Method for spraying finish paint on outer surface of car door
By adjusting the bending angle and spraying process of the door to be sprayed, the paint film thickness is ensured to be consistent, and the problems of paint accumulation and paint bead formation at the bottom of large coverings are solved, and the uniformity and appearance uniformity of the paint layer on the door surface are achieved.
Patent Information
- Application Number
- CN202411544635.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-01-10
AI Technical Summary
Paint accumulation at the bottom of large automobile covers leads to the formation of paint beads, affecting the appearance quality, and the prior art is difficult to effectively reduce such defects, resulting in rework and paint layer inhomogeneity problems.
By dividing the model to be sprayed by the car door into the upper facade and the lower bending surface, adjusting the bending angle and spraying trajectory to ensure the consistency of the paint film thickness. Use a spray robot for horizontal detour spraying, gradually increasing the spacing between guns and reducing spraying Flow rate, control the flow of paint liquid to avoid accumulation.
It effectively reduces the accumulation of paint at the bottom of the door, reduces the chance of paint bead formation, improves the uniformity of the paint layer on the surface of the door and the uniformity of the paint film appearance, and avoids rework and paint layer defects.
Smart Images
Figure CN119281617A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of automobile technology, and in particular to a method for spraying topcoat on the outer surface of a vehicle door. Background Art
[0002] 80% of the appearance performance of a truck's cab depends on the exterior covering parts, especially the doors, side panels, front hood, etc., which are Class A surfaces that are touchable by hand and visible to the human eye. Any appearance defects on them will affect the appearance quality of the cab.
[0003] Large covering parts must reduce defects such as flow marks, blooming, and the appearance of paint beads on the bottom edge while ensuring the appearance properties of the paint film, such as film thickness, vividness, gloss, orange peel, color difference, etc. Because of these defects, the cab must be reworked by repolishing, repainting, etc., which not only destroys the corrosion-resistant primer coating but also makes it difficult to ensure the paint appearance performance of the covering parts.
[0004] The reason for the formation of paint beads at the bottom of the cab's exterior panels is that the paint spraying of the doors, side panels, and rear panels at the bottom is stopped here, resulting in a short pause and an increase in the amount of paint sprayed. At the same time, the paint flowing down from the top also gathers at the bottom, where the collected paint forms water drop-shaped paint beads that bulge out and cause appearance defects. Therefore, it can be seen that how to reduce the generation of paint beads at the bottom of large panels and improve the uniformity of the paint layer thickness on the surface of the panels has long been a difficult problem in the coating industry. Summary of the invention
[0005] In response to the shortcomings or one of the shortcomings raised by the above-mentioned background technology, an embodiment of the present application provides a method for spraying topcoat on the outer surface of a vehicle door, which can reduce the accumulation of paint flowing to the bottom of the vehicle door, reduce the probability of paint beads forming, and at the same time improve the uniformity of the thickness of the paint layer on the surface of the vehicle door, thereby achieving a paint film appearance with uniform film thickness.
[0006] The present application provides a method for spraying topcoat on the outer surface of a vehicle door, comprising:
[0007] Step S1, dividing the door surface to be sprayed into an upper vertical surface and a lower bending surface, wherein the lower bending surface is bent inward relative to the upper vertical surface;
[0008] Step S2, performing a vertical spraying test on the vehicle door, respectively detecting and comparing the paint film thickness on the upper vertical surface and the lower bending surface;
[0009] Step S3, if the thickness is not consistent, adjust the inward bending angle of the lower bending surface relative to the upper vertical surface, and return to the previous step S2;
[0010] Step S4: If the thickness is consistent, determine the inward bending angle of the lower bending surface relative to the upper vertical surface, and use the current angle as the upper and lower bending angles of the door for subsequent spraying production.
[0011] In some embodiments, the inward bending angle of the lower bending surface relative to the upper vertical surface ranges from 30° to 35°.
[0012] In some embodiments, the step S3 of adjusting the inward bending angle of the lower bending surface relative to the upper vertical surface includes:
[0013] When the paint film thickness on the upper facade is greater than the paint film thickness on the lower bending surface, the inward bending angle of the lower bending surface relative to the upper facade is reduced;
[0014] When the paint film thickness on the upper vertical surface is less than the paint film thickness on the lower bending surface, the inward bending angle of the lower bending surface relative to the upper vertical surface is increased.
[0015] In some embodiments, the vehicle door is subjected to a vertical spraying test using a spraying robot, and the spraying robot performs lateral circuitous spraying on the surface of the vehicle door to be sprayed according to a preset spraying trajectory;
[0016] The upper facade includes a window frame area and a main board area. On the window frame area, the preset spraying trajectory of the spraying robot surrounds the window frame area; on the main board area, the preset spraying trajectory of the spraying robot detours horizontally and deflects downward for spraying, and the spraying robot's gun spacing increases gradually from top to bottom. Exemplarily, the optimal gun spacing is between 50 and 100 mm, so the technical solution determines that the gun spacing increases gradually from 50 mm to 100 mm from top to bottom.
[0017] In some embodiments, during the process of the spraying robot's preset spraying trajectory on the main board area winding laterally and deflecting downward for spraying, the spraying flow rate of the spraying robot decreases step by step from top to bottom.
[0018] In some embodiments, the upper facade is provided with a window frame hole and a handle mounting hole located below the window frame hole, and the gun movement speed of the spray robot at the edge of the window frame hole, the edge of the handle mounting hole and the lower edge of the upper facade is greater than the gun movement speed at other positions of the upper facade.
[0019] In some embodiments, the electrostatic spraying voltage of the spraying robot at the edge of the window frame hole, the edge of the handle installation hole and the lower edge of the upper facade is smaller than the electrostatic spraying voltage at other positions of the upper facade.
[0020] In some embodiments, the vertical distance from the spray gun of the spray robot to the vehicle door is 150 mm to 300 mm, the coating viscosity of the spray paint is 26S to 33S, the spray flow rate is 250cc / min to 480cc / min, and the spray gun speed is 450mm / s to 700mm / s.
[0021] In some embodiments, the vehicle door is sprayed twice, the first spraying adopts an electrostatic spraying voltage of 60kV to 80kV, and the second spraying adopts an electrostatic spraying voltage of 20kV to 30kV.
[0022] The beneficial effects of the technical solution provided by this application include:
[0023] The embodiment of the present application provides a method for spraying topcoat on the outer surface of a vehicle door. Since the vehicle door surface to be sprayed is divided into an upper vertical surface and a lower bent surface, the lower bent surface is bent inwardly relative to the upper vertical surface; a vertical spraying test is performed on the vehicle door, and the paint film thicknesses on the upper vertical surface and the lower bent surface are respectively detected and compared; if the thicknesses are inconsistent, the inward bending angle of the lower bent surface relative to the upper vertical surface is adjusted, and the process returns to the previous step; if the thicknesses are consistent, the inward bending angle of the lower bent surface relative to the upper vertical surface is determined, and the current angle is used as the upper and lower bending angles of the vehicle door for subsequent spraying production.
[0024] Therefore, when the angle of the lower bending surface of the car door is appropriate, part of the paint on the upper vertical surface of the car door falls off, and part of it flows to the lower bending surface, and together with the paint attached to the lower bending surface, it reaches the same paint layer thickness as the lower bending surface. There will be no excess paint accumulating on the bottom edge of the lower bending surface to form a "paint bead" defect.
[0025] That is, the present application can change the amount of paint on the lower bending surface by adjusting the inward bending angle of the bottom folded edge of the door surface to be sprayed, so that the paint film thickness on the upper vertical surface and the lower bending surface can be consistent, reducing the accumulation of paint flowing to the bottom of the door and the probability of paint bead formation. At the same time, a variety of innovative spraying methods are used to improve the uniformity of the paint layer thickness on the door surface, thereby achieving a paint film appearance with uniform film thickness. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0027] Figure 1 This is a flowchart of an embodiment of the present application;
[0028] Figure 2 A schematic diagram of the structure of a vehicle door according to an embodiment of the present application;
[0029] Figure 3 for Figure 2 Schematic diagram of the local section at AA in the middle;
[0030] Figure 4 This is a schematic structural diagram of a preset spraying trajectory on a vehicle door in an embodiment of the present application.
[0031] In the accompanying drawings, the components represented by the reference numerals are listed as follows:
[0032] 100. Car door; 110. Upper facade; 111. Window frame hole; 112. Handle mounting hole; 120. Lower bending surface; 200. Spray gun. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0034] The bottom of large covering parts should be designed with a reasonable structural surface to ensure that the spray gun sprays at a reasonable angle. The amount of paint sprayed should be neither too much nor too little. If there is too little, the paint layer will be too thin to meet the paint quality requirements. If there is too much, the paint will flow to the bottom of the parts and gather to form paint beads. The hanging paint beads will cause quality defects and affect the quality and appearance of the cab. The paint beads must be polished off and re-sprayed.
[0035] However, polishing the paint beads destroys the original corrosion-resistant primer coating of the large cover parts formed through 18 electrophoretic coating lines. The re-sprayed primer lacks multiple chemical protective layers such as pre-treatment and phosphating. The thickness of the re-sprayed topcoat and local paint layer is difficult to unify with the paint layer sprayed on a large area of the parts surface that has been sprayed in the early stage, which is prone to defects such as local color difference.
[0036] Moreover, rework also affects the production rhythm of the entire cab spraying. Therefore, how to reduce the generation of paint beads at the bottom of large covering parts to ensure the uniformity of the paint layer thickness on the door surface has long been a difficult problem in the coating industry.
[0037] In response to the above-mentioned deficiencies or one of the deficiencies, an embodiment of the present application provides a method for spraying topcoat on the outer surface of a vehicle door, which can reduce the accumulation of paint flowing to the bottom of the vehicle door, reduce the probability of paint beads forming, improve the uniformity of the paint layer thickness on the surface of the vehicle door, and achieve a paint film appearance with uniform film thickness.
[0038] See also Figures 1 to 4 As shown, the embodiment of the present application provides a method for spraying topcoat on the outer surface of a vehicle door, comprising:
[0039] Step S1, dividing the surface of the vehicle door 100 to be sprayed into an upper vertical surface 110 and a lower bending surface 120, wherein the lower bending surface 120 is bent inwardly relative to the upper vertical surface 110;
[0040] Step S2, performing a vertical spraying test on the vehicle door 100, respectively detecting and comparing the paint film thicknesses on the upper vertical surface 110 and the lower bending surface 120;
[0041] Step S3, if the thickness is not consistent, adjust the inward bending angle of the lower bending surface 120 relative to the upper vertical surface 110, and return to the previous step S2;
[0042] Step S4, if the thickness is consistent, determine the inward bending angle of the lower bending surface 120 relative to the upper vertical surface 110, and use the current angle as the upper and lower bending angles of the vehicle door 100 for subsequent spraying production.
[0043] The method for spraying the topcoat on the outer surface of a vehicle door in an embodiment of the present application starts from the perspective of optimizing the surface of the vehicle door 100 to be sprayed, divides the surface of the vehicle door 100 to be sprayed into an upper vertical surface 110 and a lower bent surface 120, and changes the amount of paint on the lower bent surface 120 by adjusting the inward bending angle of the bottom folded edge of the surface of the vehicle door 100 to be sprayed, so that the paint film thickness on the upper vertical surface 110 and the lower bent surface 120 tend to be consistent.
[0044] When the paint film thickness is approaching uniformity, the inward bending angle of the lower bending surface 120 relative to the upper vertical surface 110 is used as a curing parameter of the surface to be sprayed on the vehicle door 100, which is applied to subsequent spraying production, thereby reducing the accumulation of paint flowing to the bottom of the vehicle door 100 and reducing the probability of paint bead formation, thereby improving the uniformity of the paint layer thickness on the surface of the vehicle door 100 and achieving a paint film appearance with uniform film thickness.
[0045] It should be noted that when the lower bending surface 120 of the vehicle door 100 is bent inward at an appropriate angle relative to the upper vertical surface 110, part of the paint on the upper vertical surface 110 of the vehicle door 100 falls off, and part of it flows to the lower bending surface 120, and is superimposed with the paint attached to the lower bending surface 120 to achieve the same paint layer thickness as the lower bending surface 120. There will be no excess paint accumulating on the bottom edge of the lower bending surface 120 to form a "paint bead" defect, and the paint film thickness of the lower bending surface 120 is inconsistent with the paint film thickness of the upper vertical surface 110.
[0046] That is, by adjusting the inward bending angle of the bottom folded edge of the side of the vehicle door 100 to be sprayed, the amount of paint on the lower bending surface 120 can be changed, so that the paint film thickness on the upper vertical surface 110 and the lower bending surface 120 can be made consistent, thereby reducing the accumulation of paint flowing to the bottom of the vehicle door 100, reducing the probability of paint bead formation, and improving the uniformity of the paint layer thickness on the surface of the vehicle door 100, thereby achieving a paint film appearance with uniform film thickness.
[0047] The purpose of this application is to design a reasonable bottom profile at the bottom of a large covering part, forming a reasonable angle profile with the large surface of the large covering part, ensuring that the paint spray gun 200 sprays the surface of the component at a reasonable spraying interval, while ensuring the amount of paint sprayed on the bottom and the thickness of the paint layer without causing accumulation and reducing the formation of paint beads.
[0048] For example, the embodiment of the present application takes the car door 100 as an example, the inward deflection angle of the bottom of the car door 100 tends to be 30°, and the deflection is fine-tuned between 30° and 35° in combination with the influence of the process cycle; when the entire car door 100 is sprayed from top to bottom and the spray gun 200 is sprayed along the upper vertical surface 110 of the car door 100, a part of the paint at the lower edge of the upper vertical surface 110 is diverted and dropped due to the effect of gravity, and 80% to 85% of the paint flows down to the lower bending surface 120 of the car door 100 and preliminarily covers the lower bending surface 120;
[0049] At the same time, in one spraying cycle, the wet paint sprayed on the upper facade 110 of the car door 100 flows down along the upper facade 110, and the flowing paint overlaps with the paint attached to the lower bending surface 120, so that the lower bending surface 120 reaches the same paint layer thickness as the upper facade 110, which not only ensures the paint layer thickness of the lower bending surface 120, but also avoids excessive paint on the lower bending surface 120 and the formation of paint beads at the bottom. The probability of paint beads is reduced, the uniformity of the paint layer thickness on the surface of the car door 100 is improved, and a paint film appearance with uniform film thickness is achieved.
[0050] It should be noted that the reason for the formation of paint beads at the bottom of the cab exterior cover is that the paint spraying at the bottom of the doors, side panels, rear panels, etc. is stopped here, resulting in a short pause and an increase in the amount of paint sprayed; at the same time, the paint liquid flowing down from the upper part also gathers at the bottom, and the gathered paint liquid forms water drop-shaped paint beads at the bottom, causing appearance defects; to solve such defects, it is necessary to improve product structure, paint process and coating properties, and start from multiple aspects;
[0051] The above-mentioned determination of the inward bending angle of the lower bending surface 120 relative to the upper vertical surface 110 is based on product structure considerations. A reasonable surface structure is designed to allow the paint spray gun 200 to spray the surface of the component at a reasonable angle, and the paint liquid flows and the film thickness formed is uniform; at the same time, a reasonable spraying process is used, and a reasonable spraying speed, gun travel speed, etc. are adopted to control the amount of paint at the bottom, so that a paint coating that meets the performance standards can be sprayed out, while avoiding the formation of paint beads.
[0052] In some alternative embodiments: See Figures 1 to 4As shown, an embodiment of the present application provides a method for spraying paint on the outer surface of a vehicle door, in which the angle at which the lower bending surface 120 is bent inward relative to the upper vertical surface 110 is in the range of 30° to 35°.
[0053] The angle at which the lower bent surface 120 of the vehicle door outer surface topcoat spraying method of the embodiment of the present application is bent inwardly relative to the upper vertical surface 110 is in the range of 30° to 35°, which can enable the paint on the upper vertical surface 110 of the vehicle door 100 to flow down and merge with the paint on the lower bent surface 120, so that the paint film thickness on the upper vertical surface 110 and the lower bent surface 120 of the vehicle door 100 is consistent, thereby reducing the probability of paint bead formation and improving the spraying quality.
[0054] It should be noted that when the inward bending angle of the lower bending surface 120 of the vehicle door 100 relative to the upper vertical surface 110 is less than 30°, the bottom edge of the vehicle door 100 is prone to form a "paint bead" defect; when the inward bending angle of the lower bending surface 120 of the vehicle door 100 relative to the upper vertical surface 110 is greater than 35°, the bottom edge of the vehicle door 100 is prone to form a "dust leakage" defect.
[0055] For example, when the bottom of the door 100 is deflected inward by 35 degrees, the spray gun 200 is perpendicular to the surface of the door 100 and moves horizontally from top to bottom for spraying. In order to reduce the paint spraying and splashing of the door 100 onto the bottom door frame, according to the spraying radius of the rotary cup spray gun 200, the position of the spray gun 200 will be biased upward and 6 to 8 mm away from the bottom of the door 100. The divergent paint flow sweeps across the bottom of the door 100 and together with the paint flowing down from the upper part of the door 100, ensures the paint spraying amount and paint film thickness at the bottom of the door 100.
[0056] Moreover, the paint on the upper facade 110 of the door 100 flows to the bend, part of which falls from the bottom of the upper facade 110 due to gravity, and part of which flows along the lower bend surface 120 to the lower edge of the door 100, and the diverted paint can cover the lower bend surface 120 without being accumulated to form paint particles. Moreover, this design structure can also be applied to other large covering parts, such as the lower part of the side panel.
[0057] The following table shows the amount of paint adhered to the lower bending surface 120 corresponding to different angles X:
[0058]
[0059] In some alternative embodiments: See Figures 1 to 4 As shown, the embodiment of the present application provides a method for spraying paint on the outer surface of a vehicle door. In step S3 of the method for spraying paint on the outer surface of a vehicle door, the angle of the lower bending surface 120 bending inward relative to the upper vertical surface 110 is adjusted, including:
[0060] When the paint film thickness on the upper facade 110 is greater than the paint film thickness on the lower bending surface 120, the inward bending angle of the lower bending surface 120 relative to the upper facade 110 is reduced;
[0061] When the thickness of the paint film on the upper vertical surface 110 is less than the thickness of the paint film on the lower bending surface 120 , the inward bending angle of the lower bending surface 120 relative to the upper vertical surface 110 is increased.
[0062] In the method for spraying paint on the outer surface of a vehicle door in the embodiment of the present application, the adjustment of the inward bending angle of the lower bending surface 120 relative to the upper facade 110 is further subdivided. When the paint film thickness on the upper facade 110 is greater than the paint film thickness on the lower bending surface 120, it means that the amount of paint diverted from the upper facade 110 to the lower bending surface 120 is insufficient, corresponding to the above-mentioned "leakage" defect. Therefore, in order to reduce the amount of paint diverted and dropped from the lower edge of the upper facade 110 due to gravity, it is necessary to reduce the inward bending angle of the lower bending surface 120 relative to the upper facade 110, and increase the amount of paint diverted from the upper facade 110 to the lower bending surface 120.
[0063] When the thickness of the paint film on the upper facade 110 is less than the thickness of the paint film on the lower bending surface 120, it means that the amount of paint diverted from the upper facade 110 to the lower bending surface 120 is too much, and the paint accumulates at the lower edge of the lower bending surface 120, which corresponds to the above-mentioned "paint bead" defect. Therefore, in order to increase the amount of paint diverted and dropped at the lower edge of the upper facade 110 due to gravity, it is necessary to increase the angle of the lower bending surface 120 bending inward relative to the upper facade 110, reduce the amount of paint diverted from the upper facade 110 to the lower bending surface 120, and avoid the paint accumulation at the lower edge of the lower bending surface 120 to form a "paint bead" defect.
[0064] In some alternative embodiments: See Figures 1 to 4 As shown, the embodiment of the present application provides a method for spraying paint on the outer surface of a vehicle door. In the method for spraying paint on the outer surface of a vehicle door, a vehicle door 100 is subjected to a vertical spraying test using a spraying robot. The spraying robot performs lateral circuitous spraying on the surface of the vehicle door 100 to be sprayed according to a preset spraying trajectory.
[0065] The upper facade includes a window frame area and a main board area. On the window frame area, the preset spraying trajectory of the spraying robot surrounds the window frame area. On the main board area, the preset spraying trajectory of the spraying robot detours laterally and offsets downward for spraying, and the gun movement spacing of the spraying robot gradually increases from top to bottom.
[0066] The method for spraying paint on the outer surface of a vehicle door in the embodiment of the present application starts from the perspective of optimizing the design of the spraying process of the vehicle door 100, reduces the probability of paint beads at the bottom of the vehicle door 100, and improves the uniformity of paint on the vehicle door 100. Specifically, in order to obtain good and stable paint surface quality of the vehicle door 100, firstly, the spraying process of the entire vehicle door 100 is sprayed by robots as much as possible to reduce the randomness of manual spraying; the use of robot spraying is convenient for curing the optimal spraying parameters and ensuring the consistency of the batch.
[0067] In addition, the spraying process of the car door 100 is optimized. Specifically, the robot spraying trajectory is optimized from the existing longitudinal detour to the horizontal detour to reduce the generation of paint beads at the bottom. The basic logic is to control the amount of paint sprayed from top to bottom of the entire car door 100, gradually reduce the accumulation of paint flowing to the root of the cover, and reduce the probability of paint beads; at the same time, the wet paint flowing down from the upper part of the car door 100 supplements the reduced amount of paint below, thereby ensuring that the paint film thickness of the entire car door 100 is uniform.
[0068] Specifically, the upper facade of the vehicle door 100 is divided into a window frame area and a main board area. On the window frame area, the preset spraying trajectory of the spraying robot surrounds the window frame area; on the main board area, the preset spraying trajectory of the spraying robot detours horizontally and deflects downward for spraying, and the spraying robot's gun spacing increases gradually from top to bottom. The end of the preset spraying trajectory of the window frame area coincides with the start of the preset spraying trajectory of the main board area.
[0069] For example, in order to spray high-quality paint on the door 100 and reduce the formation of paint beads, the process adopts a horizontal gun movement method, and the gun movement spacing in the main board area is gradually widened from top to bottom. In this embodiment, according to the spray cup system and molding air parameters of the spray gun 200 used by the main engine factory spray robot, it is determined that the optimal gun movement spacing is between 50 and 100 mm. Therefore, the gun movement spacing is gradually increased from 50 mm to 100 mm from top to bottom;
[0070] For example, the main board area is divided into three areas along the longitudinal direction, and the gun spacing of the three areas is 50mm→70mm→90mm. The amount of paint sprayed is gradually reduced from top to bottom, and the paint flowing down from the top makes up for the reduced amount of paint sprayed, so that the paint layer thickness of the entire car door 100 is uniform from top to bottom, achieving a paint film appearance with uniform film thickness; at the same time, the paint accumulation flowing to the root of the car door 100 is reduced, reducing the probability of paint beads forming.
[0071] In the method for spraying the topcoat on the outer surface of a vehicle door of an embodiment of the present application, when the spraying robot as a whole makes a lateral detour and sprays with an offset from top to bottom according to a preset spraying trajectory, the spraying flow rate of the spraying robot decreases step by step from top to bottom, thereby controlling the downward flow rate of the paint on the surface of the vehicle door 100, thereby achieving the purpose of reducing the probability of paint beads being generated at the bottom of the vehicle door 100 and improving the uniformity of paint application on the vehicle door 100.
[0072] For example, in order to spray high-quality paint on the car door 100 and reduce the formation of paint beads, the process adopts a horizontal gun movement method. The spacing of the gun movement in the main board area is gradually widened from top to bottom, and the spray flow rate is gradually reduced from top to bottom. The amount of paint sprayed on the surface of the car door 100 is more on the top and less on the bottom. The paint flowing down from the top can make up for the reduced amount of paint sprayed below, so that the paint layer thickness of the entire car door 100 is uniform from top to bottom, achieving a paint film appearance with a uniform film thickness; at the same time, the paint accumulation flowing to the root of the car door 100 is reduced, reducing the chance of paint beads forming.
[0073] In some alternative embodiments: See Figures 1 to 4 As shown, an embodiment of the present application provides a method for spraying paint on the outer surface of a vehicle door, wherein the corner points of a preset spraying trajectory of the method for spraying paint on the outer surface of a vehicle door are arranged around the vehicle door 100 to 50 mm from the edge, and the spraying flow rate of the spraying robot at the corner is smaller than the spraying flow rate at other positions.
[0074] The corner points of the preset spraying trajectory of the method for spraying the topcoat on the outer surface of the vehicle door of the embodiment of the present application are arranged at 50 mm from the periphery of the vehicle door 100 to the edge. Since the corner points are usually the intersection points of the longitudinal and transverse spraying paths, in order to avoid excessive paint spraying at this point, the generation of sagging and uneven paint film thickness. Therefore, the spraying flow rate of the spraying robot at the corner is set to be smaller than the spraying flow rate at other positions, which can reduce the amount of paint sprayed at the periphery of the vehicle door 100, reduce the generation of edge sagging, and make the paint spraying amount at the periphery of the vehicle door 100 consistent with the paint spraying amount area in the middle area, thereby ensuring uniform film thickness on the surface of the vehicle door 100.
[0075] Exemplarily, painting parameter points with corresponding parameter changes are designed on the same vehicle door 100, and the painting parameter points correspond to corner points. The spraying parameters of each painting parameter point are changed accordingly according to the needs, so as to ensure the spraying quality of the entire vehicle door 100. For example, painting parameter points are set on the window frame, the edge of the vehicle door 100, the periphery of the functional holes, and the corners of the edges. Changing the spraying parameters here, such as reducing the flow rate and reducing the amount of paint sprayed at the corners, will reduce the generation of sagging; reducing the flow rate at each control point from top to bottom, etc., controls the amount of paint sprayed, the spray width, etc., and then controls the film thickness, color and other properties of the formed paint.
[0076] Exemplarily, the spray flow rate value is between 250cc / min and 480cc / min, and the spray flow rate is the lowest at the molding holes of the vehicle door 100 and the bottom edge of the vehicle door 100, such as 250cc / min, to reduce the accumulation of paint in the holes and the bottom of the vehicle door 100 to produce paint beads; at the same time, in order to ensure the coating quality of the entire vehicle door 100, such as uniform coating thickness, high-quality vividness, gloss, orange peel, and no color difference of the coating, to reduce the accumulation of paint beads at the bottom of the vehicle door 100, the flow rate of the rotary cup of the spray gun 200 decreases step by step from top to bottom.
[0077] In some alternative embodiments: See Figures 1 to 4 As shown, an embodiment of the present application provides a method for spraying paint on the outer surface of a vehicle door, in which a window frame hole 111 and a handle mounting hole 112 located below the window frame hole 111 are provided on the upper facade 110 of the vehicle door 100, and the gun movement speed of the spraying robot at the edge of the window frame hole 111, the edge of the handle mounting hole 112 and the lower edge of the upper facade 110 is greater than the gun movement speed at other positions of the upper facade 110.
[0078] In the method for spraying the outer surface of a vehicle door in an embodiment of the present application, the spray robot has a gun movement speed greater than the gun movement speed at other positions of the upper facade 110 at the edge of the window frame hole 111, the edge of the handle mounting hole 112, and the lower edge of the upper facade 110, thereby reducing the accumulation of paint in the holes, the bottom of the vehicle door 100, and the window frame, and reducing the probability of sag and paint beads.
[0079] Exemplarily, the general spray gun speed is between 450 mm / s and 700 mm / s. The gun speed parameters for spraying the same car door 100 are set according to the production rhythm of the spraying line and the appearance of the car door 100. The gun speed is increased at the handle mounting hole 112 of the car door 100, the window frame hole 111, etc., and the maximum gun speed, such as 700 mm / s, is taken at the bottom edge of the car door 100 and the hole. This can reduce the accumulation of paint in the holes, the bottom of the car door 100 and the window frame, and reduce the probability of producing paint beads.
[0080] In some alternative embodiments: See Figures 1 to 4 As shown, an embodiment of the present application provides a method for spraying paint on the outer surface of a vehicle door, in which the electrostatic spraying voltage of a spraying robot at the edge of the window frame hole 111, the edge of the handle mounting hole 112 and the lower edge of the upper facade 110 is lower than the electrostatic spraying voltage at other positions of the upper facade 110.
[0081] The electrostatic spraying voltage of the spraying robot in the method for spraying the topcoat on the outer surface of the vehicle door of the embodiment of the present application at the edge of the window frame hole 111, the edge of the handle installation hole 112 and the lower edge of the upper facade 110 is lower than the electrostatic spraying voltage at other positions of the upper facade 110, which can reduce the accumulation of paint in the holes, the bottom of the vehicle door 100 and the window frame, and reduce the probability of paint beads. For example, When spraying, The electrostatic spraying voltage at the hole, the bottom of the door 100 and the window frame is the lowest electrostatic voltage, such as 20kv.
[0082] In some alternative embodiments: See Figures 1 to 4 As shown, an embodiment of the present application provides a method for spraying paint on the outer surface of a vehicle door, in which the vertical distance from the spray gun 200 of the spray robot to the vehicle door 100 is 150mm~300mm, the coating-4 cup viscosity of the spray paint is 26S~33S, the spray flow rate is 250cc / min~480cc / min, and the spray gun speed is 450mm / s~700mm / s, which is convenient for solidifying the spray parameters to conduct a vertical spray test to adjust the inward bending angle of the lower bending surface 120.
[0083] In some alternative embodiments: See Figures 1 to 4 As shown, an embodiment of the present application provides a method for spraying paint on the outer surface of a vehicle door, in which the vehicle door 100 is sprayed twice, the electrostatic spraying voltage used in the first spraying is 60kV~80kV, and the electrostatic spraying voltage used in the second spraying is 20kV~30kV.
[0084] In order to ensure the thickness and surface quality of the paint film of the entire vehicle door 100, the vehicle door 100 is sprayed with paint twice in the method for spraying the outer surface of the vehicle door in the embodiment of the present application; the first time uses a high spraying voltage, such as 60kv spraying, to ensure the painting rate of the entire vehicle door 100 and achieve the coating thickness required by the quality standard; then the second time is adjusted to a low voltage spraying, such as 20kv spraying, to adjust the color of the paint to achieve the coating color difference value required by the quality, thereby ensuring that the paint film has a good subjective visual impact on the human eye.
[0085] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.
[0086] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.
[0087] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A method for spraying topcoat on the outer surface of a vehicle door, characterized in that: The method comprises the following steps: The surface of the vehicle door (100) to be sprayed is divided into an upper vertical surface (110) and a lower bending surface (120), wherein the lower bending surface (120) is bent inwardly relative to the upper vertical surface (110); A vertical spraying test is performed on the vehicle door (100), and the thickness of the paint film on the upper vertical surface (110) and the lower bending surface (120) are respectively detected and compared; If the thickness is not consistent, adjust the inward bending angle of the lower bending surface (120) relative to the upper vertical surface (110), and return to the previous step; If the thickness is consistent, the inward bending angle of the lower bending surface (120) relative to the upper vertical surface (110) is determined, and the current angle is used as the upper and lower bending angles of the vehicle door (100) for application in subsequent spraying production.
2. The method for spraying topcoat on the outer surface of a vehicle door according to claim 1, characterized in that: The angle at which the lower bending surface (120) bends inwardly relative to the upper vertical surface (110) is in the range of 30° to 35°.
3. The method for spraying topcoat on the outer surface of a vehicle door according to claim 1, characterized in that: The adjusting the inward bending angle of the lower bending surface (120) relative to the upper vertical surface (110) comprises: When the thickness of the paint film on the upper vertical surface (110) is greater than the thickness of the paint film on the lower bending surface (120), the inward bending angle of the lower bending surface (120) relative to the upper vertical surface (110) is reduced; When the thickness of the paint film on the upper vertical surface (110) is less than the thickness of the paint film on the lower bending surface (120), the inward bending angle of the lower bending surface (120) relative to the upper vertical surface (110) is increased.
4. The method for spraying topcoat on the outer surface of a vehicle door according to claim 1, characterized in that: The vehicle door (100) is subjected to a vertical spraying test using a spraying robot, wherein the spraying robot performs horizontal and circuitous spraying on the surface of the vehicle door (100) to be sprayed according to a preset spraying trajectory; The upper facade includes a window frame area and a main board area. On the window frame area, the preset spraying trajectory of the spraying robot surrounds the window frame area. On the main board area, the preset spraying trajectory of the spraying robot detours laterally and offsets downward for spraying, and the gun movement spacing of the spraying robot gradually increases from top to bottom.
5. The method for spraying topcoat on the outer surface of a vehicle door as claimed in claim 4, characterized in that: In the process of spraying along the preset spraying trajectory of the spraying robot on the main board area, which detours laterally and deflects downward, the spraying flow rate of the spraying robot decreases step by step from top to bottom.
6. The method for spraying topcoat on the outer surface of a vehicle door according to claim 4, characterized in that: The corner points of the preset spraying trajectory are arranged at the edges of the vehicle door (100) on all sides, and the spraying flow rate of the spraying robot at the corners is smaller than the spraying flow rate at other positions.
7. The method for spraying topcoat on the outer surface of a vehicle door according to claim 1, characterized in that: The upper facade (110) is provided with a window frame hole (111) and a handle mounting hole (112) located below the window frame hole (111); the spraying robot has a gun moving speed greater than the gun moving speed at other positions of the upper facade (110) at the edge of the window frame hole (111), the edge of the handle mounting hole (112) and the lower edge of the upper facade (110).
8. The method for spraying topcoat on the outer surface of a vehicle door according to claim 1, characterized in that: The electrostatic spraying voltage of the spraying robot at the edge of the window frame hole (111), the edge of the handle installation hole (112) and the lower edge of the upper facade (110) is lower than the electrostatic spraying voltage at other positions of the upper facade (110).
9. The method for spraying topcoat on the outer surface of a vehicle door as claimed in claim 8, characterized in that: The vertical distance between the spray gun (200) of the spray robot and the vehicle door (100) is 150 mm to 300 mm, the coating viscosity of the spray paint is 26S to 33S, the spray flow rate is 250cc / min to 480cc / min, and the spray gun speed is 450mm / s to 700mm / s.
10. The method for spraying topcoat on the outer surface of a vehicle door according to claim 1, characterized in that: The vehicle door (100) is sprayed twice, the first spraying adopts an electrostatic spraying voltage of 60kV to 80kV, and the second spraying adopts an electrostatic spraying voltage of 20kV to 30kV.