Painting process with printed mask and printing device

Description

[0001] The invention relates to a coating method and a printing device for use in such a method.

[0002] The document EP 3693617 A1 of the company Boeing Co. discloses a method for microtexturing a substrate surface, comprising: printing the substrate surface with a masking agent to define exposed surface zones on the substrate surface, forming a microtexture on the substrate surface by removing material from the exposed surface zones and removing the masking agent from the substrate surface.

[0003] Until now, aircraft components have been masked by hand before painting, not least because of their curved surfaces. The masking effort for aircraft is particularly high, for example, in the door and window areas, as well as on surfaces bearing letters or logos.

[0004] There is therefore a need to automate the masking process as much as possible.

[0005] The invention is based on the object of improving painting processes for components, preferably with a view to further automation.

[0006] The problem is solved by the subject matter of claim 1. Preferred developments are the subject matter of the dependent claims.

[0007] The invention provides a painting method for painting an aircraft component, comprising the steps in the following order: 1.1 Providing the aircraft component; 1.2 Applying a film-forming masking agent to certain areas of the aircraft component by printing the masking agent using a print head to create at least one masked surface area; 1.3 Allowing or forming a masking film from the masking agent; 1.4 Painting the aircraft component with a painting agent; 1.5 Applying a topcoat layer to the painting agent, wherein the topcoat layer reduces the adhesion of the masking film; 1.6 Mechanically removing the masking film from the aircraft component to expose the masked surface area.

[0008] It is preferred that in step 1.1 the component is or will be provided with a substrate.

[0009] It is preferred that in step 1.1 a further layer is applied to the component material or to the substrate.

[0010] It is preferred that the masking agent printed in step 1.2 be a liquid film-forming masking agent. The masking agent is preferably a spray film fluid, a printing ink, or a liquid mold release agent.

[0011] It is preferred that in step 1.3 the masking film is formed by evaporating solvent from the masking agent or by activating the masking agent by heating or by irradiation, preferably by irradiation with (UV) light.

[0012] In step 1.6, the masking film is preferably removed by mechanical peeling. It is preferred that in step 1.6 the masking film is weakened, for example by cutting or lasering. It is preferred that in step 1.6 the masking film is removed with the aid of compressed air, preferably by blowing it away. It is preferred that in step 1.6 the masking film is removed by means of a suction device, preferably by suction. It is preferred that the mechanical removal is carried out by a gripping device. It is preferred that the masking film has a starting point for removal, wherein the starting point is formed by a strip element embedded in the masking film, for example an adhesive strip, wherein in step 1.6 the starting point is mechanically gripped in order to begin the removal.

[0013] It is preferred that in step 1.6 the masking film is removed by means of brushing, rubbing, erasing, water jet and / or high-pressure cleaner.

[0014] One idea of ​​the invention is to apply the masking agent or masking film to the component using an inkjet process. This can be a fully automated process, eliminating the need for manual masking of the component before painting. Inkjet processes for printing three-dimensional objects are known as such (e.g., the Heidelberg Omnifire printing press).

[0015] The process proposed here represents a new application for inkjet printing, using the applied material as a masking film for subsequent coating. Unlike conventional printing, the masking film printed in this way can be easily removed after coating. The printing ink can be, for example, a UV ink that cures into a finished masking film upon exposure to UV light.

[0016] Tests conducted by the applicant have shown that conventional printing inks on a lacquer substrate or additional lacquer layer commonly used in aviation are functionally suitable as masking agents. While the functional printing ink is opaque, it is not necessarily color-imparting and adheres only slightly, allowing it to be removed from the component manually, using a gripper, or other methods.

[0017] It is also possible to print a spray film liquid as a masking agent, provided it has approximately the same viscosity as functional printing inks. Furthermore, it is also conceivable that a liquid mold release agent, such as that used in the production of fiber composite components in a mold, could be printed as a masking agent. The mold release agent preferably has a similar viscosity to the functional printing ink.

[0018] Furthermore, the applicant's tests have shown that the application of a top coat (clear coat or the like) can assist the removal of the masking agent.

[0019] The ideas described here enable a printable masking film that can eliminate manual work on the component. Printing preferably enables precise and targeted application on the component, reducing waste and improving the quality of the finished product. Furthermore, printing enables full automation of the masking process, ultimately enabling the entire painting process to be automated. Overall, this also reduces the overall painting process time.

[0020] Examples of embodiments are explained in more detail using the attached schematic drawings. They show: Fig. 1 shows an embodiment of a coating process; Fig. 2 shows an embodiment of a printing device; Fig. 3 shows a view of the printing device during masking; and Fig. 4 shows a view of the removal of the masking film from an experiment by the applicant.

[0021] Fig. 1 shows schematically a painting process with the steps S10 to S18.

[0022] In the first step S10, an aircraft component 10 is provided. The aircraft component 10 can, for example, be a component arranged on the outside of an aircraft. The aircraft component 10 can be painted for the first time or treated for repainting. The aircraft component 10 can undergo pretreatment (e.g., cleaning, sanding, and the like).

[0023] In the second step S12, a first paint system can be applied to the aircraft component as a substrate 12. The paint system can contain various layers, for example, adhesion promoters, primers, or other functional layers (e.g., corrosion and / or erosion protection). To improve the adhesion of further layers, a further layer 14 can also be applied to the substrate 12. Application can be carried out in the usual way by rolling, brushing, or spraying.

[0024] In the third step S14, a liquid film-forming masking agent 16 is printed. The printing is carried out using an inkjet print head. The masking agent 16 can be a spray film liquid, a functional printing ink, or a mold release agent.

[0025] The masking agent 16 forms a continuous masking film 18 by evaporating the solvent from the masking agent 16. It is also possible for the masking agent 16 to form the masking film 18 only upon activation, for example, by UV light or heat. The masking film 18 lies against the surface or adheres only minimally to the surface, but does not bond. This results in good removability of the masking film 18 from the underlying layer.

[0026] In the fourth step S16, conventional topcoats can be applied as coating agents 20 in a manner known per se. These can preferably be color-imparting, for example, to create a desired logo. A topcoat layer 22 (usually a clear coat) is additionally applied to the coating agent 20. The coating agent 20 and / or the topcoat layer 22 can assist in the removal of the masking film 18 in the further process.

[0027] In the fifth step S18, the masking film 18 is removed mechanically, for example peeled off, thereby exposing the masked surface area 24.

[0028] Fig. 2 and Fig. 3 schematically shows a printing device 26 that can be used for the method described above. The printing device 26 comprises a robot arm 28, to the end of which a print head 30 is attached. The print head 30 is designed as an inkjet print head 32 and, depending on the type of ink, can have an activation unit 34 for activating or curing the printed functional printing ink. The printing device 26 further has a reservoir 36 containing the functional printing ink or the masking agent 16.

[0029] How closer from Fig. 3As can be seen, the print head 30 follows a predetermined masking path 38 on the aircraft component 10 to mask the surface area 24, for example, in an elliptical shape. Through the targeted application, the surface area 24 is sharply masked, resulting in a clear contour after removal.

[0030] Furthermore, the pressure device 26 can include a masking film removal device. The masking film removal device can grasp the masking film 18 and mechanically remove it from the aircraft component 10. Depending on the type of mechanical removal, the masking film removal device can comprise a laser, a knife, a compressed air nozzle, a gripper, a suction cup, a suction tube, a device for a water jet or high-pressure water jet, a brush, and / or a rubbing or erasing device.

[0031] Fig. 4is a photograph of a peel-off test conducted by the applicant. The masking film 18 was applied to a white base coat layer 42 and subsequently covered with a clear coat. The masking film 18 was then successfully peeled off the base coat layer 42 manually between two predetermined separation lines 44.

[0032] To improve the complex painting process of large, three-dimensionally shaped components, preferably aircraft components, it is proposed to automate the masking step. This can be achieved by inkjet printing a masking agent onto the component, forming a masking film. The masking film masks the desired surface area and can be removed after the painting process. Spray films, functional printing inks, or mold release agents are preferably used as masking agents. List of reference symbols:

[0033] 10Aircraft component 12Substrate 14Further layer 16Masking agent 18Masking film 20Paint 22Topcoat layer 24Surface area 26Printing device 28Robot arm 30Print head 32Inkjet print head 34Activation unit 36Reservoir 38Masking path 42Basecoat layer 44Parting line

Claims

1. Painting method for painting an aircraft component (10), with the steps in the following order: 1.1 Providing the component (10); 1.2 applying a film-forming masking agent (16) to areas by printing the masking agent (16) onto the aircraft component (10) using a print head (30) to create at least one masked surface area (24); 1.3 Allowing to form or forming a masking film (18) from the masking agent (16); 1.4 Painting the aircraft component (10) with a paint (20); and 1.5 applying a topcoat layer (22) to the paint (20), the topcoat layer (22) reducing the adhesion of the masking film (18); 1.6 Mechanically removing the masking film (18) from the aircraft component (10) to expose the masked surface area (24).

2. Method according to claim 1, wherein in step 1.1 the aircraft component (10) is or will be provided with a base (12).

3. Method according to 1 of the preceding claims, wherein in step 1.1 a further layer (14) is applied to the aircraft component material or to the substrate (12).

4. A method according to any one of the preceding claims, wherein the masking agent (16) printed in step 1.2 is a liquid film-forming masking agent (16), preferably a spray film liquid, a printing ink or a liquid mold release agent.

5. Method according to any of the preceding claims, wherein in step 1.3 the masking film (18) is formed by allowing solvent to evaporate from the masking agent (16) or by activating the masking agent (16) by heating or by irradiation.