A circuit board tin plating system for soldering circuit board chips

Abstract

This invention discloses a circuit board tin plating system for chip soldering, relating to the field of circuit board tin plating. It includes a tin bath, with a local tin plating mechanism above the tin bath. The local tin plating mechanism includes a tin plating plate, a tin plating tank on the top surface of the tin plating plate, and multiple tin plating pillars fixed within the tin plating tank. Each tin plating pillar corresponds to a chip soldering position on the circuit board. A through-hole is formed on the top surface of each tin plating pillar, penetrating the bottom of the tin plating plate. The height of the top surface of the tin plating pillar is lower than the height of the top surface of the tin plating plate. A tin-containing cavity is formed below the tin plating tank on the tin plating plate. Multiple circular holes are formed on the inner bottom wall of the tin plating tank, connecting to the tin-containing cavity. Tin removal holes are formed on the side wall of the tin plating plate, with the height of the tin removal holes higher than the height of the top surface of the tin plating pillars. A tin removal path hole is formed within the tin plating plate, with both ends of the tin removal path hole connecting to one end of the tin-containing cavity. Tin is applied to multiple chip soldering positions on the circuit board in one pass, achieving automatic tin plating of the circuit board.

Description

Technical Field

[0001] This invention relates to the field of circuit board tin plating technology, specifically to a circuit board tin plating system for soldering circuit board chips. Background Art

[0002] Circuit boards (PCBs) are crucial electronic components, serving as the support for electronic devices and the carrier for their electrical connections. PCBs have evolved from single-layer to double-sided, multi-layer, and flexible designs, and continue to develop along their respective trends. Driven by continuous advancements in precision, density, and reliability, along with efforts to reduce size, lower costs, and improve performance, PCBs remain vital in the development of future electronic devices. In integrated circuit manufacturing, chips need to be soldered onto circuit boards. To ensure good solderability, tin plating is applied to the chip soldering points on the circuit board before soldering, providing a solderable metal layer. Circuit board tin plating differs from chip soldering; the tin layer on the circuit board needs to be thinner. An excessively thick tin layer will affect the height of the soldered chip, impacting the subsequent assembly accuracy of the circuit board and wasting molten solder. Since soldering guns can apply a large amount of tin, they cannot effectively tin the chip soldering points on the circuit board. Therefore, this process is primarily manual, with workers manually brushing molten solder onto the soldering points. This method suffers from harsh working environments, high labor costs, and low efficiency. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a circuit board tin plating system for soldering circuit board chips, thereby solving the deficiencies of the prior art.

[0004] The objective of this invention is achieved through the following technical solution: a circuit board tin plating system for chip soldering, comprising a tin bath, a partial tin plating mechanism above the tin bath, the partial tin plating mechanism comprising a tin plating plate, a tin plating tank on the top surface of the tin plating plate, a plurality of tin plating pillars fixed in the tin plating tank, each of the plurality of tin plating pillars corresponding to a chip soldering position on the circuit board, a through-hole for tin plating is formed on the top surface of each tin plating pillar, the through-hole for tin plating is formed through the bottom of the tin plating plate, the height of the top surface of the tin plating pillar is lower than the height of the top surface of the tin plating plate, a tin-containing cavity is formed below the tin plating tank on the tin plating plate, a plurality of circular holes are formed on the inner bottom wall of the tin plating tank, the circular holes are connected to the tin-containing cavity, a tin-removing hole is formed on the side wall of the tin plating plate, the height of the tin-removing hole is higher than the height of the top surface of the tin plating pillar, a tin-removing path hole is formed in the tin plating plate, the two ends of the tin-removing path hole are respectively connected to one end of the tin-removing hole and one end of the tin-containing cavity.

[0005] Furthermore, multiple tin-plated strips are fixed to the top of the tin-plated pillar, and each of the multiple tin-plated strips corresponds one-to-one with a multiple chip pin soldering position in the chip soldering position.

[0006] Furthermore, the top surface of the tin-plated pillar forms a tin-removing slope between two adjacent tin-plated bars, and the slope height of the tin-removing slope gradually decreases in the direction away from the tin-passing hole.

[0007] Furthermore, a desoldering piston is slidably disposed within the desoldering cavity. Two wire holes are opened on one side of the desoldering tank on the top surface of the tin-plating plate. One of the wire holes is connected to the desoldering path hole, and the other wire hole is connected to the other end of the desoldering cavity. A driving block is slidably disposed on the other side of the desoldering tank on the top surface of the tin-plating plate. The driving block moves along the length of the desoldering cavity. Steel wire ropes are connected to both ends of the driving block. One steel wire rope passes through one of the wire holes and connects to one end of the desoldering piston, and the other steel wire rope passes through the other wire hole and connects to the other end of the desoldering piston.

[0008] Furthermore, the partial tin plating mechanism also includes a tin plating frame and a lifting cylinder. The lifting cylinder is vertically mounted on the tin plating frame. The telescopic shaft of the lifting cylinder is connected to a drive vertical rod. A horizontal beam is fixed to the side wall of the tin plating plate near the drive block. The bottom end of the drive vertical rod is connected to the horizontal beam through a flange.

[0009] Furthermore, a drive plate is fixed on the tin plating frame. A lead screw groove is formed on the drive plate along the moving direction of the drive block. The lead screw groove extends through the height direction of the drive plate. A lead screw is rotatably arranged in the lead screw groove. A lead screw slider is threaded onto the lead screw. The lead screw slider is slidably adapted to the lead screw groove. A drive rod is fixed at the bottom of the lead screw slider. A small-diameter hole and a large-diameter hole are formed sequentially from bottom to top on the bottom of the drive rod. A disc is slidably adapted in the large-diameter hole. The diameter of the disc is larger than the diameter of the small-diameter hole. A sliding rod is slidably adapted in the small-diameter hole. One end of the sliding rod is fixedly connected to the disc, and the other end is fixed to a mounting disc. The mounting disc is connected to the drive block by screws. A motor is mounted on the drive plate. The output shaft of the motor is driven and connected to the lead screw.

[0010] Furthermore, a U-shaped frame is provided directly above the wire hole. The closed end of the U-shaped frame is fixedly connected to the tin-plated plate via a plate. A first guide wheel is rotatably arranged inside the U-shaped opening of the U-shaped frame. The axis of the first guide wheel is horizontally set. Two second guide wheels are arranged on the tin-plated plate along the moving direction of the driving block. The driving block is located between the two second guide wheels. The axes of the second guide wheels are vertically set. One of the steel wire ropes passes around one of the first guide wheels and one of the second guide wheels and is connected to one end of the driving block. The other steel wire rope passes around the other first guide wheel and the other second guide wheel and is connected to the other end of the driving block. This is used to arrange the steel wire ropes around the tin-plating tank.

[0011] Furthermore, a long lead screw and a guide rod are arranged parallel to each other in the tin bath. The long lead screw and the guide rod are both located on one side of the tin-plating plate. A tin scraper slide is threaded onto the long lead screw. The tin scraper slide is slidably sleeved on the guide rod. An L-shaped scraper is fixed on the side of the tin scraper slide near the tin-plating plate. Metal scraper blades are fixed on the top and bottom surfaces of the horizontal section of the L-shaped scraper. The two metal scraper blades scrape off the tin layer on the surface of the tin bath and the tin layer on the bottom of the tin-plating plate, respectively. A drive motor is arranged away from the tin bath. The output shaft of the drive motor is connected to a drive sprocket. One end of the long lead screw is connected to a driven sprocket. The driven sprocket is connected to the drive sprocket through a chain drive.

[0012] Furthermore, an annular heating chamber is formed around the tin plating tank inside the tin plating plate, and hot air holes are formed on the inner sidewall of the tin plating plate. The hot air holes are used to blow air onto the top surface of the tin plating pillar. A hot air pipe is connected to the top surface of the tin plating plate. One end of the hot air pipe is connected to the annular heating chamber, and the other end is connected to a high-temperature hot air blower.

[0013] Furthermore, it also includes a gantry conveyor mechanism, which includes a conveying beam and two parallel overhead rails. The two ends of the conveying beam are slidably mounted on the two overhead rails. A lifting and feeding rod is vertically mounted on the conveying beam. The bottom of the lifting and feeding rod slides through the conveying beam and is connected to a negative pressure suction cup. A rack is fixed to the side wall of the lifting and feeding rod. An loading and unloading motor is mounted on the conveying beam. The output shaft of the loading and unloading motor is connected to a gear, and the gear meshes with the rack.

[0014] The beneficial effects of the present invention are:

[0015] The circuit board is placed with the chip soldering positions facing down into the tin plating bath of the tin plating plate. During this process, the tin plating plate moves downward so that the height of the tin plating plate in the molten solder is higher than the height of the tin plating pillar. The molten solder overflows from the top of the tin plating pillar through the solder passage, and the excess molten solder falls into the tin plating bath, leaving a layer of molten solder on the top surface of the tin plating pillar. Then, the tin plating plate moves upward so that the tin plating pillar contacts the chip soldering positions of the circuit board, thereby coating multiple chip soldering positions on the circuit board with a tin layer at one time. This realizes the automatic tin plating operation of the circuit board, improves production efficiency, and reduces production costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a circuit board tin plating system for soldering circuit board chips according to the present invention. Figure 1 ;

[0017] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0018] Figure 3This is a schematic diagram of the structure of a circuit board tin plating system for soldering circuit board chips according to the present invention. Figure 2 ;

[0019] Figure 4 for Figure 3 Enlarged view at point B in the middle;

[0020] Figure 5 This is a schematic diagram of the structure of a circuit board tin plating system for soldering circuit board chips according to the present invention. Figure 3 ;

[0021] Figure 6 This is a schematic diagram of the internal structure of the tin-plating plate in a tin-plating system for soldering circuit board chips according to the present invention.

[0022] Figure 7 This is a schematic diagram of the internal structure of a drive rod in a circuit board tin plating system for soldering circuit board chips according to the present invention.

[0023] Figure 8 This is a schematic diagram of the structure of a circuit board tin plating system for soldering circuit board chips according to the present invention. Figure 4 ;

[0024] Figure 9 for Figure 8 Enlarged view at point C;

[0025] In the diagram, 1-tin bath, 2-tin plating plate, 3-tin plating tank, 4-tin plating pillar, 5-tin passage hole, 6-tin holding cavity, 7-tin discharge hole, 8-tin discharge path hole, 9-tin plating strip, 10-tin discharge slope, 11-round hole, 12-tin discharge piston, 13-wire hole, 14-drive block, 15-steel wire rope, 16-tin plating frame, 17-drive horizontal plate, 18-lifting cylinder, 19-horizontal beam, 20-drive vertical rod, 21-lead screw groove, 22-lead screw, 23-lead screw slider, 24-drive rod, 25-small diameter hole, 26-large diameter hole, 27-disc 28-Sliding rod, 29-Mounting disc, 30-Motor, 31-U-shaped frame, 32-First guide wheel, 33-Second guide wheel, 34-Annular heating chamber, 35-Hot air hole, 36-Hot air duct, 37-Long lead screw, 38-Guide rod, 39-Scraping slide block, 40-L-shaped scraper, 41-Metal scraper blade, 42-Drive motor, 43-Drive sprocket, 44-Driven sprocket, 45-Chain, 46-Conveying beam, 47-Ceiling rail, 48-Lifting loading rod, 49-Negative pressure suction cup, 50-Rack and pinion, 51-Loading and unloading motor, 52-Gear. Detailed Implementation

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0027] Example 1:

[0028] like Figures 1 to 9As shown, a circuit board tin plating system for chip soldering includes a tin bath 1, a local tin plating mechanism above the tin bath 1, and a tin plating plate 2. A tin plating tank 3 is formed on the top surface of the tin plating plate 2. Multiple tin plating pillars 4 are fixed inside the tin plating tank 3, each corresponding to a chip soldering position on the circuit board. A through-hole 5 is formed on the top surface of each tin plating pillar 4, penetrating the bottom of the tin plating plate 2. The height of the top surface of the tin plating pillar 4 is lower than the height of the top surface of the tin plating plate 2. A tin-receiving cavity 6 is formed below the tin plating tank 3 on the tin plating plate 2. Multiple circular holes 11 are formed on the inner bottom wall of the tin plating tank 3, connecting to the tin-receiving cavity 6. Tin-removing holes 7 are formed on the side wall of the tin plating plate 2, with a height higher than the top surface of the tin plating pillars 4. The solder plate 2 has a solder discharge path hole 8, with both ends of the solder discharge path hole 8 connected to the solder discharge hole 7 and one end of the solder receiving cavity 6, respectively. It also includes a gantry conveyor mechanism, which includes a conveying beam 46 and two parallel overhead rails 47. Both ends of the conveying beam 46 are slidably mounted on the two overhead rails 47. A lifting and feeding rod 48 is vertically mounted on the conveying beam 46. The bottom of the lifting and feeding rod 48 slides through the conveying beam 46 and is connected to a negative pressure suction cup 49. A rack 50 is fixed to the side wall of the lifting and feeding rod 48. A loading and unloading motor 51 is installed on the conveying beam 46. The output shaft of the loading and unloading motor 51 is connected to a gear 52, which meshes with the rack 50. Molten solder is contained in the solder bath 1. Solder bars are periodically added to the solder bath 1 to keep the solder bath 1 molten. The liquid level inside is maintained within a certain range. A circuit board storage box is installed at one end of the tin bath 1. The tin bath 1 and the circuit board storage box are spaced apart along the moving direction of the conveying beam 46. A storage slot is opened on the top surface of the circuit board storage box, the shape of which matches the shape of the circuit board. The circuit boards are stacked along the height direction of the circuit board storage box, with the end face of the circuit board having chip soldering positions facing downwards, thus completing the positioning of the circuit board. The conveying beam 46 first moves the negative pressure suction cup 49 to directly above the circuit board storage box. The negative pressure suction cup 49 is connected to a negative pressure pump through a negative pressure pipe, adsorbing the circuit board material for tin plating through negative pressure. Negative pressure conveying is existing technology and will not be described further. The loading and unloading motor 51 drives the gear 52 to rotate, and the gear 52 interacts with... The meshing of the rack 50 drives the lifting loading rod 48 downwards, causing the negative pressure suction cup 49 to adsorb the circuit board. Then, the loading and unloading motor 51 reverses to remove the circuit board from the circuit board storage box. The conveying beam 46 then moves the circuit board directly above the tin-plating plate 2, aligning the chip soldering positions of the circuit board with the tin-plating pillars 4. The circuit board is then placed into the tin-plating tank 3 of the tin-plating plate 2. During this process, the tin-plating plate 2 moves downwards, ensuring that the height of the tin-plating plate 2 above the height of the tin-plating pillars 4 is higher. This allows the tin-plating liquid to overflow from the top of the tin-plating pillars 4 through the tin-through holes 5. Excess tin-plating liquid falls into the tin-plating tank 3, leaving a layer of tin-plating liquid on the top surface of the tin-plating pillars 4. The tin-plating liquid overflowing from the top of the tin-plating pillars 4 flows into the tin-plating tank 3. To prevent the tin-plating liquid level in the tin-plating tank 3 from rising too high...The molten tin level in the tin plating bath 3 exceeds the height of the tin plating pillar 4, preventing further tin plating of the circuit board. A circular hole 11 is provided on the inner bottom wall of the tin plating bath 3, allowing the molten tin in the tin plating bath 3 to flow into the tin-containing cavity 6. The molten tin in the tin-containing cavity 6 flows back into the tin plating bath 1 through the tin discharge path hole 8 and the tin discharge hole 7. The tin discharge hole 7 is located above the tin plating pillar 4, preventing the molten tin in the tin plating bath 1 from flowing back into the tin plating bath 3 through the tin discharge hole 7. After molten tin remains on the top surface of the tin plating pillar 4, the tin plating plate 2 moves upward, causing the tin plating pillar 4 to contact the chip soldering positions of the circuit board. This allows for the coating of tin layers on multiple chip soldering positions of the circuit board at once, achieving automatic tin plating of the circuit board, improving production efficiency, and reducing production costs. In practical implementation, the overhead rail 47 is fixedly installed, and the conveying beam 46 is installed on the overhead rail 47 via a screw. The screw drives the conveying beam 46 to move along the length of the overhead rail 47. To reduce the length of the lifting loading rod 48, a lifting plate is installed in the storage slot of the circuit board storage box. A linear drive module is vertically installed on the outside of the circuit board storage box. A vertical groove is opened in the side wall of the circuit board storage box. The slide of the linear drive module is connected to a horizontal drive rod. The horizontal drive rod passes through the vertical groove into the storage slot and connects to the lifting plate. The lifting plate lifts the circuit boards, ensuring that the loading height of the circuit boards remains constant, thus reducing the length of the lifting loading rod 48.

[0029] Example 2:

[0030] The main purpose of tin plating on the circuit board is to plate a tin layer onto the solder holes of the chip pins, preventing the solder holes from connecting together due to the tin layer and ensuring that there will be no short circuit after the chip is soldered. Therefore, a continuous tin layer cannot be directly plated onto the chip soldering points; the molten tin needs to be plated onto the solder holes of the chip pins. Therefore, based on Example 1, as follows... Figure 1 and Figure 2 As shown, multiple tin-plating strips 9 are fixed to the top of the tin-plating pillar 4. Each tin-plating strip 9 corresponds to a chip pin soldering position in the chip soldering position. The top surface of the tin-plating pillar 4 forms a tin-removing slope 10 between two adjacent tin-plating strips 9. The slope height of the tin-removing slope 10 gradually decreases in the direction away from the tin-passing hole 5. Tin is plated on the pin soldering positions by the tin-plating strips 9. The tin-plating plate 2 moves downward, so that the tin liquid in the tin bath 1 overflows the tin-plating strips 9, leaving tin liquid on the tin-plating strips 9. Under the action of the tin-removing slope 10, the tin liquid between two adjacent tin-plating strips 9 can flow into the tin-plating bath 3 in time, thereby ensuring that no tin liquid is left between the tin-plating strips 9. In this way, each tin-plating strip 9 can contact the corresponding pin soldering position individually, realizing automatic tin plating of the pin soldering positions. This ensures that the pin soldering positions are not connected in series, so that there will be no short circuit problem after chip soldering.

[0031] Example 3:

[0032] Since the tin discharge hole 7 is located above the tin plating pillar 4, the molten tin in the tin-containing cavity 6 also needs to be discharged in a timely manner. Otherwise, the molten tin level in the tin plating tank 3 will gradually increase, affecting the tin plating operation. The molten tin needs to be discharged from the tin-containing cavity 6 through the tin discharge hole 7, that is, the molten tin needs to be discharged from a lower position to a higher position. Therefore, based on Example 2, as follows... Figures 1 to 6 As shown, a desoldering piston 12 is slidably disposed within the desoldering cavity 6. Two wire holes 13 are opened on one side of the top surface of the tin-plating plate 2 on the tin-plating tank 3. One wire hole 13 connects to the desoldering path hole 8, and the other wire hole 13 connects to the other end of the desoldering cavity 6. A driving block 14 is slidably disposed on the top surface of the tin-plating plate 2 on the other side of the tin-plating tank 3. The driving block 14 moves along the length of the desoldering cavity 6. Steel wire ropes 15 are connected to both ends of the driving block 14. One steel wire rope 15 passes through one of the wire holes 13 and connects to one end of the desoldering piston 12, while the other steel wire rope 15 passes through the other wire hole 13 and connects to the other end of the desoldering piston 12. The driving block 14 and the desoldering piston... 12 is connected to two steel wire ropes 15 to form a closed ring. The drive block 14 moves along the length of the solder cavity 6, that is, the drive block 14 moves closer to the solder discharge hole 7, so that one of the steel wire ropes 15 pulls the solder discharge piston 12 closer to the solder discharge hole 7, and the other steel wire rope 15 follows the solder discharge piston 12, so that the solder discharge piston 12 can discharge the solder in the solder cavity 6 through the solder discharge path hole 8 and the solder discharge hole 7 into the solder bath 1. Then, the drive block 14 moves in the opposite direction, so that the solder discharge piston 12 moves away from the solder discharge hole 7, so that the other steel wire rope 15 pulls the solder discharge piston 12 to reset. After each circuit board is completed, a solder discharge operation is performed on the solder cavity 6.

[0033] Example 4:

[0034] Based on Example 3, such as Figures 1 to 7As shown, the partial tin plating mechanism also includes a tin plating frame 16 and a lifting cylinder 18. The lifting cylinder 18 is vertically mounted on the tin plating frame 16. The telescopic shaft of the lifting cylinder 18 is connected to a drive vertical rod 20. A horizontal beam 19 is fixed to the side wall of the tin plating plate 2 near the drive block 14. The bottom end of the drive vertical rod 20 is connected to the horizontal beam 19 through a flange. The extension and retraction of the lifting cylinder 18 drives the drive vertical rod 20 to move up and down. The drive vertical rod 20 drives the tin plating plate 2 to move up and down through the horizontal beam 19, so that the top surface of the tin plating column 4 can smoothly... The tin plating process is completed on the soldering positions of the circuit board chips by utilizing the remaining tin liquid. A drive plate 17 is fixed on the tin plating frame 16. A lead screw groove 21 is formed on the drive plate 17 along the moving direction of the drive block 14. The lead screw groove 21 extends through the height direction of the drive plate 17. A lead screw 22 is rotatably installed in the lead screw groove 21. A lead screw slider 23 is threaded onto the lead screw 22. The lead screw slider 23 slides and adapts to the lead screw groove 21. A drive rod 24 is fixed to the bottom of the lead screw slider 23. The bottom of the drive rod 24 is arranged from bottom to top... The secondary opening includes a small-diameter hole 25 and a large-diameter hole 26. A disc 27 is slidably fitted inside the large-diameter hole 26, and the diameter of the disc 27 is larger than that of the small-diameter hole 25. A sliding rod 28 is slidably fitted inside the small-diameter hole 25. One end of the sliding rod 28 is fixedly connected to the disc 27, and the other end is fixed to a mounting disc 29. The mounting disc 29 is connected to the drive block 14 by screws. A motor 30 is mounted on the drive plate 17. The output shaft of the motor 30 is connected to a lead screw 22, and the motor 30 drives the lead screw 22 to rotate. The lead screw slider 23 moves linearly along the axis of the lead screw 22. The lead screw slider 23 drives the drive block 14 to move along the length of the tin-containing cavity 6 through the drive rod 24 and the sliding rod 28. The sliding rod 28 and the drive rod 24 are installed in a sleeve manner, so that the sliding rod 28 can slide on the drive rod 24 during the up and down movement of the tin-plating plate 2, so that the tin-plating plate 2 will not interfere with the sliding rod 28. This allows the tin-plating plate 2 to move smoothly up and down while the drive block 14 moves, thus completing the tin plating and tin removal operations. In practice, different circuit boards are equipped with tin-plated plates 2. The sliding rod 28 is mounted on the disc 29 and can be detachably connected to the drive block 14. The drive vertical rod 20 is connected to the horizontal beam 19 through a flange, thereby removing the tin-plated plates 2. This makes it convenient to install the corresponding tin-plated plates 2 according to the circuit board model for tin plating. It should be noted that by setting the drive vertical rod 20 and the set of drive rod 24 and sliding rod 28, the tin-plated plates 2 and drive block 14 can be moved over a long distance, avoiding the high temperature in the tin bath 1 from affecting the operation of the lifting cylinder 18 and motor 30.

[0035] Example 5:

[0036] Based on Example 4, such as Figures 1 to 4As shown, a U-shaped frame 31 is provided directly above the wire hole 13. The closed end of the U-shaped frame 31 is fixedly connected to the tinplate 2 via a plate. A first guide wheel 32 is rotatably arranged inside the U-shaped opening of the U-shaped frame 31. The axis of the first guide wheel 32 is horizontally set. Two second guide wheels 33 are arranged on the tinplate 2 along the moving direction of the drive block 14. The drive block 14 is located between the two second guide wheels 33. The axis of the second guide wheels 33 is vertically set. A steel wire rope 15 passes around one of the first guide wheels 32 and connects one end of the drive block 14 to one of the second guide wheels 33. Another steel wire rope 15 passes around another first guide wheel 32 and another second guide wheel 33 and connects to the other end of the drive block 14. It is used to arrange the steel wire rope 15 around the tin plating tank 3. The arrangement direction of the steel wire rope 15 is adjusted by the first guide wheel 32 and the second guide wheel 33 so that the steel wire rope 15 connects to the drive block 14 around the tin plating tank 3. At the same time, under the action of the first guide wheel 32 and the second guide wheel 33, the movement of the steel wire rope 15 is smoother, so that the drive block 14 can smoothly drive the tin discharge piston 12 to move through the steel wire rope 15, so as to realize the discharge of molten tin in the tin-containing cavity 6.

[0037] Example 6:

[0038] Since an oxide layer forms on the surface of the molten tin, to prevent this oxide layer from flowing down the molten tin and falling onto the surface of the tin plating pillar 4, thus plating the oxide layer onto the chip soldering site and affecting the tin plating effect, therefore, based on Example 5, as follows... Figures 1 to 9 As shown, a long lead screw 37 and a guide rod 38 are arranged parallel to each other in the tin bath 1. Both the long lead screw 37 and the guide rod 38 are located on one side of the tin plating plate 2. A tin scraper slide 39 is threaded onto the long lead screw 37 and slides on the guide rod 38. An L-shaped scraper 40 is fixed to the side of the tin scraper slide 39 near the tin plating plate 2. Metal scraper blades 41 are fixed to the top and bottom surfaces of the horizontal section of the L-shaped scraper 40. The two metal scraper blades 41 scrape off the tin layer on the surface of the tin bath and the tin layer at the bottom of the tin plating plate 2, respectively. A drive motor 42 is arranged away from the tin bath 1. The output shaft of the drive motor 42 is connected to a drive sprocket 43. One end of the long lead screw 37 is connected to a driven sprocket 44. 4. The drive sprocket 43 is connected to the drive sprocket 45 via chain 45. Before the tin-plated plate 2 enters the molten tin, the drive motor 42 is started, causing the drive sprocket 43 to drive the driven sprocket 44 to rotate via chain 45. The driven sprocket 44 drives the long screw 37 to rotate. The rotational freedom of the tin scraper slide 39 is restricted by the guide rod 38, so that the tin scraper slide 39 moves linearly along the axis of the long screw 37. The tin scraper slide 39 drives the metal scraper 41 to move. The bottom surface of the lower metal scraper 41 contacts the surface of the molten tin, and the top surface of the upper metal scraper 41 contacts the bottom surface of the tin-plated plate 2. Thus, the oxide layer is scraped off by the metal scraper 41, avoiding the oxide layer from being plated onto the circuit board and improving the tin plating effect of the circuit board.

[0039] Embodiment seven:

[0040] Based on Example 6, such as Figures 1 to 9 As shown, an annular heating chamber 34 is formed around the tin plating bath 3 inside the tin plating plate 2. Hot air holes 35 are formed on the inner side wall of the tin plating plate 2. The hot air holes 35 are used to blow air onto the top surface of the tin plating pillar 4. A hot air pipe 36 is connected to the top surface of the tin plating plate 2. One end of the hot air pipe 36 is connected to the annular heating chamber 34, and the other end is connected to a high-temperature hot air blower. The oxide layer in the tin hole 5 will also flow with the molten tin. There is still a risk of oxide layer adhering to the top surface of the tin plating strip 9. Therefore, hot air is generated by the high-temperature hot air blower. The hot air enters the annular heating chamber 34 through the hot air pipe 36. Finally, hot air is blown onto the tin plating strip 9 through the hot air holes 35 to blow off the oxide layer on the surface of the tin plating strip 9, so that the subsequent molten tin remains on the tin plating strip 9. The hot air can also ensure that the molten tin on the tin plating strip 9 does not solidify, so that it can be successfully plated on the circuit board.

Claims

1. A circuit board tin plating system for soldering circuit board chips, comprising a tin bath (1), characterized in that, A partial tin plating mechanism is provided above the tin bath (1). The partial tin plating mechanism includes a tin plating plate (2). A tin plating tank (3) is opened on the top surface of the tin plating plate (2). Multiple tin plating pillars (4) are fixed in the tin plating tank (3). Each of the multiple tin plating pillars (4) corresponds to a chip soldering position on the circuit board. A tin-passing hole (5) is opened through the top surface of the tin plating pillar (4). The tin-passing hole (5) passes through the bottom of the tin plating plate (2). The height of the top surface of the tin plating pillar (4) is lower than the height of the top surface of the tin plating plate (2). A tin-containing cavity (6) is opened below the tin plating tank (3) of the tin plating plate (2). The inner bottom wall of the tin plating tank (3) is provided with multiple round holes (11), which are connected to the tin-containing cavity (6). The side wall of the tin plating plate (2) is provided with tin discharge holes (7), which are higher than the top surface of the tin plating pillar (4). The tin plating plate (2) is provided with tin discharge path holes (8), which are connected to one end of the tin discharge holes (7) and the tin-containing cavity (6) respectively. Multiple tin plating strips (9) are fixed on the top of the tin plating pillar (4). The multiple tin plating strips (9) correspond one-to-one with the multiple chip pin soldering positions in the chip soldering position. A tin-removing piston (12) is slidably disposed inside the tin-removing cavity (6). Two wire holes (13) are opened on one side of the tin-plating tank (3) on the top surface of the tin-plating plate (2). One of the wire holes (13) is connected to the tin-removing path hole (8), and the other wire hole (13) is connected to the other end of the tin-removing cavity (6). A driving block (14) is slidably disposed on the other side of the tin-plating tank (3) on the top surface of the tin-plating plate (2). The driving block (14) moves along the length direction of the tin-removing cavity (6). Both ends of the driving block (14) are connected to steel wire ropes (15), one of which is inserted through the tin-plating tank (6). A wire hole (13) is inserted into one end of the tin removal piston (12), and another wire rope (15) is inserted into the other end of the tin removal piston (12) through another wire hole (13). The partial tin plating mechanism also includes a tin plating frame (16) and a lifting cylinder (18). The lifting cylinder (18) is vertically mounted on the tin plating frame (16). The telescopic shaft of the lifting cylinder (18) is connected to a drive rod (20). A horizontal beam (19) is fixed to the side wall of the tin plate (2) near the drive block (14). The bottom end of the drive rod (20) is connected to the horizontal beam (19) through a flange.

2. The circuit board tin plating system for soldering circuit board chips according to claim 1, characterized in that, The top surface of the tin-plated pillar (4) forms a tin-removing slope (10) between two adjacent tin-plated bars (9), and the slope height of the tin-removing slope (10) gradually decreases in the direction away from the tin-passing hole (5).

3. The circuit board tin plating system for soldering circuit board chips according to claim 1, characterized in that, A drive plate (17) is fixed on the tin plating frame (16). A lead screw groove (21) is provided on the drive plate (17) along the moving direction of the drive block (14). The lead screw groove (21) passes through the height direction of the drive plate (17). A lead screw (22) is rotatably arranged in the lead screw groove (21). A lead screw slider (23) is threaded on the lead screw (22). The lead screw slider (23) slides and adapts to the lead screw groove (21). A drive rod (24) is fixed at the bottom of the lead screw slider (23). Small openings are sequentially formed at the bottom of the drive rod (24) from bottom to top. A large diameter hole (26) and a small diameter hole (25) are provided. A disc (27) is slidably fitted inside the large diameter hole (26). The diameter of the disc (27) is larger than that of the small diameter hole (25). A sliding rod (28) is slidably fitted inside the small diameter hole (25). One end of the sliding rod (28) is fixedly connected to the disc (27), and the other end is fixed to a mounting disc (29). The mounting disc (29) is connected to the drive block (14) by screws. A motor (30) is mounted on the drive plate (17). The output shaft of the motor (30) is connected to the lead screw (22).

4. A circuit board tin plating system for soldering circuit board chips according to claim 3, characterized in that, A U-shaped frame (31) is provided directly above the wire hole (13). The closed end of the U-shaped frame (31) is fixedly connected to the tin-plated plate (2) through a plate. A first guide wheel (32) is rotatably arranged inside the U-shaped opening of the U-shaped frame (31). The axis of the first guide wheel (32) is set horizontally. Two second guide wheels (33) are arranged on the tin-plated plate (2) along the moving direction of the drive block (14). The drive block (14) is located between the two second guide wheels (33). The axis of the second guide wheels (33) is set vertically. One of the steel wire ropes (15) passes around one of the first guide wheels (32) and one of the second guide wheels (33) and is connected to one end of the drive block (14). The other steel wire rope (15) passes around another first guide wheel (32) and another second guide wheel (33) and is connected to the other end of the drive block (14). The steel wire rope (15) is used to arrange the steel wire rope (15) around the tin-plating tank (3).

5. A circuit board tin plating system for soldering circuit board chips according to claim 1, characterized in that, A long screw (37) and a guide rod (38) are arranged parallel to each other in the tin bath (1). The long screw (37) and the guide rod (38) are both located on one side of the tin-plating plate (2). A tin scraper slide (39) is threaded onto the long screw (37). The tin scraper slide (39) is slidably mounted on the guide rod (38). An L-shaped scraper (40) is fixed on the side of the tin scraper slide (39) near the tin-plating plate (2). The L-shaped scraper (40) is horizontal. Metal scrapers (41) are fixed on the top and bottom surfaces of the section. The two metal scrapers (41) scrape off the tin layer on the surface of the tin liquid and the tin layer at the bottom of the tin-plated plate (2) respectively. A drive motor (42) is arranged away from the tin liquid tank (1). The output shaft of the drive motor (42) is connected to a drive sprocket (43). One end of the long screw (37) is connected to a driven sprocket (44). The driven sprocket (44) is connected to the drive sprocket (43) through a chain (45).

6. A circuit board tin plating system for soldering circuit board chips according to claim 5, characterized in that, The tin-plating plate (2) has an annular heating chamber (34) surrounding the tin plating tank (3). The inner sidewall of the tin-plating plate (2) has a hot air hole (35) for blowing air onto the top surface of the tin-plating pillar (4). The top surface of the tin-plating plate (2) is connected to a hot air pipe (36). One end of the hot air pipe (36) is connected to the annular heating chamber (34), and the other end is connected to a high-temperature hot air blower.

7. A circuit board tin plating system for soldering circuit board chips according to claim 1, characterized in that, It also includes a gantry conveyor mechanism, which includes a conveyor beam (46) and two parallel overhead rails (47). The two ends of the conveyor beam (46) are slidably mounted on the two overhead rails (47). A lifting and feeding rod (48) is vertically mounted on the conveyor beam (46). The bottom of the lifting and feeding rod (48) slides through the conveyor beam (46) and is connected to a negative pressure suction cup (49). A rack (50) is fixed to the side wall of the lifting and feeding rod (48). A loading and unloading motor (51) is installed on the conveyor beam (46). The output shaft of the loading and unloading motor (51) is connected to a gear (52), and the gear (52) meshes with the rack (50).

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