Front edge protection film coating method for avoiding coating wrinkles

Abstract

The application belongs to the technical field of wind power blade protection, and specifically discloses a front edge protection film coating method capable of avoiding coating wrinkles, mainly comprising the following steps: cleaning the blade front edge area, marking the positioning point, laying the sealant, preparing and laying the reinforcing glass fiber cloth, cutting and pasting the front edge protection film and eliminating wrinkles, establishing a vacuum system, vacuumizing, heating and curing, and cleaning, etc. The cutting of the front edge protection film before laying can effectively avoid the generation of defects such as coating wrinkles, edge lifting, and waves, and improve the appearance quality and protection performance of the front edge protection film. Meanwhile, the rework caused by wrinkles, edge lifting and other defects of the front edge protection film is reduced, the construction efficiency of the blade post-processing is improved, the material scrap rate is reduced, and the application cost of the protection film is reduced. The method does not need to pre-heat the protection film and pre-shape the blade front edge, reduces the construction process, and further improves the coating efficiency of the protection film.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine blade protection technology, and particularly relates to a method for applying a leading edge protective film to avoid coating wrinkles. Background Technology

[0002] With the rapid development of the offshore wind power industry, the tip linear velocity of wind turbine blades has significantly increased, currently reaching a high level of 95 meters per second. This high-speed environment causes the leading edge of the blades to suffer continuous rain erosion and particle impact, leading to serious corrosion problems. This not only reduces the power generation efficiency of the unit but may also induce blade structural damage, posing a potential threat to the safe and stable operation of wind farms. Traditional leading edge protective paints, due to limitations in material properties, lack sufficient rain erosion resistance and cannot meet the long-term protection requirements of modern large wind turbine blades. In contrast, leading edge protective films, with their superior mechanical strength and weather resistance, are gradually becoming the mainstream choice for the protection of ultra-large blades.

[0003] Existing coating processes mainly fall into two categories: one involves directly bonding the pressure-sensitive adhesive on the inner surface of the protective film to the leading edge of the blade, and sealing the edges with edge-sealing adhesive, with each film overlapping to form a continuous protective layer; the other combines this with the blade leading edge reinforcement process, using a hand lay-up process to heat and cure epoxy resin-impregnated fiberglass cloth and the protective film together. However, the protective film used in the second process is usually not customized based on the three-dimensional shape of the blade, and the film is a single piece rather than segmented overlaps. In actual operation, it is necessary to pre-soften local areas of the protective film with a hot air gun before pre-applying it to the leading edge of the blade tip to adapt to the high curvature shape. This process requires a high level of operator skill and is prone to wrinkles, curling, and wavy defects during the application process, especially in high curvature areas such as the blade tip, where the coating failure rate is high, leading to frequent rework and repairs, seriously hindering coating efficiency and quality stability. Currently, the domestic wind power industry is limited by technical conditions and generally relies on the second coating process. However, its inherent process is not adaptable to the high curvature blade tip area, and is prone to defects such as wrinkles, curling edges and waves. This makes it impossible for the protective film to be flat and adhered, making it difficult to fully exert its protective effect. It also causes the scrapping of the installed protective film and waste of materials. At the same time, the additional hot baking and pre-forming steps complicate the construction process, significantly increase the coating cost and reduce the overall efficiency.

[0004] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a method for coating a leading edge protective film that avoids coating wrinkles. This method can effectively prevent wrinkles from forming during the coating process, ensure a smooth and even application of the protective film, and improve the coating success rate and protective effect. It solves the problem that the protective film is not evenly applied in existing film application processes, making it difficult to fully exert its protective effectiveness.

[0006] To achieve the above objectives, the technical solution of the present invention is: a method for applying a leading edge protective film to avoid coating wrinkles, the method specifically including the following steps:

[0007] S1. Clean the dust in the film application area set at the leading edge of the blade and remove the release cloth corresponding to the film application area;

[0008] S2. Mark multiple positioning points on the PS and SS surfaces of the film-coating area of ​​the blade at intervals of 0.5m, and connect the multiple positioning points on the PS and SS surfaces respectively to form positioning lines.

[0009] S3. Apply a ring of sealant around the perimeter of the film application area;

[0010] S4. Apply the hand lay-up resin evenly onto the fiberglass until it is completely saturated. Then use a scraper to remove the excess hand lay-up resin to make a reinforcing fiberglass cloth for later use.

[0011] S5. Lay the set number of reinforcing fiberglass cloth layers in the film application area set by the positioning line on the blade.

[0012] S6. According to the position of the positioning line, unfold the leading edge protective film from the leaf root to the leaf tip, flatten it and stick it to the film application area of ​​the leaf.

[0013] S7. After the front edge protective film is laid, lay the release cloth on the surface of the blade. Place the release cloth symmetrically on the PS and SS surfaces of the blade. After laying, the release cloth covers the front edge protective film and the hand lay-up reinforcing cloth.

[0014] S8. Lay out the guide net, spiral tube and vacuum bag to establish a vacuum system;

[0015] S9. Vacuum the area where the film is applied;

[0016] S10. Heat and cure the film-applied area;

[0017] S11. Clean the surface of the area where the film is applied.

[0018] Furthermore, in step S6, the method for applying the leading edge protective film is as follows:

[0019] Determine the start and end points of the cut. Based on the start and end points, cut the leading edge protective film from the PS surface to the SS surface. The start point of the cut is located at the edge of the leading edge protective film corresponding to the SS surface, and the distance from the start point of the cut to the edge of the leading edge protective film corresponding to the blade tip is 0.3-0.7m. The end point of the cut is located at the SS surface of the leading edge protective film, and the distance from the end point of the cut to the parting line of the leading edge protective film corresponding to the blade is no more than 20mm.

[0020] According to the positioning lines, paste and fix the cut leading edge protective film to the film application area of ​​the blade. Check the degree of adhesion between the leading edge protective film and the blade at fixed intervals. If there are wrinkles in the leading edge protective film, stop pasting and fix the leading edge protective film, and re-paste the wrinkled area until the wrinkles are eliminated.

[0021] Furthermore, in step S8, the establishment of the vacuum system specifically includes the following steps:

[0022] S81. Guide nets are arranged on the PS and SS surfaces of the blade respectively. The distance from any guide net to the corresponding sealing strip is 20mm-50mm, and the distance from any guide net to the edge of the corresponding leading edge protective film is greater than 50mm.

[0023] S82. Arrange spiral tubes at the middle positions of the guide nets corresponding to the PS and SS surfaces of the blades respectively.

[0024] S83. An air extraction port is set at the middle position of the leading edge protective film corresponding to the PS surface and SS surface of the blade, and the air extraction port is connected to the mobile vacuum pump through a vacuum nylon tube. The air extraction port is sealed with sealant.

[0025] S84. Attach the vacuum bag according to the circumferential sealant position of the leaf film application area, and press the vacuum bag to make it adhere tightly;

[0026] S85. The surface wrinkles or wavy patterns of the leading edge protective film are eliminated by rolling and pressing to ensure the surface flatness of the leading edge protective film.

[0027] Furthermore, in step S9, the vacuum level of the vacuum bag is set to be less than -90 kPa.

[0028] Furthermore, in step S10, the heating temperature for heat curing is 50-70°C, and the heating time is at least 4 hours.

[0029] The beneficial effects of this technical solution are as follows:

[0030] This invention discloses a method for applying a leading-edge protective film to avoid coating wrinkles. The method involves steps such as cleaning the leading edge area of ​​the blade, marking positioning points, applying sealant, preparing and laying reinforcing fiberglass cloth, cutting and pasting the leading-edge protective film and eliminating wrinkles, establishing a vacuum system, vacuuming, heat curing, and cleaning. Combined with pre-cutting of the leading-edge protective film, this method effectively avoids defects such as coating wrinkles, curling edges, and wavy edges, improving the appearance quality and protective performance of the leading-edge protective film. Simultaneously, it reduces rework caused by wrinkles and curling edges, improves the efficiency of blade post-processing, reduces material scrap rates, and lowers the application cost of the protective film. Compared to existing processes, this method eliminates the need for pre-heating the protective film and pre-shaping the leading edge of the blade, reducing construction steps and further improving coating efficiency. This effectively improves coating quality, reduces rework rates, saves materials, simplifies processes, and increases production efficiency. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the operation of a leading edge protective film coating method for avoiding coating wrinkles according to the present invention.

[0032] Figure 2 This is a schematic diagram of the cutting of the leading edge protective film of the present invention. Detailed Implementation

[0033] The following detailed description illustrates the specific implementation method:

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Figure 2 In the diagram, point S is the starting point of the cut, point E is the ending point of the cut, R is the blade root side, T is the blade tip side, line PL is the parting line, PS refers to the PS surface (pressure surface) of the blade, SS refers to the SS surface (suction surface) of the blade, and the line connecting SE is the cutting path. This is something that those skilled in the art can understand, and will not be elaborated here.

[0036] The basic implementation examples are as follows: Figure 1-2 As shown: A method for applying a leading edge protective film to avoid coating wrinkles, the method specifically includes the following steps:

[0037] S1. Blade Cleaning and Surface Treatment: Clean the dust from the designated film-applying area and its surroundings at the leading edge of the blade. Wipe the film-applying area clean with a cotton cloth and remove the release cloth corresponding to the film-applying area. Use a utility knife, putty knife, or other tools to clean areas that are difficult to remove. In this embodiment, the film-applying area refers to the area of ​​the blade where the reinforcing fiberglass cloth and leading edge protective film need to be applied. Its actual size can be larger than the designed area for the reinforcing fiberglass cloth and leading edge protective film to allow sufficient space to ensure the application effect. Those skilled in the art can adjust the specific size according to the actual situation, but it should be ensured that it is not smaller than the area of ​​the blade where the reinforcing fiberglass cloth and leading edge protective film need to be applied.

[0038] S2. Marking Positioning Lines: Based on the designed leading edge reinforcing fiberglass cloth laying area and the leading edge protective film bonding position, mark a positioning point every 0.5m on the PS and SS surfaces corresponding to the film application area of ​​the blade, and connect the positioning points on the PS and SS surfaces respectively to form positioning lines in the corresponding planes; as a preferred embodiment, the position of the positioning line can be determined at a distance of 60mm from the mold parting line, or determined according to the single-side width parameter of the leading edge protective film. Those skilled in the art can adjust it according to the actual situation, which will not be elaborated here.

[0039] S3. Apply sealant: Apply a ring of sealant around the perimeter of the film application area; apply a ring of black sealant around the perimeter of the film application area. Specifically, the position of the black sealant along the axial direction is: 50mm beyond the film application area in the direction of the blade root, and pasted on the aluminum blade tip in the direction of the blade tip; the position of the black sealant along the chord direction is 250±20mm from the parting line of the leading edge.

[0040] S4. Preparation of reinforcing fiberglass cloth: On the operating platform, first use a roller to evenly coat the hand lay-up resin onto the fiberglass until the fiberglass is completely saturated. Then use a scraper to remove the excess hand lay-up resin to make reinforcing fiberglass cloth for later use.

[0041] S5. Reinforcing Fiberglass Cloth Laying: Based on the positioning line, lay reinforcing fiberglass cloth in the film application area at the leading edge of the blade. The specific number of layers should be implemented according to the design specifications. During the laying process, after each layer of fiberglass cloth is hand-laid, use a plastic scraper to flatten the reinforcing fiberglass cloth along the ±45° direction, then use an aluminum roller to remove air bubbles before hand-laying the next layer. At the same time, be careful to wipe away any dripping resin with a cloth until the laying is completed.

[0042] S6. Applying the Leading Edge Protective Film: Based on the position of the positioning line, unfold and flatten the leading edge protective film from the leaf root to the leaf tip and adhere it to the film application area on the leaf. During the application process, the leading edge protective film must be stretched taut. The specific application method for the leading edge protective film is as follows:

[0043] Determine the start and end points of the cut. The start point is located on the SS surface corresponding to the leading edge protective film, and cutting begins at the edge of the leading edge protective film. The distance l1 from the start point to the edge of the leading edge protective film on the blade tip side is 0.3-0.7m. The end point is located on the SS surface corresponding to the leading edge protective film, and the distance l2 from the end point to the parting line of the leading edge protective film is no greater than 20mm. Based on the start and end points, cut the leading edge protective film from the PS surface towards the SS surface. That is, take any point within 0.3-0.7m from the blade tip as the start point, and cut the leading edge protective film from the PS surface towards the SS surface. The furthest cutting distance from the end point should not exceed 20mm from the parting line, i.e., l2 ≤ 20mm. Figure 2 As shown. After the leading edge protective film is cut open, it can bend and fit better according to the curvature of the blade during the installation process, thus ensuring a smooth and wrinkle-free finish after installation.

[0044] Using masking tape, adhere the cut leading edge protective film to the film application area of ​​the blade according to the positioning lines. Check the protective film at fixed intervals to ensure it adheres well to the blade and does not wrinkle due to subsequent bag pressure. If wrinkles appear during the application process, stop applying the protective film and re-apply the wrinkled area until there are no wrinkles. In this embodiment, the set distance is 0.5m, but those skilled in the art can adjust this distance according to actual conditions.

[0045] Meanwhile, during the pasting process, check whether the periphery of the front protective film is flush with the positioning line. If it is not flush, stop pasting the front protective film and re-paste the front protective film in the uneven area until it is flush.

[0046] S7. Laying the release cloth: Lay the release cloth on the surface of the front edge protective film after it has been laid. Place the release cloth symmetrically on the PS and SS surfaces of the blade. After laying, the release cloth covers the front edge protective film and the reinforcing fiberglass cloth. Note that the release cloth should not be embedded under the protective film or the reinforcing fiberglass cloth.

[0047] S8. Establish a vacuum system: Lay out the flow guide net, spiral tube and vacuum bag to establish a vacuum system. Note that the paper tape for fixing the release cloth and flow guide net should overlap with the paper tape for fixing the protective film. Cut the flow guide net at the cut of the protective film and overlap it by 10mm.

[0048] The establishment of a vacuum system specifically includes the following steps:

[0049] S81. Guide meshes are arranged on the PS and SS surfaces of the blade, respectively. The distance from any guide mesh to the corresponding sealing strip is 20mm-50mm, and the distance from any guide mesh to the edge of the corresponding leading edge protective film is greater than 50mm. The guide meshes are attached to the leading edge area of ​​the blade in a dotted pattern with black adhesive every 1.5-2.5 meters.

[0050] S82. Spiral tubes are arranged at the middle positions of the guide nets corresponding to the PS and SS surfaces of the blade. The spiral tubes are fixed to the corresponding guide nets every 1-2 meters using sealant dots, and the spiral tubes are the same length as the corresponding guide nets. Spiral tubes within a 5m range of the blade tip are fixed with masking tape. In this embodiment, "corresponding" refers to a relative position, specifically meaning they are located at the same position. For example, "the spiral tube and the corresponding guide net are the same length" means that the spiral tube on the PS surface and the guide net on the PS surface are the same length. This is understandable to those skilled in the art and will not be elaborated further.

[0051] S83. An air extraction port is set at the middle position of the leading edge protective film corresponding to the PS surface and SS surface of the blade, and the air extraction port is connected to the mobile vacuum pump through a vacuum nylon tube. The air extraction port is sealed with sealing tape.

[0052] S84. Apply the vacuum bag to the circumferential sealing area along the leading edge of the blade, pressing it firmly with your fingers. If the lightning arrester and drain hole are located in the vacuum sealing area, they must be sealed separately with a separate bag film.

[0053] S85. After the vacuum system is established, you can touch the surface of the protective film with your hand or observe the smoothness through a flashlight. You can roll and press the film with a watercolor pen or other tools to eliminate wrinkles or wavy patterns. Afterwards, you must ensure the vacuum pressure and avoid depressurization.

[0054] S9. Vacuuming: Vacuum the film-coated area. During vacuuming, check the adhesion of the leading edge protective film to the shell, ensuring there are no wrinkles and that the release liner is not embedded under the reinforcing fiberglass cloth or the leading edge protective film. If wrinkles exist, smooth them out by hand. Simultaneously check the bag pressure vacuum level; it should reach below -90 kPa, and the pressure drop should not exceed 10 mbar after 10 minutes. Pay attention to the sealing of the lightning arrester and drainage hole positions on the blade leading edge. After bag pressure, check the leading edge protective film at the blade tip, smoothing out any wrinkles, focusing on the area within 3 meters of the blade tip. Simultaneously observe the seam condition of the release liner and vacuum film, addressing any issues promptly until all seams are eliminated.

[0055] S10. Heat Curing Treatment: The film-applied area is heat-cured. Before heat curing, it is necessary to confirm on-site that the surface of the leading edge protective film is free of wrinkles or other defects. Then, wrap the leading edge film-applied area with an electric blanket or other heating device, set the temperature to 50℃ for 4 hours, and maintain a vacuum below -90KPa to allow the reinforcing fiberglass cloth to cure and form a good bond with the leading edge protective film. As heating progresses, control the temperature not to exceed 70℃, ensuring the heat curing temperature is between 50-70℃ to prevent softening of the leading edge protective film. As a preferred implementation, the temperature can be controlled at a constant 60℃. After heat curing, samples are taken to test the Tg value (glass transition temperature) of the hand lay-up resin of the reinforcing fiberglass cloth. The median Tg value is required to be ≥70℃.

[0056] S11. Surface cleaning of the film application area: After heat curing, remove the surface auxiliary materials, check the quality of the protective film at the cutting position, and apply sealant or leading edge protective paint to the position for subsequent coating treatment. Continue to complete the post-treatment work of the protective film edge and paint.

[0057] Thus, by applying the leading edge protective film using this method, defects such as coating wrinkles, curling edges, and wavy lines can be effectively avoided, improving the appearance quality and protective performance of the leading edge protective film. Simultaneously, it reduces rework caused by defects such as wrinkles and curling edges, improves the efficiency of blade post-processing, reduces material scrap rates, and lowers the application cost of the protective film. This effectively improves coating quality, reduces rework rates, saves materials, simplifies processes, and increases production efficiency.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0059] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for applying a leading-edge protective film to avoid coating wrinkles, characterized in that, The method includes: S1. Clean the dust in the film application area set at the leading edge of the blade and remove the release cloth corresponding to the film application area; S2. Mark multiple positioning points on the PS and SS surfaces of the film-coating area of ​​the blade at intervals of 0.5m, and connect the multiple positioning points on the PS and SS surfaces respectively to form positioning lines. S3. Apply a ring of sealant around the perimeter of the film application area; S4. Apply the hand lay-up resin evenly onto the fiberglass until it is completely saturated. Then use a scraper to remove the excess hand lay-up resin to make a reinforcing fiberglass cloth for later use. S5. Lay the set number of reinforcing fiberglass cloth layers in the film application area set by the positioning line on the blade. S6. According to the position of the positioning line, unfold the leading edge protective film from the leaf root to the leaf tip, flatten it and stick it to the film application area of ​​the leaf. S7. After the front edge protective film is laid, lay the release cloth on the surface of the blade. Place the release cloth symmetrically on the PS and SS surfaces of the blade. After laying, the release cloth covers the front edge protective film and the hand lay-up reinforcing cloth. S8. Lay out the guide net, spiral tube and vacuum bag to establish a vacuum system; S9. Vacuum the area where the film is applied; S10. Heat and cure the film-applied area; S11. Clean the surface materials of the film application area and complete the subsequent surface optimization treatment.

2. The method for applying a protective film at the leading edge to avoid coating wrinkles according to claim 1, characterized in that: In step S6, the method for applying the leading edge protective film is as follows: Determine the start and end points of the cut. Based on the start and end points, cut the leading edge protective film from the PS surface to the SS surface. The start point of the cut is located at the position of the leading edge protective film corresponding to the SS surface, and the distance from the start point of the cut to the edge position of the leading edge protective film corresponding to the blade tip is 0.3-0.7m. The end point of the cut is located at the position of the leading edge protective film corresponding to the SS surface, and the distance from the end point of the cut to the parting line of the leading edge protective film corresponding to the blade is not greater than 20mm. According to the positioning lines, paste and fix the cut leading edge protective film to the film application area of ​​the blade. Check the degree of adhesion between the leading edge protective film and the blade at fixed intervals. If there are wrinkles in the leading edge protective film, stop pasting and fix the leading edge protective film, and re-paste the wrinkled area until the wrinkles are eliminated.

3. The method for applying a protective film to the leading edge to avoid coating wrinkles according to claim 1, characterized in that: Step S8, the establishment of the vacuum system specifically includes the following steps: S81. A guide net is arranged on the PS and SS surfaces of the blade respectively. The distance from any guide net to the corresponding sealing strip is 20mm-50mm, and the distance from any guide net to the edge of the corresponding leading edge protective film is greater than 50mm. S82. Arrange spiral tubes at the middle positions of the guide nets corresponding to the PS and SS surfaces of the blades respectively. S83. An air extraction port is set at the middle position of the leading edge protective film corresponding to the PS surface and SS surface of the blade, and the air extraction port is connected to the mobile vacuum pump through a vacuum nylon tube. The air extraction port is sealed with sealant. S84. Attach the vacuum bag according to the circumferential sealant position of the leaf film application area, and press the vacuum bag to make it adhere tightly; S85. The surface wrinkles or wavy patterns of the leading edge protective film are eliminated by rolling and pressing to ensure the surface flatness of the leading edge protective film.

4. The method for applying a protective film to the leading edge to avoid coating wrinkles according to claim 1, characterized in that: In step S9, the vacuum level of the vacuum bag is set to less than -90 kPa.

5. The method for applying a protective film to the leading edge to avoid coating wrinkles according to claim 1, characterized in that: In step S10, the heating temperature for curing is 50-70℃, and the heating time is at least 4 hours.

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