Bipolar spraying system

Abstract

The utility model provides a bipolar spraying system which comprises a conveying mechanism used for conveying workpieces to be sprayed and spraying mechanisms used for spraying the workpieces, the spraying mechanisms are arranged on the two sides of the conveying mechanism, each spraying mechanism comprises a plurality of spraying devices, and the spraying devices are arranged on the conveying mechanism. The spraying devices are used for spraying charged powder paint to a workpiece to be sprayed, a plurality of spray guns facing the conveying mechanism are arranged on the spraying devices on the two sides, the spray guns comprise the spray guns with the positive polarity and the spray guns with the negative polarity, and the positive spray guns and the negative spray guns located on the same side are arranged in a staggered mode and used for spraying the workpiece. The spraying device of the bipolar spraying system provided by the utility model adopts a mode of combining the positive spray gun and the negative spray gun, weakens free ions in a workpiece through the positive spray gun, simultaneously enables the workpiece to be charged with different charges, and then sprays through the negative spray gun, so that the powdering rate of the workpiece is improved, and the working efficiency is improved. And the high-quality coating surface effect can be obtained while the high film thickness is obtained.

Description

Technical Field

[0001] The utility model belongs to the technical field of electrostatic powder spraying, and in particular relates to a bipolar spraying system. Background Art

[0002] Electrostatic powder spraying is a process of using a coating machine with an atomizing nozzle and a discharge electrode to micronize the paint, apply a charge to it, form an electric field between the electrode and the object to be coated, and use its electrostatic adsorption to coat. In the current practical application environment, the spray gun used in electrostatic powder spraying operations often adopts a negative electrode spray gun, that is, the spray gun is negatively charged. In theory, either positive or negative corona can be used to charge the powder (to charge the powder), but in practical applications, negative corona is mostly used because the breakdown voltage of the occasional spark generated by the positive corona is lower than that of the negative corona, and the corona discharge current obtained is relatively smaller, so the charging efficiency is also lower, making the spraying effect and efficiency not as good as that of the spray gun using the negative corona.

[0003] In electrostatic powder spraying operation, when the spray gun is spraying the workpiece, only a small part of the negative charge is combined with the powder coating and adsorbed onto the workpiece, while most of the negative charge is in a free state (i.e., in a free ion state) and is also adsorbed onto the workpiece; at the beginning of spraying, the workpiece is grounded during the transportation process, and the negative charge in a free state will be taken away from the workpiece ground; but when the powder coating on the workpiece reaches a certain thickness, due to the insulating properties of the plastic powder coating, the negative charge in a free state cannot be taken away by the workpiece grounding. When this part of the negative charge in a free state accumulates to a certain extent on the workpiece, it will reach a saturation value. When this saturation value is exceeded, the repulsive force generated by static electricity will reduce the adhesion and reduce the powder application. Excessive voltage will also break through the powder, causing surface defects of the coating, which will be particularly obvious in the case of insulating powder spraying.

[0004] Therefore, it is necessary to design a powder spraying device that can meet the coating thickness and has good coating surface effect. Utility Model Content

[0005] In view of this, the purpose of the utility model is to provide a bipolar spraying system that can achieve a higher coating thickness and good coating effect.

[0006] In order to solve the above technical problems, the utility model provides a bipolar spraying system, including a conveying mechanism for conveying a workpiece to be sprayed and a spraying mechanism for spraying the workpiece, the spraying mechanism is arranged on both sides of the conveying mechanism, the spraying mechanism includes a plurality of spraying devices, the spraying devices are used to spray charged powder coatings onto the workpiece to be sprayed, the spraying devices on both sides are provided with a plurality of spray guns facing the conveying mechanism, the spray guns include spray guns with positive and negative polarities, and the positive spray guns and the negative spray guns located on the same side are arranged alternately for spraying the workpiece.

[0007] Preferably, the spraying mechanism includes a first spraying device, a second spraying device, a third spraying device and a fourth spraying device, the first spraying device and the third spraying device are arranged on the same side relative to the conveying mechanism, the second spraying device and the fourth spraying device are arranged on the side opposite to the first spraying device and the third spraying device, relative to the conveying direction of the workpiece to be sprayed, the first spraying device and the second spraying device are at the front end, and the third spraying device and the fourth spraying device are at the rear end, the first spraying device, the second spraying device, the third spraying device and the fourth spraying device are all provided with spray gun assemblies, and the spray gun assemblies on the first spraying device, the second spraying device, the third spraying device and the fourth spraying device are arranged alternately.

[0008] Preferably, each of the spraying devices is provided with the spray gun assembly, and each of the spray gun assemblies is provided with four groups of spray guns in the horizontal direction, and the spray guns arranged on both sides of the conveying mechanism are staggered.

[0009] Preferably, each group of the spray guns on the spray gun assembly is provided with a plurality of spray guns in the vertical direction, and the spray guns are arranged at intervals in the vertical direction.

[0010] Preferably, the polarities of the four groups of spray guns on the first spray device, the second spray device, the third spray device and the fourth spray device are alternately arranged with positive and negative poles, and relative to the forward direction of the workpiece to be sprayed, the polarities of the first group of spray guns of the first spray device and the second spray device are the same, all are positive or all are negative.

[0011] Preferably, relative to the conveying direction of the workpiece to be sprayed, the polarity of the spray gun of the first spray device is negative, positive, negative, and negative in sequence; the polarity of the spray gun of the third spray device is positive, negative, positive, and negative in sequence; the polarity of the spray gun of the second spray device is negative, positive, negative, and positive in sequence; and the polarity of the spray gun of the fourth spray device is negative, negative, positive, and negative in sequence.

[0012] Preferably, the first and second groups of spray guns of the first spray device and the second spray device are arranged alternately, the third and fourth groups of spray guns of the first spray device are arranged between the second and third groups of spray guns of the second spray device, the first group of spray guns of the third spray device is arranged between the third and fourth groups of spray guns of the second spray device, the first and second groups of spray guns of the fourth spray device are arranged between the second and third groups of spray guns of the third spray device, and the third and fourth groups of spray guns of the third spray device and the fourth spray device are arranged alternately.

[0013] Preferably, the spray guns of the second spray device and the third spray device are evenly spaced, the spacing distance between the third and fourth groups of spray guns of the first spray device is smaller than the spacing distance between the first and second groups of spray guns, and the spacing distance between the first and second groups of spray guns of the fourth spray device is smaller than the spacing distance between the third and fourth groups of spray guns.

[0014] Preferably, a workpiece detection device is provided at the front end of the spraying mechanism for scanning the working condition of the workpiece to be sprayed; and a re-spraying station is provided at the rear end of the spraying mechanism for manually re-spraying the workpiece with spraying defects.

[0015] Preferably, the rear end of the spraying mechanism is provided with a powder solidification mechanism for heating the sprayed workpiece, a cooling mechanism for cooling the sprayed workpiece, and a material discharge area connected to the cooling mechanism.

[0016] The spraying device of the bipolar spraying system provided by the utility model adopts a combination of a positive spray gun and a negative spray gun, and adopts a method of first spraying the negative spray gun and then the positive spray gun. The free ions in the workpiece can be weakened by the positive spray gun, and the workpiece is charged with a different charge, and then sprayed by the negative spray gun at the rear, thereby improving the powder application rate of the workpiece, and a higher film thickness can be obtained while obtaining a high-quality coating surface effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other purposes, features and advantages of the present invention will become more apparent through a more specific description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals in all the accompanying drawings indicate the same parts, and the drawings are not intentionally scaled to the actual size, but the focus is on illustrating the subject matter of the present invention.

[0018] Figure 1 A schematic diagram of the structure of a bipolar spraying system provided in an embodiment of the utility model;

[0019] Figure 2 A side view of a spraying device provided by an embodiment of the utility model;

[0020] Figure 3 A schematic top view of a first spraying device provided in an embodiment of the utility model;

[0021] Figure 4 A schematic top view of a second spraying device provided in an embodiment of the utility model;

[0022] Figure 5 A schematic top view of a third spraying device provided in an embodiment of the utility model;

[0023] Figure 6A schematic top view of a fourth spraying device provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0024] The technical scheme of the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the utility model and implement it, but the examples given are not intended to limit the utility model. In the present embodiments, it should be understood that the orientations or positional relationships indicated by terms such as "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", and "outside" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the utility model, 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 of the utility model.

[0025] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element and integrated therewith, or there may be an intermediate element at the same time. The terms "installed", "one end", "the other end" and similar expressions used in this utility model are for illustrative purposes only.

[0026] For specific products, the coating thickness is required to meet the design requirements, and the coating thickness is thicker. The existing practice is to use more spray guns to spray to increase the coating thickness, but this practice has many disadvantages. First, it is necessary to design a larger powder spraying room to install more spray guns, and the resulting equipment cost is also higher. At the same time, more spray guns also mean more powder use and more powder recovery, that is, higher recovery costs; second, simply using more negative electrode spray guns to increase the coating thickness will make the surface effect of the coating extremely poor. The reason is that when a single negative polarity spray gun is used for spraying, when the coating thickness reaches a certain thickness, the free negative charge cannot be transported away by grounding and will accumulate on the coating surface. When the free negative charge reaches the saturation value, the repulsive force generated by static electricity will reduce the adhesion of the powder, that is, the powder coating rate decreases. When the voltage is too high, it will also break through the powder to cause pinholes, craters and other surface defects.

[0027] The embodiment of the utility model provides a bipolar spraying system, which includes a conveying mechanism 1 for conveying a workpiece 10 to be sprayed and a spraying mechanism 9 for spraying the workpiece 10. The spraying mechanism 9 is arranged on both sides of the conveying mechanism 1. The bipolar spraying system provided in this embodiment adopts a walking spraying process, that is, the workpiece 10 is continuously sprayed without stopping during the conveying process of the workpiece 10. The conveying mechanism 1 can be selected according to the parameters such as the shape and volume of the workpiece 10 to be sprayed, including a skid, a stacking chain, a common chain or a self-propelled hoist. The spraying mechanism 9 includes a plurality of spraying devices, each of which is provided with a spray gun assembly 6. The spray gun assemblies 6 on both sides face the workpiece 10 to be sprayed. The spray gun assemblies 6 on both sides are provided with a plurality of spray guns facing the conveying mechanism 9. The spray guns include spray guns with positive and negative polarities. The positive and negative polarities mentioned here refer to the powder coating being positively charged or negatively charged after being sprayed out by the spray gun. The spraying mechanism 9 includes a first spraying device 2, a second spraying device 3, a third spraying device 4 and a fourth spraying device 5. In actual production, the spraying mechanism 9 can be further increased according to the design parameters of the coating thickness required by the workpiece 10 to be sprayed, and is not limited to the use of four groups of spraying mechanisms 9. The first, second, third and fourth described here are also only used for description and are not used as specific limitations on the spraying mechanism 9. The first spraying device 2 and the third spraying device 4 are arranged on the same side relative to the conveying mechanism 1, and the second spraying device 3 and the fourth spraying device 5 are arranged on the same side, and are on the opposite side to the first spraying device 2 and the third spraying device 4, that is, when the workpiece 10 to be sprayed is conveyed through the spraying mechanism 9, the spraying devices on both sides will spray the workpiece 10 on both sides at the same time, which can effectively improve the spraying efficiency and complete the spraying operation at one time. Relative to the conveying direction of the workpiece 10 to be sprayed, the first spraying device 2 and the second spraying device 3 are at the front end, and the third spraying device 4 and the fourth spraying device 5 are at the rear end. The front end specifically refers to the first spraying device 2 and the second spraying device 3 first spraying the workpiece 10 when the workpiece 10 is conveyed. The rear end specifically refers to the third spraying device 4 and the fourth spraying device 5 arranged behind the first spraying device 2 and the second spraying device 3. The workpiece 10 is first sprayed by the first spraying device 2 and the second spraying device 3 and then by the third spraying device 4 and the fourth spraying device 5. The spray gun assemblies 6 on the first spraying device 2, the second spraying device 3, the third spraying device 4 and the fourth spraying device 5 are arranged alternately, and the spray gun assembly 6 includes a positive spray gun and a negative spray gun.By staggeredly arranging the positive electrode spray gun and the negative electrode spray gun and utilizing the attraction characteristics of heterogeneous charges, the saturation of free charge on the coating can be avoided. At the same time, the method of weakening first and then strengthening is adopted, that is, after spraying with the negative electrode spray gun, the positive electrode spray gun is used for spraying. At this time, the positive electrode spray gun neutralizes a large amount of free negative charges, reducing the adsorption of free negative charges to the surface of the workpiece 10. At this time, neutralizing the free negative charges will also reduce the powder application rate. The negative electrode spray gun is used again behind the positive electrode spray gun. Compared with the negative electrode spray gun at the back, the use of the positive electrode spray gun also makes the workpiece 10 carry heterogeneous charges, thereby improving the adsorption of negative charges of the negative electrode spray gun at the back, thereby improving the powder application rate and compensating for the weakened powder application rate of the positive electrode spray gun. The thickness of the coating can be continuously superimposed to obtain a coating with a higher film thickness. This is the working principle of the bipolar spray gun used in this embodiment.

[0028] In a preferred embodiment, the spray gun assemblies 6 on the first spray device 2, the second spray device 3, the third spray device 4 and the fourth spray device 5 each include four groups of spray guns, and the spray guns arranged on both sides of the conveying mechanism 1 are staggered. The so-called staggered arrangement specifically means that the muzzles of the spray guns opposite to each other on both sides of the conveying mechanism 1 are not directly opposite to each other, but the muzzles are staggered. This can avoid that during the spraying process, the muzzles that are directly opposite to the gap between adjacent workpieces 10 will directly spray powder onto the opposite muzzles. For each group of spray guns, multiple spray guns with the same polarity can be arranged in the vertical direction, that is, all are positive spray guns or all are negative spray guns, such as Figure 2 As shown, each group of spray guns is provided with three spray guns in the vertical direction, so that the workpiece 10 can be sprayed "over a large surface", which can meet the spraying needs of large-sized workpieces 10 and complete the spraying in one time.

[0029] Preferred embodiment 1: The polarity of the four groups of spray guns on the first spray device 2, the second spray device 3, the third spray device 4 and the fourth spray device 5 is alternately arranged with positive and negative poles, that is, the spray guns on any spray device are alternately arranged with positive pole spray guns and negative pole spray guns, that is, positive pole, negative pole, positive pole, negative pole spray guns, or negative pole, positive pole, negative pole, positive pole spray guns. The spray guns alternately arranged with positive and negative poles can release free charges, and a high film thickness coating can be easily obtained. To achieve the same coating thickness, the number of spray guns required is much less than that of pure negative pole spray guns. Relative to the forward direction of the workpiece 10 to be sprayed, the polarity of the first group of spray guns of the first spray device 2 and the second spray device 3 is the same, both are positive poles or both are negative poles, that is, the polarity of the spray guns opposite to each other on both sides of the conveying mechanism 1 is the same, so as to ensure that during the spraying process, the charge polarity of the powder coating received on both sides of the workpiece 10 is the same, and charge neutralization will not occur at the same position, thereby causing the problem of low powder coating rate. In the preferred embodiment 1, a spraying method with alternating positive and negative spray guns is adopted, so that a high film thickness coating can be easily obtained, and the surface effect of the coating is also significantly improved compared with the surface effect of the coating sprayed with only a single polarity spray gun.

[0030] Preferred embodiment 2: adopt the method of staggered arrangement of positive electrode spray guns and negative electrode spray guns, that is, it is not limited to the evenly alternating arrangement of positive electrode spray guns and negative electrode spray guns, but adopts a specific staggered arrangement order. Relative to the conveying direction of the workpiece 10 to be sprayed, the polarities of the spray guns 201, 202, 203, 204 of the first spraying device 2 are negative, positive, negative, negative, respectively, the polarities of the spray guns 401, 402, 403, 404 of the third spraying device 4 are positive, negative, positive, negative, respectively, the polarities of the spray guns 301, 302, 303, 304 of the second spraying device 3 are negative, positive, negative, positive, respectively, and the polarities of the spray guns 501, 502, 503, 504 of the fourth spraying device 5 are negative, negative, positive, negative, respectively. It can be obtained from Figure 1 It can be seen that the polarity order of the four groups of spray guns of the first, second, third and fourth spray devices 5 is not consistent, but in the case of the same side of the conveying mechanism 1, such as the side of the first spray device 2 and the third spray device 4, the two spray devices form eight groups of spray guns, and the positive spray guns are arranged between the two adjacent negative spray guns. In this way, the positive spray gun arranged between the negative spray guns plays a role in neutralizing the free negative charge, thereby reducing the negative charge accumulated on the surface of the workpiece 10, and can carry part of the positive charge at the same time, which can significantly improve the powder coating rate compared to the next negative spray gun; in addition, since there are fewer positive spray guns than negative spray guns, the weakening of the powder coating on the workpiece 10 is limited, but it is a proper weakening and then strengthening method, so that the surface effect of the coating has good quality, and the surface is smooth without pinholes and craters.

[0031] In this embodiment, the multiple groups of spray guns arranged relatively to the conveying mechanism 1 are arranged alternately, and the first group of spray guns of the first spray device 2 is located at the front end. The so-called front end means that the first group of spray guns of the first spray device 2 first sprays the workpiece 10. For example, the first group of spray guns mentioned above uses a negative electrode spray gun, which ensures that the workpiece 10 is sprayed with the negative electrode spray gun first.

[0032] In the second embodiment, Figure 1 As shown, the distances of the four groups of spray guns of each spraying device are set differently, specifically, the first and second groups of spray guns of the first spraying device 2 and the second spraying device 3 are arranged alternately, the third and fourth groups of spray guns of the first spraying device 2 are arranged between the second and third groups of spray guns of the second spraying device 3, the first group of spray guns of the third spraying device 4 is arranged between the third and fourth groups of spray guns of the second spraying device 3, the first and second groups of spray guns of the fourth spraying device 5 are arranged between the second and third groups of spray guns of the third spraying device 4, and the third and fourth groups of spray guns of the third spraying device 4 and the fourth spraying device 5 are arranged alternately. As shown in the figure, the spray guns of the second spraying device and the third spraying device are arranged evenly spaced, the spacing distance between the third and fourth groups of spray guns of the first spraying device is smaller than the spacing distance between the first and second groups of spray guns, and the spacing distance between the first and second groups of spray guns of the fourth spraying device is smaller than the spacing distance between the third and fourth groups of spray guns. Such an arrangement can effectively improve the powder coating rate of the workpiece 10. Specifically, compared with the arrangement with equal spacing distance, the arrangement in Example 2 increases the density of the negative electrode spray guns between the positive electrode spray guns. Specifically, considering the spray guns on both sides of the conveying mechanism 1 as a whole, it can be seen that there are three pairs of relatively staggered positive electrode spray guns, the first pair is the second group of spray guns of the first spraying device 2 and the second group of spray guns of the second spraying device 3, the second pair is the fourth group of spray guns of the second spraying device 3 and the first group of spray guns of the third spraying device 4, the third pair is the third group of spray guns of the third spraying device 4 and the third group of spray guns of the fourth spraying device 5, and three groups of negative electrode spray guns are arranged between each pair of positive electrode spray guns, while ensuring that the workpiece 10 is sprayed with negative electrode spray guns at the beginning and the end during the conveying process. After the free negative charge is weakened by the positive electrode spray gun, the use of the negative electrode spray gun is increased immediately, which can greatly make up for the powder coating rate, and the coating effect is of excellent quality.

[0033] In other preferred embodiments, a workpiece detection device 7 is provided at the front end of the spraying mechanism 9 for scanning the working condition of the workpiece 10 to be sprayed; a re-spraying station 8 is provided at the rear end of the spraying mechanism 9 for manually re-spraying the workpiece 10 with spraying defects.

[0034] In other preferred embodiments, the rear end of the spraying mechanism 9 is provided with a powder solidification mechanism for heating the sprayed workpiece 10 , a cooling mechanism for cooling the sprayed workpiece 10 , and a material discharge area connected to the cooling mechanism.

[0035] The embodiment of the utility model uses any of the above-mentioned bipolar spraying systems to spray a workpiece, comprising the following steps:

[0036] The conveying mechanism conveys the workpiece to be sprayed through the workpiece detection device first, scans the workpiece to be sprayed, and the spraying mechanism adjusts the working condition of the spraying device;

[0037] The multiple spraying devices of the spraying mechanism spray the workpiece to be sprayed in sequence, and the negative electrode spray gun and the positive electrode spray gun work alternately;

[0038] The workpieces that have been sprayed are transported to the re-spraying station, and the workpieces with spraying defects are re-sprayed;

[0039] The sprayed workpiece is heated, solidified and cooled.

[0040] The positive electrode spray gun of the spray device located on the same side is located between two adjacent negative electrode spray guns. Relative to the conveying direction of the workpiece to be sprayed, the first group and the last group of spray guns of the spray device are both negative electrode spray guns.

[0041] In order to illustrate in detail the spraying effect of the embodiment of the utility model and a single negative electrode spray gun on the same batch of workpieces, a comparative example is designed in which only the polarity of the spray gun is different from that of the second embodiment, and the other parameters are the same. All the spray guns in the comparative example are negative electrode spray guns. The workpieces are sprayed successively using the spraying method of the second embodiment and the spraying method of the comparative example. The measured values ​​of the coating thickness at the corresponding positions of the same batch of workpieces are as follows:

[0042] Table 1 Coating thickness values ​​of sprayed workpieces of Example 2 and Comparative Example

[0043] Thickness (μm) Position 1 Position 2 Position three Position Four Position Five Embodiment 2 344 352 360 359 352 Comparative Example 270 269 275 268 275

[0044] It can be seen from the above table that, using the same number of spray guns, the thickness of the workpiece sprayed with a bipolar spray gun is significantly greater than the thickness of the workpiece sprayed with a single cathode spray gun. By comparison, the workpieces sprayed with the bipolar spray gun of Example 2 and the single cathode spray gun have a smooth and flat surface without pinholes, craters and other defects, while the workpiece sprayed in the control example is uneven and has an uneven surface, and is an unqualified defective product.

[0045] The spraying device of the bipolar spraying system provided by the utility model adopts a combination of a positive spray gun and a negative spray gun, and adopts a method of first spraying the negative spray gun and then the positive spray gun. The free ions in the workpiece can be weakened by the positive spray gun, and the workpiece is charged with a different charge, and then sprayed by the negative spray gun at the rear, thereby improving the powder application rate of the workpiece, and obtaining a higher film thickness while obtaining a high-quality coating surface effect.

[0046] In this specification, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0047] In the description of this specification, the description with reference to the terms "preferred embodiment", "further embodiment", "other embodiments" or "specific example" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0048] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A bipolar spraying system, characterized in that: It includes a conveying mechanism for conveying a workpiece to be sprayed and a spraying mechanism for spraying the workpiece, the spraying mechanism is arranged on both sides of the conveying mechanism, the spraying mechanism includes multiple spraying devices, the spraying devices are used to spray charged powder coating on the workpiece to be sprayed, and the spraying devices on both sides are provided with multiple spray guns facing the conveying mechanism, the spray guns include spray guns with positive and negative polarity, and the positive spray guns and negative spray guns located on the same side are staggered for spraying the workpiece.

2. The bipolar spray system according to claim 1, characterized in that: The spraying mechanism includes a first spraying device, a second spraying device, a third spraying device and a fourth spraying device, the first spraying device and the third spraying device are arranged on the same side relative to the conveying mechanism, the second spraying device and the fourth spraying device are arranged on the side opposite to the first spraying device and the third spraying device, relative to the conveying direction of the workpiece to be sprayed, the first spraying device and the second spraying device are at the front end, and the third spraying device and the fourth spraying device are at the rear end, the first spraying device, the second spraying device, the third spraying device and the fourth spraying device are all provided with spray gun assemblies, and the spray gun assemblies on the first spraying device, the second spraying device, the third spraying device and the fourth spraying device are arranged alternately.

3. The bipolar spray system according to claim 1, characterized in that: Each of the spraying devices is provided with the spray gun assembly, and each of the spray gun assemblies is provided with four groups of spray guns in the horizontal direction. The spray guns arranged on both sides of the conveying mechanism are staggered.

4. The bipolar spray system according to claim 3, characterized in that: Each group of the spray guns on the spray gun assembly is provided with a plurality of spray guns in the vertical direction, and the spray guns are arranged at intervals in the vertical direction.

5. The bipolar spray system according to claim 2, characterized in that: The polarities of the four groups of spray guns on the first spray device, the second spray device, the third spray device and the fourth spray device are alternately arranged with positive and negative poles. Relative to the forward direction of the workpiece to be sprayed, the polarities of the first group of spray guns of the first spray device and the second spray device are the same, all positive or all negative.

6. The bipolar spray system according to claim 2, characterized in that: Relative to the conveying direction of the workpiece to be sprayed, the polarity of the spray gun of the first spraying device is negative, positive, negative, and negative in sequence; the polarity of the spray gun of the third spraying device is positive, negative, positive, and negative in sequence; the polarity of the spray gun of the second spraying device is negative, positive, negative, and positive in sequence; and the polarity of the spray gun of the fourth spraying device is negative, negative, positive, and negative in sequence.

7. The bipolar spray system according to claim 6, characterized in that: The first and second groups of spray guns of the first spray device and the second spray device are arranged alternately, the third and fourth groups of spray guns of the first spray device are arranged between the second and third groups of spray guns of the second spray device, the first group of spray guns of the third spray device is arranged between the third and fourth groups of spray guns of the second spray device, the first and second groups of spray guns of the fourth spray device are arranged between the second and third groups of spray guns of the third spray device, and the third and fourth groups of spray guns of the third spray device and the fourth spray device are arranged alternately.

8. The bipolar spray system according to claim 7, characterized in that: The spray guns of the second spray device and the third spray device are evenly spaced apart, the spacing distance between the third and fourth groups of spray guns of the first spray device is smaller than the spacing distance between the first and second groups of spray guns, and the spacing distance between the first and second groups of spray guns of the fourth spray device is smaller than the spacing distance between the third and fourth groups of spray guns.

9. The bipolar spray system according to claim 1, characterized in that: The front end of the spraying mechanism is provided with a workpiece detection device for scanning the working condition of the workpiece to be sprayed; the rear end of the spraying mechanism is provided with a re-spraying station for manually re-spraying the workpiece with spraying defects.

10. The bipolar spray system according to claim 1, characterized in that: The rear end of the spraying mechanism is provided with a powder solidifying mechanism for heating the sprayed workpiece, a cooling mechanism for cooling the sprayed workpiece, and a material unloading area connected to the cooling mechanism.

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