A method for detecting sealing performance of vehicle door edge

Abstract

The present invention relates to a method for detecting the sealing performance of vehicle door hemming. The method comprises the following steps: immersing a vehicle door to be tested in a fluorescent solution and then drying the solution; removing the coating sealant at the hemming of the vehicle door to be tested, wetting the coating sealant, and then performing fluorescence detection to determine the sealing performance of the coating sealant; removing the hemming glue, wetting the contact surface between the vehicle door hemming and the hemming glue, and then performing fluorescence detection to determine the sealing performance of the hemming glue; performing fluorescence detection on the cavity wax in the gap area between the inner and outer panels of the vehicle door to be tested to determine the sealing performance of the cavity wax; and comprehensively determining the sealing performance of the vehicle door hemming based on the sealing performance of the coating sealant, the sealing performance of the hemming glue, and the sealing performance of the cavity wax. The present invention can accurately evaluate the sealing performance of the hemming glue, coating sealant, and cavity wax at the hemming of the vehicle door.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile parts detection, and in particular to a method for detecting the sealing performance of a vehicle door edge. Background Art

[0002] Car doors have always been a key challenge in automotive corrosion prevention. After-sales rust is frequent and severe, even leading to rust-through, especially in the areas where the lower door edging and sharp corners meet. The primary cause of rust is poor sealing of the door edging, which creates gaps that allow corrosive media such as water and dust to accumulate. Over time, this accumulation can cause electrochemical reactions, leading to crevice corrosion. Corrosion of the door edging typically spreads from the inside out, making it difficult to detect immediately. Once discovered, severe corrosion, even rust-through, has already occurred, making it difficult to fundamentally resolve the corrosion problem. Therefore, sealing quality is a key control point for car door corrosion prevention, but the automotive industry currently lacks effective verification methods.

[0003] The sealing of vehicle door hemming involves hemming glue, coating sealant, and cavity wax. Hemming glue fills the mating surface of the inner and outer panels to form a seal, coating sealant seals the flanged edge of the outer panel, and cavity wax isolates water and prevents it from seeping into the interlocking gap. Generally speaking, welding workshops will tear open the vehicle door to observe the application track of the hemming glue, and the painting workshop will monitor the application track of the sealant. Cavity wax is observed by analyzing the electrophoresis car. However, the above-mentioned detection methods are only visual observation, which is simple and crude. Not only will it cause significant damage to the hemming glue, sealant, etc., but it will also have the problem of inaccurate results. It is impossible to identify hidden, subtle gaps and holes with the naked eye. There are no corresponding instruments and tools for detection and quantitative evaluation. It is not systematic and comprehensive, and it cannot effectively evaluate the sealing of vehicle door hemming. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for detecting the sealing performance of vehicle door hemming, so as to accurately evaluate the sealing performance of the folding glue, coating sealant and cavity wax at the vehicle door hemming, thereby comprehensively evaluating the sealing performance of the vehicle door hemming.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for detecting the sealing performance of a vehicle door edge, comprising the following steps:

[0007] S1. Immerse the vehicle door to be tested in a fluorescent solution and then dry it;

[0008] S2. Remove the coating sealant from the edge of the door to be tested, wet the coating sealant, and then perform fluorescence testing to determine the sealing performance of the coating sealant;

[0009] S3. Remove the hemming glue, wet the contact surface between the door hem and the hemming glue, and then perform fluorescence testing to determine the sealing performance of the hemming glue.

[0010] S4. Performing fluorescence detection on the cavity wax in the gap between the inner and outer panels of the vehicle door to be tested to determine the sealing performance of the cavity wax;

[0011] S5. Comprehensively judge the sealing performance of the door hemming to be tested based on the sealing performance of the coating sealant, the sealing performance of the hemming sealant, and the sealing performance of the cavity wax.

[0012] Because the water flow traces disappear after evaporation and drying, it is impossible to determine whether the door hem under test has a poor sealing problem, nor is it possible to track which part of the door hem under test has a poor sealing problem. Therefore, the present application immerses the door under test in a fluorescent solution, and then performs fluorescent testing on the coating sealant, hem glue, and cavity wax on the door hem after immersion. This allows accurate judgment of the sealing performance of the door hem under test, with the advantages of simple operation, high accuracy, and low cost.

[0013] The purpose of drying in S1 is that there is residual fluorescent solution in the parts after immersion, and the edge wrapping cannot be opened immediately, otherwise the residual fluorescent solution is likely to enter the edge wrapping, thereby affecting the result judgment.

[0014] Among them, the principle of fluorescence detection is: after the fluorescent substance in the fluorescent solution absorbs ultraviolet rays, the electrons undergo transition and release a visible fluorescence. By detecting whether there is fluorescence on the coating sealant at the door edge to be tested and the contact surface between the door edge and the folding glue, it can be determined whether water has entered the door edge to be tested. At the same time, combined with the detection of whether the cavity wax distribution in the gap area is uniform, it can be comprehensively and accurately determined whether the sealing of the door edge to be tested is qualified.

[0015] Preferably, the fluorescent solution includes fluorescent liquid and water, and the mass percentage of fluorescent liquid in the fluorescent solution is 0.2%; the components of the fluorescent liquid include, by mass percentage: 8% to 10% xanthine, 8% to 10% isooctanoic acid, 3% to 5% of a polymer of methyl ethylene oxide, ethylene oxide and monoisotridecyl ether, 0 to 1% diethylene glycol butyl ether, and the balance is pure water.

[0016] The fluorescent liquid is dark green, non-toxic, odorless, completely miscible with water, and has a density (20°C) of 1.25 g / cm 3 , the boiling point (20℃) is between 105℃ and 115℃.

[0017] Preferably, the pH value of the fluorescent liquid is between 6.5 and 7.5; the conductivity of the pure water in the fluorescent liquid is ≤20 μs / cm, and the pH value of the pure water in the fluorescent liquid is between 6 and 8.

[0018] Preferably, the soaking method is repeated soaking, the number of repeated soaking is at least three times, and the time of each soaking is at least 1 minute.

[0019] Preferably, the drying temperature is between 130° C. and 160° C., and the drying time is between 20 and 40 minutes.

[0020] Preferably, S2 specifically includes: cutting the coating sealant from the edge of the vehicle door to be tested, spraying the cut surface of the coating sealant with water, and then irradiating the cut surface with ultraviolet light to observe whether there is fluorescence to judge the sealing performance of the coating sealant. If there is fluorescence, it is determined that the sealing performance of the coating sealant is unqualified; if there is no fluorescence, it is determined that the sealing performance of the coating sealant is qualified.

[0021] The cut surface of the coating sealant refers to the cross section of the coating sealant cut from the edge of the vehicle door to be tested.

[0022] Since dry fluorescent materials cannot absorb ultraviolet light, electrons cannot jump and fluorescence cannot appear. Therefore, wetting treatment must be performed before fluorescence detection.

[0023] Preferably, the S3 specifically includes: opening the outer panel flange at the edging of the vehicle door to be tested, removing the folding glue, spraying the contact surface of the folding glue that contacts the outer panel and the inner panel at the edging of the vehicle door to be tested with water, and then irradiating the contact surface with ultraviolet light to observe whether there is fluorescence to judge the sealing of the folding glue. If there is fluorescence, it is determined that the sealing of the folding glue is unqualified; if there is no fluorescence, it is determined that the sealing of the folding glue is qualified.

[0024] Preferably, the S4 specifically includes: using ultraviolet light to irradiate the cavity wax in the gap area between the inner and outer panels in the inner cavity of the vehicle door to be tested, and judging the sealing performance of the cavity wax according to the area of ​​the fluorescent area. If the area of ​​the fluorescent area meets the set requirements, the sealing performance of the cavity wax is judged to be qualified; if the area of ​​the fluorescent area does not meet the set requirements, the sealing performance of the cavity wax is judged to be unqualified.

[0025] Preferably, the angle formed between the incident light of the ultraviolet light and the cutting surface, the contact surface or the surface of the cavity wax is between 45° and 60°.

[0026] Preferably, the distance between the emission end of the ultraviolet light and the cutting surface, the contact surface or the surface of the cavity wax is between 10 and 15 cm;

[0027] During the ultraviolet light irradiation process, the ambient brightness is controlled to be less than 100lx.

[0028] Experiments have shown that by controlling the angle between the incident UV light and the detection surface between 45° and 60°, the distance between the UV light emitter and the detection surface between 10 and 15 cm, and the ambient brightness below 100 lx, the fluorescence phenomenon is more pronounced, the UV light coverage area is maximized, and the detection results are more accurate. The detection method of the present invention can also be used to inspect the sealing properties of the hemming of automotive parts such as front hoods, back doors, and trunk lids.

[0029] Beneficial effects of the present invention:

[0030] The vehicle door edge sealing detection method of the present invention simulates the actual situation of a real vehicle door encountering water by immersing the vehicle door to be tested in a fluorescent solution, and strengthens, accelerates and amplifies the possibility of water ingress, so that the detection result is more accurate, and then the coating sealant, folding glue and cavity wax at the edge of the vehicle door to be tested after immersion are subjected to fluorescent detection respectively, thereby realizing a comprehensive and systematic evaluation of the sealing of the vehicle door edge, and fluorescent detection is more intuitive and more accurate than naked eye observation, thereby accurately judging the sealing performance of the vehicle door edge to be tested, and at the same time, if water ingress occurs, fluorescent detection can also accurately identify the water inlet channel and locate the water inlet part, thereby providing a reliable reference for improving the sealing quality, and has the advantages of simple operation, high accuracy and low cost, and has promotion and application value in the field of automobile parts detection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of the vehicle door edge sealing detection method of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the vehicle door to be tested being immersed;

[0033] Figure 3 This is a schematic diagram of the structure of the door to be tested for draining water;

[0034] Figure 4 This is a schematic diagram of the structure of cutting the sealant coating on the vehicle door to be tested;

[0035] Figure 5 It is a schematic diagram of the structure of the coating sealant after cutting;

[0036] Figure 6 Schematic diagram of the structure for removing the door hem glue to be tested;

[0037] Figure 7 The schematic diagram of the structure of the vehicle door to be tested with the hem glue removed;

[0038] Figure 8 It is a structural diagram of the door to be tested;

[0039] Figure 9 for Figure 8Cross-sectional view along the middle line AA;

[0040] Among them, 1-electric hoist; 2-vehicle door to be tested, 21-vehicle door outer panel, 211-outer panel overlapping surface, 212-outer panel bonding surface, 22-vehicle door inner panel, 221-inner panel overlapping surface, 222-inner panel bonding surface; 3-fluorescent solution; 4-test tank; 5-coating sealant, 51-cutting surface; 6-UV flashlight, 61-incident light; 7-fluorescent reflection direction; 8-folding glue; 9-cavity wax. DETAILED DESCRIPTION

[0041] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0042] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0043] Example 1

[0044] like Figure 1 As shown, a method for detecting the sealing performance of a vehicle door edge includes the following steps:

[0045] S1. Immerse the vehicle door to be tested in a fluorescent solution and then dry it, specifically including:

[0046] S11. Fluorescent liquid and pure water are mixed in a volume ratio of 1:499 to prepare a 0.2% fluorescent solution; wherein the conductivity of the pure water is ≤20 μs / cm, and the pH value is 6-8. The components of the fluorescent liquid include, by mass percentage, 9% xanthine, 9% isooctanoic acid, 4% polymer of methyl ethylene oxide, ethylene oxide, and monoisotridecyl ether, 0.5% diethylene glycol butyl ether, and the balance is pure water. The pH value of the fluorescent liquid is between 6.5 and 7.5. The conductivity of the pure water in the fluorescent liquid is ≤20 μs / cm, and the pH value is 6-8. During the preparation of the fluorescent solution, the temperature of the pure water and the fluorescent liquid is controlled between 0°C and 40°C, and the fluorescent liquid is added to the pure water to avoid serious foaming during the preparation of the fluorescent solution.

[0047] S12. Pre-immersion inspection: Inspect the sealant coating on the edge of the vehicle door 1 under test using a 50x magnifying glass to observe whether there are any defects such as pinholes, cracks, deviation from the glue coating position, or exposed bottom of the glue scraping or brushing area. If no defects are found, proceed to the next step;

[0048] The vehicle door 1 to be tested in this embodiment is a vehicle door that has completed the welding and painting processes, and has undergone the hem glue coating, coating sealant coating and baking, and cavity wax process operations;

[0049] S13, immersion test, such as Figure 2 and Figure 3 As shown, the electric hoist 1 is used to slowly immerse the vehicle door 2 to be tested into the test tank 4 filled with the fluorescent solution 3 prepared in S11. The timing starts when the vehicle door 2 to be tested is completely immersed. After the vehicle door 2 to be tested has been immersed for a certain period of time, the electric hoist 1 is used to slowly lift the vehicle door 2 to above the liquid surface, and the water is drained until there is no obvious liquid accumulation in the door cavity of the vehicle door 2 to be tested. Then, the vehicle door 2 to be tested is slowly immersed in the test tank 4 filled with the fluorescent solution 3. The immersion-lifting-draining operation is repeated 3 times in total. The immersion time for each time is the same. After the first two liftings, it is not necessary to completely drain the water before immersing again. After the third lifting, it needs to be drained until there are no obvious droplets.

[0050] The liquid level of the fluorescent solution 3 in the test tank 4 is no less than 1 meter. The immersion time of the vehicle door 2 to be tested is 1 minute each time. The drainage time after the first two liftings of the vehicle door 2 to be tested is no less than 2 minutes, and the drainage time after the final lifting of the vehicle door 2 to be tested is no less than 5 minutes. The lifting and lowering of the vehicle door is controlled by an electric hoist with a lifting capacity of 0.5 tons.

[0051] S13, drying the vehicle door 2 to be tested that has been drained in S12, and then naturally cooling it to room temperature. Because fluorescent solution remains on the vehicle door 2 to be tested after soaking, if the edge is opened immediately, the residual fluorescent solution is likely to enter the edge, thereby affecting the accuracy of the result determination. Therefore, the vehicle door 2 to be tested must be dried first, wherein the drying temperature is 150° C. and the drying time is 30 minutes;

[0052] S2. Remove the coating sealant from the door edge to be tested, wet the coating sealant, and then perform fluorescence testing to determine the sealing performance of the coating sealant, including:

[0053] like Figure 4As shown, a utility knife is used to cut the coating sealant 5 along the edge of the vehicle door 2 to be tested, and a thin layer of water mist is evenly sprayed on the cut surface 51 of the coating sealant 5 for wetting. Then, a UV flashlight is used to illuminate the cut surface 51 to detect whether there is fluorescence. If fluorescence is detected, it means that water has entered the cut surface 51, and the sealing of the coating sealant 5 is determined to be unqualified. If no fluorescence is detected, it means that water has not entered the cut surface 51, and the sealing of the coating sealant 5 is determined to be qualified.

[0054] like Figure 5 As shown, the wavelength of the UV flashlight 6 is 365nm, and the rated power is 4~6W. During the detection, in order to make the fluorescence phenomenon more obvious and thus ensure the accuracy of the detection result, the ambient brightness needs to be controlled to be less than 100lx, and the incident light 61 of the ultraviolet light emitted by the UV flashlight 6 needs to be irradiated at an angle a of 45°~60° to the cutting surface 51, and the distance H1 between the UV flashlight 6 and the cutting surface 51 needs to be controlled to be 10~15cm. Figure 5 In the figure, the direction of the arrow marked 7 is the direction of fluorescence reflection;

[0055] S3. Remove the hemming glue and wet the contact surface between the door hem and the hemming glue. Then perform a fluorescence test to determine the sealing performance of the hemming glue. Specifically, the test includes:

[0056] S31, such as Figure 4 and Figure 6 As shown, use a nutcracker to gradually open the outer panel flange along the edge of the door outer panel 21 at the hemming of the vehicle door 2 to be tested until β is 180°, and use a magnifying glass to check whether the outer panel overlap surface 211 of the door outer panel 21 flanged in contact with the hemming glue 8 and the inner panel overlap surface 221 of the door inner panel 22 flanged in contact with the hemming glue 8 meet the filling requirements;

[0057] S32, such as Figure 7 As shown, the hemming glue 8 between the door outer panel 21 and the door inner panel 22 is completely separated, and a magnifying glass is used to check whether the hemming glue 8 on the surface in contact with the outer panel bonding surface 212 and the inner panel bonding surface 222 meets the filling requirements;

[0058] S33. Evenly spray a thin layer of water mist on the surfaces of the outer panel overlap surface 211, the outer panel bonding surface 212, the inner panel overlap surface 221, and the inner panel bonding surface 222 for moistening. Then, use a UV flashlight 6 to illuminate the outer panel overlap surface 211, the outer panel bonding surface 212, the inner panel overlap surface 221, and the inner panel bonding surface 222 to detect whether there is fluorescence.

[0059] If the hem glue 8 on any of the outer panel lap joint surface 211, the outer panel bonding surface 212, the inner panel lap joint surface 221, and the inner panel bonding surface 222 does not meet the filling requirements, it means that there are gaps in the hem of the vehicle door 2 to be tested. During the coating and baking process, the gas expansion may break through the hem glue or the coating sealant to form gaps or holes, thereby posing a risk of water ingress. Therefore, the sealing performance of the hem glue 8 is unqualified.

[0060] If the hem glue 8 on each of the outer panel lap joint surface 211, the outer panel bonding surface 212, the inner panel lap joint surface 221, and the inner panel bonding surface 222 meets the filling requirements, but fluorescence is detected on any of the outer panel lap joint surface 211, the outer panel bonding surface 212, the inner panel lap joint surface 221, and the inner panel bonding surface 222, indicating a risk of water ingress, the sealing performance of the hem glue 8 is also unqualified, and it is necessary to analyze the cause of the water inlet channel at the fluorescent part, formulate measures, and make corrections;

[0061] If the hemming glue 8 on each of the outer panel lap joint surface 211, the outer panel bonding surface 212, the inner panel lap joint surface 221, and the inner panel bonding surface 222 meets the filling requirements, and no fluorescence is detected on each of the outer panel lap joint surface 211, the outer panel bonding surface 212, the inner panel lap joint surface 221, and the inner panel bonding surface 222, indicating that no water has entered, then the sealing performance of the hemming glue 8 is qualified;

[0062] S4. Fluorescence testing is performed on the cavity wax in the gap between the inner and outer panels of the vehicle door to determine the sealing performance of the cavity wax, specifically including:

[0063] Because cavity wax will have blue-green fluorescence under ultraviolet light, it does not need to be wetted and can be directly observed under ultraviolet light;

[0064] like Figure 8 and Figure 9 As shown, a UV flashlight 6 is used to illuminate the cavity wax 9 in the gap between the inner and outer panels of the inner cavity of the vehicle door 2 to be tested, and the sealing performance of the cavity wax is judged based on the size of the fluorescent area.

[0065] If the area of ​​the fluorescent region meets the set requirements, it means that the cavity wax can effectively isolate water, and the sealing performance of the cavity wax is determined to be qualified;

[0066] If the area of ​​the fluorescent region does not meet the set requirements, it means that the cavity wax cannot effectively isolate water, and the sealing performance of the cavity wax is judged to be unqualified;

[0067] In this embodiment, the height H2 between the bottom and the top of the cavity wax 9 is detected to determine whether the area of ​​the fluorescence generating region meets the set requirements. If the height H2 is between 100 mm and 150 mm, it is determined that the area of ​​the fluorescence generating region meets the set requirements. Otherwise, it is determined that the area of ​​the fluorescence generating region does not meet the set requirements.

[0068] S5. Comprehensively judge the sealing performance of the door hemming to be tested based on the sealing performance of the coating sealant, the sealing performance of the hemming sealant, and the sealing performance of the cavity wax, including:

[0069] If the sealing properties of the coating sealant, hemming sealant, and cavity wax are all qualified, the sealing property of the hemming of the vehicle door 2 to be tested is determined to be qualified;

[0070] If the sealing performance of any one of the coating sealant, the hemming sealant and the cavity wax is unqualified, the sealing performance of the hemming of the vehicle door 2 to be tested is determined to be unqualified.

[0071] Example 2

[0072] Example of door edge sealing qualified

[0073] A method for detecting the sealing performance of a left front door hem, comprising the following steps:

[0074] S1. Soak the left front door in a fluorescent solution and then dry it, specifically including:

[0075] S11, mixing the fluorescent liquid and pure water at a volume ratio of 1:499 to prepare a 0.2% fluorescent solution; wherein the composition, preparation method and conditions of the fluorescent solution are the same as those in Example 1;

[0076] S12. Pre-immersion inspection: Use a magnifying glass to inspect the sealant applied to the left front door edge to confirm that there are no defects such as pinholes, cracks, deviation from the application position, or exposed areas where the sealant is scraped or applied.

[0077] The left front door in this embodiment is a left front door that has completed the welding and painting processes, and has undergone the folding glue coating, coating sealant coating and baking, and cavity wax process operations;

[0078] S13. Immersion test: Use an electric hoist to slowly immerse the left front door in a test tank containing the fluorescent solution prepared in S11. Start timing when the left front door is completely immersed. Soak for 1 minute. Slowly lift the left front door above the liquid level using the electric hoist. Drain for 2.5 minutes until there is no obvious liquid accumulation in the door cavity of the left front door. Slowly immerse the left front door in the test tank. After soaking for 1 minute, slowly lift the left front door above the liquid level using the electric hoist. Drain for 2.5 minutes until there is no obvious liquid accumulation in the door cavity of the left front door. Slowly immerse the left front door in the test tank again. After soaking for 1 minute, slowly lift the left front door above the liquid level using the electric hoist. Drain for 6 minutes until there is no obvious liquid dripping.

[0079] Among them, the liquid level of the fluorescent solution in the test tank is 1.5m;

[0080] S13, drying the left front door after draining in S12 at 150° C. for 30 minutes, taking it out and letting it cool naturally to room temperature;

[0081] S2. Remove the sealant from the left front door edging, moisten the sealant, and then perform a fluorescence test to determine the sealability of the sealant. Specifically, the following tests are performed:

[0082] Use a utility knife to cut the coating sealant along the left front door hem. Spray a thin layer of water mist evenly on the cut surface of the coating sealant to moisten it. Then use a UV flashlight to illuminate the cut surface. No fluorescence is detected, indicating that the cut surface has not been water-logged. The sealing performance of the coating sealant is considered qualified.

[0083] The wavelength of the UV flashlight is 365nm, and the rated power is 4~6W. During the inspection, the ambient brightness must be controlled to be less than 100lx. The incident ultraviolet light emitted by the UV flashlight is irradiated at an angle of 45°~60° to the cutting surface, and the distance between the UV flashlight and the cutting surface is 10~15cm.

[0084] S3. Remove the hemming glue and wet the contact surface between the left front door hem and the hemming glue. Then perform a fluorescence test to determine the sealing performance of the hemming glue, including:

[0085] S31. Use a nutcracker to gradually open the door outer panel flange along the edge of the left front door hem to 180 degrees. Use a magnifying glass to check that the outer panel overlap surface of the door outer panel flange that contacts the hem glue and the inner panel overlap surface 101 of the door inner panel flange that contacts the hem glue meet the filling requirements.

[0086] S32. Completely separate the hem glue between the door outer panel and the door inner panel, and use a magnifying glass to check that the hem glue on the surface in contact with the outer panel and the inner panel meets the filling requirements;

[0087] S33. Evenly spray a thin layer of water mist on the outer panel overlap, outer panel bonding surface, inner panel overlap, and inner panel bonding surface to moisten them. Then, use a UV flashlight to illuminate the outer panel overlap, outer panel bonding surface, inner panel overlap, and inner panel bonding surface. No fluorescence is detected on any of these surfaces, indicating no water ingress and acceptable sealing performance of the hem glue.

[0088] S4. Perform fluorescence testing on the cavity wax in the gap between the inner and outer panels of the left front door to determine the sealing performance of the cavity wax, specifically including:

[0089] Ultraviolet light was used to irradiate the cavity wax in the gap between the inner and outer panels of the left front door. The area of ​​the fluorescent area met the set requirements, indicating that the cavity wax can effectively isolate water and has qualified sealing performance.

[0090] S5. Comprehensively assess the sealing performance of the left front door hemming based on the sealing performance of the applied sealant, hemming sealant, and cavity wax, specifically including:

[0091] If the sealing performance of the coating sealant, hemming sealant and cavity wax are determined to be qualified through testing, then the sealing performance of the left front door edging is determined to be qualified.

[0092] Example 3

[0093] Example of unqualified door edge sealing

[0094] A method for detecting the sealing performance of a left rear door hem, comprising the following steps:

[0095] S1. Soak the left rear door in a fluorescent solution and then dry it, specifically including:

[0096] S11, mixing the fluorescent liquid and pure water at a volume ratio of 1:499 to prepare a 0.2% fluorescent solution; wherein the composition, preparation method and conditions of the fluorescent solution are the same as those in Example 1;

[0097] S12. Pre-immersion inspection: Use a magnifying glass to inspect the sealant applied to the left rear door edge to confirm that there are no defects such as pinholes, cracks, deviation from the application position, or exposed areas where the sealant is scraped or applied.

[0098] The left rear door in this embodiment is a left rear door that has completed the welding and painting processes, and has undergone the folding glue coating, coating sealant coating and baking, and cavity wax process operations;

[0099] S13. Immersion test: Use an electric hoist to slowly immerse the left rear door in a test tank containing the fluorescent solution prepared in S11. Start timing when the left rear door is completely immersed. Soak for 1 minute. Slowly lift the left rear door above the liquid level using the electric hoist. Drain for 2.5 minutes until there is no obvious liquid accumulation in the door cavity of the left rear door. Slowly immerse the left rear door in the test tank. After soaking for 1 minute, slowly lift the left rear door above the liquid level using the electric hoist. Drain for 2.5 minutes until there is no obvious liquid accumulation in the door cavity of the left rear door. Slowly immerse the left rear door in the test tank again. After soaking for 1 minute, slowly lift the left rear door above the liquid level using the electric hoist. Drain for 6 minutes until there is no obvious liquid dripping.

[0100] Among them, the liquid level of the fluorescent solution in the test tank is 1.5m;

[0101] S13, drying the left rear door after draining in S12 at 150° C. for 30 minutes, taking it out and letting it cool naturally to room temperature;

[0102] S2. Remove the sealant from the left rear door edging, moisten the sealant, and then perform a fluorescence test to determine the sealability of the sealant. Specifically, the following tests are performed:

[0103] Use a utility knife to cut the coating sealant along the left rear door hem. Spray a thin layer of water mist evenly on the cut surface of the coating sealant to moisten it. Then use a UV flashlight to illuminate the cut surface. No fluorescence is detected, indicating that the cut surface has not been water-logged. The sealing performance of the coating sealant is considered qualified.

[0104] The wavelength of the UV flashlight is 365nm, and the rated power is 4~6W. During the inspection, the ambient brightness must be controlled to be less than 100lx. The incident ultraviolet light emitted by the UV flashlight is irradiated at an angle of 45°~60° to the cutting surface, and the distance between the UV flashlight and the cutting surface is 10~15cm.

[0105] S3. Remove the hemming glue and wet the contact surface between the left rear door hem and the hemming glue. Then perform a fluorescence test to determine the sealing performance of the hemming glue. Specifically, the following steps are required:

[0106] S31. Use a nutcracker to gradually open the door outer panel flange along the edge of the left rear door hem to 180 degrees. Use a magnifying glass to check that the outer panel overlap surface of the door outer panel flange that contacts the hem glue and the inner panel overlap surface 101 of the door inner panel flange that contacts the hem glue meet the filling requirements.

[0107] S32. Completely separate the hem glue between the door outer panel and the door inner panel, and use a magnifying glass to check that the hem glue on the surface in contact with the outer panel and the inner panel meets the filling requirements;

[0108] S33. Evenly spray a thin layer of water mist on the outer panel overlap, outer panel bonding, inner panel overlap, and inner panel bonding surfaces to moisten them. Then, use a UV flashlight to illuminate the outer panel overlap, outer panel bonding, inner panel overlap, and inner panel bonding surfaces. Fluorescence is detected on the outer panel bonding and inner panel bonding surfaces, indicating water ingress and unsatisfactory sealing of the hem glue.

[0109] S4. Perform fluorescence testing on the cavity wax in the gap between the inner and outer panels of the left rear door to determine the sealing performance of the cavity wax, including:

[0110] Ultraviolet light was used to irradiate the cavity wax in the gap between the inner and outer panels of the left rear door. The area of ​​the fluorescent area met the set requirements, indicating that the cavity wax can effectively isolate water and has qualified sealing performance.

[0111] S5. Comprehensively assess the sealing performance of the left rear door hemming based on the sealing performance of the applied sealant, the hemming sealant, and the cavity wax, specifically including:

[0112] The test found that the sealing of the folding glue was unqualified, so it was determined that the sealing of the left rear door edging was unqualified.

[0113] The vehicle door hemming sealing test method of the present invention simulates the actual situation of a real vehicle door encountering water by immersing the vehicle door to be tested in a fluorescent solution, and strengthens, accelerates and amplifies the possibility of water ingress, making the test results more accurate. Then, the coating sealant, folding glue and cavity wax at the hemming of the vehicle door to be tested after immersion are subjected to fluorescent detection respectively, thereby achieving a comprehensive and systematic evaluation of the sealing of the vehicle door hemming. In addition, fluorescent detection is more intuitive and accurate than naked eye observation, thereby accurately judging the sealing performance of the vehicle door hemming to be tested. At the same time, if water ingress occurs, fluorescent detection can also accurately identify the water inlet channel and locate the water inlet part, thereby providing a reliable reference for improving the sealing quality. The test operation is simple, fast and efficient. The vehicle door hemming sealing test method of the present invention can effectively improve the anti-corrosion performance of the door cover and reduce after-sales rust complaints. At the same time, the present invention also fills the technical gap in the field of vehicle door anti-corrosion sealing, and has promotion and application value in the field of automotive parts testing technology.

[0114] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A method for detecting the sealing performance of a vehicle door edge, characterized in that: The following steps are involved: S1. Immerse the vehicle door to be tested in a fluorescent solution and then dry it; S2. Remove the coating sealant from the edge of the door to be tested, wet the coating sealant, and then perform fluorescence testing to determine the sealing performance of the coating sealant; S3. Remove the hemming glue, wet the contact surface between the door hem and the hemming glue, and then perform fluorescence testing to determine the sealing performance of the hemming glue. S4. Performing fluorescence detection on the cavity wax in the gap between the inner and outer panels of the vehicle door to be tested to determine the sealing performance of the cavity wax; S5. Comprehensively judge the sealing performance of the door hemming to be tested based on the sealing performance of the coating sealant, the sealing performance of the hemming sealant, and the sealing performance of the cavity wax.

2. The method for detecting the sealing performance of the vehicle door edge according to claim 1, characterized in that: The fluorescent solution includes fluorescent liquid and water, and the mass percentage of the fluorescent liquid in the fluorescent solution is 0.2%; the components of the fluorescent liquid include, by mass percentage: 8% to 10% of xanthine, 8% to 10% of isooctanoic acid, 3% to 5% of a polymer of methyl ethylene oxide, ethylene oxide and monoisotridecyl ether, 0 to 1% of diethylene glycol butyl ether, and the balance is pure water.

3. The method for detecting the sealing performance of the vehicle door edge according to claim 2, wherein: The pH value of the fluorescent liquid is between 6.5 and 7.5; the conductivity of the pure water in the fluorescent liquid is ≤20 μs / cm, and the pH value of the pure water in the fluorescent liquid is between 6 and 8.

4. The method for detecting the sealing performance of the vehicle door edge according to claim 3, wherein: The soaking method is repeated soaking, the number of repeated soaking is at least three times, and the time of each soaking is at least 1 minute.

5. The method for detecting the sealing performance of the vehicle door edge according to claim 4, characterized in that: The drying temperature is between 130° C. and 160° C., and the drying time is between 20 and 40 minutes.

6. The method for detecting the sealing performance of vehicle door hemming according to claim 1, wherein: The S2 specifically includes: cutting the coating sealant from the edge of the vehicle door to be tested, spraying the cut surface of the coating sealant with water, and then irradiating the cut surface with ultraviolet light to observe whether there is fluorescence to judge the sealing performance of the coating sealant. If there is fluorescence, it is determined that the sealing performance of the coating sealant is unqualified; if there is no fluorescence, it is determined that the sealing performance of the coating sealant is qualified.

7. The method for detecting the sealing performance of the vehicle door edge according to claim 6, wherein: The S3 specifically includes: opening the outer panel flange at the edge of the vehicle door to be tested, removing the folding glue, spraying the contact surface of the folding glue that contacts the outer panel and the inner panel at the edge of the vehicle door to be tested with water, and then irradiating the contact surface with ultraviolet light to observe whether there is fluorescence to judge the sealing performance of the folding glue. If there is fluorescence, it is determined that the sealing performance of the folding glue is unqualified; if there is no fluorescence, it is determined that the sealing performance of the folding glue is qualified.

8. The method for detecting the sealing performance of vehicle door edge binding according to claim 7, wherein: The S4 specifically includes: using ultraviolet light to irradiate the cavity wax in the gap area between the inner and outer panels in the inner cavity of the vehicle door to be tested, and judging the sealing performance of the cavity wax according to the area of ​​the fluorescent area. If the area of ​​the fluorescent area meets the set requirements, the sealing performance of the cavity wax is determined to be qualified; if the area of ​​the fluorescent area does not meet the set requirements, the sealing performance of the cavity wax is determined to be unqualified.

9. The method for detecting the sealing performance of the vehicle door edge according to claim 8, wherein: The angle formed between the incident light of the ultraviolet light and the cutting surface, the contact surface or the surface of the cavity wax is between 45° and 60°.

10. The method for detecting the sealing performance of vehicle door edge binding according to claim 8, wherein: The distance between the emission end of the ultraviolet light and the cutting surface, the contact surface or the surface of the cavity wax is between 10 and 15 cm; During the ultraviolet light irradiation process, the ambient brightness is controlled to be less than 100lx.

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