Defect repairing method for automotive liquid damping spraying material

Abstract

The invention belongs to the technical field of automobile paint surface repairing, and discloses an automobile liquid damping spraying material defect repairing method which comprises the following steps: driving a defective automobile body into an off-line room for reconditioning, and selecting a repairing method according to a station and a repairing area; the method specifically comprises the following steps: scraping a defective part; shaping the appearance of the repaired part by using a shaping tool; pouring the LASD material for repairing on a scraper, uniformly smearing the LASD material on the surface to be repaired, and uniformly and stably scraping the surface to be repaired; removing and cleaning the shaping tool; after repairing is finished, the LASD wet film thickness is measured, or whether obvious defects exist or not is checked after the repaired part is dried, and if the wet film thickness does not reach the standard or the repaired part has defects, repairing needs to be conducted again. According to the method, the problem of stop caused by off-line repair is avoided, the repair method ensures the size, thickness and appearance of the liquid damping spraying surface, the influence of a poor repair method on subsequent procedures is eliminated, and the quality of a body in white and the precision of the whole vehicle are improved.

Description

Technical Field

[0001] This invention belongs to the field of automotive paint repair technology, specifically relating to a method for repairing defects in automotive liquid damping spray coating materials. Background Technology

[0002] With the increasing popularity of automobiles, customers are paying more and more attention to the performance and quality of car bodies, and in-vehicle noise has become a focal point for customers. Currently, there are two commonly used damping and sound insulation materials: traditional pre-formed asphalt sheet damping pads that require manual installation, and liquid applied sound deadeners (LASD) that are automatically sprayed by robots. Compared with traditional asphalt pads, LASD materials have advantages such as light weight, low odor, excellent damping performance, and good workability. They are not limited by material forming or sheet metal surface factors, and contribute significantly to environmental protection and lightweighting, gradually becoming the mainstream technology in the industry. LASD material itself is a high-viscosity liquid colloid, which is formed after drying. Its performance is related to the spraying position, shape, and size. The automotive industry uses automated robotic spraying to achieve high-quality spraying. However, in actual production, there are still process problems such as cracking, bubbling, and uneven spraying. In particular, some defects only appear after drying, affecting the actual quality and appearance of the car body. Due to the stringent requirements on the spraying position and dimensions of the LASD spraying process, it cannot be performed manually at a station like the traditional asphalt pad process; nor can it be repaired like adhesive materials by simply filling in the coating defects. LASD material repair must ensure the accuracy of material dimensions and position, consider various process states before and after drying, and avoid excessive disruption to the production cycle. Therefore, the need for a LASD repair process that guarantees normal workability and spraying quality on the vehicle body is particularly important.

[0003] The current mainstream coating production process mainly follows these steps: pretreatment electrophoresis → fixture replacement → masking → base plate protection → manual glue application → masking removal → robot GADin → robot LASD (automatic station) → fine sealing → glue drying → electrophoretic sanding → topcoat 1 → topcoat 2 → topcoat drying → finishing → waxing. Generally, after the automatic station robot LASD process is debugged, major quality problems will not occur. However, if sudden or occasional LASD quality defects occur due to equipment malfunctions, the coating professionals must have the ability to repair them, as production line rework will cause downtime. Summary of the Invention

[0004] This invention proposes a method for repairing defects in automotive liquid damping spray coating materials. Through offline repair, it does not interrupt production cycles and avoids the problem of downtime caused by rework on the production line. At the same time, through this system and professional repair method, the size, thickness and appearance of the liquid damping spray coating surface are guaranteed, eliminating the possible impact on subsequent processes caused by poor repair methods, and improving the quality of the body-in-white and the overall vehicle finish.

[0005] The specific details of the plan are as follows:

[0006] A method for repairing defects in automotive liquid damping spray coating materials, comprising the following steps:

[0007] S1. Enter the LASD defective car body into the offline workshop for preparation, check the work station where the defect appears and the size of the area that needs to be repaired, and select the appropriate repair method.

[0008] S2. The specific repair steps include:

[0009] S201. Use a clean scraper to clean the defective area;

[0010] S202. Use a shaping tool to shape the area to be repaired / filled;

[0011] S203. Pour the LASD material for repair onto the scraper and apply it evenly to the surface of the car body that needs to be repaired. Make a suitable angle between the scraper and the surface of the car body, and use a uniform and stable force to scrape the surface flat, repairing / filling the required parts smoothly.

[0012] S204. Remove the shaping tools and clean any excess LASD material from the vehicle body;

[0013] S205. Depending on the repair method, after the repair is completed, measure the wet film thickness of the LASD spray or check for obvious defects after the repaired area is dried. Ensure that the wet film thickness meets the standard requirements. If it does not meet the standard requirements or has defects, it needs to be repaired again with LASD material.

[0014] This invention primarily addresses the rework issue of defects appearing after LASD coating, such as forks, blistering, and cracking. The specific repair criteria for a single LASD strip are as follows: if the repair area is ≤3cm², no special repair is needed; if 3cm² < repair area < 70% of the total area, partial repair is required; if the repair area ≥ 70% of the total area, full repair is required. When defects appear at the fine sealing station or electrophoretic sanding station, and when 3cm² < repair area < 70% of the total area, repair must be completed within 24 hours to prevent quality issues in other parts of the vehicle body due to incomplete drying. If a LASD defect is found at the fine sealing station, the repair state is a wet film; if a defect is found at the electrophoretic sanding station, the repair state is a surface-dried film, and the LASD is semi-dry before the topcoat drying oven. Before the topcoat drying oven, the vehicle body with the LASD defect is brought into the offline preparation room for repair using steps S201-S205. In step S202, washi tape is used to shape the area to be repaired and filled. This invention uses yellow washi tape. Washi tape is made from washi paper, has a soft paper surface, moderate adhesion, and leaves no residue after removal. The width of the yellow washi tape should be as consistent as possible with the width of the LASD spraying area to be repaired, and its length should be the same as the length of the repair area. When the defect occurs at the fine sealing station or electrophoretic polishing station, and when the repair area is ≥70% of the total area, step S202 uses a special mold to shape the area to be repaired and filled. In step S203, after shaping, the LASD material for repair is poured onto a scraper, and then the scraper is used to evenly apply the LASD material to the surface of the car body that needs repair. Use a scraper to gradually smooth the LASD material, maintaining a 25-35 degree angle (approximately 30 degrees) between the scraper and the vehicle surface. Apply even and consistent pressure to smooth the surface, ensuring a uniform and smooth finish after repairing or filling any missing areas, avoiding scraping marks or unevenness. Use any existing production line material for the LASD repair. After repair in step S204, remove the masking tape used for shaping. During removal, avoid bumping or damaging the repaired area or other areas that might affect the thickness. If accidentally bumped, smooth the surface again with a scraper. After removal, use a non-woven cloth dampened with pure water to wipe away any excess LASD material from the vehicle body that might affect subsequent assembly processes. In step S205, after repair, measure the wet film thickness of the repaired LASD coating, maintaining it at 2-3 mm. If the thickness deviates significantly from the standard after measurement, additional LASD material needs to be applied.

[0015] If LASD defects need to be repaired at the finishing station, and the repair condition is a dry film after the topcoat drying oven, the LASD is completely dry, making repair more difficult. When the on-site assessment indicates that the defect area is less than 3cm² and less than 70% of the total area, the method in steps S202-S205 is used for repair. This means that scraping the defective area with a scraper is unnecessary. In S202, yellow washi tape is used to shape the area to be repaired. In step S205, an infrared oven lamp is used to bake the area for 30 minutes at a temperature of 140℃. After drying, the repaired area is checked to ensure there are no other obvious defects.

[0016] When the repair station repairs LASD defects and the on-site determination is that the repair area is ≥ 70% of the total area, the repair is carried out using the methods in steps S202-S205. In step S202, a special template is used to shape the shape of the part to be repaired and filled.

[0017] Furthermore, the work stations where defects occur include fine sealing, electrophoretic polishing, and finishing. The specific repair criteria for a single LASD strip are as follows: if the repair area is ≤3cm2, no special repair is required; if 3cm2 < repair area < 70% of the total area, partial repair is required; if the repair area is ≥70% of the total area, full repair is required.

[0018] Furthermore, LASD repair materials are used in LASD spraying production lines.

[0019] Furthermore, the scraper used for repair is 40mm wide.

[0020] Furthermore, the angle between the scraper and the car body surface ranges from 25° to 35°.

[0021] Furthermore, when the defect occurs at the fine sealing station / electrophoretic polishing station, the repair operation must be completed within 24 hours. The repair method for defects occurring at the fine sealing station / electrophoretic polishing station includes steps S201-S205. In step 205, after the repair is completed, the wet film thickness of the repaired LASD spray is measured, and the wet film thickness is maintained at 2-3mm. If it is not reached, it needs to be repaired again with LASD material.

[0022] Furthermore, when the defect occurs at a finishing station, the repair method includes steps S202-S205. In step S205, after the repair is completed, the repaired area is baked with an infrared lamp for 30 minutes at a temperature of 140°C. After drying, check whether there are any obvious defects. If there are defects, they need to be repaired again with LASD material.

[0023] Furthermore, when the defect occurs at a fine sealing station and / or an electrophoretic polishing station and / or a finishing station, and 3cm2 < the repair area < 70% of the total area, step S202 uses washi tape to shape the shape of the part to be repaired and filled.

[0024] Furthermore, when the defect occurs at a fine sealing station and / or an electrophoretic polishing station and / or a finishing station, and the repair area is ≥ 70% of the total area, step S202 uses a special mold to bond and shape the required repair and filling part.

[0025] Furthermore, the special mold is a rectangular shell made of PP material with open top and bottom ends. The length of the rectangular shell matches the length of the repair area, the width is 70mm, the height is 30mm, and the wall thickness of the shell is 2mm. When the repair area is ≥ 70% of the entire area, after the special mold is used to bond and shape the area in step S202, the required repair / filling part is all located inside the shell.

[0026] Preferably, the length of the rectangular shell in this invention matches the length of the repair area, with a width of 70mm, a height of 30mm, and a wall thickness of 2mm. When the repair area is ≥ 70% of the total area, after bonding and shaping using a special mold in step S202, the required repair / filling portion is entirely located within the shell. Adjustments can be made as needed in practical applications, but these dimensional adjustments should not affect the inventiveness of this invention.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] This invention enables offline repair without disrupting production cycles, thus avoiding downtime caused by rework on the production line. At the same time, this system and professional repair methods ensure the size, thickness, and appearance of the liquid damping sprayed surface, eliminating the potential impact on subsequent processes caused by poor repair methods, and improving the quality of the body-in-white and the overall vehicle finish. Attached Figure Description

[0029] Figure 1 These are before-and-after comparison images of the defective areas being scraped clean according to the present invention.

[0030] Figure 2 This is a before-and-after comparison of the repair process using washi tape for shaping according to the present invention.

[0031] Figure 3 These are before-and-after comparison images of the repair process using a special mold, as described in this invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0034] It should be noted that the terms "front", "rear", "inner", "outer", "left", "right", etc., used in this invention to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] It is particularly important to note that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals. The following section will discuss this further. Figure 1 , Figure 2 and Figure 3 The present invention will now be described in detail.

[0036] Example 1:

[0037] A forked defect was found in the LASD strip at the fine sealing station. The repair condition was a wet film before the topcoat drying oven. When the on-site assessment determined that the defect was less than 3cm² and the repair area was less than 70% of the total strip area, the specific repair steps are as follows:

[0038] 1. Car bodies with LASD defects are sent to the offline workshop for repair, and the repair operation is completed within 24 hours to prevent other parts of the car body from causing quality problems due to incomplete drying;

[0039] 2. See Figure 1 As shown, use a clean 40mm wide scraper to scrape the defective area clean. A small amount of residual material is allowed in the repaired area. For contamination in other areas, wipe clean with a non-woven cloth dampened with pure water.

[0040] 3. See Figure 2 As shown, use yellow masking tape to shape the area to be filled. This type of tape has moderate adhesion and good workability. It can be quickly removed after use without leaving any residue. The masking width should be as consistent as possible with the width of the spray coat, and the length should be consistent with the requirements of the drawing.

[0041] 4. LASD repair material uses the material used in the LASD spraying production line. After the material is shaped, pour the LASD material for repair onto the scraper. Then, use the scraper to evenly apply the LASD material to the surface of the car body that needs to be repaired. Use the scraper to gradually smooth the LASD material, keeping the scraper at an angle of about 30 degrees to the surface of the car body. Use even and stable force to smooth the surface to ensure that the LASD material after repairing or filling the missing part is even and flat, and to avoid the appearance of knife marks or unevenness.

[0042] 5. After the repair is completed, remove the paper tape used for shaping. When removing it, do not bump the repair or other areas that may affect the thickness. If it is accidentally bumped, it should be smoothed again with a scraper. After removal, use a non-woven cloth dampened with pure water to wipe off any excess LASD material on the car body that may affect the subsequent assembly process.

[0043] 6. After the repair is completed, use a ruler to measure the thickness of the repaired LASD coating. Keep it at 2-3mm for wet film. If the thickness differs significantly from the standard after measurement, LASD material needs to be reapplied.

[0044] Example 2:

[0045] When a LASD defect is found at the fine sealing station, and the repair condition is a wet film before the topcoat drying oven, if the on-site assessment determines that the repair area is ≥ 70% of the total area, the specific repair steps are as follows:

[0046] 1. Car bodies with LASD defects are sent to the offline workshop for repair, and the repair operation is completed within 24 hours to prevent other parts of the car body from causing quality problems due to incomplete drying;

[0047] 2. See Figure 1 As shown, use a clean 40mm wide scraper to completely scrape away the defect along the entire LASD. A small amount of residual material is allowed in the repaired area. For contamination in other areas, wipe clean with a non-woven cloth dampened with pure water.

[0048] 3. See Figure 3 As shown, a special mold for LASD repair is used to shape the part to be repaired / filled. The part to be repaired / filled is inside the shell of the special mold. The special mold is fixed by washi tape and can be quickly removed after use without leaving any residue. The special mold is a rectangular shell made of PP material with open top and bottom ends. The length of the rectangular shell matches the length of the repair area, the width is 70mm, the height is 30mm, and the wall thickness of the shell is 2mm.

[0049] 4. LASD repair material uses the material used in the LASD spraying production line. After the material is shaped, pour the LASD material for repair onto the scraper. Then, use the scraper to evenly apply the LASD material to the surface of the car body that needs to be repaired. Use the scraper to gradually smooth the LASD material, keeping the scraper at an angle of about 30 degrees to the surface of the car body. Use even and stable force to smooth the surface to ensure that the LASD material after repairing or filling the missing part is even and flat, and to avoid the appearance of knife marks or unevenness.

[0050] 5. After the repair is completed, remove the washi tape used for shaping and take off the special mold. When removing it, do not bump the repair or other areas that may affect the thickness. If it is accidentally bumped, it should be smoothed again with a scraper. After removal, use a non-woven cloth dampened with pure water to wipe off any excess LASD material on the car body that may affect the subsequent assembly process.

[0051] 6. After the repair is completed, use a ruler to measure the thickness of the repaired LASD coating. Keep it at 2-3mm for wet film. If the thickness differs significantly from the standard after measurement, LASD material needs to be reapplied.

[0052] Example 3:

[0053] A LASD defect was found at the electrophoretic polishing station. The repair condition was a surface-dried film before the topcoat drying oven, at which point the LASD was semi-dry. When the on-site assessment determined that the defect was less than 3cm² < the repair area < 70% of the total area, the specific repair steps are as follows:

[0054] 1. Car bodies with LASD defects are sent to the offline workshop for repair, and the repair operation is completed within 24 hours to prevent other parts of the car body from causing quality problems due to incomplete drying;

[0055] 2. See Figure 1 As shown, use a clean 40mm wide scraper to scrape the defective area clean. A small amount of residual material is allowed in the repaired area. For contamination in other areas, wipe clean with a non-woven cloth dampened with pure water.

[0056] 3. See Figure 2 As shown, use yellow masking tape to shape the area to be filled. This type of tape has moderate adhesion and good workability. It can be quickly removed after use without leaving any residue. The masking width should be as consistent as possible with the width of the spray coat, and the length should be consistent with the requirements of the drawing.

[0057] 4. LASD repair material uses the material used in the LASD spraying production line. After the material is shaped, pour the LASD material for repair onto the scraper. Then, use the scraper to evenly apply the LASD material to the surface of the car body that needs to be repaired. Use the scraper to gradually smooth the LASD material, keeping the scraper at an angle of about 30 degrees to the surface of the car body. Use even and stable force to smooth the surface to ensure that the LASD material after repairing or filling the missing part is even and flat, and to avoid the appearance of knife marks or unevenness.

[0058] 5. After the repair is completed, remove the paper tape used for shaping. When removing it, do not bump the repair or other areas that may affect the thickness. If it is accidentally bumped, it should be smoothed again with a scraper. After removal, use a non-woven cloth dampened with pure water to wipe off any excess LASD material on the car body that may affect the subsequent assembly process.

[0059] 6. After the repair is completed, use a ruler to measure the thickness of the repaired LASD coating. Keep it at 2-3mm for wet film. If the thickness differs significantly from the standard after measurement, LASD material needs to be reapplied.

[0060] Example 4:

[0061] A LASD defect was found at the electrophoretic polishing station. The repair condition was a surface-dried film before the topcoat drying oven, at which point the LASD was in a semi-dry state. When the on-site assessment determined that the repair area was ≥ 70% of the total area, the specific repair steps were as follows:

[0062] 1. Car bodies with LASD defects are sent to the offline workshop for repair, and the repair operation is completed within 24 hours to prevent other parts of the car body from causing quality problems due to incomplete drying;

[0063] 2. See Figure 1 As shown, use a clean 40mm wide scraper to scrape the defective area clean. A small amount of residual material is allowed in the repaired area. For contamination in other areas, wipe clean with a non-woven cloth dampened with pure water.

[0064] 3. See Figure 3 As shown, see Figure 3 As shown, a special mold for LASD repair is used to shape the part to be repaired / filled. The part to be repaired / filled is inside the shell of the special mold. The special mold is fixed by washi tape and can be quickly removed after use without leaving any residue. The special mold is a rectangular shell made of PP material with open top and bottom ends. The length of the rectangular shell matches the length of the repair area, the width is 70mm, the height is 30mm, and the wall thickness of the shell is 2mm.

[0065] 4. LASD repair material uses the material used in the LASD spraying production line. After the material is shaped, pour the LASD material for repair onto the scraper. Then, use the scraper to evenly apply the LASD material to the surface of the car body that needs to be repaired. Use the scraper to gradually smooth the LASD material, keeping the scraper at an angle of about 30 degrees to the surface of the car body. Use even and stable force to smooth the surface to ensure that the LASD material after repairing or filling the missing part is even and flat, and to avoid the appearance of knife marks or unevenness.

[0066] 5. After the repair is completed, remove the paper tape used for shaping and take off the special mold. When removing it, do not bump the repair or other areas that may affect the thickness. If it is accidentally bumped, it should be smoothed again with a scraper. After removal, use a non-woven cloth dampened with pure water to wipe off any excess LASD material on the car body that may affect the subsequent assembly process.

[0067] 6. After the repair is completed, use a ruler to measure the thickness of the repaired LASD coating. Keep it at 2-3mm for wet film. If the thickness differs significantly from the standard after measurement, LASD material needs to be reapplied.

[0068] Example 5:

[0069] When a LASD defect occurs at the finishing station, and the repair condition is a dry film after the topcoat drying oven, at which point the LASD is completely dry, and the on-site assessment indicates that the defect is less than 3cm² and the repair area is less than 70% of the total area, the specific repair steps are as follows:

[0070] 1. Vehicles with LASD defects are sent to the offline maintenance room for repair;

[0071] 2. Use yellow masking tape to shape the area to be filled. This type of tape has moderate adhesion and good workability. It can be quickly removed after use without leaving any residue. The masking width should be as consistent as possible with the width of the spraying pass, and the length should be consistent with the requirements of the drawing.

[0072] 3. LASD repair material uses the material used in the LASD spraying production line. After the material is shaped, the LASD material for repair is poured onto a scraper. Then, the scraper is used to evenly apply the LASD material to the surface of the car body that needs to be repaired. The scraper is used to gradually smooth the LASD material, keeping the scraper at an angle of about 30 degrees to the surface of the car body. The surface is smoothed with a uniform and stable force to ensure that the LASD material after repairing or filling the missing part is uniform and flat, and to avoid the appearance of knife marks or unevenness.

[0073] 4. After the repair is completed, remove the paper tape used for shaping. When removing it, do not bump the repair or other areas that may affect the thickness. If it is accidentally bumped, it should be smoothed again with a scraper. After removal, use a non-woven cloth dampened with pure water to wipe off any excess LASD material on the car body that may affect the subsequent assembly process.

[0074] 5. Then bake with an infrared lamp for 30 minutes at a temperature of 140℃. After drying, check the repaired area for any other obvious defects. If there are any obvious defects, they need to be repaired again.

[0075] Example 6:

[0076] If a LASD defect occurs at the finishing station, and the repair condition is a dry film after the topcoat drying oven, at which point the LASD is completely dry, and the on-site assessment determines that the repair area is ≥ 70% of the total area, the specific repair steps are as follows:

[0077] 1. Vehicles with LASD defects are sent to the offline maintenance room for repair;

[0078] 2. See Figure 3 As shown, a special mold for LASD repair is used to shape the part to be repaired / filled. The part to be repaired / filled is inside the shell of the special mold. The special mold is fixed by washi tape and can be quickly removed after use without leaving any residue. The special mold is a rectangular shell made of PP material with open top and bottom ends. The length of the rectangular shell matches the length of the repair area, the width is 70mm, the height is 30mm, and the wall thickness of the shell is 2mm.

[0079] 3. LASD repair material uses the material used in the LASD spraying production line. After the material is shaped, the LASD material for repair is poured onto a scraper. Then, the scraper is used to evenly apply the LASD material to the surface of the car body that needs to be repaired. The scraper is used to gradually smooth the LASD material, keeping the scraper at an angle of about 30 degrees to the surface of the car body. The surface is smoothed with a uniform and stable force to ensure that the LASD material after repairing or filling the missing part is uniform and flat, and to avoid the appearance of knife marks or unevenness.

[0080] 4. After the repair is completed, remove the paper tape used for shaping and take off the special mold. When removing it, do not bump the repair or other areas that may affect the thickness. If it is accidentally bumped, it should be smoothed again with a scraper. After removal, use a non-woven cloth dampened with pure water to wipe off any excess LASD material on the car body that may affect the subsequent assembly process.

[0081] 5. Then bake with an infrared lamp for 30 minutes at a temperature of 140℃. After drying, check the repaired area for any other obvious defects. If there are any obvious defects, they need to be repaired again.

[0082] The above embodiments are provided only to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for repairing defects in automotive liquid damping spray coating materials, characterized by the following steps: include: S1. Enter the LASD defective car body into the offline workshop for preparation, check the work station where the defect appears and the size of the area that needs to be repaired, and select the appropriate repair method. S2. The specific repair steps include: S201. Use a clean scraper to clean the defective area; S202. Use a shaping tool to shape the area to be repaired / filled; S203. Pour the LASD material for repair onto the scraper and apply it evenly to the surface of the car body that needs to be repaired. Make a suitable angle between the scraper and the surface of the car body, and use a uniform and stable force to smooth the surface and repair / fill the required parts. S204. Remove the shaping tools and clean any excess LASD material from the vehicle body; S205. Depending on the repair method, after the repair is completed, measure the wet film thickness of the LASD spray or check for obvious defects after the repaired area is dried. Ensure that the wet film thickness meets the standard requirements. If it does not meet the standard requirements or has defects, it needs to be repaired again with LASD material.

2. The method for repairing defects in automotive liquid damping spray coating material according to claim 1, characterized in that, The work stations where defects occur include the fine sealing work station, the electrophoretic polishing work station, and the finishing work station. The specific repair judgment criteria for a single LASD strip are as follows: if the repair area is ≤3cm2, no special repair is required; if 3cm2 < repair area < 70% of the total area, partial repair is required; if the repair area is ≥70% of the total area, full repair is required.

3. The method for repairing defects in automotive liquid damping spray coating material according to claim 2, characterized in that, LASD repair material is used in LASD spraying production lines.

4. The method for repairing defects in automotive liquid damping spray coating material according to claim 3, characterized in that, The scraper used for repair is 40mm wide.

5. The method for repairing defects in automotive liquid damping spray coating material according to claim 4, characterized in that, The angle between the scraper and the car body surface ranges from 25° to 35°.

6. The method for repairing defects in automotive liquid damping spray coating material according to claim 5, characterized in that, When the defect occurs at the fine sealing station / electrophoretic polishing station, the repair operation must be completed within 24 hours. The repair method for the defect occurring at the fine sealing station / electrophoretic polishing station includes steps S201-S205. In step 205, after the repair is completed, the wet film thickness of the repaired LASD spray is measured, and the wet film thickness is maintained at 2-3mm. If it is not reached, it needs to be repaired again with LASD material.

7. The method for repairing defects in automotive liquid damping spray coating material according to claim 5, characterized in that, When the defect occurs at the finishing station, the repair method includes steps S202-S205. In step S205, after the repair is completed, the repaired area is baked with an infrared lamp for 30 minutes at a temperature of 140°C. After drying, check whether there are any obvious defects. If there are defects, they need to be repaired again with LASD material.

8. The method for repairing defects in automotive liquid damping spray coating material according to claim 5, characterized in that, When the defect occurs at a fine sealing station and / or an electrophoretic polishing station and / or a finishing station, and 3cm2 < the repair area < 70% of the total area, step S202 uses washi tape to shape the shape of the part to be repaired and filled.

9. The method for repairing defects in automotive liquid damping spray coating material according to claim 5, characterized in that, When the defect occurs at a fine sealing station and / or an electrophoretic polishing station and / or a finishing station, and the repair area is ≥ 70% of the total area, step S202 uses a special mold to bond and shape the required repair / filling part.

10. The method for repairing defects in automotive liquid damping spray coating material according to claim 9, characterized in that, The special mold is a rectangular shell made of PP material with open top and bottom ends. The length of the rectangular shell matches the length of the repair area, the width is 70mm, the height is 30mm, and the wall thickness of the shell is 2mm. When the repair area is ≥ 70% of the total area, after the special mold is used to bond and shape the area in step S202, the required repair / filling part is all located inside the shell.

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