.7 filed on Jul. 15, 2022, the entire disclosures of which are incorporated herein by way of reference.
The present invention is directed to the manufacture of a composite part. The manufacturing process comprises steps that allow a subsequent reuse of a breather fabric.
The composite material comprises plies that are usually of carbon or glass fiber. The composite plies are cured and the composite part is formed.
Vacuum bagging is a clamping method that uses atmospheric pressure to hold the laminate in place until the resin cures. The composite part is cured under temperature, pressure and vacuum conditions. The composite part is cured when the resin vitrifies beyond the glass transition point under certain conditions. Pressure, which can be up to several atmospheres, keeps the laminate in place but also affects the speed of the chemical reaction that occurs in the curing cycle of the part and helps to minimize the porosity of the part. Vacuum is an important parameter for curing the composite part, as it allows an evacuation of any air that may be trapped in the bag so that there are no pores/air inclusions in the laminate and also helps to maintain the position of the laminate.
A vacuum bagging for a composite part usually comprises the following elements:
A manufacturing tooling which is a mold on which the composite plies lie.
Once the composite part has been cured, in an autoclave or in an oven, the vacuum bag film, the breather fabric and the release film are removed from the cured part, either manually or by automatic unwrapping, and normally discarded.
Reusable vacuum bag films are known. The reusable bags are specially made of materials such as silicone.
Currently, the breather fabric used in the curing of aircraft parts inside the vacuum bag film is not reused for manufacturing subsequent composite parts.
It is an object of the invention a composite part manufacturing method wherein the manufacturing method comprises the following steps that are performed consecutively although they may have additional stages between two consecutive steps:
Therefore, at the end of the manufacturing process of a first composite part, the removed and cleaned of residues breather fabric is transported, i.e., transferred to another place in which another manufacturing process is or is going to be performed. In an embodiment, the removed breather fabric may be transported and stored, and the same manufacturing tooling may be prepared for another manufacturing process. In an embodiment, the removed breather fabric may be transported to another manufacturing tooling and immediately reused or being stored until it is reused.
The claimed invention allows a reuse of the breather fabric in subsequent manufacturing processes of composite parts. Advantages of the reuse of the breather fabric include the following:
The reused breather fabric could be applied in the manufacture of composite parts of any part of the aircraft. Preferably, the parts may have an irregular or uneven profile. Irregular profile means other than a flat surface and/or constant thickness, i.e., varying from the straight or parallel.
After the curing cycle, the breather fabric may have lost part of its aeration, breathing, capacity and flexibility, but as previously stated, it can be used in those composite parts having an uneven surface. In these composite parts not having a uniform thickness and/or not having a flat surface, the uneven surface generates a vacuum path that allows the reuse of a breather fabric may be having a lower aeration capacity.
Small resin residues may remain on the surface of the breather fabric due to breaks in the release film during or prior to curing. These areas, if any, with resin residues are removed, for instance, during storage of the material for reuse.
In an embodiment, it can be considered that the mentioned resin residues have to be removed only if they exceed a certain surface area. For instance, if the density is small, in the order of 1% or less of the surface of the breather fabric to be reused, the breather fabric is left as it is.
In a preferred embodiment, the manufacturing method minimizes the probability of contamination of the breather fabric, having a limited manual handling and providing automatic means.
To complete the description and to provide for a better understanding of the invention, a set of drawings is provided. The drawings form an integral part of the description and illustrate preferred embodiments of the invention. The drawings comprise the following figures.
As previously stated, the manufacturing method object of the invention comprises the following consecutive steps:
In an embodiment, the composite part manufacturing method comprises the step of providing a sealing tape (5) for sealing the vacuum bag film (4) to the manufacturing tooling (1). Preferably, the sealing tape (5) is positioned onto the manufacturing tooling (1) before providing the release film (6).
The release film (6) may be removed after removing the breather fabric (3) or after inspecting the breather fabric (3) to detect resin residues or after removing the resin residues from the breather fabric (3) or, preferably, after transporting the removed breather fabric (3) to the manufacturing process of another composite part.
According to the above described, in an embodiment the stage in which the vacuum bagging is performed comprises the following steps:
Afterwards, in an embodiment, a connection of vacuum intakes is done, and a vacuum leak test is performed to the above vacuum bagging structure. Finally, the complete set is load into an autoclave or oven and the composite part is cured.
After the curing stage, the vacuum bag film (4) is removed. In an embodiment, the following steps are performed:
In an embodiment, if the area with resin residues is approximately 1% or less of the area of the removed breather fabric (3), the resin residues are not removed.
In an embodiment, to minimize the risk of contamination of the breather fabric (3) during the removal of the material from the cured part and to be able to reuse it (3), the removal of the vacuum bag film (4) is performed automatically. It could be done manually but with assisted support to guarantee the non-contamination of the material.
In the shown embodiment, the removal is done by automatic winding on a roller (8) that may be attached to a gantry crane which in turn has a translational movement along, for instance, a cradle axis.
In the shown embodiment, the removed breather fabric (3) is stored before being reused, for instance, in a container (9). Thus, the removed breather fabric (3) is transported to a manufacturing process of another composite part and stored until it is reused in another manufacturing process. The removed breather fabric (3) can be used several times.
The vacuum bag film (4) may also be manually removed or automatically removed. On their part, the release film (6) is also removed after removing the breather fabric (3). The removal may also be done by automatic winding on the roller (8) that is attached to the gantry crane.
In an embodiment, the removed breather fabric (3) is cut to fit the subsequent composite part to be cured. The cutting step may be carried out when storing the breather fabric (3), if it is stored, or when removing it (3).
As previously stated, the composite part of the manufacturing process of another composite part comprises an uneven surface that may generate a vacuum path that allows the reuse of a breather fabric (3) although it may be has a lower aeration capacity.
While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22382677.7 | Jul 2022 | EP | regional |
