PCB solder mask spraying apparatus and spraying method

Abstract

A PCB solder mask spraying apparatus and a spraying method. The apparatus comprises a first spraying device (200), a turnover device (100), a second spraying device (200) and a pre-baking device (300), which are sequentially arranged. The spraying device (200) comprises a conveying module (240), and a first spray gun (210), a second spray gun (220) and a third spray gun (230), which are sequentially arranged. The conveying module (240) is configured to convey a PCB (800); the first spray gun (210) is configured to spray a first ink on a top surface of the PCB (800), wherein same, upon being left to stand, forms a first layer (910); the second spray gun (220) is configured to spray a second ink on the first layer (910), wherein same, upon being left to stand, forms a second layer (920); the third spray gun (230) is configured to spray a third ink on the second layer (920), wherein same, upon being left to stand, forms a third layer (930); and the viscosity of the first ink is greater than that of the second and third inks. The turnover device (100) is capable of turning over the PCB (800) on the first spraying device (200) and conveying same to the second spraying device (200). The pre-baking device (300) is capable of pre-baking the PCB (800) on the second spraying device (200) and moving same out.

Description

PCB solder mask spraying equipment and spraying methods

[0001] This application claims priority to Chinese Patent Application No. 202510107978.6, filed with the Chinese Patent Office on January 23, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of PCB manufacturing technology, such as PCB solder mask spraying equipment and spraying methods. Background Technology

[0003] During the printing of printed circuit boards (PCBs), a layer of ink is often coated onto the surface of the PCB. After settling, this ink provides protection against moisture, insulation, and solder resist. Currently, the industry generally uses spray coating machines to apply solder resist ink to the PCB surface. The coating thickness and uniformity of the solder resist ink are crucial. However, due to the inherent fluidity of liquid ink, a sagging effect can occur when it is sprayed onto the PCB conductor lines, affecting the coverage of the conductors.

[0004] As shown in Figures 1 and 2, PCB 800' includes a substrate 820', an outer copper layer 830', and circuitry 810'. The outer copper layer 830' covers the substrate 820', and the circuitry 810' is located on the surface of the outer copper layer 830' and on both sides of the substrate 820'. The solder resist coating operation is performed by spraying ink onto the surface of PCB 800' using a spray gun 700'. After the ink settles, a solder resist layer 900' is formed. The nozzle diameter of the traditional spray gun 700' is 0.7-1.1 mm, the spray gun pressure is 3-6 kg, and the ink viscosity (Iwata cup viscosity) is 35-45 seconds. A single low-viscosity spraying operation can meet the solder resist thickness requirements of the finished product. When using the traditional horizontal low-pressure spraying method to spray thick copper boards (copper thickness ≥ 2 oz) of PCB 800', the solder resist layer 900' cannot simultaneously meet the requirements for circuitry thickness and board surface thickness. The requirements for line oil thickness are as follows: the top oil thickness L ≥ 10 micrometers and the corner oil thickness M ≥ 5 micrometers; the surface oil thickness requirement is as follows: surface oil thickness N ≤ 35 micrometers.

[0005] Currently, conventional low-pressure spraying inks have low viscosity, low atomization, and high ink volume. Low-viscosity inks have poor adhesion at thick copper line corners, easily resulting in thin ink and exposed copper. Furthermore, ink tends to accumulate at the openings of vias on PCB 800', easily leading to ink entering the vias. In actual production, if the board surface ink thickness N≦35 micrometers is controlled, the actual ink thickness will only be 2-3 micrometers, which is insufficient to meet the ink thickness requirements and easily leads to false copper leakage defects. Conversely, if the PCB 800' meets the ink thickness requirements, the corresponding board surface ink thickness N will exceed 45 micrometers, and at least half of the PCB 800' openings will exhibit ink entry and ink blockage defects.

[0006] The conventional solution is to use multiple spraying processes to solve this problem, but this process seriously affects production efficiency, and frequent operations increase the risk of scratches on the PCB800' surface. In addition, this process is only suitable for samples and small-batch production and cannot be mass-produced. Summary of the Invention

[0007] This application provides PCB solder mask spraying equipment and spraying method to simultaneously meet the solder mask thickness requirements of the circuit and the board surface, solve the problems of ink entering the hole and ink clogging the hole, and enable the large-scale industrialization of PCB spraying solutions.

[0008] To achieve this objective, the following technical solution is adopted in this application:

[0009] A PCB solder resist coating equipment is used to process PCBs. The equipment includes a first coating device, a flipping device, a second coating device, and a pre-baking device arranged sequentially along a conveying direction. Each coating device includes a conveying module and a first spray gun, a second spray gun, and a third spray gun arranged sequentially along the conveying direction. The conveying module conveys the PCB along the conveying direction. The first spray gun sprays a first ink onto the top surface of the PCB, and the first ink is allowed to stand for a first time to form a first layer. The second spray gun sprays a second ink onto the first layer, and the second ink is allowed to stand for a second time to form a second layer. The third spray gun sprays a third ink onto the second layer, and the third ink is allowed to stand to form a third layer. The viscosity of the first ink is greater than the viscosity of the second ink, and the viscosity of the third ink is greater than the viscosity of the second ink. The flipping device flips the PCB on the first coating device and conveys it to the second coating device. The pre-baking device pre-baks the PCB on the second coating device and removes it from the PCB solder resist coating equipment.

[0010] As an optional technical solution for PCB solder resist spraying equipment, the first spray gun can move closer to or further away from the conveying module; and / or, the second spray gun can move closer to or further away from the conveying module; and / or, the third spray gun can move closer to or further away from the conveying module.

[0011] As an optional technical solution for PCB solder resist spraying equipment, the first spray gun is slidably connected to the conveying module along the moving direction; and / or, the second spray gun is slidably connected to the conveying module along the moving direction; and / or, the third spray gun is slidably connected to the conveying module along the moving direction, wherein the moving direction is perpendicular to the conveying direction.

[0012] As an optional technical solution for PCB solder mask spraying equipment, the operating speed of the first spray gun is greater than that of the second spray gun; and / or, the operating speed of the first spray gun is greater than that of the third spray gun.

[0013] As an optional technical solution for PCB solder mask spraying equipment, the nozzle diameter of the first spray gun is smaller than that of the second spray gun; and / or, the nozzle diameter of the first spray gun is smaller than that of the third spray gun.

[0014] As an optional technical solution for PCB solder mask spraying equipment, the total amount of ink sprayed by the first spray gun, the second ink sprayed by the second spray gun, and the third ink sprayed by the third spray gun is the ink volume. The first ink sprayed by the first spray gun accounts for 40-60% of the ink volume, the second ink sprayed by the second spray gun accounts for 20-30% of the ink volume, and the third ink sprayed by the third spray gun accounts for 20-30% of the ink volume.

[0015] As an optional technical solution for PCB solder mask spraying equipment, in one of the spraying devices, the first spray gun and the second spray gun are arranged at intervals, and the second spray gun and the third spray gun are arranged at intervals.

[0016] As an optional technical solution for PCB solder mask spraying equipment, the distance between the first spray gun and the second spray gun in the conveying direction is a first distance, and the distance between the second spray gun and the third spray gun in the conveying direction is a second distance, wherein the first distance is equal to the second distance.

[0017] As an optional technical solution for PCB solder resist spraying equipment, the spray gun pressure of the first spray gun is greater than that of the second spray gun; and / or, the spray gun pressure of the first spray gun is greater than that of the third spray gun.

[0018] The PCB solder mask spraying method, applied to the aforementioned PCB solder mask spraying equipment, includes the following steps:

[0019] S1: Place the PCB on the first spraying device, first use the first spray gun to repeatedly spray the first ink on the top surface of the PCB, let it stand for the first time to form the first layer, then use the second spray gun to repeatedly spray the first layer with the second ink, let it stand for the second time to form the second layer, and then use the third spray gun to repeatedly spray the third ink on the top surface of the PCB.

[0020] S2: The PCB is flipped using the flipping device and conveyed to the second spraying device;

[0021] S3: Repeat the ink spraying process of S1 in the second spraying device;

[0022] S4: The PCB on the second spraying device is pre-baked horizontally and vertically using the pre-baking device, and then the PCB is removed from the PCB solder resist spraying equipment.

[0023] The beneficial effects of this application are:

[0024] This PCB solder mask coating equipment achieves double-sided solder mask coating on PCBs by setting up a first coating unit, a flipping unit, and a second coating unit. The coating unit uses three spray guns to sequentially spray inks of different viscosities, improving production efficiency and coating quality. This allows for layer-by-layer ink application, enabling rapid and continuous multi-layer solder mask coating and increasing coating efficiency. The high-viscosity first ink sprayed by the first spray gun forms a first layer with better ink adhesion to the circuitry, providing a stable base for subsequent second and third layers and improving the adhesion of the solder mask layer. The low-viscosity second and third inks sprayed by the second and third spray guns continue to coat the first layer, ensuring the uniformity and consistency of the multi-layer solder mask. The method of sequentially spraying high-viscosity first ink, low-viscosity second ink, and low-viscosity third ink can simultaneously meet the PCB circuitry ink thickness requirements and the board surface ink thickness requirements during the coating process. Furthermore, the scheme of spraying the required surface ink thickness in three stages reduces the wet film thickness of each spray gun, thereby reducing the risk of ink entering vias and minimizing ink entry problems.

[0025] In conventional low-pressure spraying, the corresponding spraying equipment only has a single spray gun for spraying a single type of ink, and PCB processing requires multiple spraying and baking cycles. However, the PCB solder mask spraying equipment provided in this embodiment can achieve a single spraying and baking process. Compared to conventional low-pressure spraying, this significantly improves work efficiency and product quality, while also reducing the number of spraying and baking steps, thereby effectively reducing the risk of scratches on the PCB surface.

[0026] The above improvements, combined with the conveyor module, enable smooth PCB transport, enhancing the automation of the production process and reducing operator workload. The flipping device allows for automatic PCB flipping, ensuring both sides receive uniform spraying and processing, minimizing manual intervention and meeting process requirements. The pre-baking device can connect to a second spraying unit to pre-bake the sprayed PCB, achieving a seamless transition, facilitating subsequent processing, improving solder mask performance, and ensuring PCB stability and stability during spraying. This design makes the PCB solder mask spraying equipment precise, efficient, and stable, enabling efficient and continuous solder mask spraying of PCBs, improving production efficiency and product quality, reducing production costs, and allowing for large-scale industrialization of PCB spraying solutions with broad application prospects and market value.

[0027] This PCB solder mask spraying method, through multiple reciprocating spraying and resting processes, ensures that each layer of solder mask ink evenly covers and tightly bonds the circuitry, improving the ink adhesion and uniformity of the solder mask layer. This reduces defects and scrap rates caused by uneven spraying. The first layer formed by the first ink sprayed from the first spray gun has higher thickness and viscosity, effectively enhancing the adhesion and uniformity of subsequent spraying. Using a flipping device to turn the PCB over and spray again achieves uniform ink spraying and treatment on both sides of the PCB, improving the PCB's integrity and functionality without requiring additional steps, thus simplifying the operation process. Repeating the ink spraying process in the second spraying device ensures consistent solder mask spraying quality and solder mask layer thickness on both sides, improving product quality and aesthetics. The pre-baking device can quickly and effectively pre-bake the PCB, improving production efficiency, shortening the production cycle, and the pre-baking process also improves the wear resistance and heat resistance of the solder mask layer. Meanwhile, horizontal pre-baking effectively reduces ink dripping and running, while vertical pre-baking helps reduce the risk of PCB bending due to gravity, thus improving the PCB's appearance quality. The aforementioned PCB solder mask spraying method is simple, efficient, stable, and reliable, reducing production costs and scrap rates, meeting the high efficiency and high quality requirements of modern electronics manufacturing, and possessing significant economic benefits and technological advantages. Attached Figure Description

[0028] Figure 1 is a partial structural diagram of the PCB and solder mask layer in the related technology;

[0029] Figure 2 is a schematic diagram of the structure of the spray gun, PCB and solder mask in the related technology;

[0030] Figure 3 is a structural schematic diagram of the PCB solder resist spraying equipment provided in an embodiment of this application;

[0031] Figure 4 is a schematic diagram of the spraying device provided in an embodiment of this application;

[0032] Figure 5 is a schematic diagram of the spraying device, PCB and solder mask layer provided in the embodiment of this application;

[0033] Figure 6 is a partial structural diagram of the PCB and solder mask layer provided in an embodiment of this application.

[0034] In Figures 1 and 2:

[0035] 700', Spray gun; 800', PCB; 810', Circuit board; 820', Substrate; 830', Outer copper layer; 900', Solder mask layer;

[0036] Figures 3 to 6:

[0037] X: Direction of transport; Y: Direction of movement;

[0038] 100. Tilting device;

[0039] 200. Spraying device; 210. First spray gun; 220. Second spray gun; 230. Third spray gun; 240. Conveyor module;

[0040] 300. Pre-baking device;

[0041] 800, PCB; 820, substrate; 830, outer copper layer;

[0042] 900, solder mask layer; 910, first layer; 920, second layer; 930, third layer. Detailed Implementation

[0043] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. The described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and for 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 this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Specifically, the terms "first position" and "second position" refer to two different positions. Moreover, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0047] As shown in Figures 3 to 6, this embodiment provides a PCB solder resist spraying device for processing PCB 800. The PCB solder resist spraying device includes a first spraying device 200, a flipping device 100, a second spraying device 200, and a pre-baking device 300 arranged sequentially along the conveying direction X. The spraying device 200 includes a conveying module 240 and a first spray gun 210, a second spray gun 220, and a third spray gun 230 arranged sequentially along the conveying direction X. The conveying module 240 is used to convey the PCB 800 along the conveying direction X. The first spray gun 210 is used to spray a first ink onto the top surface of the PCB 800. The first ink is allowed to stand for a first time to form... A first layer 910 is formed. A second spray gun 220 is used to spray a second ink onto the first layer 910. The second ink is allowed to stand for a second time to form a second layer 920. A third spray gun 230 is used to spray a third ink onto the second layer 920. The third ink is allowed to stand to form a third layer 930. The viscosity of the first ink is greater than that of the second ink, and the viscosity of the third ink is greater than that of the third ink. A flipping device 100 can flip the PCB 800 on the first spraying device 200 and transfer it to the second spraying device 200. A pre-baking device 300 can pre-bake the PCB 800 on the second spraying device 200 and remove it from the PCB solder resist spraying equipment.

[0048] For ease of description, the following defines the first layer 910, the second layer 920 and the third layer 930 stacked in sequence as forming the solder mask layer 900; the PCB 800 includes a substrate 820 and an outer copper layer 830, the outer copper layer 830 covering the substrate 820, and the first layer 910 formed on the outer copper layer 830.

[0049] This PCB solder resist coating equipment achieves double-sided solder resist coating on PCB 800 by setting up a first coating device 200, a flipping device 100, and a second coating device 200. The coating device 200 uses three spray guns to sequentially spray inks of different viscosities, improving production efficiency and coating quality. This allows for layer-by-layer ink coating, enabling rapid and continuous multi-layer solder resist coating and increasing efficiency. The high-viscosity first ink sprayed by the first spray gun 210 forms the first layer 910, which has better ink adhesion to the circuitry, providing a stable substrate for the subsequent second and third layers 920 and 930, thus improving the adhesion of the solder resist layer 900. The low-viscosity second and third inks sprayed by the second and third spray guns 220 and 230 respectively continue to coat the first layer 910, ensuring the uniformity and consistency of the multi-layer solder resist. The method of sequentially spraying high-viscosity first ink, low-viscosity second ink, and low-viscosity third ink can simultaneously meet the ink thickness requirements of the PCB 800 circuitry and the board surface during the coating process. Meanwhile, the solution of spraying the required surface ink thickness in three stages can reduce the wet film thickness of each spray, thereby reducing the risk of ink entering the hole and minimizing ink entry problems.

[0050] In conventional low-pressure spraying, the corresponding spraying equipment only has a single spray gun for spraying a single type of ink, and the PCB processing requires multiple spraying and baking cycles. However, the PCB solder mask spraying equipment provided in this embodiment can achieve a single spraying and baking process. Compared with the conventional low-pressure spraying solution, it significantly improves work efficiency and product quality, while also reducing the number of spraying and baking steps, thereby effectively reducing the risk of scratches on the PCB800 surface.

[0051] The above improvements, combined with the conveyor module 240, enable smooth transport of the PCB800, contributing to increased automation in the production process and reducing operator workload. The flipping device 100 automatically flips the PCB800, ensuring both sides receive uniform spraying and processing, reducing manual intervention and meeting process requirements. The pre-baking device 300 can connect to the second spraying device 200 to pre-bake the sprayed PCB800, achieving a seamless transition and facilitating subsequent processing. This improves the performance of the solder mask layer 900 and ensures the stability and stability of the PCB800 during the spraying process. The above design makes the PCB solder mask spraying equipment precise, efficient, and stable, achieving efficient and continuous solder mask spraying of the PCB800. This improves production efficiency and product quality, reduces production costs, and enables large-scale industrialization of the PCB800 spraying solution, demonstrating broad application prospects and market value.

[0052] In this embodiment, the Iwata cup viscosity of the first ink is 80.00-100.00 seconds, the Iwata cup viscosity of the second ink is 35.00-45.00 seconds, and the Iwata cup viscosity of the third ink is 35.00-45.00 seconds.

[0053] In one embodiment of this invention, the first spray gun 210 can move closer to or further away from the conveying module 240; the second spray gun 220 can move closer to or further away from the conveying module 240; and the third spray gun 230 can move closer to or further away from the conveying module 240.

[0054] The first spray gun 210, the second spray gun 220, and the third spray gun 230 can move closer to or further away from the conveyor module 240. This design allows the spray guns to be positioned according to actual needs, making the spraying process more flexible and adaptable to PCBs 800 of different sizes and shapes, thus improving the flexibility and versatility of the PCB solder mask spraying equipment. At the same time, the movable design of the spray guns helps to achieve a more uniform spraying effect and reduces ink waste.

[0055] In other embodiments of this example, only the first spray gun 210 is limited to moving closer to or further away from the conveying module 240, or only the third spray gun 230 is limited to moving closer to or further away from the conveying module 240.

[0056] In one embodiment of this invention, the first spray gun 210 is slidably connected to the conveying module 240 along the moving direction Y; the second spray gun 220 is slidably connected to the conveying module 240 along the moving direction Y; and the third spray gun 230 is slidably connected to the conveying module 240 along the moving direction Y, wherein the moving direction Y is perpendicular to the conveying direction X.

[0057] The design of the spray gun slidingly connected to the conveyor module 240 along the moving direction Y allows for more stable spraying operations, thereby achieving precise control over the spraying of the PCB800 surface, improving the uniformity and accuracy of the spraying, and reducing errors caused by the movement of the PCB solder resist spraying equipment. Simultaneously, the limitation that the moving direction Y is perpendicular to the conveying direction X also allows for more precise control of the spraying range, contributing to improved spraying accuracy.

[0058] In other embodiments of this example, only at most two of the first spray gun 210, the second spray gun 220, and the third spray gun 230 are slidably connected to the conveying module 240 along the moving direction Y.

[0059] In one embodiment of this invention, the operating speed of the first spray gun 210 is greater than that of the second spray gun 220; the operating speed of the first spray gun 210 is greater than that of the third spray gun 230. Specifically, the operating speed of the first spray gun 210 is 2200.00-2500.00 mm / s, the operating speed of the second spray gun 220 is 1800.00-2000.00 mm / s, and the operating speed of the third spray gun 230 is 1500.00-1700.00 mm / s.

[0060] By limiting the spray gun's operating speed, different spray guns can operate at different speeds, allowing for independent control of the thickness and uniformity of each ink layer, thus improving product quality and reliability. Simultaneously, adjusting the spray gun's operating speed enables uniform spraying of different ink layers, thereby increasing work efficiency.

[0061] In other embodiments of this example, the operating speed of the first spray gun 210 is limited to being greater than the operating speed of the second spray gun 220; or the operating speed of the first spray gun 210 is limited to being greater than the operating speed of the third spray gun 230.

[0062] In one embodiment of this invention, the nozzle diameter of the first spray gun 210 is smaller than that of the second spray gun 220; the nozzle diameter of the first spray gun 210 is smaller than that of the third spray gun 230.

[0063] The nozzle diameters of the first spray gun 210, the second spray gun 220, and the third spray gun 230 differ, which helps to control the ink flow and distribution, resulting in more precise and uniform ink coating for each layer and improving the overall quality of the solder resist layer 900. Simultaneously, the different nozzle diameters allow for ink coating with varying ink viscosities, spraying pressures, and solder resist thicknesses, meeting the multi-layered requirements of the solder resist layer 900.

[0064] Specifically, the nozzle diameter of the first spray gun 210 is 0.13-0.23 mm, the nozzle diameter of the second spray gun 220 is 0.70 mm, and the nozzle diameter of the third spray gun 230 is 0.70 mm.

[0065] Under high pressure, the small-diameter nozzle of the first spray gun 210 can highly atomize the high-viscosity first ink, preferentially depositing a uniform layer of solder resist ink on the board surface and line corners of PCB800. This layer of solder resist ink has poor fluidity and can provide and supplement good ink coating ability for thick copper line corners and tops.

[0066] In other embodiments of this example, only the nozzle diameter of the first spray gun 210 is limited to be smaller than the nozzle diameter of the second spray gun 220; or only the nozzle diameter of the first spray gun 210 is limited to be smaller than the nozzle diameter of the third spray gun 230.

[0067] In this embodiment, the total amount of ink applied by the first spray gun 210, the second ink applied by the second spray gun 220, and the third ink applied by the third spray gun 230 is the ink application amount. The first ink applied by the first spray gun 210 accounts for 40-60% of the ink application amount, the second ink applied by the second spray gun 220 accounts for 20-30%, and the third ink applied by the third spray gun 230 accounts for 20-30%. Specifically, the first ink applied by the first spray gun 210 accounts for 40% of the ink application amount, the second ink applied by the second spray gun 220 accounts for 30%, and the third ink applied by the third spray gun 230 accounts for 30%. The total amount of ink applied by the first spray gun 210, the second spray gun 220, and the third spray gun 230 is 100% of the set ink application amount, thus ensuring both surface leveling and ink coverage.

[0068] By rationally allocating the ink spraying ratio of the first spray gun 210, the second spray gun 220, and the third spray gun 230, the uniformity and integrity of each ink layer can be ensured, thereby achieving optimized structure and precise control of the solder resist layer 900 and improving the consistency and stability of the PCB800.

[0069] In one embodiment of this invention, the spray pressure of the first spray gun 210 is greater than that of the second spray gun 220; the spray pressure of the first spray gun 210 is greater than that of the third spray gun 230. Specifically, the spray pressure of the first spray gun 210 is 60.00-100.00 kg, the spray pressure of the second spray gun 220 is 3.00-6.00 kg, and the spray pressure of the third spray gun 230 is 3.00-6.00 kg.

[0070] This design allows the first spray gun 210 to more effectively spray high-viscosity ink onto the PCB800 surface, improving the uniformity and adhesion of the high-viscosity ink. By limiting the spray gun pressure, precise control of the ink spraying amount can be achieved, ensuring uniform ink distribution and effective spraying, improving the spraying effect and product performance, and further enhancing the quality and precision of the process.

[0071] In other embodiments of this example, only the spray gun pressure of the first spray gun 210 is limited to be greater than the spray gun pressure of the second spray gun 220; or only the spray gun pressure of the first spray gun 210 is limited to be greater than the spray gun pressure of the third spray gun 230.

[0072] The process route of first spraying a high-viscosity ink followed by two sprays of low-viscosity ink is chosen because the high-viscosity first ink has a low flow rate at the PCB800 openings. Using the high-viscosity first ink in small, multiple applications allows for better ink adhesion and a better base coat, improving the ink adhesion of the first layer of 910 lines. However, using only the high-viscosity first ink can easily lead to a rough and grainy appearance on the PCB800 surface. Therefore, two additional sprays of low-viscosity ink with good flow properties are needed to ensure a smooth and flat solder mask surface. This process route can simultaneously meet the requirements for both the trace ink thickness and the overall ink thickness of the PCB800 thick copper board.

[0073] Meanwhile, the above process route can also solve the problems of ink entering holes and ink clogging. Traditional spraying methods are completed in one spraying, with spraying pressure and ink spraying volume both exceeding the current three-spraying method, and the risk of ink entering holes and clogging is extremely high. The above process route uses high-pressure spraying of high-viscosity ink. Under high pressure, the high-viscosity ink has a higher degree of atomization, which can uniformly cover the PCB800 surface. High-pressure spraying of high-viscosity ink can also effectively prevent high-viscosity ink from clogging the nozzles. At the same time, it reduces the proportion of low-viscosity ink, thus reducing the probability of clogging. This achieves the goal of reducing spraying pressure and ink volume, reducing the risk of ink entering holes, reducing the proportion of ink entering holes and clogging, and thus avoiding clogging of openings with a diameter of less than 0.20 mm on the PCB800.

[0074] For example, in a spraying apparatus 200, a first spray gun 210 and a second spray gun 220 are spaced apart, and a second spray gun 220 and a third spray gun 230 are spaced apart.

[0075] A well-designed spray gun spacing allows each spray gun to operate independently without interference, improving spraying efficiency and accuracy. These improvements help achieve uniform ink application and coverage, preventing missed areas and overspray, and ultimately enhancing product quality.

[0076] Furthermore, the distance between the first spray gun 210 and the second spray gun 220 in the conveying direction X is the first distance, and the distance between the second spray gun 220 and the third spray gun 230 in the conveying direction X is the second distance, and the first distance is equal to the second distance.

[0077] By setting the same spacing between the first spray gun 210 and the second spray gun 220, and between the second spray gun 220 and the third spray gun 230 in the X-direction of the conveying direction, the precise correspondence of the spraying positions of the two layers of ink can be ensured. This reduces the difficulty for the conveying module 240 to adjust the position of the PCB 800, and helps to improve the accuracy and automation of the solder resist spraying process. At the same time, the requirement of equal spacing also helps to control the drying time and distribution of the ink, improving the stability and continuity of the spraying process, and contributing to increased production efficiency and product quality.

[0078] This embodiment also provides a PCB solder resist spraying method, applied to the aforementioned PCB solder resist spraying equipment, including the following steps:

[0079] Step 1: Place PCB800 on the first spraying device 200. First, use the first spray gun 210 to repeatedly spray the first ink onto the top surface of PCB800, and let it stand for a first time to form the first layer 910. Then, use the second spray gun 220 to repeatedly spray the first layer 910 with the second ink, and let it stand for a second time to form the second layer 920. After that, use the third spray gun 230 to repeatedly spray the top surface of PCB800 with the third ink.

[0080] Step 2: Use the flipping device 100 to flip the PCB800 and transfer it to the second spraying device 200.

[0081] Step 3: Repeat the ink spraying process of Step 1 in the second spraying device 200.

[0082] Step 4: Use the pre-baking device 300 to perform horizontal and vertical pre-baking on the PCB800 on the second spraying device 200, and then remove the PCB800 from the PCB solder mask spraying equipment.

[0083] This PCB solder resist spraying method, through multiple reciprocating spraying and resting, ensures that each layer of solder resist ink is evenly covered and tightly bonded, improving the ink adhesion and uniformity of the solder resist layer 900, reducing defects and scrap rates caused by uneven spraying. The first layer 910 formed by the first ink sprayed by the first spray gun 210 has higher thickness and viscosity, effectively enhancing the adhesion and uniformity of subsequent spraying. Using the flipping device 100 to flip the PCB 800 and perform re-spraying achieves uniform ink spraying and treatment on both sides of the PCB 800, improving the integrity and functionality of the PCB 800, eliminating the need for additional processes and simplifying the operation. Repeating the ink spraying process in the second spraying device 200 ensures consistent spraying quality and solder resist layer 900 thickness on both sides, improving product quality and aesthetics. The pre-baking device 300 can quickly and effectively pre-bake the PCB 800, improving production efficiency, shortening the production cycle, and the pre-baking process also improves the wear resistance, heat resistance, and other properties of the solder resist layer 900. Meanwhile, horizontal pre-baking effectively reduces ink dripping and running, while vertical pre-baking helps reduce the risk of PCB bending due to gravity, thus improving the appearance quality of the PCB. The aforementioned PCB solder mask spraying method is simple, efficient, stable, and reliable, reducing production costs and scrap rates, meeting the high efficiency and high quality requirements of modern electronics manufacturing, and possessing significant economic benefits and technological advantages.

[0084] Using the above-described PCB solder mask spraying method, a layer of high-viscosity ink can be preferentially deposited by high-pressure atomization at the edge of the PCB 800 opening. Under the gravity of the first ink and the interfacial force of the first ink itself, the subsequent spraying of low-viscosity ink is less likely to seep into or accumulate in the opening, thus effectively improving the clogging rate of small-diameter through-holes. With the above process, the solder mask layer 900 thickness on the PCB 800 after solder mask spraying treatment, when the solder mask layer 900 thickness is the same as that on the PCB 800 after traditional single-stage low-viscosity spraying treatment, has a 30%-40% higher ink adhesion capacity than traditional single-stage low-viscosity spraying treatment, and can effectively reduce the probability of ink entering and clogging the opening.

[0085] In other embodiments of this example, the low-viscosity ink is sprayed more than twice, and the number of spray guns other than the first spray gun 210 is the same as the number of times the low-viscosity ink is sprayed. The number of times the low-viscosity ink is sprayed is determined by those skilled in the art based on actual engineering conditions, and the method of determination is common knowledge in the art, and will not be elaborated here.

[0086] In this embodiment, the first time interval is 7.00 seconds, and the second time interval is 7.00 seconds. Specifically, the first and second spacing are both 350.00 mm, and the transmission speed of the transmission module 240 to the PCB800 is 4.00-5.00 meters per minute.

[0087] The above limits ensure that the ink remains on the board surface for at least 7.00 seconds, ensuring sufficient settling of the ink. This settling process eliminates air bubbles within the solder resist layer 900 and allows the ink to air dry naturally, significantly improving ink pinholes and flatness defects.

[0088] In this embodiment, a sensor is installed at the inlet of the spraying device 200. The sensor can detect the PCB 800, which is 550.00 mm away from the first spray gun 210 in the conveying direction X. Then, the first spray gun 210, the second spray gun 220, and the third spray gun 230 start working simultaneously at different speeds. This design not only ensures the stability of the PCB solder resist spraying equipment, but also allows for multiple small-batch spraying operations for high-viscosity inks, ensuring the uniformity of ink application on the PCB 800 circuits. For low-viscosity spraying operations, the conveying speed of the conveying module 240 can be slowed down to ensure the flatness of the second layer 920 and the third layer 930. The above process ensures the uniformity of the ink sprayed onto the board surface without wasting ink. Only one operator is needed to operate the entire PCB solder resist spraying equipment, enabling continuous automatic operation. Compared with the previous manual production, the efficiency is increased by more than 50%, thus improving work efficiency while ensuring quality.

[0089] Furthermore, the spraying device 200 is also equipped with an ink supply component, which is used to adjust 100% viscosity ink into first ink, second ink and third ink with different viscosities, and to replenish the corresponding spray guns.

Claims

1. A PCB solder resist spraying device for processing PCBs (800), the PCB solder resist spraying device comprising a first spraying device (200), a flipping device (100), a second spraying device (200) and a pre-baking device (300) arranged sequentially along the conveying direction (X). The spraying device (200) includes a conveying module (240) and a first spray gun (210), a second spray gun (220) and a third spray gun (230) arranged sequentially along the conveying direction (X). The conveying module (240) is used to convey the PCB (800) along the conveying direction (X). The first spray gun (210) is used to spray a first ink on the top surface of the PCB (800). The first ink is allowed to stand for a first time to form a first layer (910). The second spray gun (220) is used to spray a second ink on the first layer (910). The second ink is allowed to stand for a second time to form a second layer (920). The third spray gun (230) is used to spray a third ink on the second layer (920). The third ink is allowed to stand to form a third layer (930). The viscosity of the first ink is greater than the viscosity of the second ink, and the viscosity of the first ink is greater than the viscosity of the third ink. The flipping device (100) is capable of flipping the PCB (800) on the first spraying device (200) and conveying it to the second spraying device (200). The pre-baking device (300) is capable of pre-baking the PCB (800) on the second spraying device (200) and removing it from the PCB solder resist spraying equipment.

2. The PCB solder mask painting apparatus of claim 1, wherein, The first spray gun (210) is capable of moving closer to or further away from the conveyor module (240); and / or, The second spray gun (220) can move closer to or further away from the conveyor module (240); and / or, The third spray gun (230) can move closer to or further away from the conveying module (240).

3. The PCB solder mask painting apparatus of claim 2, wherein, The first spray gun (210) is slidably connected to the conveying module (240) along the moving direction (Y); and / or, The second spray gun (220) is slidably connected to the conveying module (240) along the moving direction (Y); and / or, The third spray gun (230) is slidably connected to the conveying module (240) along the moving direction (Y), wherein the moving direction (Y) is perpendicular to the conveying direction (X).

4. The PCB solder mask painting apparatus of claim 3, wherein, The operating speed of the first spray gun (210) is greater than the operating speed of the second spray gun (220); and / or, The operating speed of the first spray gun (210) is greater than that of the third spray gun (230).

5. The PCB solder mask painting apparatus of claim 4, wherein, The nozzle diameter of the first spray gun (210) is smaller than the nozzle diameter of the second spray gun (220); and / or, The nozzle diameter of the first spray gun (210) is smaller than that of the nozzle diameter of the third spray gun (230).

6. The PCB solder mask painting apparatus of claim 1, wherein, The total amount of ink applied by the first spray gun (210), the second ink applied by the second spray gun (220), and the third ink applied by the third spray gun (230) is the ink volume. The first ink applied by the first spray gun (210) accounts for 40-60% of the ink volume, the second ink applied by the second spray gun (220) accounts for 20-30% of the ink volume, and the third ink applied by the third spray gun (230) accounts for 20-30% of the ink volume.

7. The PCB solder mask painting apparatus of claim 1, wherein, Within one of the spraying devices (200), the first spray gun (210) and the second spray gun (220) are spaced apart, and the second spray gun (220) and the third spray gun (230) are spaced apart.

8. The PCB solder mask painting apparatus of claim 7, wherein, The distance between the first spray gun (210) and the second spray gun (220) in the conveying direction (X) is the first distance, and the distance between the second spray gun (220) and the third spray gun (230) in the conveying direction (X) is the second distance. The first distance is equal to the second distance.

9. The PCB solder mask painting apparatus according to any one of claims 1-8, wherein, The spray pressure of the first spray gun (210) is greater than the spray pressure of the second spray gun (220); and / or, The spray gun pressure of the first spray gun (210) is greater than that of the third spray gun (230).

10. A PCB solder mask spraying method, applied to the PCB solder mask spraying equipment according to any one of claims 1-9, comprising: The PCB (800) is placed on the first spraying device (200). First, the first ink is sprayed repeatedly on the top surface of the PCB (800) using the first spray gun (210). After standing for the first time, the first layer (910) is formed. Then, the second ink is sprayed repeatedly on the first layer (910) using the second spray gun (220). After standing for the second time, the second layer (920) is formed. Afterward, the third ink is sprayed repeatedly on the top surface of the PCB (800) using the third spray gun (230). The PCB (800) is flipped over using the flipping device (100) and conveyed to the second spraying device (200). The ink spraying process of S1 is repeated in the second spraying device (200); The PCB (800) on the second spraying device (200) is pre-baked horizontally and vertically using the pre-baking device (300), and then the PCB (800) is removed from the PCB solder resist spraying equipment.

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