Method and apparatus for solder joint surface treatment

Abstract

The present application relates to the technical field of welding, and provides a welding spot surface treatment method and device.The method comprises electrolytic scar removal on the welding spot of the workpiece surface, overall passivation on the workpiece surface based on the workpiece qualified by electrolytic scar removal, and cleaning of the workpiece surface to clean electrolytic scar removal liquid and electrolytic passivation liquid attached to the workpiece surface.The method can quickly and conveniently eliminate oxidation color, eliminate color difference and improve the corrosion resistance of the workpiece after spot welding of the workpiece, thereby ensuring the quality of surface treatment and improving the efficiency of surface treatment.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a method and apparatus for surface treatment of weld joints. Background Technology

[0002] During spot welding, the heating process causes oxidation on the workpiece surface, resulting in an oxidized color at the weld joint. Spot welding also damages the passivation film on the workpiece surface, leading to significant surface defects. Therefore, surface treatment is necessary before the workpiece can be used. Traditional surface treatment methods are complex and unstable, involving a large amount of time and effort, severely impacting the efficiency of weld joint surface treatment and the quality of commercially viable products. Summary of the Invention

[0003] This invention provides a surface treatment method for solder joints to solve the technical problem of low efficiency caused by the complexity of existing surface treatment methods, thereby achieving fast, effective and reliable surface treatment and improving the efficiency of solder joint surface treatment.

[0004] The present invention also provides a solder joint surface treatment apparatus.

[0005] This invention provides a method for surface treatment of solder joints, comprising the following steps:

[0006] Electrolytic removal of weld marks on the surface of the workpiece;

[0007] Based on the workpiece that has passed the electrolytic mark removal test, the workpiece surface is passivated as a whole;

[0008] Clean the surface of the workpiece to remove the electrolytic scratch remover and electrolytic passivation solution adhering to the surface.

[0009] According to a surface treatment method for solder joints provided by the present invention, the step of electrolytically removing solder joint marks on the surface of a workpiece includes:

[0010] The descratching program is selected based on the degree of oxidation at the weld points on the workpiece surface. The drive unit grasps the descratching brush head and introduces electrolytic descratching liquid into the brush head. Based on the descratching program, the drive unit drives the brush head to grind the weld points and surrounding areas on the workpiece surface until the workpiece surface produces a metallic luster.

[0011] According to a solder joint surface treatment method provided by the present invention, the step of selecting a descaling procedure based on the degree of oxidation at the solder joint on the workpiece surface includes:

[0012] The degree of oxidation at the weld points on the workpiece surface is divided into light oxidation of the outer ring of the weld point, moderate oxidation of the outer ring of the weld point, and heavy oxidation of the entire weld point.

[0013] Based on the slight oxidation of the outer ring of the solder joint, the de-marking brush head grinds the solder joint and the area around the solder joint on the workpiece surface at a first grinding power;

[0014] Based on the moderate oxidation of the outer ring of the solder joint, the de-marking brush head grinds the solder joint and the area around the solder joint on the workpiece surface at a second grinding power;

[0015] Based on the overall severe oxidation of the weld joint, the de-marking brush head grinds the weld joint and the area around the weld joint on the workpiece surface at the third grinding power.

[0016] Wherein, the first grinding power is less than the second grinding power, and the second grinding power is less than the third grinding power.

[0017] According to a solder joint surface treatment method provided by the present invention, the first grinding power is 220 watts, the second grinding power is 500 watts, the third grinding power is 750 watts, and the electrolytic trace removal solution includes a 10% sodium gluconate solution.

[0018] According to the present invention, a method for surface treatment of solder joints includes a step of using a driving unit to drive a scratch-removing brush head to grind the solder joints and surrounding areas on the workpiece surface until a metallic luster is produced on the workpiece surface, based on the scratch-removing procedure.

[0019] Based on the aforementioned scratch removal procedure, the driving unit drives the scratch removal brush head to grind the solder joints on the workpiece surface and the area surrounding the solder joints within a 6 mm radius of the solder joint edge. After the electrolytic scratch removal solution of the brush head reacts with the solder joint surface, the driving unit drives the brush head to grind the solder joints on the workpiece surface. Once a metallic luster is produced at the solder joint, the driving unit drives the brush head to perform multi-stage circular motions around the solder joint as the center, and then grinds the area surrounding the solder joint on the workpiece surface. Along the direction from the solder joint to the area surrounding it, the radius of each stage of circular motion gradually increases, and the direction of rotation for each stage of circular motion is the same.

[0020] According to a surface treatment method for weld joints provided by the present invention, the step of performing overall passivation on the workpiece surface includes:

[0021] The passivation path is set based on the shape of the workpiece and the position of the weld points. The drive unit grasps the passivation brush head and introduces electrolytic passivation liquid into the passivation brush head. After the electrolytic passivation liquid of the passivation brush head reacts with the workpiece surface, the passivation brush head performs overall passivation on the workpiece surface along the passivation path at a preset passivation speed and preset passivation power. The passivation brush head stays at each weld point for a preset passivation time.

[0022] According to a solder joint surface treatment method provided by the present invention, the preset passivation speed is 1 minute per meter, the preset passivation power is 500 watts, the preset passivation time is 30 seconds, and the electrolytic passivation solution includes an 8% citric acid solution.

[0023] According to a surface treatment method for solder joints provided by the present invention, the passivation path includes multiple U-shaped paths connected in sequence, and the passivation path passes through each solder joint on the surface of the workpiece.

[0024] According to a solder joint surface treatment method provided by the present invention, the step of cleaning the workpiece surface to remove the electrolytic mark-removing solution and electrolytic passivation solution adhering to the workpiece surface includes:

[0025] The workpiece surface is cleaned by spraying to rinse away the electrolytic trace removal solution and electrolytic passivation solution adhering to the workpiece surface.

[0026] The present invention also provides a solder joint surface treatment apparatus, comprising:

[0027] Central control unit;

[0028] The drive unit is electrically connected to the central control unit;

[0029] A brush head library is suitable for storing scratch-removing brush heads and passivation brush heads. The scratch-removing brush heads are suitable for being detachably connected to the drive unit and used for electrolytic scratch removal of weld points on the surface of a workpiece. The passivation brush heads are suitable for being detachably connected to the drive unit and used for overall passivation of the surface of a workpiece.

[0030] The cleaning unit, electrically connected to the central control unit, is used to clean the surface of the workpiece to remove the electrolytic trace removal solution and electrolytic passivation solution adhering to the surface of the workpiece.

[0031] The solder joint surface treatment method provided in this invention eliminates surface oxidation color of the solder joints on the workpiece surface after resistance spot welding through electrolytic de-marking. A passivation step eliminates the color difference between the de-marked solder joints and the workpiece surface, improves the corrosion resistance of the workpiece in the solder joint area, and maintains the uniformity and consistency of the workpiece, ensuring commercial viability. A cleaning step cleans the workpiece surface to remove residual electrolytic de-marking and passivation solutions, ensuring surface cleanliness. This method enables rapid and convenient elimination of oxidation color and color difference, and improves the corrosion resistance of the workpiece after spot welding, ensuring both the quality and efficiency of surface treatment.

[0032] The solder joint surface treatment apparatus provided in this invention uses a de-marking brush head mounted on a drive unit and a central control unit to control the movement of the drive unit and the de-marking brush head to perform electrolytic de-marking on the workpiece surface. This electrolytic de-marking eliminates the surface oxidation color of the solder joints after resistance spot welding. A passivation brush head is mounted on the drive unit and its movement is controlled by the central control unit to passivate the entire workpiece surface. This passivation step eliminates the color difference between the de-marked solder joints and the workpiece surface, improves the corrosion resistance of the workpiece in the solder joint area, and maintains the uniformity and consistency of the workpiece, ensuring commercial viability. A cleaning unit cleans the workpiece surface to remove residual electrolytic de-marking and passivation solutions, ensuring surface cleanliness. Using this apparatus, oxidation color and color difference can be quickly and conveniently eliminated after spot welding, and the corrosion resistance of the workpiece can be improved. This not only ensures the quality of surface treatment but also improves its efficiency. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a schematic flowchart of the solder joint surface treatment method provided by the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of the solder joint surface treatment device provided by the present invention;

[0036] Figure 3 This is a schematic diagram of the electrolytic mark removal path in this invention;

[0037] Figure 4 This is a schematic diagram of the overall passivation path in this invention;

[0038] Figure 5 This is a diagram showing the degree of passivation of the workpiece surface and a schematic table showing the grinding power. Detailed Implementation

[0039] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0040] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0042] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0043] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0044] The following is combined Figures 1-5 The solder joint surface treatment method of the present invention includes the following steps:

[0045] S100. Electrolytically remove weld marks from the surface of the workpiece.

[0046] S200. Based on the workpiece that has passed the electrolytic demarking test, the workpiece surface is passivated as a whole.

[0047] S300 Clean the workpiece surface to remove the electrolytic trace removal solution and electrolytic passivation solution adhering to the workpiece surface.

[0048] In this embodiment, electrolytic de-marking eliminates the surface oxidation color of the weld points on the workpiece surface after resistance spot welding. A passivation step eliminates the color difference between the de-marked weld points and the workpiece surface, improves the corrosion resistance of the workpiece in the weld area, and maintains the uniformity and consistency of the workpiece, ensuring commercial viability. A cleaning step cleans the workpiece surface, removing residual electrolytic de-marking and passivation solutions to ensure surface cleanliness. This method allows for the rapid and convenient elimination of oxidation color and color difference, as well as improved corrosion resistance, after spot welding. It not only ensures the quality of surface treatment but also enhances its efficiency.

[0049] This weld joint surface treatment method is particularly applicable to the surface treatment process of spot welding on the sidewalls of rail vehicles, specifically the sidewalls of rail vehicles referred to in this embodiment. After spot welding of the rail vehicle sidewalls is completed, the weld joints on the sidewall surface are sequentially subjected to electrolytic de-marking, overall passivation, and surface cleaning. This achieves the effects of quickly and conveniently eliminating surface oxidation, eliminating color differences, and improving corrosion resistance after spot welding, thereby enhancing the commercial quality of rail vehicles.

[0050] Electrolytic demarking and overall passivation are both based on electrochemical principles. A drive unit assembles demarking brush heads and passivation brush heads to form the electrolytic devices for the demarking stage and the overall passivation stage, respectively. After eliminating the oxidation color on the weld surface following resistance spot welding, the demarking process eliminates the color difference between the weld and the sidewall base material surface, and improves the corrosion resistance of the sidewall weld area. This ensures a uniform and consistent commercial appearance for exposed parts of unpainted stainless steel vehicles. Vehicles are delivered in the correct condition after cleaning.

[0051] When there is only one weld point on the workpiece surface, the weld point is sequentially subjected to electrolytic demarking, overall passivation, and cleaning to complete the surface treatment of the weld point. When there are at least two weld points on the workpiece surface, at least two weld points are sequentially subjected to electrolytic demarking. After all weld points have been electrolytically demarked, overall passivation and cleaning are then sequentially performed to complete the surface treatment of the weld points.

[0052] When a workpiece has solder joints on only one surface, electrolytic demarking, overall passivation, and cleaning are performed sequentially on that surface to complete the solder joint surface treatment. When a workpiece has solder joints on at least two surfaces, electrolytic demarking is performed sequentially on the solder joints of at least two surfaces. After all solder joints have been electrolytically demarked, overall passivation is performed sequentially on at least two surfaces. After all surfaces have been overall passivated, cleaning is performed to complete the solder joint surface treatment. Alternatively, when a workpiece has solder joints on at least two surfaces, electrolytic demarking and overall passivation are performed sequentially on each surface. After each surface has undergone electrolytic demarking and overall passivation, cleaning is performed to complete the solder joint surface treatment.

[0053] The steps for electrolytically removing weld marks from the surface of a workpiece include:

[0054] The descratching program is selected based on the degree of oxidation at the weld points on the workpiece surface. The drive unit grasps the descratching brush head and introduces electrolytic descratching liquid into the brush head. Based on the descratching program, the drive unit drives the descratching brush head to grind the weld points and surrounding areas on the workpiece surface until the workpiece surface produces a metallic luster.

[0055] Understandably, the electrolytic resurfacing process is considered successful once a metallic luster is achieved on the workpiece surface. Electrolytic resurfacing should be stopped once this luster is achieved to avoid prolonged grinding, which could lead to white spots on the weld joints and negatively impact the resurfacing effect.

[0056] The drive unit can be a robot with a gripping end. The robot grips the scratch-removing brush head and grinds the weld points and surrounding areas on the workpiece surface based on the scratch-removing program. A liquid conduit is embedded within the scratch-removing brush head, and the robot has an electrolytic scratch-removing liquid channel. When the robot grips the scratch-removing brush head, the electrolytic scratch-removing liquid channel connects to the liquid conduit, allowing the electrolytic scratch-removing liquid to be injected sequentially through both the channel and the liquid conduit.

[0057] The robot may have an electrolytic trace removal storage area for storing electrolytic trace removal liquid. The electrolytic trace removal liquid channel is connected to the electrolytic trace removal storage area, and a pump is configured at the connection point to pump the electrolytic trace removal liquid stored in the electrolytic trace removal storage area to the electrolytic trace removal liquid channel.

[0058] When there is only one weld point on the workpiece surface, the drive unit grasps the descratching brush head and moves it to the weld point. Electrolytic descratching is then performed on the weld point and surrounding area until a metallic luster is achieved. Afterward, the drive unit automatically returns the brush head to its original position at an idle speed. When there are at least two weld points on the workpiece surface, the drive unit grasps the descratching brush head and moves it to the first weld point. Electrolytic descratching is then performed on the first weld point and surrounding area until a metallic luster is achieved. The drive unit then drives the brush head to perform electrolytic descratching on the remaining weld points sequentially until all weld points and their surrounding areas achieve a metallic luster. Afterward, the drive unit automatically returns the brush head to its original position at an idle speed.

[0059] When a workpiece has solder joints on only one surface, the drive unit grasps the de-marking brush head and performs electrolytic de-marking on all solder joints on that surface until all solder joints and the surrounding area produce a metallic luster. Afterward, the drive unit automatically returns the de-marking brush head to its original position at an idle speed. When a workpiece has solder joints on at least two surfaces, after completing the electrolytic de-marking on all solder joints on the first surface, the remaining surfaces are sequentially electrolytically de-marked until all solder joints and the surrounding area on all surfaces of the workpiece produce a metallic luster. Afterward, the drive unit automatically returns the de-marking brush head to its original position at an idle speed.

[0060] The steps for selecting a scratch removal procedure based on the degree of oxidation at the weld joints on the workpiece surface include:

[0061] The degree of oxidation at the weld points on the workpiece surface is divided into light oxidation of the outer ring of the weld point, moderate oxidation of the outer ring of the weld point, and heavy oxidation of the entire weld point.

[0062] Based on the slight oxidation of the outer ring of the solder joint, the scratch removal brush head grinds the solder joint and the area around the solder joint on the workpiece surface at the first grinding power.

[0063] Based on the moderate oxidation of the outer ring of the solder joint, the scratch removal brush head grinds the solder joint and the area around the solder joint on the workpiece surface at the second grinding power.

[0064] Based on the overall severe oxidation of the solder joint, the scratch removal brush head is used to grind the solder joint and the area around the solder joint on the workpiece surface at the third grinding power.

[0065] Among them, the first grinding power is less than the second grinding power, and the second grinding power is less than the third grinding power.

[0066] The degree of oxidation of the solder joint will affect the polishing power; the higher the polishing power, the greater the degree of trace removal. When the oxidation level is only light on the outer ring of the solder joint, electrolytic trace removal only needs to be performed at a lower polishing power; when the oxidation level is only moderate on the outer ring of the solder joint, electrolytic trace removal needs to be performed at a medium polishing power; when the oxidation level is heavy on the entire solder joint, electrolytic trace removal needs to be performed at a higher polishing power to ensure the effectiveness of electrolytic trace removal.

[0067] Figure 5 The second column shows a schematic diagram of the approximate shape of the solder joint under each degree of surface passivation. The criteria for judging mild oxidation of the outer ring of the solder joint is that there is a small amount of slight oxidation area on the outer ring of the solder joint. The criteria for judging moderate oxidation of the outer ring of the solder joint is that there is a small amount of relatively obvious oxidation area on the outer ring of the solder joint. The criteria for judging severe oxidation of the solder joint as a whole is that there is a large amount of relatively obvious oxidation area on both the solder joint and the outer ring of the solder joint.

[0068] like Figure 5 As shown, the first grinding power is 220 watts (W), the second grinding power is 500 watts, and the third grinding power is 750 watts. The electrolytic removal solution includes a 10% sodium gluconate solution. Using a 10% sodium gluconate solution as the electrolytic removal solution makes the surface treatment process green and environmentally friendly, and eliminates the need for waste liquid recycling.

[0069] The process of using a descratching procedure to drive a descratching brush head to grind the solder joints and surrounding areas on the workpiece surface until a metallic luster is achieved includes:

[0070] Based on the descratching process, the drive unit drives the descratching brush head to grind the solder joints on the workpiece surface and the area surrounding the solder joints within a 6 mm radius of the solder joint edge. After the electrolytic descratching solution of the descratching brush head reacts with the solder joint surface, the drive unit drives the descratching brush head to grind the solder joints on the workpiece surface. After the solder joints produce a metallic luster, the drive unit drives the descratching brush head to perform multi-stage circular motions around the solder joint as the center and grind the area surrounding the solder joint on the workpiece surface. In the direction from the solder joint to the area surrounding the solder joint, the radius of each stage of circular motion gradually increases, and the rotation direction of each stage of circular motion is the same.

[0071] like Figure 3 The diagram shows the path of the multi-stage circular motion. The solder joint and the 6m annular area around the edge of the solder joint are all subjected to de-marking grinding to ensure the thoroughness of electrolytic de-marking and to completely remove the oxide color from the solder joint and the surrounding area.

[0072] The de-marking brush head first moves to the solder joint to perform electrolytic de-marking. After the electrolytic de-marking at the solder joint is satisfactory, the brush head is driven to make a circular motion with a radius of R1, centered on the solder joint. When the electrolytic de-marking at the corresponding position in this area is satisfactory, the brush head is driven to make a circular motion with a radius of R2, centered on the solder joint. R2 is greater than R1, thus gradually increasing the radius of the circular motion to gradually complete the electrolytic de-marking of the solder joint and a 6 mm annular area around the solder joint edge. Each level of circular motion corresponds to a specific radius value. For example, the circular motion with a radius of R1 can be defined as the first level, the circular motion with a radius of R2 as the second level, the circular motion with a radius of R3 as the third level, and so on. The drive unit drives the brush head to perform multiple levels of circular motions and uses the brush head to grind the area around the solder joint on the workpiece surface.

[0073] The same direction of rotation in each stage of the circular motion ensures that the exposed substrate at each location has a roughly the same shape after the oxide layer is processed, thus ensuring aesthetics.

[0074] The steps for performing overall passivation on the workpiece surface include:

[0075] The passivation path is set based on the shape of the workpiece and the position of the weld points. The drive unit grabs the passivation brush head and introduces the electrolytic passivation solution into the passivation brush head. After the electrolytic passivation solution of the passivation brush head reacts with the workpiece surface, the passivation brush head performs overall passivation on the workpiece surface along the passivation path at a preset passivation speed and preset passivation power. The passivation brush head stays at each weld point for a preset passivation time.

[0076] The drive unit can be a robot with a gripping end. The robot grips the passivation brush head and performs overall passivation on the workpiece surface along the passivation path at a preset passivation speed and power. A liquid conduit is embedded within the passivation brush head, and the robot has an electrolytic passivation fluid channel. When the robot grips the passivation brush head, the electrolytic passivation fluid channel connects to the liquid conduit, allowing the electrolytic passivation fluid to be injected sequentially through both the channel and the conduit.

[0077] The robot may have an electrolytic passivation storage area for storing electrolytic passivation liquid. The electrolytic passivation liquid channel is connected to the electrolytic passivation storage area, and a pump is configured at the connection point to pump the electrolytic passivation liquid stored in the electrolytic passivation storage area to the electrolytic passivation liquid channel.

[0078] When a workpiece has only one surface with solder joints, a passivation path is planned on that plane, and the robot's gripping end picks up the passivation brush head and performs overall passivation on the surface along the passivation path at a preset passivation speed and power. When a workpiece has at least two surfaces with solder joints, a passivation path is planned for each surface based on the solder joint situation, and each surface is then passivated using the corresponding passivation path.

[0079] In this embodiment, the preset passivation speed is 1 meter per minute (m / min), the preset passivation power is 500 watts, and the preset passivation time is 30 seconds (s). The electrolytic passivation solution includes an 8% citric acid solution. The drive unit drives the passivation brush head to move along the passivation path at a speed of 1 meter per minute, stopping at each solder joint for 30 seconds. After passivation along the passivation path is completed, the drive unit drives the passivation brush head to automatically return to its original position at an idle speed. Using an 8% citric acid solution as the electrolytic passivation solution makes the surface treatment process green and environmentally friendly, eliminating the need for waste liquid recycling.

[0080] Given the more complex state of the solder joints, a longer passivation process is required. Therefore, this solution involves a 30-second passivation period at the solder joints to ensure the passivation effect.

[0081] like Figure 4 As shown, the passivation path consists of multiple sequentially connected U-shaped paths, and the passivation path passes through every solder joint on the workpiece surface. The lines and arrows indicate the passivation path and direction. The drive unit drives the passivation brush head along this path to perform overall passivation on the workpiece surface, ensuring that every location can be passivated by the electrolytic passivation solution.

[0082] When the passivation brush head moves to the door or window opening on the side wall, the passivation brush head stops discharging the electrolytic passivation solution to avoid wasting the solution.

[0083] Multiple interconnected U-shaped paths create a continuous passivation path, facilitating the movement of the passivation brush heads. Simultaneously, this ensures that the passivation brush heads cover all areas of the workpiece surface during passivation, guaranteeing complete overall passivation.

[0084] Of course, when passivating other plates or other components of a rail vehicle, the passivation path can be redesigned according to the shape of the plate. For example, when the plate is circular, the passivation path can be spiral.

[0085] The steps of cleaning the workpiece surface to remove the electrolytic mark-removing solution and electrolytic passivation solution adhering to the workpiece surface include:

[0086] The workpiece surface is cleaned by spraying to rinse away the electrolytic trace removal solution and electrolytic passivation solution adhering to the workpiece surface.

[0087] Taking the side wall of a rail vehicle as an example, the entire vehicle can be sprayed and cleaned after the side wall is assembled, so that the aforementioned electrolytic demarking and overall passivation can share a single cleaning system and process. This not only reduces the number of cleaning units but also shortens the cleaning process and reduces the time required for surface treatment.

[0088] The surface is rinsed by spraying. The electrolytic trace removal solution and electrolytic passivation solution adhering to the workpiece surface are sprayed off and flow down to the ground with the water. The surface is rinsed multiple times during the continuous spraying process to ensure the cleaning effect.

[0089] The solder joint surface treatment apparatus provided by the present invention is described below. The solder joint surface treatment apparatus described below can be referred to in correspondence with the solder joint surface treatment method described above.

[0090] like Figure 2 As shown, the solder joint surface treatment device of this embodiment includes a central control unit, a drive unit, a brush head library, and a cleaning unit. The drive unit is electrically connected to the central control unit. The brush head library is suitable for storing scratch-removing brush heads and passivation brush heads. The scratch-removing brush heads are suitable for being detachably connected to the drive unit and are used for electrolytically removing scratches from the solder joints on the workpiece surface. The passivation brush heads are suitable for being detachably connected to the drive unit and are used for overall passivation of the workpiece surface. The cleaning unit is electrically connected to the central control unit and is used for cleaning the workpiece surface to remove the electrolytic scratch-removing solution and electrolytic passivation solution adhering to the workpiece surface.

[0091] In this embodiment, by assembling a de-marking brush head on the drive unit and controlling the movement of the drive unit and the de-marking brush head using a central control unit, electrolytic de-marking is performed on the workpiece surface. This electrolytic de-marking eliminates the surface oxidation color of the weld points after resistance spot welding. By assembling a passivation brush head on the drive unit and controlling the movement of the drive unit and the passivation brush head using a central control unit, the entire workpiece surface is passivated. This passivation step eliminates the color difference between the weld points and the workpiece surface after de-marking, improves the corrosion resistance of the workpiece in the weld area, and maintains the uniformity and consistency of the workpiece, ensuring commercial viability. A cleaning unit cleans the workpiece surface to remove residual electrolytic de-marking and passivation solutions, ensuring the cleanliness of the workpiece surface. Using this device, oxidation color and color difference can be quickly and conveniently eliminated after spot welding, and the corrosion resistance of the workpiece can be improved. This not only ensures the quality of surface treatment but also improves its efficiency.

[0092] This weld joint surface treatment device is particularly suitable for the surface treatment of spot welds on the sidewalls of rail vehicles, that is, the workpiece referred to in this embodiment specifically includes the sidewalls of rail vehicles. After the spot welding of the rail vehicle sidewall is completed, the weld joints on the sidewall surface are sequentially subjected to electrolytic de-marking, overall passivation, and surface cleaning, achieving the effects of quickly and conveniently eliminating surface oxidation color, eliminating color difference, and improving corrosion resistance after spot welding, and improving the commercial quality of rail vehicles.

[0093] Both electrolytic demarking and overall passivation are based on electrochemical principles. Demarking brush heads and passivation brush heads are respectively assembled into electrolytic devices for the demarking stage and the overall passivation stage, based on a drive unit. After eliminating the oxidation color on the weld surface after resistance spot welding, the color difference between the weld and the sidewall base material surface is eliminated, and the corrosion resistance of the sidewall weld area is improved. This ensures a uniform and consistent commercial appearance for exposed parts of unpainted stainless steel vehicles. Vehicles are delivered in the correct condition after cleaning.

[0094] When there is only one weld point on the workpiece surface, the weld point is sequentially subjected to electrolytic demarking, overall passivation, and cleaning to complete the surface treatment of the weld point. When there are at least two weld points on the workpiece surface, at least two weld points are sequentially subjected to electrolytic demarking. After all weld points have been electrolytically demarked, overall passivation and cleaning are then sequentially performed to complete the surface treatment of the weld points.

[0095] When a workpiece has solder joints on only one surface, electrolytic demarking, overall passivation, and cleaning are performed sequentially on that surface to complete the solder joint surface treatment. When a workpiece has solder joints on at least two surfaces, electrolytic demarking is performed sequentially on the solder joints of at least two surfaces. After all solder joints have been electrolytically demarked, overall passivation is performed sequentially on at least two surfaces. After all surfaces have been overall passivated, cleaning is performed to complete the solder joint surface treatment. Alternatively, when a workpiece has solder joints on at least two surfaces, electrolytic demarking and overall passivation are performed sequentially on each surface. After each surface has undergone electrolytic demarking and overall passivation, cleaning is performed to complete the solder joint surface treatment.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for surface treatment of solder joints, characterized in that, Includes the following steps: The descratching process is selected based on the degree of oxidation at the weld points on the workpiece surface, and the weld points on the workpiece surface are electrolytically descratched; wherein, the degree of oxidation of the weld points affects the grinding power, and the greater the grinding power, the greater the degree of descratching. Based on the workpiece that has passed the electrolytic mark removal test, the workpiece surface is passivated as a whole; Clean the surface of the workpiece to remove the electrolytic mark-removing solution and electrolytic passivation solution adhering to the surface of the workpiece; The step of electrolytically removing weld marks from the workpiece surface includes: The drive unit grasps the scratch removal brush head and introduces electrolytic scratch removal liquid into it. Based on the scratch removal program, the drive unit drives the scratch removal brush head to grind the solder joints and surrounding areas on the workpiece surface until a metallic luster is produced. After the solder joints produce a metallic luster, the drive unit drives the scratch removal brush head to perform multi-stage circular motions around the solder joints and grind the surrounding areas on the workpiece surface. In this process, the radius of each stage of circular motion gradually increases along the direction from the solder joint to the surrounding area, and the rotation direction of each stage of circular motion is the same. The step of performing overall passivation on the workpiece surface includes: The passivation path is set based on the shape of the workpiece and the position of the weld points. The drive unit grasps the passivation brush head and introduces electrolytic passivation solution into the passivation brush head. After the electrolytic passivation solution of the passivation brush head reacts with the workpiece surface, the passivation brush head performs overall passivation on the workpiece surface along the passivation path at a preset passivation speed and preset passivation power. The passivation brush head stays at each weld point for a preset passivation time. The passivation path includes multiple U-shaped paths connected in sequence, and the passivation path passes through each weld point on the workpiece surface.

2. The solder joint surface treatment method according to claim 1, characterized in that, The step of selecting a descaling procedure based on the degree of oxidation at the weld points on the workpiece surface includes: The degree of oxidation at the weld points on the workpiece surface is divided into light oxidation of the outer ring of the weld point, moderate oxidation of the outer ring of the weld point, and heavy oxidation of the entire weld point. Based on the slight oxidation of the outer ring of the solder joint, the de-marking brush head grinds the solder joint and the area around the solder joint on the workpiece surface at a first grinding power; Based on the moderate oxidation of the outer ring of the solder joint, the de-marking brush head grinds the solder joint and the area around the solder joint on the workpiece surface at a second grinding power; Based on the overall severe oxidation of the weld joint, the de-marking brush head grinds the weld joint and the area around the weld joint on the workpiece surface at the third grinding power. Wherein, the first grinding power is less than the second grinding power, and the second grinding power is less than the third grinding power.

3. The solder joint surface treatment method according to claim 2, characterized in that, The first grinding power is 220 watts, the second grinding power is 500 watts, the third grinding power is 750 watts, and the electrolytic trace removal solution includes a 10% sodium gluconate solution.

4. The solder joint surface treatment method according to claim 1, characterized in that, The step of using the drive unit to drive the scratch removal brush head to grind the solder joints and surrounding area on the workpiece surface based on the scratch removal program until the workpiece surface produces a metallic luster includes: Based on the aforementioned descratching procedure, the driving unit drives the descratching brush head to grind the solder joints on the workpiece surface and the area surrounding the solder joints within a 6 mm radius of the solder joint edge. Specifically, after the electrolytic descratching solution of the descratching brush head reacts with the solder joint surface, the driving unit drives the descratching brush head to grind the solder joints on the workpiece surface.

5. The solder joint surface treatment method according to claim 1, characterized in that, The preset passivation speed is 1 minute per meter, the preset passivation power is 500 watts, the preset passivation time is 30 seconds, and the electrolytic passivation solution includes an 8% citric acid solution.

6. The surface treatment method for solder joints according to any one of claims 1-5, characterized in that, The step of cleaning the workpiece surface to remove the electrolytic trace remover and electrolytic passivation solution adhering to the workpiece surface includes: The workpiece surface is cleaned by spraying to rinse away the electrolytic trace removal solution and electrolytic passivation solution adhering to the workpiece surface.

7. A solder joint surface treatment device, characterized in that, Used to perform the solder joint surface treatment method as described in any one of claims 1-6; The solder joint surface treatment device includes: Central control unit; The drive unit is electrically connected to the central control unit; A brush head library is suitable for storing scratch-removing brush heads and passivation brush heads. The scratch-removing brush heads are suitable for being detachably connected to the drive unit and used for electrolytic scratch removal of weld points on the surface of a workpiece. The passivation brush heads are suitable for being detachably connected to the drive unit and used for overall passivation of the surface of a workpiece. The cleaning unit, electrically connected to the central control unit, is used to clean the surface of the workpiece to remove the electrolytic trace removal solution and electrolytic passivation solution adhering to the surface of the workpiece.

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