A method of repairing a paint edge on an engineered machine vehicle

Abstract

The application discloses a method for solving the virtual edge of engineering machinery vehicle repair coating, and belongs to the technical field of vehicle coating. In the method, three spray guns with diameters of 1.5 mm, 1.3 mm and 1.3 mm are adopted, sandpaper polishing is performed on the area needing repair, and multiple sprayings are performed from the center to the periphery, so that the repair coating is completed. Whether in an outdoor high-temperature environment or just after entering the factory, the surface paint film of the engineering machinery vehicle is repaired and coated by the method of the application, the problem of the virtual edge can be solved, and the repair effect can meet the requirements of the engineering machinery industry on the surface of the paint film.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vehicle painting, and particularly relates to a method for solving virtual edge in repair painting of engineering machinery vehicles. BACKGROUND

[0002] In the production process of engineering machinery vehicles, each part is first overall painted, and the paint used for overall painting is generally powder paint or baking paint. After the paint is dried, the parts are assembled, and then the assembled engineering machinery vehicles are transported outdoors for factory acceptance inspection. The surface effect of the paint film in this field is relatively low. For example, if the surface paint film is scratched, it does not need to be repaired and painted like a car. Generally, only the scratched area is repaired and painted. The repair paint is generally an acrylic polyurethane product.

[0003] At present, the newly produced engineering machinery vehicles mainly have the following problems in the repair painting process: after normal repair painting, the repaired area has obvious virtual edge. The degree of virtual edge is related to the skills of the repairer, the temperature and wind speed of the environment, etc. Generally, the repair virtual edge of the painting personnel with high skills or long service length in the repair section is less in low temperature and windless environment, and the repair virtual edge is more in summer high temperature environment, and the rework situation often exists. There is no standard and unified method to solve the virtual edge problem in the repair process of engineering machinery vehicles. SUMMARY

[0004] The present application is directed to the technical problem of virtual edge in the repaired area after the existing normal painting process is used to repair and paint the surface paint film of the engineering machinery vehicle, and proposes a method for solving the virtual edge in the repair painting of the engineering machinery vehicle.

[0005] In order to achieve the above purpose, the present application adopts the following technical solution:

[0006] A method for solving the virtual edge in the repair painting of engineering machinery vehicles, comprising the following steps:

[0007] Step 1, preparing acrylic polyurethane paint of the same color as the surface paint film of the engineering machinery vehicle, and preparing three spray guns with diameters of 1.5mm, 1.3mm and 1.3mm respectively;

[0008] Step 2, determining the area that needs to be repaired according to the minimum area;

[0009] Step 3, sanding the area that needs to be repaired;

[0010] Step four, taking the polyurethane special diluent for acrylic polyurethane coating to adjust the viscosity to 20-23", using a 1.5mm caliber spray gun to paint the repair area, keeping the spray gun and the repair area vertical and the distance between them controlled between 150-300mm, the walking speed controlled between 30-60cm / s, the air inlet pressure adjusted to 0.3-0.4MPa, and the spraying thickness controlled between 30-40μm;

[0011] Step five, taking another polyurethane special diluent for acrylic polyurethane coating to adjust the viscosity to 14-16", using one of the 1.3mm caliber spray guns to immediately paint the periphery of the repair area treated in step four, keeping the spray gun and the repair area at an angle of 110°-120° and the distance between them controlled at 10-15cm, the walking speed controlled at 20-30cm / s, the air inlet pressure adjusted to 0.1-0.2MPa, and the coating thickness controlled at 10-20μm;

[0012] Step six, adding PMA in an amount of 20-60% of its mass to the polyurethane special diluent to configure a spraying agent, using another 1.3mm caliber spray gun to paint the outer periphery of the area treated in step five at a substrate temperature of 10-35℃, keeping the spray gun and the repair area at an angle of 160°-170° and the distance between them controlled within 10cm, the walking speed controlled at 20-30cm / s, the air inlet pressure adjusted to below 0.1MPa, and spraying 2 times with an interval of 3-5min.

[0013] Further, the raw material composition of the acrylic polyurethane coating includes, by mass ratio, 45-55% of hydroxyl acrylic acid resin, 14-16% of pigment, 2-4% of anti-settling agent, 6-8% of anti-settling clay, 0.01-0.1% of organic tin, 0.1-1% of defoaming agent, 0.1-0.5% of leveling agent, 0.5-1% of dispersing agent, 3-7% of ethyl acetate, and 7-30% of 100# solvent oil.

[0014] Further, the model of the spray gun is W-71.

[0015] Further, the model of the sandpaper is 1000-1500 mesh.

[0016] Further, the raw material composition of the polyurethane special diluent includes, by mass ratio, 70-90% of xylene and 10-30% of cyclohexanone.

[0017] Further, the periphery of the repair area treated in step four is an area extending 2-3cm outward from the virtual edge painted in step four.

[0018] Further, the outer periphery of the area treated in step five is an area extending 1-2cm outward from the virtual edge painted in step five.

[0019] Further, in steps five and six, the fluid control button of the spray gun is kept at maximum during the spraying process, the mode control button is rotated clockwise by 360°-540°, and the atomizing holes on the left or right side of the air cap are completely blocked by the masking paper.

[0020] With the above technical solutions, the present application has the following beneficial technical effects:

[0021] In the method of the present application, three spray guns are used. After the area to be repaired is polished with sandpaper, the area is sprayed multiple times from the center to the periphery, thereby completing the repair coating, and the spraying process is easy to control. Whether in an outdoor high-temperature environment or just after entering the factory, the method of the present application can solve the problem of virtual edges and the repair effect can meet the requirements of the engineering machinery industry for the surface of the paint film. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is an effect diagram after repair coating of the engineering machinery vehicle is performed by using a normal coating process;

[0023] Figure 2 is an effect diagram after repair coating of the engineering machinery vehicle is performed by using the method of the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present application more clear and explicit, the present application will be further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0025] Example 1

[0026] A method for solving the problem of virtual edges in repair coating of engineering machinery vehicles, the steps are as follows:

[0027] Step one, prepare acrylic polyurethane paint of the same color as the surface paint film of the engineering machinery vehicle, and prepare three W-71 spray guns with diameters of 1.5 mm, 1.3 mm and 1.3 mm respectively;

[0028] Step two, determine the area to be repaired according to the minimum area;

[0029] Step three, polish the area to be repaired with 1000 mesh sandpaper;

[0030] Step four, adjust the viscosity of the acrylic polyurethane paint to 20" with a polyurethane special thinner, and use the 1.5 mm diameter spray gun to coat the repair area. During the spraying process, the spray gun and the repair area are kept perpendicular, and the distance is controlled at 150 mm, the walking speed is controlled at 30 cm / s, the air inlet pressure is adjusted to 0.3 MPa, and the spraying thickness is controlled at 30 μm.

[0031] Step five, another acrylic polyurethane coating polyurethane special diluent viscosity to 14" adjustment, using one of the 1.3mm caliber spray gun on the step four painted the edge of the area extending 2cm immediately outside the repair, spraying process to maintain the spray gun and the repair area angle of 110°, and the distance control in 10cm, walk the gun speed control in 20cm / s, the air pressure adjustment to 0.1MPa, coating thickness control in 10μm; spraying process to maintain the fluid control button adjustment of the spray gun maximum, mode control button clockwise rotation 360°, air cap left or right side of the atomizing hole with masking paper completely blocked;

[0032] Step six, in the polyurethane special diluent to add its mass 20% PMA configuration into the spray agent, at the substrate temperature 10℃ environment, using another 1.3mm caliber spray gun on the step five painted the edge of the area extending 1cm outside the repair, spraying process to maintain the spray gun and the repair area angle of 160°, and the distance control in 10cm, walk the gun speed control in 20cm / s, the air pressure adjustment to 0.1MPa below, spraying process to maintain the fluid control button adjustment of the spray gun maximum, mode control button clockwise rotation 360°, air cap left or right side of the atomizing hole with masking paper completely blocked; spray 2 times, each interval control in 3min.

[0033] The raw material composition of the acrylic polyurethane coating used in the embodiment includes, by mass ratio, hydroxyl acrylic resin 45%, pigment 14%, anti-settling agent 2%, anti-settling clay 6%, organic tin 0.01%, defoaming agent 0.1%, leveling agent 0.1%, dispersing agent 0.5%, ethyl acetate 3%, 100# solvent oil 29.29%; the raw material composition of the polyurethane special diluent includes, by mass ratio, dimethylbenzene 70%, cyclohexanone 10%.

[0034] Example 2

[0035] A method for repairing and coating the edge of an engineering machinery vehicle, comprising the following steps:

[0036] Step one, prepare acrylic polyurethane coating with the same color as the surface paint film of the engineering machinery vehicle, and prepare three W-71 spray guns with caliber of 1.5mm, 1.3mm and 1.3mm respectively;

[0037] Step two, determine the area needing to be repaired according to the minimum area;

[0038] Step three, polish the area needing to be repaired with 1500 mesh sandpaper;

[0039] Step four, take the acrylic polyurethane coatings with polyurethane special diluent viscosity adjustment to 23", using 1.5 mm caliber spray gun on the repair area for painting, spraying process to keep the spray gun and repair area vertical, and the distance control in 300 mm, walk the gun speed control in 60 cm / s, air pressure adjustment to 0.4 MPa, spraying thickness control in 40 μm;

[0040] Step five, take another acrylic polyurethane coatings with polyurethane special diluent viscosity adjustment to 16", using one of the 1.3 mm caliber spray gun on the step four painted virtual edge outward extending 3 cm area immediately for painting, spraying process to keep the spray gun and repair area angle is 120°, and the distance control in 15 cm, walk the gun speed control in 30 cm / s, air pressure adjustment to 0.2 MPa, coating thickness control in 20 μm; spraying process to keep the spray gun fluid control button adjustment maximum, mode control button clockwise rotation 360°, air cap left or right atomizing hole with masking paper completely shielded;

[0041] Step six, in the polyurethane special diluent adding its mass 60% PMA configuration into the spray agent, at the substrate temperature 35℃ environment, using another 1.3 mm caliber spray gun on the step five painted virtual edge outward extending 2 cm area for painting, spraying process to keep the spray gun and repair area angle is 170°, and the distance control in 10 cm, walk the gun speed control in 30 cm / s, air pressure adjustment to 0.1 MPa below; spraying process to keep the spray gun fluid control button adjustment maximum, mode control button clockwise rotation 540°, air cap left or right atomizing hole with masking paper completely shielded; spraying 2 times, each interval control in 5 min.

[0042] The raw material composition of the acrylic polyurethane coating used in the embodiment includes, by mass ratio, 55% of hydroxyl acrylic resin, 16% of pigment, 4% of anti-settling agent, 8% of anti-settling clay, 0.1% of organic tin, 1% of defoaming agent, 0.5% of leveling agent, 1% of dispersing agent, 7% of ethyl acetate, and 7.4% of 100# solvent oil; the raw material composition of the polyurethane special diluent includes, by mass ratio, 90% of dimethylbenzene and 10% of cyclohexanone.

[0043] Example 3

[0044] A method for repairing and painting virtual edges of engineering machinery vehicles, comprising the following steps:

[0045] Step one, prepare acrylic polyurethane coatings with the same color as the surface paint film of engineering machinery vehicles, and prepare three W-71 spray guns with caliber of 1.5 mm, 1.3 mm, and 1.3 mm respectively;

[0046] Step two, determine the area needing to be repaired according to the minimum area.

[0047] Step three, sand the area to be repaired with 1200 grit sandpaper;

[0048] Step four, adjust the viscosity of the acrylic polyurethane paint with polyurethane special diluent to 22", use a 1.5mm caliber spray gun to paint the repair area, keep the spray gun and the repair area vertical during the spraying process, and the distance is controlled between 200mm, the walking speed is controlled at 40cm / s, the air inlet pressure is adjusted to 0.35MPa, and the spraying thickness is controlled at 35μm;

[0049] Step five, adjust the viscosity of the acrylic polyurethane paint with polyurethane special diluent to 15", use one of the 1.3mm caliber spray guns to paint the area extending 2.5cm outward from the virtual edge painted in step four, keep the spray gun and the repair area at an angle of 115° during the spraying process, and the distance is controlled at 12cm, the walking speed is controlled at 25cm / s, the air inlet pressure is adjusted to 0.15MPa, and the coating thickness is controlled at 15μm; keep the fluid control knob of the spray gun adjusted to the maximum, the mode control knob is rotated clockwise by 450°, and the atomizing holes on the left or right side of the air cap are completely covered with masking paper;

[0050] Step six, add PMA with a mass of 40% to the polyurethane special diluent to configure a spraying agent, at a substrate temperature of 25℃, use another 1.3mm caliber spray gun to paint the area extending 1.5cm outward from the virtual edge painted in step five, keep the spray gun and the repair area at an angle of 165° during the spraying process, and the distance is controlled within 10cm, the walking speed is controlled at 25cm / s, and the air inlet pressure is adjusted to below 0.1MPa; keep the fluid control knob of the spray gun adjusted to the maximum, the mode control knob is rotated clockwise by 450°, and the atomizing holes on the left or right side of the air cap are completely covered with masking paper; spray 2 times, and the interval between each time is controlled within 4min.

[0051] The raw material composition of the acrylic polyurethane paint used in this embodiment includes, by mass ratio, hydroxyl acrylic resin 50%, pigment 15%, anti-settling agent 3%, anti-settling clay 7%, organic tin 0.05%, defoaming agent 0.5%, leveling agent 0.25%, dispersing agent 0.75%, ethyl acetate 5%, and 100# solvent oil 18.45%; the raw material composition of the polyurethane special diluent includes, by mass ratio, dimethylbenzene 80% and cyclohexanone 20%.

[0052] Test example 1: influence of different spraying viscosities on the repair painting of engineering machinery vehicles

[0053] In the environment of temperature 25℃, control the same conditions of spraying angle, spraying distance, spraying speed, spraying pressure, adopt different spraying viscosity to repair coating of engineering machinery vehicle, the test results are shown in Table 1.

[0054] Table 1 Repair coating results of engineering machinery vehicle under different spraying viscosity

[0055]

[0056] As the results of Table 1 show, on the basis of normal spraying viscosity, the width of virtual edge can be reduced by increasing the viscosity of paint, but there will be particles at the virtual edge when the viscosity is too large, which affects the overall appearance and feel of the repaired part; on the basis of normal spraying viscosity, the width of virtual edge is not affected when the viscosity of paint is reduced, but the width of virtual edge is increased when the viscosity is reduced to 16-18'', the width of virtual edge is slightly improved when the viscosity is reduced to 14-16'', the width of virtual edge is reduced when the viscosity is reduced to 13-14'', but sagging occurs on the board; it can be seen that when the viscosity of paint is 14-16'', it is the optimal balance point of paint dryness and atomization.

[0057] Test example 2 Influence of different spraying angles on repair coating of engineering machinery vehicle

[0058] In the environment of temperature 25℃, control the same conditions of spraying viscosity, spraying distance, spraying speed, spraying pressure, adopt different spraying angles to repair coating of engineering machinery vehicle, the test results are shown in Table 2.

[0059] Table 2 Repair coating results of engineering machinery vehicle under different spraying angles

[0060]

[0061]

[0062] As the results of Table 2 show, on the basis of normal spraying angle, the width of virtual edge is obviously increased by reducing the spraying angle; the width of virtual edge is improved by increasing the spraying angle, but sagging is increased when the angle exceeds 120°.

[0063] Test example 3 Influence of different spraying distances on repair coating of engineering machinery vehicle

[0064] In the environment of temperature 25℃, control the same conditions of spraying viscosity, spraying angle, spraying speed, spraying pressure, adopt different spraying distances to repair coating of engineering machinery vehicle, the test results are shown in Table 3.

[0065] Table 3 Repair coating results of engineering machinery vehicle under different spraying distances

[0066]

[0067]

[0068] As the results of Table 3 show, on the basis of normal spraying distance, increasing the spraying distance increases the width of the virtual edge; reducing the spraying distance can reduce the width of the virtual edge, but sagging occurs.

[0069] Test Example 4: Influence of different spraying speeds on the repair coating of engineering machinery vehicles

[0070] In an environment with a temperature of 25℃, the spraying viscosity, spraying angle, spraying distance, and spraying pressure were controlled to be the same, and different spraying angles were used for the repair coating of engineering machinery vehicles, and the test results are shown in Table 4.

[0071] Table 4: Results of the repair coating of engineering machinery vehicles at different spraying speeds

[0072]

[0073] As the results of Table 4 show, on the basis of normal spraying speed, reducing the spraying speed reduces the width of the virtual edge, but sagging occurs; increasing the spraying speed does not improve the width of the virtual edge, and there are obvious particles at the virtual edge.

[0074] Test Example 5: Influence of different spraying pressures on the repair coating of engineering machinery vehicles

[0075] In an environment with a temperature of 25℃, the spraying viscosity, spraying angle, spraying distance, and spraying speed were controlled to be the same, and different spraying pressures were used for the repair coating of engineering machinery vehicles, and the test results are shown in Table 5.

[0076] Table 5: Results of the repair coating of engineering machinery vehicles at different spraying pressures

[0077]

[0078] As the results of Table 5 show, on the basis of normal spraying pressure, reducing the spraying pressure reduces the width of the virtual edge, but when it is reduced to 0.1-0.2 MPa, there are a small amount of particles at the virtual edge; increasing the spraying pressure increases the width of the virtual edge.

[0079] The above test results are only for the single factor of spraying viscosity, spraying angle, spraying distance, spraying speed, spraying pressure under specific circumstances, the inventor considers the results of the above single test, and makes a large number of cross tests, and according to the large area and long time test on site, and a large number of tests on the fluid control knob and mode control knob, finally the optimal adjustment method is obtained; In the process of a large number of tests, it is found that the shielding air side of the atomizing hole can well control the shape and direction of the fan face during the spraying process, which plays a great role in solving the virtual edge, and after comprehensive consideration, the step five of the method of the application is formed. After solving the virtual edge according to step five of the method of the application, the virtual edge is improved obviously, and the width of the virtual edge is below 0.5cm.

[0080] In order to completely solve the problem of virtual edge, the inventor adopts the method of step five of the application, and then adopts the slow solvent mode to spray on the virtual edge periphery in the later stage to eliminate the virtual edge, that is, step six is carried out.

[0081] Test example 6: Screening of slow solvent

[0082] After the step five of the method of the application is completed, different slow solvents are used to eliminate the virtual edge, and the slow solvent suitable for step six is screened, and the test results are shown in Table 6.

[0083] Table 6: Results of different slow solvents on engineering machinery vehicle repair coating virtual edge treatment

[0084]

[0085] The environmental temperature of this test example is 25℃, different slow solvents with a mass of 40% are added into the polyurethane special diluent respectively, DBE and PMA are selected in the early stage of the test, and PMA is screened out considering the specific market factors in the later stage. Then, the amount of PMA, the spraying angle, the spraying distance, the gun speed, the air inlet pressure, the spraying number and the interval time parameters are determined in the environment of 10-35℃ to form step six of the method of the application.

[0086] Test example

[0087] Under the condition that other conditions are the same, the method of embodiment 3 of the application and the normal coating process are used respectively for engineering machinery vehicle repair coating, and the results are shown in Figure 1 and 2 .

[0088] As shown in Figure 1 , the repair area treated by the normal coating process has obvious white virtual edge, as shown in Figure 2 , the repair area treated by the method of embodiment 3 of the application has no virtual edge problem.

Claims

1. A method for solving the problem of loose edges in the paint of engineering machinery vehicles during repair, characterized in that, Includes the following steps: Step 1: Prepare acrylic polyurethane coating of the same color as the paint film on the surface of the construction machinery vehicle, and prepare three spray guns with nozzle diameters of 1.5mm, 1.3mm, and 1.3mm respectively; Step 2: Determine the areas requiring rework and repair based on the smallest possible area; Step 3: Sand the area that needs repair. Step 4: Adjust the viscosity of the acrylic polyurethane coating to 20-23″ using polyurethane-specific thinner. Apply the coating to the repair area using a 1.5mm nozzle spray gun. During the spraying process, keep the spray gun perpendicular to the repair area and control the distance between the spray gun and the repair area between 150-300mm. Control the gun speed at 30-60cm / s, adjust the air pressure to 0.3-0.4MPa, and control the coating thickness at 30-40μm. Step 5: Take another acrylic polyurethane coating and adjust the viscosity to 14-16″ using polyurethane-specific thinner. Immediately apply the coating to the perimeter of the repair area treated in Step 4 using one of the spray guns with a 1.3mm nozzle. During the spraying process, maintain an angle of 110°-120° between the spray gun and the repair area, and control the distance at 10-15cm. Control the gun speed at 20-30cm / s, adjust the air pressure to 0.1-0.2MPa, and control the coating thickness at 10-20μm. Step 6: Add 20-60% PMA by weight to the polyurethane-specific thinner to prepare a spraying agent. Under the condition of substrate temperature of 10-35℃, use another 1.3mm diameter spray gun to coat the outer perimeter of the area treated in Step 5. During the spraying process, keep the angle between the spray gun and the repair area at 160°-170° and the distance within 10cm. Control the gun speed at 20-30cm / s and adjust the air pressure to below 0.1MPa. Spray 2 coats, with an interval of 3-5 minutes between each coat. The spray gun used is model W-71; In steps five and six, keep the fluid control knob of the spray gun at its maximum setting during the spraying process, rotate the mode control knob clockwise 360°-540°, and completely cover the atomizing holes on the left or right side of the air cap with masking tape.

2. The method according to claim 1, characterized in that: The raw material composition of the acrylic polyurethane coating, by mass ratio, includes 45-55% hydroxyl acrylic resin, 14-16% pigment, 2-4% anti-settling agent, 6-8% anti-settling paste, 0.01-0.1% organotin, 0.1-1% defoamer, 0.1-0.5% leveling agent, 0.5-1% dispersant, 3-7% ethyl acetate, and 7-30% 100# solvent oil.

3. The method according to claim 1, characterized in that: The sandpaper used is of a grit size of 1000-1500.

4. The method according to claim 1, characterized in that: The raw material composition of the polyurethane-specific diluent, by mass ratio, includes 70-90% xylene and 10-30% cyclohexanone.

5. The method according to claim 1, characterized in that: The area surrounding the repaired area processed in step four is a region extending outward 2-3 cm from the virtual edge of the coating in step four.

6. The method according to claim 1, characterized in that: The outer perimeter of the area processed in step five is the area extending outward 1-2 cm from the virtual edge of the coating in step five.

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