An ultra-thin solder mask process for circuit boards based on micro-nano technology

Abstract

The present invention relates to the technical field of solder mask processing for circuit boards, and discloses an ultra-thin solder mask process for circuit boards based on micro-nano technology, including S1, cleaning the circuit board to ensure that the surface is free of oil, dust and other pollutants to ensure good adhesion between the solder mask and the substrate; S2, coating the cleaned and dried circuit board with a solder mask using a coating machine. The ultra-thin solder mask process for circuit boards based on micro-nano technology can effectively solve the problem that when the solder mask ink is printed on the surface of the circuit board in the prior art, due to the lack of effective fixing means, the circuit board is in a free state, and the circuit board will be slightly displaced when the printing equipment is running, making it difficult for the solder mask ink to be accurately attached to the predetermined position, thereby causing the design elements such as the pad and the circuit to be offset, which has an adverse effect on the manufacturing quality of the circuit board, increases the product defective rate and production cost, and reduces production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of circuit board solder mask processing, and in particular to a circuit board ultra-thin solder mask process based on micro-nano technology. Background Art

[0002] Circuit board solder mask is a protective coating applied to printed circuit boards. Its main function is to prevent solder from being deposited in unwanted places and to protect the copper traces (wires, pads, hole rings, etc.) on the circuit board from environmental factors. The material of the solder mask is usually a heat-resistant and chemical-resistant synthetic resin. The solder mask is an important part of the circuit board manufacturing process and plays a vital role in ensuring the reliability and long-term stability of the circuit board.

[0003] In the prior art, when the solder mask ink is printed on the surface of the circuit board, due to the lack of effective fixing means, the circuit board is in a free state. When the printing equipment is running, the circuit board will be slightly displaced, making it difficult for the solder mask ink to be accurately attached to the predetermined position, thereby causing the pads, circuits and other design elements to shift, which has an adverse effect on the manufacturing quality of the circuit board, increases the product defective rate and production costs, and reduces production efficiency. Summary of the invention

[0004] Technical issues solved

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides an ultra-thin solder mask process for circuit boards based on micro-nano technology, which can effectively solve the problem that when the prior art prints solder mask ink on the surface of the circuit board, due to the lack of effective fixing means, the circuit board is in a free state, and the circuit board will be slightly displaced when the printing equipment is running, making it difficult for the solder mask ink to be accurately attached to the predetermined position, thereby causing the design elements such as the pads and circuits to shift, which has an adverse effect on the manufacturing quality of the circuit board, increases the product defective rate and production cost, and reduces production efficiency.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] The present invention provides a circuit board ultra-thin solder mask process based on micro-nano technology, comprising:

[0008] S1. The circuit board is cleaned to ensure that the surface is free of oil, dust and other contaminants to ensure good adhesion between the solder mask layer and the substrate;

[0009] S2. Use a coating machine to evenly coat the cleaned and dried circuit board with solder resist ink on the circuit board using a screen printing method. Screen printing is to press the ink onto a specific area of ​​the circuit board through a screen printing plate;

[0010] S3. The solder mask layer after coating needs to be pre-dried to remove the solvent components in the ink and make the ink initially solidified;

[0011] S4. The pre-dried solder mask layer needs to be cured to make the polymer material undergo a cross-linking reaction to form a stable protective film;

[0012] S5. Cooling the solidified circuit board to stabilize the size and prevent thermal deformation;

[0013] S6. Check the cured solder mask layer, including appearance, thickness, and alignment accuracy. Smooth the surface as needed, package qualified circuit boards, and store them in a dry and clean environment.

[0014] Wherein, the coating machine in S2 includes a loading part, the loading part includes a side plate, one side of the side plate is rotatably connected to a chain plate conveyor belt, and the lower surface of the side plate is fixedly connected to a bottom plate, and the outer surface of the chain plate conveyor belt is provided with a positioning component that can be used to fix the external circuit board;

[0015] The coating part includes a lifting seat, the outer surface of which is fixedly connected to the side of the side plate away from the chain conveyor belt, the lifting seat is slidably connected to a driving seat via a lifting rod arranged on the upper surface thereof, and the driving seat is internally rotatably connected to a rotating shaft, and a printing mechanism is arranged on the circumferential outer surface of the rotating shaft;

[0016] Wherein, the printing mechanism comprises a rolling shaft, the rolling shaft is sleeved on the circumferential outer surface of the rotating shaft, and the rolling shaft is meshed and connected with a synchronous belt through a main gear arranged at the outer end thereof, a fixing rod is fixedly connected to the side of the side plate away from the lifting seat, a roller brush cylinder is sleeved on the circumferential outer surface of the fixing rod, and a sub-gear meshed with the synchronous belt is fixedly connected to the outer end of the roller brush cylinder, and a screen is arranged on the outer surface of the synchronous belt to fit the circumferential outer surface of the rolling shaft and the roller brush cylinder;

[0017] Among them, the positioning assembly includes a snap seat, one side of the snap seat is fixedly connected to the circumferential outer surface of the chain conveyor belt, the outer surface of the snap seat is slidably connected with a positioning piece that can fit with the side of the external circuit board, and the outer surface of the chain conveyor belt is provided with a guide rail fixedly connected to the upper surface of the base plate.

[0018] Furthermore, the positioning member includes a sliding seat, a side of the sliding seat away from the side plate is fixedly connected to a pressure rod, the upper surface of the pressure rod is fixedly connected to a vertical pressure rod, and the lower surface of the vertical pressure rod adopts an arc surface design, and the guide rails are provided with two groups and are symmetrically distributed left and right with the chain conveyor belt as the center.

[0019] Furthermore, a fixing frame is fixedly connected to the circumferential outer surface of the fixing rod, a supporting seat is fixedly connected to the top of the fixing frame, and a calibration component is rotatably connected to the interior of the supporting seat via an axle.

[0020] Furthermore, the calibration assembly includes an L-shaped magnetic plate, the circumferential outer surface of the shaft is sleeved with a torsion spring connected to the inside of the L-shaped magnetic plate, and one side of the L-shaped magnetic plate is fixedly connected to a connecting plate, and the rolling shaft is slidably connected to a reciprocating plate via a sliding groove opened inside it.

[0021] Furthermore, a side of the reciprocating plate close to the connecting plate adopts an arc edge design, and a side of the reciprocating plate away from the connecting plate is magnetically connected to the outer surface of the L-shaped magnetic plate.

[0022] Furthermore, a paint box is fixedly connected to one side of the L-shaped magnetic plate away from the connecting plate. The paint box adopts an open design, and a paint brush is rotatably connected to the open end of the paint box.

[0023] Furthermore, a scraper frame is fixedly connected to one end of the fixing frame away from the side plate, the outer surface of the scraper frame is in contact with the inner wall of the wire mesh, and a material guide groove is provided on the upper surface of the scraper frame.

[0024] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0025] The present invention is provided with a chain conveyor belt and a positioning assembly. The circuit board is placed on the upper surface of the chain conveyor belt and moves toward the coating part. The guide rails and the bottom plate arranged on the outer surface of the chain conveyor belt remain fixed, and the buckle seat moves with the chain conveyor belt, causing the positioning piece sliding on the outer surface of the buckle seat to move horizontally following the twisting direction of the guide rails. Before coating, the circuit board is placed on the upper surface of the chain conveyor belt. After being conveyed for a short distance, its two sides will be clamped toward the middle synchronously by the positioning pieces. When the circuit board is about to reach the bottom of the screen, the positioning piece will be loosened, which will not affect the coating process of the circuit board. In the process of just starting to coat, the positioning piece at the rear end of the circuit board remains clamped; and in the process of finishing coating, the positioning piece at the front end of the circuit board clamps it again, which can effectively limit the movement and shaking of the circuit board. The circuit board can be kept fixed at a certain distance during the coating process. The positioning clamping method can ensure high coating accuracy. By clamping the uncoated rear end and the coated front end, the coating area of ​​the circuit board can be accurately controlled to ensure that the solder mask is only coated on the required parts and avoid coating on areas that should not be coated, such as welding pins, etc., thereby ensuring the manufacturing quality of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 It is a flow chart of the process for manufacturing the solder mask layer of the circuit board of the present invention;

[0028] Figure 2 It is a three-dimensional structural schematic diagram of an embodiment of the present invention;

[0029] Figure 3 It is a top view of the chain conveyor belt and the positioning assembly according to an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the structure of the guide rail according to an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of a positioning member and a buckle seat according to an embodiment of the present invention;

[0032] Figure 6 This is a schematic structural diagram of a coating portion according to an embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the separation structure of the coating part of an embodiment of the present invention;

[0034] Figure 8 Schematic diagram of the cross-sectional structure of the screen according to the embodiment of the present invention;

[0035] Fig. 9 For the embodiment of the present invention Figure 8 A schematic diagram of the structure with a partial enlargement at the center;

[0036] Fig.10 It is a schematic diagram of the structure of the calibration component, the paint box and the fixing frame according to an embodiment of the present invention.

[0037] The numbers in the figure represent: 1. feeding part; 11. side plate; 12. chain conveyor belt; 13. positioning assembly; 131. snap seat; 132. positioning piece; 1321. sliding seat; 1322. pressure rod; 1323. vertical pressure rod; 133. guide rail; 2. coating part; 21. lifting seat; 22. driving seat; 23. rotating shaft; 24. printing mechanism; 241. rolling shaft; 2411. slide groove; 242. main gear; 243. synchronous belt; 244. fixing rod; 245. roller brush; 246. auxiliary gear; 25. screen; 26. fixing frame; 261. supporting seat; 27. calibration assembly; 271. L-shaped magnetic plate; 272. torsion spring; 273. connecting plate; 274. reciprocating plate; 28. coating box; 281. coating brush; 29. ​​scraper frame; 291. guide trough. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The present invention will be further described below in conjunction with the embodiments.

[0040] Example:

[0041] See also Figure 1-Figure 10 The present invention provides a technical solution: a circuit board ultra-thin solder mask process based on micro-nano technology, comprising:

[0042] S1. The circuit board is cleaned to ensure that the surface is free of oil, dust and other contaminants to ensure good adhesion between the solder mask layer and the substrate;

[0043] S2. Use a coating machine to evenly coat the cleaned and dried circuit board with solder resist ink on the circuit board using a screen printing method. Screen printing is to press the ink onto a specific area of ​​the circuit board through a screen printing plate;

[0044] S3. The solder mask layer after coating needs to be pre-dried to remove the solvent components in the ink and make the ink initially solidified;

[0045] S4. The pre-dried solder mask layer needs to be cured to make the polymer material undergo a cross-linking reaction to form a stable protective film;

[0046] S5. Cooling the solidified circuit board to stabilize the size and prevent thermal deformation;

[0047] S6. Check the cured solder mask layer, including appearance, thickness, and alignment accuracy. Smooth the surface as needed, package qualified circuit boards, and store them in a dry and clean environment.

[0048] The coating machine in S2 includes a loading part 1, which includes a side plate 11, one side of the side plate 11 is rotatably connected to a chain plate conveyor belt 12, and the lower surface of the side plate 11 is fixedly connected to a bottom plate, and the outer surface of the chain plate conveyor belt 12 is provided with a positioning component 13 that can be used to fix an external circuit board;

[0049] The coating part 2 includes a lifting seat 21, the outer surface of which is fixedly connected to the side of the side plate 11 away from the chain conveyor belt 12, the lifting seat 21 is slidably connected to a driving seat 22 via a lifting rod arranged on the upper surface thereof, and the driving seat 22 is internally rotatably connected to a rotating shaft 23, and a printing mechanism 24 is arranged on the circumferential outer surface of the rotating shaft 23;

[0050] The printing mechanism 24 includes a rolling shaft 241, which is sleeved on the outer circumferential surface of the rotating shaft 23, and the rolling shaft 241 is meshed with a synchronous belt 243 through a main gear 242 arranged at the outer end thereof. A fixing rod 244 is fixedly connected to the side of the side plate 11 away from the lifting seat 21, and a roller brush cylinder 245 is sleeved on the outer circumferential surface of the fixing rod 244, and a sub-gear 246 meshed with the synchronous belt 243 is fixedly connected to the outer end of the roller brush cylinder 245, and a screen 25 that fits the outer circumferential surface of the rolling shaft 241 and the roller brush cylinder 245 is arranged on the outer surface of the synchronous belt 243;

[0051] Among them, the positioning assembly 13 includes a snap seat 131, one side of the snap seat 131 is fixedly connected to the circumferential outer surface of the chain conveyor belt 12, the outer surface of the snap seat 131 is slidably connected with a positioning piece 132 that can fit with the side of the external circuit board, and the outer surface of the chain conveyor belt 12 is provided with a guide rail 133 fixedly connected to the upper surface of the base plate.

[0052] The positioning member 132 includes a sliding seat 1321, and a pressure rod 1322 is fixedly connected to the side of the sliding seat 1321 away from the side plate 11. The upper surface of the pressure rod 1322 is fixedly connected to a vertical pressure rod 1323, and the lower surface of the vertical pressure rod 1323 adopts an arc surface design. The guide rail 133 is provided with two groups and is symmetrically distributed left and right with the chain conveyor belt 12 as the center.

[0053] The outer circumferential surface of the fixing rod 244 is fixedly connected to a fixing frame 26 , the top of the fixing frame 26 is fixedly connected to a supporting seat 261 , and the interior of the supporting seat 261 is rotatably connected to a calibration component 27 via a shaft.

[0054] The calibration assembly 27 includes an L-shaped magnetic plate 271, and the circumferential outer surface of the shaft is sleeved with a torsion spring 272 connected to the inside of the L-shaped magnetic plate 271, and a connecting plate 273 is fixedly connected to one side of the L-shaped magnetic plate 271, and the rolling shaft 241 is slidably connected to the reciprocating plate 274 through a sliding groove 2411 opened therein.

[0055] The side of the reciprocating plate 274 close to the connecting plate 273 adopts an arc edge design, and the side of the reciprocating plate 274 away from the connecting plate 273 is magnetically connected to the outer surface of the L-shaped magnetic plate 271.

[0056] A paint box 28 is fixedly connected to one side of the L-shaped magnetic plate 271 away from the connecting plate 273 . The paint box 28 is of an open design, and a paint brush 281 is rotatably connected to the open end of the paint box 28 .

[0057] A scraper frame 29 is fixedly connected to one end of the fixing frame 26 away from the side plate 11 . The outer surface of the scraper frame 29 is in contact with the inner wall of the screen 25 , and a guide groove 291 is formed on the upper surface of the scraper frame 29 .

[0058] Circuit board loading process:

[0059] In actual application, a suitable wire mesh 25 is prepared according to the solder mask requirements of the circuit board, and the wire mesh 25 is sleeved on the outer surface surrounded by the rolling shaft 241 and the roller brush cylinder 245, and both sides of the wire mesh 25 are fixed to the outer surface of the synchronous belt 243. The lifting seat 21 lifts the two driving seats 22 evenly upward through the lifting rod set on its upper surface, so that the wire mesh 25 is evenly stretched to reach the required state and remain motionless.

[0060] The circuit board to be processed is placed on the upper surface of the chain conveyor belt 12 in the loading part 1 by using an external conveying device, and the chain conveyor belt 12 is started by a driving motor (the side of the chain conveyor belt 12 away from the screen 25 is the loading end, and the other side is the unloading end), and the circuit board is transported from the loading end to the coating part 2 following the conveying direction of the chain conveyor belt 12. A guide rail 133 is arranged on the outer circumference of the chain conveyor belt 12. There are two groups of guide rails 133, which are symmetrically distributed with the screen 25 as the center. The gap between a pair of guide rails 133 generally shows a trend of first large, then small, then large, and then small from the loading end to the unloading end. Each guide rail 133 is composed of two rails, and the lower part of the two rails is fixedly connected to the bottom plate, and the outer circumferential surface of the sliding seat 1321 is in contact with the two rails of the guide rail 133. The guide rail 133 is fixedly installed on the upper surface of the bottom plate according to the width of the line board. When the circuit board is placed on the feeding end of the chain conveyor belt 12, the distance between the pair of guide rails 133 on both sides is relatively large, and the circumferential outer surface of the sliding seat 1321 in the positioning member 132 fits with the inner surface of the guide rail 133. Under the limiting action of the guide rail 133, the positioning member 132 shrinks inside it and does not affect the feeding of the circuit board.

[0061] After the circuit board moves a short distance in the direction of movement of the chain conveyor belt 12, the distance between the guide rails 133 on both sides gradually decreases, and the guide rails 133 are converted from straight lines to curved lines. Since the bottom end of the buckle seat 131 is fixedly connected to the outer surface of the chain conveyor belt 12 and rotates with the chain conveyor belt 12, but the guide rails 133 are fixed, the guide rails 133 and the positioning member 132 on the outer surface of the buckle seat 131 move relative to each other, and the chain conveyor belt 12 drives the positioning member 132 to slide on the outer surface of the buckle seat 131 toward the middle side close to the circuit board, and the pressure rods 1322 on both sides follow the sliding seat 1321 to move on the outer surface of the buckle seat 131 toward the circuit board. The lower surface of the vertical pressure rod 1323 in the positioning assembly 13 is designed with an arc surface. When processing a thicker circuit board, the arc edge of the vertical pressure rod 1323 can contact the side of the circuit board without affecting the coating of solder resist ink. When the positioning assembly 13 approaches the circuit board, one of the pressure rods 1322 contacts the side of the circuit board away from the sliding seat 1321, pushing the circuit board toward the middle, and the other pressure rod 1322 also slides toward the middle, making the front end of the circuit board parallel to the roller brush 245. The circuit board is placed in the center above the chain conveyor belt 12 as a whole, and the position of the circuit board is corrected by the positioning assembly 13 sliding toward the middle on both sides.

[0062] When the gap between the guide rails 133 on both sides is reduced to the minimum, the guide rails 133 reach a straight line. At this time, the positioning assembly 13 has reached its maximum stroke, and the gap between the pressure rods 1322 on both sides is the minimum. The side of the pressure rods 1322 away from the sliding seat 1321 is in contact with the side of the circuit board, and the circuit board is tightly fixed in the middle of the upper surface of the chain conveyor belt 12. As the chain conveyor belt 12 continues to operate, the positioning assemblies 13 on both sides clamp the circuit board and move it toward the screen 25.

[0063] Circuit board coating process:

[0064] In the initial state, the rotating shaft 23 does not move, the screen 25 at the bottom end of the roller brush 245 is a sealed area, and the solder mask ink will not penetrate. The slide groove 2411 in the coating part 2 is at the bottom end of the rolling shaft 241, and the side of the reciprocating plate 274 away from the axis slides on the outer surface of the rolling shaft 241. One side of the reciprocating plate 274 is an arc edge, and the other side adopts a magnetic design. The magnetic edge of the reciprocating plate 274 is tightly fitted with the L-shaped magnetic plate 271, and the bottom end of the L-shaped magnetic plate 271 is in contact with the support seat 261. The bottom end of the inner wall fits tightly, the bottom of the support seat 261 is fixedly connected to the fixed rod 244 through the fixing frame 26, the torsion spring 272 inside the L-shaped magnetic plate 271 is also in a compressed state, and the reciprocating plate 274 remains in a vertical state under the action of the L-shaped magnetic plate 271 and the slide groove 2411. The paint box 28 fixedly connected to the side of the L-shaped magnetic plate 271 away from the connecting plate 273 is parallel to the chain conveyor belt 12, and the paint brush 281 rotatably connected at its open end does not contact the inside of the screen 25.

[0065] When the circuit board is about to reach the designated position below the screen 25 above the chain conveyor belt 12, the drive seat 22 starts to rotate the shaft 23 connected to the internal transmission. The shaft 23 rotates and drives the rolling shaft 241 and the main gear 242 connected to it to rotate synchronously. When the main gear 242 rotates, it drives the sub-gear 246 to rotate synchronously through the synchronous belt 243 meshing with it, and the screen 25 rotates synchronously with the synchronous belt 243 on the outer surface of the rolling shaft 241 and the roller brush cylinder 245. When the rolling shaft 241 rotates clockwise, the reciprocating plate 274 moves along with the rolling shaft 241 inside the slide groove 2411. Under the rotation trend, the reciprocating plate 274 breaks away from the magnetic connection with the L-shaped magnetic plate 271, and the arc edge of the reciprocating plate 274 fits with the side of the connecting plate 273 close to the L-shaped magnetic plate 271. The upper surface of the connecting plate 273 adopts a small arc edge design. During the rotation of the reciprocating plate 274, the arc edge of the reciprocating plate 274 contacts the small arc edge on the upper surface of the connecting plate 273, and shrinks upward to a short distance in the slide groove 2411 and passes smoothly through the connecting plate 273.

[0066] After the connecting plate 273 and the L-shaped magnetic plate 271 lose the restriction of the reciprocating plate 274, under the action of the torsion spring 272 inside the L-shaped magnetic plate 271, the connecting plate 273 and the L-shaped magnetic plate 271 are driven to rotate clockwise a certain angle inside the support seat 261 to complete the reset, and the paint box 28 fixedly connected to the outer surface of the L-shaped magnetic plate 271 rotates synchronously, and the connecting plate 273 is slightly tilted to the upper right at a certain angle. The paint brush 281 is rotatably installed inside the paint box 28. After rotation, the paint brush 281 contacts the inner wall surface of the screen 25. The position of the paint box 28 remains fixed, and the screen 25 is constantly rotating. The contact edge between the paint brush 281 and the inner wall surface of the screen 25 is constantly changing, so that the paint brush 281 is constantly rotating inside the paint box 28, so that the solder mask ink contacting the surface of the screen 25 is more uniform, thereby ensuring the uniformity of the solder mask printing. When there is too much solder mask ink in the same area of ​​the inner wall of the screen 25, the screen 25 rotates clockwise through the scraper rack 29, and the excess solder mask ink will flow to the positions on both sides of the guide groove 291, which is beneficial to maintaining the uniformity of the solder mask ink on the circumferential outer surface of the roller brush cylinder 245. The reciprocating plate 274 continues to rotate clockwise along with the rolling shaft 241 . When the arc edge of the reciprocating plate 274 contacts the screen 25 , the screen 25 is in a taut state, so the reciprocating plate 274 slides into the slide groove 2411 .

[0067] At the same time, the chain conveyor belt 12 is running non-stop, driving the circuit board to move toward the side of the roller brush cylinder 245. The position of the guide rail 133 close to the screen 25 adopts an arc path again, and the distance between the two side guide rails 133 increases. The positioning member 132 moves toward the side of the side plate 11 on the outer surface of the buckle seat 131 under the action of the guide rail 133. At this time, the positioning member 132 moves horizontally away from the screen 25, without affecting the normal operation of the coating part 2. After the positioning member 132 at the front end of the circuit board is horizontally released, the front end of the circuit board moves to the bottom of the roller brush cylinder 245, and its front upper surface contacts the screen 25. Since the roller brush cylinder 245 at the bottom of the screen 25 is rotating continuously, the arc surface of the vertical pressure rod 1323 in the positioning member 132 behind the circuit board restricts the circuit board to the upper surface of the chain conveyor belt 12, and will not be affected by the roller brush cylinder 245 and tilt upward, so as to maintain the stability of the circuit board and improve the accuracy of the solder mask ink printing process.

[0068] By controlling the driving motor and the driving seat 22, the rotation speed of the chain conveyor belt 12 and the screen 25 are kept consistent, ensuring the accuracy of the solder mask coating process. When the screen 25 has been released from the front end of the circuit board to start printing, the positioning member 132 at the rear end of the circuit board remains in a clamped state, effectively ensuring the stability of the circuit board during the printing process and avoiding low quality of the circuit board caused by inaccurate printing.

[0069] The bottom end of the screen 25 sleeved on the outer surface of the roller brush cylinder 245 is close to the outer surface of the chain conveyor belt 12. The roller brush cylinder 245 is sleeved on the circumferential outer surface of the fixed rod 244, and rotates clockwise by meshing with the synchronous belt 243 through the sub-gears 246 fixed at both ends. When the circuit board is transported to the bottom of the roller brush cylinder 245, the bottom edge of the roller brush cylinder 245 is tightly fitted with the upper surface of the circuit board. After the roller brush cylinder 245 absorbs the solder mask ink, the required printed pattern is applied to the upper surface of the circuit board through the screen 25. The area to be printed cannot be penetrated by the screen 25. After the screen 25 passes through the roller brush 245 to absorb more solder resist ink, the screen 25 follows the clockwise rotation direction. After passing through the left end of the scraper frame 29, the left end of the scraper frame 29 contacts the screen 25 at a certain angle, so that the excess solder resist ink on the inner wall of the screen 25 is scraped off and flows into the inside of the roller brush 245. The excess solder resist ink cannot follow the screen 25 to the outer surface of the rolling shaft 241, thereby avoiding contamination of the rolling shaft 241.

[0070] When the circuit board is half coated, the gap between the two guide rails 133 at the unloading end of the chain conveyor belt 12 is reduced again, driving the positioning member 132 inside to move to one side of the circuit board again, clamping the two sides of the front end of the circuit board. At this time, the front and rear ends of the circuit board are clamped by the positioning member 132, and the positioning member 132 in the middle of the circuit board is spread out to both sides, which does not affect the coating of the solder mask ink. As the circuit board continues to be conveyed, after more than half of the circuit board is coated, after more than half of the circuit board passes through the screen 25, the positioning member 132 at the rear end of the circuit board is loosened, and the positioning member 132 at the front end of the circuit board is clamped. As the circuit board continues to be conveyed, the distance between the two side guide rails 133 increases to the maximum distance again, and the positioning member 132 moves with it to the side of the side plate 11. The coated circuit board is no longer restricted and is conveyed to the next step on the surface of the chain conveyor belt 12.

[0071] After the coating of the circuit board is completed, the rotating shaft 23 continues to rotate, and the reciprocating plate 274 in the slide groove 2411 rotates clockwise along with the rolling shaft 241. When the outer end of the reciprocating plate 274 is separated from the inner wall surface of the screen 25, under the action of its own gravity, the reciprocating plate 274 fits the inner wall of the slide groove 2411 and slides toward the outside of the rolling shaft 241. When the reciprocating plate 274 is about to return to its initial position, the arc edge of the reciprocating plate 274 contacts the connecting plate 273, and the connecting plate 273 drives the L-shaped magnetic plate 271 to rotate counterclockwise by a certain angle under the influence of the rotation potential energy of the reciprocating plate 274. The rotating shaft 23 drives the screen 25 to rotate on the outer surface of the rolling shaft 241 and the roller brush cylinder 245 for a whole cycle (i.e., one circle) and then stops. At this time, the L-shaped magnetic plate 271 is close to the straight edge of the reciprocating plate 274. Under the action of the magnetic force, the magnetic surfaces of the L-shaped magnetic plate 271 and the reciprocating plate 274 are rapidly attracted and tightly fitted. The L-shaped magnetic plate 271 and the connecting plate 273 rotate counterclockwise and are restricted inside the support seat 261. The paint box 28 that fits the outer surface of the L-shaped magnetic plate 271 drives the paint brush 281 inside it to rotate counterclockwise synchronously, driving the outer surface of the paint brush 281 to break away from the contact with the inner wall of the screen 25, reducing the waste of solder mask ink, and avoiding the problem that the paint brush 281 is always in contact with the screen 25 during the pause, causing a large amount of solder mask ink to precipitate and pollute the outer surface of the screen 25.

[0072] Under the limiting action of the slide groove 2411 and the L-shaped magnetic plate 271, the reciprocating plate 274 maintains a vertical state and pulls the rolling shaft 241 to completely restore to its original position. After printing a circuit board, a correction is started to restore the screen 25 to its initial state, waiting for the next circuit board to reach the specified position, and the coating part 2 is started again to coat the surface of the circuit board with a printed solder mask.

[0073] In summary, there are several advantages in the process of applying solder mask to circuit boards:

[0074] Advantage 1: Printing is achieved based on the rotation of the roller brush 245 and the synchronous movement of the circuit board, so that the circuit board can complete the printing of the solder mask layer during the continuous transportation process, without the need to frequently stop and start the scraper movement like traditional printing, thereby greatly improving the printing speed and efficiency. This continuous printing method can complete more printing tasks per unit time, which helps to improve production capacity and meet the market's large demand for circuit boards.

[0075] Advantage 2: The screen 25 is stretched tight on the surface of the rolling shaft 241 and the roller brush 245. During the rotation, the force is more uniform and stable. The friction between the screen 25 and the scraper in the plane collapse method is more frequent and intense, which can easily cause surface wear of the screen 25, affecting the printing quality and the service life of the screen 25. Compared with the traditional plane collapse method, the supporting effect of the roller brush 245 can reduce the local stretching and deformation of the screen 25 during printing, and reduce the risk of fatigue damage of the screen 25 due to uneven force, thereby extending the service life of the screen 25 and reducing production costs.

[0076] Advantage three: the guide rail 133 provided on the outer surface of the chain conveyor belt 12 remains fixed to the bottom plate, and the buckle seat 131 moves with the chain conveyor belt 12, causing the positioning piece 132 sliding on the outer surface of the buckle seat 131 to move horizontally following the twisting direction of the guide rail 133. Before coating, the circuit board is placed on the upper surface of the chain conveyor belt 12. After being transported for a short distance, its two sides will be clamped toward the middle by the positioning pieces 132 synchronously. When the circuit board is about to reach the bottom of the screen 25, the positioning piece 132 will be loosened, which will not affect the coating process of the circuit board; at the beginning of the coating process, the positioning piece 132 at the rear end of the circuit board remains clamped; and when the coating is about to be completed, the positioning piece 132 at the front end of the circuit board clamps it again. This can effectively limit the movement and shaking of the circuit board. Because the coating of the roller brush 245 requires precise control of the coating position and thickness, if the circuit board shakes, it will cause uneven coating, inconsistent thickness, uneven edges and other problems, affecting the performance and quality of the circuit board, and the clamping method of the positioning member 132 can ensure high precision of coating. By clamping the uncoated rear end and the coated front end, the coating area of ​​the circuit board can be precisely controlled to ensure that the solder mask layer is only coated on the required parts, avoiding coating on areas that should not be coated, such as welding pins, etc., thereby ensuring the electrical performance and solderability of the circuit board.

[0077] Advantage 4: During the coating process, the circuit board can be kept fixed at a certain distance, and the positioning member 132 can maintain a relatively stable contact pressure between the circuit board and the roller brush 245, ensuring that the coating material can be evenly attached to the surface of the circuit board during the coating process. If the contact pressure is uneven, it will lead to inconsistent coating thickness, and even partial coating or over-thick coating, which will affect the protective performance and electrical performance of the solder mask layer.

[0078] Advantage 5: After each rotation of the screen 25, the calibration component 27 inside it will calibrate the position of the rolling shaft 241 to reduce the tiny errors generated in each rotation cycle and avoid large errors in the printing position between the screen 25 and the circuit board in the same batch due to long-term rotation.

[0079] Advantage 6. When the screen 25 is moving, the paint brush 281 at the open end of the paint box 28 fits against the inner wall of the screen 25. The rotation of the screen 25 drives the paint brush 281 to rotate inside the paint box 28, and the solder mask ink inside the paint box 28 is evenly applied to the inner wall of the screen 25. When the screen 25 stops moving, the paint box 28 is fixedly connected to the L-shaped magnetic plate 271, and rotates counterclockwise with the L-shaped magnetic plate 271, so that the paint brush 281 is out of contact with the inner wall of the screen 25, reducing the waste of solder mask ink and avoiding the problem that the paint brush 281 is always in contact with the screen 25 during the pause period, causing a large amount of solder mask ink to precipitate and pollute the outer surface of the screen 25.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A circuit board ultra-thin solder mask process based on micro-nano technology, characterized in that: include: S1. The circuit board is cleaned to ensure that the surface is free of oil, dust and other contaminants to ensure good adhesion between the solder mask layer and the substrate; S2. Use a coating machine to evenly coat the cleaned and dried circuit board with solder resist ink on the circuit board using a screen printing method. Screen printing is to press the ink onto a specific area of ​​the circuit board through a screen printing plate; S3. The solder mask layer after coating needs to be pre-dried to remove the solvent components in the ink and make the ink initially solidified; S4. The pre-dried solder mask layer needs to be cured to make the polymer material undergo a cross-linking reaction to form a stable protective film; S5. Cooling the solidified circuit board to stabilize the size and prevent thermal deformation; S6. Check the cured solder mask layer, including appearance, thickness, and alignment accuracy. Smooth the surface as needed, package qualified circuit boards, and store them in a dry and clean environment. The coating machine in S2 comprises a loading part (1), the loading part (1) comprises a side plate (11), one side of the side plate (11) is rotatably connected to a chain plate conveyor belt (12), and the lower surface of the side plate (11) is fixedly connected to a bottom plate, and the outer surface of the chain plate conveyor belt (12) is provided with a positioning component (13) that can be used to fix an external circuit board; A coating part (2), the coating part (2) comprising a lifting seat (21), the outer surface of the lifting seat (21) being fixedly connected to a side of the side plate (11) away from the chain plate conveyor belt (12), the lifting seat (21) being slidably connected to a driving seat (22) via a lifting rod arranged on its upper surface, and the driving seat (22) is internally rotatably connected to a rotating shaft (23), and a printing mechanism (24) is arranged on the circumferential outer surface of the rotating shaft (23); The printing mechanism (24) comprises a rolling shaft (241), the rolling shaft (241) is sleeved on the circumferential outer surface of the rotating shaft (23), and the rolling shaft (241) is meshedly connected with a synchronous belt (243) through a main gear (242) arranged at the outer end thereof, a fixing rod (244) is fixedly connected to the side of the side plate (11) away from the lifting seat (21), a rolling brush cylinder (245) is sleeved on the circumferential outer surface of the fixing rod (244), and the outer end of the rolling brush cylinder (245) is fixedly connected with a sub-gear (246) meshed with the synchronous belt (243), and a silk screen (25) is arranged on the outer surface of the synchronous belt (243) to fit the circumferential outer surfaces of the rolling shaft (241) and the rolling brush cylinder (245); The positioning assembly (13) comprises a buckle seat (131), one side of which is fixedly connected to the circumferential outer surface of the chain plate conveyor belt (12), the outer surface of which is slidably connected to a positioning piece (132) that can fit with the side of an external circuit board, and the outer surface of the chain plate conveyor belt (12) is provided with a guide rail (133) that is fixedly connected to the upper surface of the bottom plate; The outer circumferential surface of the fixed rod (244) is fixedly connected to a fixed frame (26), the top of the fixed frame (26) is fixedly connected to a support seat (261), the interior of the support seat (261) is rotatably connected to a calibration component (27) via an axle, the calibration component (27) comprises an L-shaped magnetic plate (271), the outer circumferential surface of the axle is sleeved with a torsion spring (272) connected to the interior of the L-shaped magnetic plate (271), and one side of the L-shaped magnetic plate (271) is fixedly connected to a connecting plate (273), and the rolling shaft (241) is slidably connected to a reciprocating plate (274) via a slide groove (2411) provided therein.

2. According to claim 1, a circuit board ultra-thin solder mask process based on micro-nano technology is characterized in that: The positioning member (132) comprises a sliding seat (1321), a side of the sliding seat (1321) away from the side plate (11) is fixedly connected to a pressure rod (1322), an upper surface of the pressure rod (1322) is fixedly connected to a vertical pressure rod (1323), and a lower surface of the vertical pressure rod (1323) is designed with an arc surface, and two groups of guide rails (133) are arranged and are symmetrically distributed left and right with the chain conveyor belt (12) as the center.

3. The process for producing an ultra-thin solder mask layer for a circuit board based on micro-nano technology according to claim 1, characterized in that: The side of the reciprocating plate (274) close to the connecting plate (273) adopts an arc edge design, and the side of the reciprocating plate (274) away from the connecting plate (273) is magnetically connected to the outer surface of the L-shaped magnetic plate (271).

4. The process for producing an ultra-thin solder mask layer for a circuit board based on micro-nano technology according to claim 3 is characterized in that: A paint box (28) is fixedly connected to one side of the L-shaped magnetic plate (271) away from the connecting plate (273); the paint box (28) is of an open design; and a paint brush (281) is rotatably connected to the open end of the paint box (28).

5. The process for producing an ultra-thin solder mask layer for a circuit board based on micro-nano technology according to claim 1, characterized in that: A scraper frame (29) is fixedly connected to one end of the fixed frame (26) away from the side plate (11); the outer surface of the scraper frame (29) is in contact with the inner wall of the wire mesh (25); and a material guide groove (291) is provided on the upper surface of the scraper frame (29).

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