PCB developing tank liquid circulation structure with flow uniformizing guide plate

Abstract

The utility model relates to the technical field of PCB manufacturing discloses a kind of PCB developing tank liquid medicine circulation structure with uniform flow guide plate, including support seat, transmission group, conveying net and liquid medicine tank.The inside of support seat is provided with liquid medicine tank, and the top of liquid medicine tank is provided with transmission group, and the outside of transmission group is equipped with conveying net for conveying PCB.Support seat is provided with U-shaped support pipe, and the bottom of U-shaped support pipe is provided with spray group, overflow group and slit group respectively.Through setting spray group, overflow group and slit group, the "impact-coverage-stable" three-level processing to PCB is realized, and the developing uniformity is good, there is no dead angle, effectively improve developing quality, especially suitable for fine circuit and HDI board.

Description

Technical Field

[0001] This utility model relates to the field of PCB manufacturing technology, and in particular to a PCB developing tank chemical circulation structure with a flow equalization guide plate. Background Technology

[0002] PCB, or Printed Circuit Board, is an important electronic component that serves as a carrier for interconnecting electronic components. The PCB manufacturing process mainly includes steps such as material preparation, drilling, copper plating, lamination, exposure, development, copper plating, soldering, film removal, etching, solder stripping, baking, tin plating, inspection, and packaging. PCB development is one of the most important steps in PCB manufacturing. The main process involves using the chemical reaction between the developer and the unexposed parts of the photosensitive adhesive layer to remove the unexposed portions, thereby forming the circuit pattern through a chemical reaction. The development process requires strict control of time, temperature, and chemical concentration to ensure the quality and stability of the PCB.

[0003] Patent document CN206497306U discloses a PCB developing device, which mainly uses a first overflow port and a second overflow port located at the top of the developing tank, along with a liquid level sensing control device, to accelerate the renewal of the chemical solution in the developing working area, in order to quickly remove the old solution on the surface and floating impurities. However, in practical applications, this type of existing technology, which mainly relies on overflow, still has limited flow uniformity. Its chemical solution circulation and renewal mainly depend on the passive overflow of the overflow port, lacking an effective active mechanical flow uniformity structure. Moreover, the single overflow mode cannot simultaneously meet the needs of strong mechanical flushing and gentle comprehensive coverage. The effect of removing stubborn residues and ensuring the development integrity of fine circuit sidewalls may not be satisfactory. Therefore, we provide a PCB developing tank chemical solution circulation structure with a flow uniform guide plate to improve this. Utility Model Content

[0004] To overcome the above shortcomings, this utility model provides a PCB developing tank solution circulation structure with a flow equalization guide plate, which aims to improve the problems of limited flow equalization effect of developing tank solution, reliance on passive overflow for circulation and renewal, and difficulty in balancing the needs of strong rinsing and gentle coverage in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a PCB developing tank chemical circulation structure with a uniform flow guide plate, comprising a support base, a transmission assembly, a conveyor net, and a chemical tank. The support base has a chemical tank inside, the top of the chemical tank is provided with a transmission assembly, and the outer side of the transmission assembly is fitted with a conveyor net for conveying PCBs. The top of the support base is provided with a U-shaped support tube, and the bottom of the U-shaped support tube is respectively provided with a spray assembly for impact developing the PCB, an overflow assembly for forming a stable liquid curtain, and a slit flow assembly for generating uniform laminar flow. A chemical circulation component is provided on one side of the chemical tank, and the two ends of the chemical circulation component are respectively connected to the chemical tank and the U-shaped support tube.

[0006] As a further description of the above technical solution:

[0007] The spray assembly includes a first transmission pipe connected to a U-shaped support pipe, a first diversion pipe at the bottom of the first transmission pipe, and multiple flat nozzles at the bottom of the first diversion pipe.

[0008] As a further description of the above technical solution:

[0009] The overflow group includes a second transmission pipe connected to a U-shaped support pipe. A second diversion pipe is provided at the bottom of the second transmission pipe. A flow equalization guide plate is provided at the bottom of the second diversion pipe. Multiple overflow ports of the same size and arranged at equal intervals are opened at the bottom of the flow equalization guide plate.

[0010] As a further description of the above technical solution:

[0011] The slit flow group includes a No. 3 transmission pipe connected to a U-shaped support pipe, a No. 3 diversion pipe at the bottom of the No. 3 transmission pipe, and a narrow slit flow plate capable of generating sheet-like laminar flow at the bottom of the No. 3 diversion pipe.

[0012] As a further description of the above technical solution:

[0013] The liquid circulation assembly includes a circulation pump and an outlet pipe connected to a U-shaped support pipe. The inlet of the circulation pump is connected to a cartridge filter through a pipe fitting, and the inlet of the cartridge filter is connected to the liquid tank through a pipe fitting.

[0014] As a further description of the above technical solution:

[0015] The top of the U-shaped support pipe is equipped with valves that are respectively connected to the first transmission pipe, the second transmission pipe and the third transmission pipe, and a heater is installed in the medicine tank.

[0016] As a further description of the above technical solution:

[0017] The surface of the conveyor network is provided with positioning clips for fixing the PCB, and the top two sides of the support base are provided with sliding grooves, and a protective cover is slidably fitted in the sliding grooves.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of this application are as follows:

[0019] 1. In this utility model, by setting up a spray group, an overflow group and a slit flow group, a three-stage treatment of "impact-coverage-stabilization" for PCB is achieved, resulting in good development uniformity, no dead corners, and effectively improved development quality. It is especially suitable for fine lines and HDI boards.

[0020] 2. In this invention, by setting up a chemical circulation assembly, the developer solution in the chemical tank can be continuously pumped into the U-shaped support tube, and after passing through the spray assembly, overflow assembly, and slit flow assembly, it flows back to the chemical tank, forming a closed-loop circulation system. The cartridge filter effectively removes impurities and photosensitive residue generated during the developing process, preventing clogging of the spray assembly, ensuring the cleanliness of the chemical solution, and, with the cooperation of valves, flexibly adjusts the flow rate of the chemical solution in each component to meet the needs of different developing processes. Attached Figure Description

[0021] Figure 1 A three-dimensional view of a support structure for a PCB developing tank with a uniform flow guide plate for circulating pharmaceutical solution, as proposed in this utility model.

[0022] Figure 2 A perspective view of the protective cover and support base connection structure of a PCB developing tank with a uniform flow guide plate for circulating pharmaceutical solution, as proposed in this utility model.

[0023] Figure 3 This is an internal sectional view of the overall structure of a PCB developing tank with a uniform flow guide plate for circulating pharmaceutical solution, as proposed in this utility model.

[0024] Figure 4 This invention presents a schematic diagram of the bottom of a flat nozzle, a flow equalization guide plate, and a narrow slit flow plate, which constitute the chemical circulation structure of a PCB developing tank with a flow equalization guide plate.

[0025] Legend:

[0026] 1. Support base; 2. Transmission assembly; 3. Conveyor net; 4. Liquid tank; 5. U-shaped support pipe; 6. Spray assembly; 601. Transmission pipe No. 1; 602. Diverter pipe No. 1; 603. Flat nozzle; 7. Overflow assembly; 701. Transmission pipe No. 2; 702. Diverter pipe No. 2; 703. Flow equalization guide plate; 704. Overflow port; 8. Slit flow assembly; 801. Transmission pipe No. 3; 802. Diverter pipe No. 3; 803. Narrow slit flow plate; 9. Liquid circulation assembly; 901. Circulation pump; 902. Discharge pipe; 903. Cartridge filter; 10. Valve; 11. Heater; 12. Positioning clamp; 13. Slide groove; 14. Protective cover. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the present invention provides a PCB developing tank liquid circulation structure with a uniform flow guide plate, which mainly consists of a support base 1, a transmission group 2, a conveying net 3, a liquid tank 4, a U-shaped support pipe 5, and a spray group 6, an overflow group 7 and a slit flow group 8 installed on the U-shaped support pipe 5.

[0029] The interior of the support base 1 is a chemical tank 4 for storing developing chemicals. The transmission assembly 2 (such as a motor-driven roller assembly) is mounted on top of the chemical tank 4, and a conveyor net 3 is fitted around its outside to carry and horizontally transport the PCB. The PCB is fixed by positioning clips 12 on the conveyor net 3 to prevent displacement during movement.

[0030] The U-shaped support tube 5 spans the top of the support base 1, with the spray group 6, overflow group 7, and slit flow group 8 suspended sequentially at its bottom. The spray group 6, located at the foremost position, uses its flat nozzles 603 to generate a fan-shaped jet that powerfully washes the upper surface of the PCB, peeling away most of the unexposed photosensitive film. Following closely behind is the overflow group 7, whose multiple equidistant overflow ports 704 at the bottom of its flow equalization plate 703 form a uniform and gentle chemical curtain, providing full coverage wetting and development of the lower surface of the PCB. Finally, the slit flow group 8, with its narrow slit flow plate 803, generates a stable laminar flow, performing final "flattening" and "displacement" on the PCB surface, removing residue and ensuring uniform development.

[0031] The liquid circulation assembly 9 is responsible for the purification and circulation of the liquid medicine. During operation, the circulation pump 901 draws the liquid medicine from the liquid medicine tank 4, removes impurities such as glue residue from the filter cartridge 903, and then pumps it into the U-shaped support pipe 5 through the outlet pipe 902. By adjusting the three valves 10 at the top of the U-shaped support pipe 5, the flow rate and pressure of the liquid medicine leading to the spray group 6, overflow group 7, and slit flow group 8 can be independently controlled. The protective cover 14 is installed via the slide 13 and can be closed during operation to prevent liquid medicine splashing and external light from entering.

[0032] The implementation principle of the PCB developing tank chemical circulation structure with a flow equalization guide plate of this application is as follows: In use, the PCB board to be developed is first fixed to the surface of the conveyor belt 3 by the positioning clamp 12. The transmission group 2 is started to drive the conveyor belt 3 to move at a uniform speed. Then, the circulation pump 901 and the heater 11 are started, and the chemical solution is drawn out from the chemical solution tank 4. At this time, the operator can adjust the flow rate of each group by adjusting the valve 10 according to the line width / spacing requirements of the HDI board to be produced. The PCB board first enters the area below the spray group 6. The chemical solution is pressure equalized in the first transmission pipe 601 and the first diversion pipe 602, and then ejected at high speed in a fan shape from multiple flat nozzles 603, vertically impacting the upper surface of the PCB board. The main function of this stage is to use mechanical kinetic energy to peel off most of the unexposed photosensitive film and process the main part of the circuit. Subsequently, the PCB board enters the overflow group 7 area. The chemical solution enters the flow equalization guide plate 703 through the second transmission pipe 701 and the second diversion pipe 702. Because the overflow ports 704 at the bottom of the flow equalization guide plate 703 are of uniform size and equidistantly arranged, the chemical solution overcomes surface tension to form a continuous, uniform, and stable chemical solution curtain, gently covering the lower surface of the PCB board. This stage mainly involves chemical wetting to ensure that the dead corners and lower surface of the board are fully developed. Finally, the PCB board passes through the slit flow group 8. The chemical solution is distributed to the narrow slit flow plate 803 through the third distribution pipe 802. The narrow slit flow plate 803 generates an extremely thin and uniform laminar flow, flowing smoothly over the upper and lower surfaces of the PCB board like a "scraper". The purpose of this stage is to smooth the flow field and perform final displacement, gently carrying away any trace products that may remain from the first two stages, ensuring the neatness and uniformity of the developed edges, and eliminating watermark defects. The developed PCB board is then sent out of the equipment by the conveyor mesh 3. All used chemical solution falls back to the bottom of the chemical solution tank 4 under gravity to participate in the next cycle. When it is necessary to replace the medicine solution or perform equipment maintenance, the water outlet valve located at the bottom of the medicine solution tank 4 can be opened to discharge the waste liquid through the water outlet pipe.

[0033] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A PCB developing tank solution circulation structure with a flow-equalizing guide plate, characterized in that, The device includes a support base (1), a transmission assembly (2), a conveyor net (3), and a liquid tank (4). The support base (1) has a liquid tank (4) inside. The top of the liquid tank (4) is provided with a transmission assembly (2), and the outside of the transmission assembly (2) is provided with a conveyor net (3) for conveying PCBs. The top of the support base (1) is provided with a U-shaped support tube (5). The bottom of the U-shaped support tube (5) is provided with a spray assembly (6) for impact developing the PCB, an overflow assembly (7) for forming a stable liquid curtain, and a slit flow assembly (8) for generating uniform laminar flow. A liquid circulation assembly (9) is provided on one side of the liquid tank (4). The two ends of the liquid circulation assembly (9) are connected to the liquid tank (4) and the U-shaped support tube (5), respectively.

2. The PCB developing tank solution circulation structure with a flow-equalizing guide plate according to claim 1, characterized in that: The spray assembly (6) includes a first transmission pipe (601) connected to a U-shaped support pipe (5), a first diversion pipe (602) is provided at the bottom of the first transmission pipe (601), and a plurality of flat nozzles (603) are provided at the bottom of the first diversion pipe (602).

3. The PCB developing tank solution circulation structure with a flow-equalizing guide plate according to claim 1, characterized in that: The overflow group (7) includes a second transmission pipe (701) connected to a U-shaped support pipe (5). A second diversion pipe (702) is provided at the bottom of the second transmission pipe (701). A flow equalization guide plate (703) is provided at the bottom of the second diversion pipe (702). Multiple overflow ports (704) of the same size and equidistant arrangement are opened at the bottom of the flow equalization guide plate (703).

4. The PCB developing tank solution circulation structure with a flow equalization guide plate according to claim 1, characterized in that: The slit flow group (8) includes a third transmission pipe (801) connected to a U-shaped support pipe (5), a third diversion pipe (802) is provided at the bottom of the third transmission pipe (801), and a narrow slit flow plate (803) capable of generating sheet-like laminar flow is provided at the bottom of the third diversion pipe (802).

5. The PCB developing tank solution circulation structure with a flow-equalizing guide plate according to claim 1, characterized in that: The liquid circulation assembly (9) includes a circulation pump (901) and an outlet pipe (902) connected to a U-shaped support pipe (5). The inlet end of the circulation pump (901) is connected to a cartridge filter (903) through a pipe fitting. The inlet end of the cartridge filter (903) is connected to the liquid tank (4) through a pipe fitting.

6. The PCB developing tank solution circulation structure with a flow-equalizing guide plate according to claim 1, characterized in that: The top of the U-shaped support pipe (5) is provided with valves (10) that are respectively connected to the first transmission pipe (601), the second transmission pipe (701) and the third transmission pipe (801), and a heater (11) is provided in the medicine tank (4).

7. The PCB developing tank solution circulation structure with a flow-equalizing guide plate according to claim 1, characterized in that: The surface of the conveyor mesh (3) is provided with a positioning clip (12) for fixing the PCB. The top two sides of the support base (1) are provided with sliding grooves (13), and a protective cover (14) is slidably fitted in the sliding grooves (13).

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