Circuit board resin hole plugging technology

Abstract

The invention relates to the field of circuit board processing, in particular to a resin hole plugging process for a circuit board. According to the circuit board resin hole plugging technology, the wire drawing type injection equipment is used for conducting resin injection hole plugging treatment on the through hole structure of the circuit board, and in the process that the injection pipe injects resin into the through hole structure of the circuit board, the resin injection hole plugging treatment is conducted on the through hole structure of the circuit board through the wire drawing type injection equipment; the suction pipe performs low-negative-pressure suction treatment at the bottom of the through hole structure of the circuit board, then the injection pipe applies upward pulling force to resin in the process of upwards leaving the circuit board, so that the resin is tightened for wire drawing treatment, and then a resin wire drawing part is pinched off by the clamping block heated by the micro heater, so that the resin overflow phenomenon can be avoided. The technical defect that in the resin hole plugging process of the circuit board, when an injection pipe leaves the through hole of the circuit board, a large amount of grease spills out of the top of the through hole of the circuit board is overcome.

Description

Technical Field

[0001] The present invention relates to the field of printed circuit board processing, and particularly to a printed circuit board resin plugging process for holes. Background Art

[0002] The resin plugging process for holes in thickened multi-layer printed circuit boards is a technology used to repair holes and defects during the manufacturing process of multi-layer printed circuit boards, aiming to improve the quality, reliability, and production efficiency of multi-layer printed circuit boards. This process seals the holes by filling resin materials, thereby solving the limitations that the green oil plugging or press-fitting filling resin cannot fully solve the problem. Among them, resin plugging is suitable for filling small-diameter holes. In the resin plugging process for holes in multi-layer printed circuit boards, there is a method of using an injection tube to align with one side of the through-hole of the multi-layer printed circuit board while applying low negative pressure suction to the other side of the multi-layer printed circuit board. In this way, the resin can be sucked into the through-hole of the multi-layer printed circuit board, improving the filling effect of the resin for through-holes with a certain depth. However, during the process of the injection tube moving away from the through-hole of the multi-layer printed circuit board, resin drawing will occur between the nozzle of the injection tube and the through-hole of the multi-layer printed circuit board. Existing equipment generally either ignores the resin drawing or cuts the resin drawing from the nozzle of the injection tube with a cutter. After the resin drawing breaks, it will fall and accumulate at the through-hole of the multi-layer printed circuit board, and even flow and spread to the surrounding area, resulting in a large amount of resin overflow at the top of the through-hole of the multi-layer printed circuit board. After the resin is dried and cured, a large amount of grinding and cleaning work needs to be carried out on the resin overflow area of the multi-layer printed circuit board in the later stage, which is likely to cause excessive wear on the surface of the multi-layer printed circuit board. Summary of the Invention

[0003] In order to overcome the drawback that during the resin plugging process for holes in a printed circuit board, resin drawing occurs when the injection tube leaves the through-hole of the printed circuit board, and after the resin drawing breaks, it accumulates around the through-hole of the printed circuit board, resulting in a large amount of resin overflow at the top of the through-hole of the printed circuit board, the present invention provides a printed circuit board resin plugging process for holes.

[0004] A resin plugging process for a circuit board of the present invention uses a wire-drawing type injection device to perform resin injection plugging treatment on the through-hole structure of the circuit board. A wire-drawing type injection device includes an installation table, a carrier frame, a multi-axis electric control moving machine, a fixing plate, an electric control lifting frame, an injection pipe, a support ring block, an external compression spring, a reciprocating moving component, a clamping block, a micro heater, and a suction pipe; the installation table is fixed with a carrier frame for placing the circuit board; a multi-axis electric control moving machine is installed on the installation table; a fixing plate is fixedly connected to the moving component of the multi-axis electric control moving machine; an electric control lifting frame is installed on the fixing plate; an injection pipe is fixedly connected to the electric control lifting frame; a support ring block is slidably connected to the injection pipe; an external compression spring is fixedly connected between the support ring block and the injection pipe; a reciprocating moving component is connected to the support ring block; two clamping blocks for clamping and breaking the resin wire-drawing part are connected to the reciprocating moving component; a lower groove structure adapted to the resin wire-drawing part is formed at the bottom of the clamping block; a micro heater for heating the clamping block is installed on the reciprocating moving component; a suction pipe aligned below the injection pipe is fixedly connected to the fixing plate; the steps of the resin injection plugging treatment are as follows: place the circuit board on the carrier frame, then inject resin into the through-hole structure of the circuit board through the injection pipe, and at the same time, the suction pipe performs suction at the bottom of the through-hole structure to allow the resin to smoothly fill the through-hole structure. After that, the injection pipe moves upward away from the through-hole structure, and then the clamping block cooperates with the micro heater to heat and clamp off the resin wire-drawing part between the injection pipe and the through-hole structure.

[0005] Further, the reciprocating moving component is composed of a transverse wedge-shaped slider, an internal compression spring, and a push rod; two transverse wedge-shaped sliders are slidably connected to the support ring block; the transverse wedge-shaped sliders are respectively fixedly connected to the corresponding clamping blocks; the micro heater is installed in the transverse wedge-shaped slider; an internal compression spring is fixedly connected between each transverse wedge-shaped slider and the support ring block; a push rod is fixedly connected to the electric control lifting frame and abuts against the corresponding transverse wedge-shaped slider.

[0006] Further, the clamping block is divided into an upper non-heating area and a lower heating area, and the lower groove structure is located in the lower heating area of the clamping block.

[0007] Further, a heat insulation filling material is provided in the upper non-heating area of the clamping block.

[0008] Further, a non-stick coating is provided on the surface of the upper non-heating area of the clamping block.

[0009] Further, a main heater is installed on the fixing plate; a cavity structure is provided in the middle of the main heater.

[0010] Further, a blocking block for blocking the resin from continuing to flow downward is connected to the top of the suction pipe, and the upper air port of the suction pipe surrounds the blocking block and is connected to the cavity structure of the main heater.

[0011] Further, a sealing ring is provided on the main heater.

[0012] Further, an electric slider is slidably connected to the carrier frame; a suction cylinder is installed on the electric slider; a scraper is fixedly connected to the suction cylinder, and the scraper is located below the suction port structure of the suction cylinder.

[0013] Further, a plurality of partition sheets for guiding an object toward the suction port structure of the suction cylinder are fixedly connected to the scraper.

[0014] Beneficial effects: In a resin plugging process for a circuit board of the present invention, a wire drawing type injection device is used to perform resin injection plugging on the through-hole structure of the circuit board. For the wire drawing type injection device provided by the present invention, during the process of injecting resin into the through-hole structure of the circuit board by the injection tube, the suction tube performs low negative pressure suction treatment at the bottom of the through-hole structure of the circuit board. Then, during the process of the injection tube moving upward away from the circuit board, an upward pulling force is applied to the resin to tighten it for wire drawing treatment. Then, the resin wire drawing part is clamped and cut off by the clamp block heated by the micro heater, so as to avoid the phenomenon of resin overflow; it overcomes the technical defect that when the injection tube leaves the through-hole of the circuit board in the resin plugging process of the circuit board, there is a large amount of resin overflow at the top of the through-hole of the circuit board. Description of the Drawings

[0015] Figure 1 Structural diagram of a wire drawing type injection device of the present invention; Figure 2 Structural diagram of the electric control lifting frame of a wire drawing type injection device of the present invention; Figure 3 Structural diagram of the injection tube of a wire drawing type injection device of the present invention; Figure 4 Cross-sectional view of the support ring block structure of a wire drawing type injection device of the present invention; Figure 5 Structural diagram of the clamp block of a wire drawing type injection device of the present invention; Figure 6 Structural diagram of the main heater of a wire drawing type injection device of the present invention; Figure 7 Structural diagram of the scraper of a wire drawing type injection device of the present invention.

[0016] Names and serial numbers of components in the figure: 11 - mounting table, 12 - carrier frame, 13 - multi-axis electric control moving machine, 14 - fixing plate, 15 - electric control lifting frame, 21 - injection tube, 22 - support ring block, 23 - outer compression spring, 24 - transverse wedge-shaped slider, 25 - inner compression spring, 26 - push rod, 31 - clamp block, 3101 - lower groove structure, 32 - micro heater, 41 - suction tube, 42 - main heater, 4201 - cavity structure, 43 - stopper, 44 - sealing ring, 51 - electric slider, 52 - suction cylinder, 5201 - suction port structure, 53 - scraper, 54 - partition sheet. Detailed implementation manners

[0017] The present invention will be specifically introduced below in conjunction with the accompanying drawings and specific embodiments.

[0018] Embodiment 1 A resin plugging process for a circuit board uses a wire-drawing type injection device to perform resin injection plugging treatment on the through-hole structure of the circuit board. As Figures 1 - 5 shown, a wire-drawing type injection device provided by the present invention includes an installation table 11, a carrier frame 12, a multi-axis electric control moving machine 13, a fixing plate 14, an electric control lifting frame 15, an injection tube 21, a support ring block 22, an external compression spring 23, a reciprocating moving assembly, clamping blocks 31, a micro heater 32, and a suction pipe 41; the installation table 11 is fixed with a carrier frame 12 for placing the circuit board; a multi-axis electric control moving machine 13 for driving the fixing plate 14 to move in the up and down, left and right, and front and back directions is installed on the installation table 11; an electric control lifting frame 15 is installed on the fixing plate 14; an injection tube 21 is fixedly connected to the electric control lifting frame 15, and the injection tube 21 is externally connected to a resin conveying device; a support ring block 22 is slidably connected to the outer surface of the injection tube 21, and the nozzle of the injection tube 21 is contracted within the support ring block 22; an external compression spring 23 is fixedly connected between the support ring block 22 and the injection tube 21; a reciprocating moving assembly is connected to the support ring block 22; two clamping blocks 31 are connected to the reciprocating moving assembly, and the two clamping blocks 31 are located below the injection tube 21; a lower groove structure 3101 adapted to the resin wire-drawing part is formed at the bottom of the clamping block 31, and an anti-adhesion coating is provided on the surface of the non-heating area of the upper layer of the clamping block 31 to prevent the resin at the nozzle of the injection tube 21 from adhering to the end surface of the clamping block 31; the clamping block 31 is divided into an upper non-heating area and a lower heating area, the lower groove structure 3101 is located in the lower heating area of the clamping block 31, and a heat insulation filling material is provided in the upper non-heating area of the clamping block 31; two micro heaters 32 for heating the two clamping blocks 31 are installed on the reciprocating moving assembly; a suction pipe 41 aligned below the injection tube 21 is fixedly connected to the fixing plate 14, and the suction pipe 41 is externally connected to a suction machine.

[0019] As Figure 3 and Figure 4 shown, the reciprocating moving assembly of this embodiment is composed of a transverse wedge-shaped slider 24, an internal compression spring 25, and a push rod 26; two mutually left and right symmetric transverse wedge-shaped sliders 24 are slidably connected to the support ring block 22; the two transverse wedge-shaped sliders 24 are respectively fixedly connected to the corresponding clamping blocks 31; the two micro heaters 32 are respectively installed in the two transverse wedge-shaped sliders 24; an internal compression spring 25 is fixedly connected between each of the two transverse wedge-shaped sliders 24 and the support ring block 22, and the internal compression spring 25 is initially in a compressed state; a push rod 26 for pushing the transverse wedge-shaped slider 24 to move horizontally is fixedly connected to the electric control lifting frame 15, and the push rod 26 is closely attached to the lower surface of the corresponding transverse wedge-shaped slider 24, so that the two transverse wedge-shaped sliders 24 are in a state of being closely attached to each other.

[0020] The specific operation steps for resin injection plug hole treatment of a wire drawing type injection device provided in this embodiment are as follows.

[0021] First, the operator places the circuit board on the carrier frame 12 of the installation table 11. A groove for accommodating the circuit board is provided in the middle of the carrier frame 12. After placing the circuit board in the groove, the circuit board can be fixed. Then, the multi-axis electric control moving machine 13 controls the movement of the injection tube 21 and the suction tube 41 on the fixed plate 14 and the electric control lifting frame 15 according to the set program, and aligns them with each through-hole structure on the circuit board in sequence. After the injection tube 21 and the suction tube 41 are respectively aligned with the upper and lower sides of a certain through-hole structure on the circuit board, the multi-axis electric control moving machine 13 pushes the suction tube 41 on the fixed plate 14 upward to closely adhere to the bottom of the corresponding through-hole structure on the circuit board. The externally connected suction machine performs low-negative pressure suction treatment on the through-hole structure of the circuit board through the suction tube 41. At the same time, the electric control lifting frame 15 pulls the injection tube 21 and the support ring block 22 to move downward together. When the support ring block 22 closely adheres to the upper surface of the corresponding through-hole structure, the support ring block 22 stops moving due to the obstruction of the circuit board. At this time, the bottom of the clamping block 31 is slightly higher than the upper surface of the circuit board, but the electric control lifting frame 15 can continue to pull the injection tube 21 downward. At the same time, the injection tube 21 drives the external compression spring 23 to compress downward. The electric control lifting frame 15 also drives the push rod 26 to move downward. In the initial state, the push rod 26 is in a state of closely adhering to and limiting the lateral wedge-shaped slider 24, so that the two lateral wedge-shaped sliders 24 are in a state of closely adhering to each other. Therefore, after the push rod 26 moves downward, the two internal compression springs 25 that are simultaneously compressed push the lateral wedge-shaped sliders 24 connected to them to drive the clamping blocks 31 to open to both sides respectively, so that the injection tube 21 can smoothly move downward to a position close to the top of the through-hole structure of the circuit board. Then, the externally connected resin conveying device injects resin into the through-hole structure of the circuit board through the injection tube 21. The resin is smoothly filled into the through-hole structure of the circuit board under the low-negative pressure suction treatment of the suction tube 41, completing the resin injection filling treatment work. During this process, the micro heater 32 continuously heats the lower heating area of the clamping block 31.

[0022] After the injection filling is completed, the external suction machine stops the low negative pressure suction treatment of the through-hole structure of the circuit board through the suction pipe 41, and then the electric control lifting frame 15 pulls the injection pipe 21 upward to leave the through-hole structure of the circuit board. During this process, the resin between the injection pipe 21 and the through-hole structure of the circuit board will not automatically disconnect. The injection pipe 21 will apply an upward pulling force to the resin, and the resin outside the through-hole structure of the circuit board is pulled upward to form a conical wire-drawing part with a gradually upward shrinking shape. At the same time, the electric control lifting frame 15 pulls the push rod 26 upward to reset. The external compression spring 23 releases elastic force at this time to make the support ring block 22 still closely adhere to the surface of the circuit board. The two push rods 26 push the corresponding horizontal wedge-shaped sliders 24 to drive the two clamping blocks 31 to approach the resin wire-drawing part below the injection pipe 21. At the same time, the horizontal wedge-shaped slider 24 drives the internal compression spring 25 to be compressed again. In the middle of the two clamping blocks 31 that approach each other, the resin wire-drawing part is transversely clamped off below the nozzle of the injection pipe 21. The resin wire-drawing part is divided into a small part remaining at the nozzle of the injection pipe 21 and the vast majority wrapped in the lower groove structure 3101.

[0023] After clamping off, the resin wire-drawing part inside it is heated through the lower groove structure 3101. The outer surface of the resin wire-drawing part is heated and condensed into a pre-cured state with greatly weakened fluidity, thus avoiding the downward collapse and diffusion of the resin wire-drawing part to the area around the through-hole structure. There is heat-insulating filling material, such as glass wool or ceramic fiber, in the upper non-heating area of the clamping block 31, which can basically exempt the influence of the upward diffusion of heat in the lower heating area of the clamping block 31 on the nozzle of the injection pipe 21 and the residual resin inside. After that, the electric control lifting frame 15 continues to pull the push rod 26 and the support ring block 22 upward to leave the circuit board. There is an upward shrinking vertical wire-drawing part reserved at the upper end of the resin filled in the through-hole structure of the circuit board, and because the surface of the resin wire-drawing part has been transformed into a pre-cured state, it restricts the inside of the wire-drawing part, so that the whole wire-drawing part will not collapse and contact the upper surface of the circuit board. Therefore, when starting to grind the surface of the circuit board after the resin is completely cured later, the area that the grinding equipment needs to grind on the surface of the circuit board can be greatly reduced, and the probability of excessive wear on the surface of the multi-layer circuit board can be reduced. Moreover, by adjusting the excess resin from a spread-out sheet shape to a vertical wire column shape, the resin is easier to break, reducing the removal difficulty.

[0024] Embodiment 2 On the basis of Embodiment 1, as Figures 1 - 6 shown, a main heater 42 is installed on the fixed plate 14 of this embodiment; a cavity structure 4201 is provided in the middle of the main heater 42; a block 43 for blocking the resin from continuing to flow downward is connected to the top of the suction pipe 41, and the upper air port of the suction pipe 41 surrounds the block 43 and is connected to the cavity structure 4201 of the main heater 42; a sealing ring 44 is fixedly connected to the outer edge of the main heater 42.

[0025] In this embodiment, whenever the multi-axis electric control moving machine 13 drives the suction pipe 41 on the fixed plate 14 to align with a through-hole structure of the circuit board, the multi-axis electric control moving machine 13 drives the main heater 42 to replace the suction pipe 41 and press tightly against the bottom of the through-hole structure of the circuit board upwards. The sealing ring 44 on the upper edge of the main heater 42 also presses tightly against the bottom of the circuit board, so that the cavity structure 4201 of the main heater 42 is connected to the through-hole structure of the circuit board and the through-hole structure of the circuit board is subjected to low negative pressure suction treatment through the cavity structure 4201 of the main heater 42. At the same time, the main heater 42 heats the periphery of the through-hole structure of the circuit board. When the injection pipe 21 injects resin into the through-hole structure of the circuit board, the contact between the resin and the heated through-hole structure of the circuit board can weaken the fluidity of the resin. Coupled with the blockage of the block 43, it is more difficult for the resin to flow downward into the cavity structure 4201, greatly reducing the probability of blockage problems in the cavity structure 4201.

[0026] Embodiment 3 On the basis of Embodiment 1, as Figures 1 - 5 and Figure 7 shown, an electric slider 51 is slidably connected to the carrier frame 12 of this embodiment; a suction cylinder 52 is installed on the electric slider 51, and the suction cylinder 52 is externally connected to a suction machine; a scraper 53 is fixedly connected to the suction cylinder 52, and the scraper 53 is located below the suction port structure 5201 of the suction cylinder 52. After the circuit board is placed in a groove for accommodating the circuit board provided in the middle of the carrier frame 12, the upper surface of the circuit board is flush with the scraper 53; a plurality of partition plates 54 for guiding an object towards the suction port structure 5201 of the suction cylinder 52 are welded on the scraper 53.

[0027] In this embodiment, after the resin plugging hole operation of the circuit board is completed, the electric control lifting frame 15 pulls the injection tube 21 upward away from the surface of the circuit board. At this time, there are resin drawing parts above each plugging hole position of the circuit board. Since the actual diameter of the resin drawing part is small and the resin drawing part has been heat-treated by the clamping block 31, the resin drawing part will generally be preferentially heated to the state of preliminary gelation first, where the resin completely loses fluidity and establishes preliminary mechanical strength. However, due to its own size limitation, its ability to resist shear or breakage is not strong. Subsequently, an external suction machine performs suction work through all the suction port structures 5201 of the suction cylinder 52. At the same time, the electric slider 51 drives the suction cylinder 52 and the scraper 53 to move horizontally across the surface of the circuit board. The scraper 53 horizontally cuts off the resin drawing parts in the gelation state at all the plugging hole positions on the circuit board, so that the circuit board has a high surface flatness. The cut resin drops along the partition piece 54 of the scraper 53 to the adjacent suction port structure 5201 of the suction cylinder 52, and the external suction machine sucks away all the cut resin through this suction port structure 5201, achieving the removal of the resin drawing parts at all the plugging hole positions on the circuit board in one step, without the need to continue with the subsequent work of grinding the excess resin on the circuit board. After the cutting is completed, the circuit board is taken away for further complete curing treatment of the resin in the through-hole structure.

[0028] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A circuit board resin plugging process, characterized in that: A wire drawing injection device is used to perform resin injection plugging treatment on the through hole structure of the circuit board; A wire drawing type injection device comprises a mounting platform (11); a supporting frame (12) for placing a circuit board is fixed on the mounting platform (11); a multi-axis electric control moving machine (13) is installed on the mounting platform (11); a fixing plate (14) is fixedly connected to the moving part of the multi-axis electric control moving machine (13); an electric control lifting frame (15) is installed on the fixing plate (14); an injection tube (21) is fixedly connected to the electric control lifting frame (15); a support ring block (22) is slidably connected to the injection tube (21); the support ring block (22) and An external compression spring (23) is fixedly connected between the injection tubes (21); a reciprocating assembly is connected to the support ring block (22); two clamping blocks (31) for clamping off the resin wire drawing portion are connected to the reciprocating assembly; a lower groove structure (3101) adapted to the resin wire drawing portion is provided at the bottom of the clamping block (31); a micro heater (32) for heating the clamping block (31) is installed on the reciprocating assembly; a suction tube (41) aligned with the bottom of the injection tube (21) is fixedly connected to the fixed plate (14); The steps of resin injection plugging treatment are as follows: placing the circuit board on the supporting frame (12), and then injecting resin into the through-hole structure of the circuit board through the injection tube (21), while the suction tube (41) performs suction at the bottom of the through-hole structure to allow the resin to smoothly fill the through-hole structure, and then the injection tube (21) moves upward away from the through-hole structure, and then the resin drawing part between the injection tube (21) and the through-hole structure is heated and clamped off by the clamping block (31) and the micro heater (32).

2. A circuit board resin plugging process according to claim 1, characterized in that: The reciprocating moving assembly is composed of a transverse wedge-shaped slider (24), an internal pressure spring (25) and a push rod (26); two transverse wedge-shaped sliders (24) are slidably connected to the support ring block (22); the transverse wedge-shaped sliders (24) are respectively fixedly connected to corresponding clamping blocks (31); the micro heater (32) is installed in the transverse wedge-shaped slider (24); an internal pressure spring (25) is respectively fixedly connected between the transverse wedge-shaped slider (24) and the support ring block (22); a push rod (26) is fixedly connected to the electric control lifting frame (15), and the push rod (26) is closely attached to the corresponding transverse wedge-shaped slider (24).

3. A circuit board resin plugging process according to claim 1, characterized in that: The clamping block (31) is divided into an upper non-heating zone and a lower heating zone, and the lower groove structure (3101) is located in the lower heating zone of the clamping block (31).

4. A circuit board resin plugging process according to claim 3, characterized in that: A heat-insulating filling material is provided in the upper non-heating area of ​​the clamping block (31).

5. A circuit board resin plugging process according to claim 1, characterized in that: The surface of the upper non-heating area of ​​the clamping block (31) is coated with an anti-stick coating.

6. A circuit board resin plugging process according to claim 1, characterized in that: A main heater (42) is mounted on the fixed plate (14); a cavity structure (4201) is provided in the middle of the main heater (42).

7. A circuit board resin plugging process according to claim 6, characterized in that: A stopper (43) is connected to the top of the suction pipe (41) to prevent the resin from continuing to flow downward, and an air port at the upper end of the suction pipe (41) surrounds the stopper (43) and is connected to the cavity structure (4201) of the main heater (42).

8. A circuit board resin plugging process according to claim 7, characterized in that: A sealing ring (44) is provided on the main heater (42).

9. A circuit board resin plugging process according to any one of claims 2 to 8, characterized in that: An electric slider (51) is slidably connected to the support frame (12); a suction cylinder (52) is mounted on the electric slider (51); a scraper (53) is fixedly connected to the suction cylinder (52), and the scraper (53) is located below the suction port structure (5201) of the suction cylinder (52).

10. A circuit board resin plugging process according to claim 9, characterized in that: A plurality of separation sheets (54) are fixedly connected to the scraper (53) and are used to guide the object towards the suction port structure (5201) of the suction cylinder (52).

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