An automatic tinning device for circuit board chip soldering

Abstract

The application discloses an automatic tinning device for circuit board chip welding and relates to the technical field of chip welding, which comprises a tin liquid pool, a chip feeding workbench, a four-way conveying mechanism and a heat resistance mechanism, a chip stacking cylinder is vertically installed on the chip feeding workbench, the heat resistance mechanism comprises a rack, a lifting seat, a finger air cylinder and a cold piece, the lifting seat is installed on the rack, one end of the lifting seat is provided with the finger air cylinder, the two clamping jaws of the finger air cylinder are both provided with the cold piece, cold air is introduced into the cold piece, the four-way conveying mechanism comprises a gantry, a three-way conveying mechanism and a turnover plate, the three-way conveying mechanism is installed on the gantry, the three-way conveying mechanism has the movement freedom degrees of X, Y and Z directions in a space coordinate system, the turnover plate is rotationally installed on the three-way conveying mechanism, the bottom of the turnover plate is rotationally provided with a rotating disc, and the rotating disc is provided with a negative pressure suction disc. The cold piece can isolate high temperature from being transmitted to the chip, and the chip can be well protected from being affected in the tinning process.

Description

Technical Field

[0001] This invention relates to the field of chip welding technology, specifically to an automatic tin plating device for welding circuit board chips. Background Technology

[0002] Soldering chips onto circuit boards is a crucial production step. Traditionally, this was done manually, resulting in high production efficiency and labor costs. With the rapid development of automation, welding robots are now used for automated chip soldering. A negative pressure feeding mechanism places the chips onto the circuit board, and the robot then performs the soldering operation, significantly improving production efficiency. Before soldering, the chip pins need to be tin-plated to improve their conductivity, corrosion resistance, and solderability. This is done by immersing the chip pins in a solder bath. During this process, high temperatures can easily be transferred through the pins to the chip, affecting its performance. Summary of the Invention

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

[0004] The objective of this invention is achieved through the following technical solution: an automatic tin plating device for soldering circuit board chips, comprising a tin bath, a chip loading workbench, a four-way conveying mechanism, and a thermal resistance mechanism. A chip stacking cylinder is vertically mounted on the chip loading workbench. A stacking groove is formed through the top of the chip stacking cylinder along its own axial direction. A lead groove is formed on the sidewall of the stacking groove along the axial direction of the chip stacking cylinder. The lead groove extends to the top of the chip stacking cylinder. Chips are stacked in the stacking groove along the axial direction of the chip stacking cylinder, and the leads of the chips pass through the lead grooves.

[0005] The thermal resistance mechanism includes a frame, a lifting seat, a finger cylinder, and a cold plate. The lifting seat is mounted on the frame and has the freedom to move along the height direction of the frame. The finger cylinder is mounted on one end of the lifting seat. The cold plate is mounted on both jaws of the finger cylinder. Cold air is introduced into the cold plate. The upper part of the chip pin is tinned by clamping the two cold plates. The cold plates prevent the heat of the tinning process from being transferred to the chip.

[0006] The four-way conveying mechanism includes a gantry frame, a three-way conveying mechanism, and a tilting plate. The three-way conveying mechanism is mounted on the gantry frame and has three degrees of freedom of movement in the X, Y, and Z directions in the spatial coordinate system. The tilting plate is rotatably mounted on the three-way conveying mechanism. The deflection axis of the tilting plate is horizontally set. A rotating disk is rotatably mounted on the bottom of the tilting plate. The rotation axis of the rotating disk is perpendicular to the deflection axis of the tilting plate. A negative pressure suction cup is provided on the rotating disk.

[0007] Furthermore, a lifting cylinder is vertically mounted on the frame, and the telescopic shaft of the lifting cylinder is connected to the lifting base. A cold air chamber is provided inside the cold plate. One end of the cold plate connected to the gripper is connected to a cold air cylinder through an air inlet pipe. The air inlet pipe is connected to the cold air chamber. Several cold air holes are opened at the bottom of the cold plate along its own length direction. The cold air holes are inclined towards the clamping center so that cold air can be sprayed onto the lower part of the chip pins through the cold air holes.

[0008] Furthermore, a tin surface positioning plate is fixed inside the tin bath, and the tin surface positioning plate is located on the moving path of the cold sheet. The height of the tin liquid in the tin bath is flush with the top surface height of the tin surface positioning plate. The cold sheet is L-shaped, and the vertical piece of the cold sheet is connected to the clamp. During tin plating, the cold sheet contacts the tin surface positioning plate to immerse the lower part of the chip in the tin liquid.

[0009] Furthermore, a liquid level sensor is installed on the frame, and the liquid level sensor is located above the lifting seat. The liquid level sensor is used to detect the liquid level in the molten solder pool. A solder replenishment pool is provided on one side of the molten solder pool. The solder replenishment pool is connected to the molten solder pool through a solder replenishment pipe. A high-temperature valve is connected to the solder replenishment pipe. An electric heating rod is installed in the solder replenishment pool.

[0010] Furthermore, a solder scraping mechanism is provided in the solder bath, which includes a crossbeam, a recessed plate, and a scraper. The crossbeam is located above the solder surface positioning plate. Horizontal grooves are formed on two opposite inner walls of the solder bath. The two ends of the crossbeam extend through the two horizontal grooves respectively. A push cylinder is connected to both ends of the crossbeam. The push cylinders are installed horizontally. The recessed plate is fixedly sleeved on the crossbeam. The scraper passes through the bottom of the recessed plate and has the freedom to move along the height direction of the solder bath.

[0011] Furthermore, a rectangular mounting groove is provided at the bottom of the sinking plate, and a high-temperature resistant spring is provided in the rectangular mounting groove. The top of the scraper is slidably adapted to the rectangular mounting groove. The two ends of the high-temperature resistant spring are respectively connected to the sinking plate and the scraper. Both sides of the bottom of the scraper are provided with wedge-shaped surfaces, and the tin surface positioning plate is located on the moving path of the wedge-shaped surfaces.

[0012] Furthermore, a top-feeding mechanism is provided on one side of the chip stacking cylinder. The top-feeding mechanism includes a column and a top-feeding plate. The top-feeding plate is located in the stacking groove. A lead screw groove is provided on the side of the column near the chip stacking cylinder. A first lead screw is rotatably installed in the lead screw groove. A lead screw slider is threaded onto the first lead screw. The lead screw slider is connected to the top-feeding plate through a horizontal connecting rod. A vertical clearance groove is provided on the side wall of the chip stacking cylinder for the horizontal connecting rod to pass through. The vertical clearance groove extends to the bottom of the chip stacking cylinder.

[0013] Furthermore, a lead screw motor is installed on the top of the column, and the output shaft of the lead screw motor is connected to the first lead screw. Two Z-shaped connecting rods are symmetrically fixed on the outer side wall of the chip stacking cylinder, and the Z-shaped connecting rods are connected to the chip loading worktable by bolts.

[0014] Furthermore, the three-way conveying mechanism includes a moving beam, a sliding plate, and a Z-axis slide block. Two sets of linear moving modules are arranged in parallel on the moving beam. The two ends of the moving beam are respectively connected to the slide blocks of the two sets of linear moving modules. A horizontal lead screw groove is opened at the bottom of the moving beam. A second lead screw is rotatably installed in the horizontal lead screw groove. A second lead screw slider is threaded onto the second lead screw. The sliding plate is connected to the second lead screw slider. The moving direction of the sliding plate is perpendicular to the moving direction of the moving beam. A first motor is installed at one end of the moving beam. The output shaft of the first motor is connected to the second lead screw. A Z-axis cylinder is vertically installed on the sliding plate. The telescopic shaft of the Z-axis cylinder moves through the sliding plate and connects to the Z-axis slide block.

[0015] Furthermore, the bottom of the Z-axis slide is provided with a flip-mounting groove, and a horizontal main shaft is rotatably mounted in the flip-mounting groove. The flip plate is inverted T-shaped, and the vertical plate of the flip plate is fixedly mounted on the horizontal main shaft. A second motor is mounted on the side wall of the Z-axis slide, and the output shaft of the second motor is connected to the horizontal main shaft. The end of the rotating disk away from the negative pressure suction cup is rotatably connected to the flip plate through a bearing. A large gear is mounted on the rotating disk, and a third motor is mounted on the horizontal plate of the flip plate. The output shaft of the third motor is connected to a small gear, and the small gear meshes with the large gear.

[0016] The beneficial effects of this invention are:

[0017] Two cold plates hold the upper part of the chip pins, immersing them in a molten solder bath to perform tin plating on the lower part of the chip pins. The cold plates are filled with cold air, which can isolate the high temperature from the chip and protect the chip from being affected during the tin plating process. In addition, the cold plates can also quickly solidify and cool the molten solder on the chip pins, preventing the molten solder from dripping and improving the tin plating effect. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an automatic tin plating device for soldering circuit board chips according to the present invention. Figure 1 ;

[0019] Figure 2 This is a schematic diagram of the structure of an automatic tin plating device for soldering circuit board chips according to the present invention. Figure 2 ;

[0020] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0021] Figure 4 This is a schematic diagram of the structure of an automatic tin plating device for soldering circuit board chips according to the present invention. Figure 3 ;

[0022] Figure 5 This is a schematic diagram of the structure of an automatic tin plating device for soldering circuit board chips according to the present invention. Figure 4 ;

[0023] Figure 6 This is a schematic diagram of the structure of an automatic tin plating device for soldering circuit board chips according to the present invention. Figure 5 ;

[0024] Figure 7 for Figure 5 Enlarged view at point B in the middle;

[0025] Figure 8 This is a partial cross-sectional view of the cold plate in an automatic tin plating device for soldering circuit board chips according to the present invention.

[0026] Figure 9 This is a schematic diagram of the internal structure of the sinking plate in an automatic tin plating device for soldering circuit board chips according to the present invention.

[0027] In the diagram, 1-molten solder pool, 3-chip loading workbench, 5-chip stacking cylinder, 6-stacking slot, 7-lead slot, 8-frame, 9-lifting seat, 10-finger cylinder, 11-cold wafer, 12-gantry frame, 13-flipping plate, 14-negative pressure suction cup, 15-lifting cylinder, 16-cold air chamber, 17-cold air hole, 18-rotary disk, 19-molten solder surface positioning plate, 20-liquid level sensor, 21-molten solder replenishment pool, 22-molten solder replenishment tube, 23-electric heating rod, 24-crossbeam, 25-sinking plate, 26-scraper, 27-horizontal chute, 28-push cylinder, 29-rectangular... 30-High temperature resistant spring, 31-Wedge-shaped surface, 32-Column, 33-Top plate, 34-Screw slide groove, 35-Screw slider, 36-Horizontal connecting rod, 37-Vertical clearance groove, 38-Screw motor, 39-First screw, 42-Moving beam, 43-Sliding plate, 44-Z-axis slide block, 45-Linear movement module, 46-Horizontal screw groove, 47-Second screw, 48-First motor, 49-Z-axis cylinder, 50-Flipping mounting groove, 51-Horizontal spindle, 52-Second motor, 53-Large gear, 54-Third motor, 55-Small gear. Detailed Implementation

[0028] 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.

[0029] Example 1: As Figures 1 to 9As shown, an automatic tin plating device for circuit board chip soldering includes a tin bath 1, a chip loading workbench 3, a four-way conveying mechanism, and a thermal resistance mechanism. A chip stacking cylinder 5 is vertically mounted on the chip loading workbench 3. A stacking groove 6 is formed through the top of the chip stacking cylinder 5 along its axial direction. A lead groove 7 is formed on the sidewall of the stacking groove 6 along the axial direction of the chip stacking cylinder 5, extending to the top of the chip stacking cylinder 5. Chips are stacked in the stacking groove 6 along the axial direction of the chip stacking cylinder 5, with the chip leads passing through the lead groove 7. Chips to be tinned are stacked together along the axial direction of the chip stacking cylinder 5. The lead groove 7 accommodates the chip pins, preventing the pins from colliding with the sidewall of the chip stacking cylinder 5 and causing bending, and also positioning the chips to ensure neat arrangement. The chips are stacked in the chip stacking cylinder 5, so that the four-way conveying mechanism picks up the chips from the chip stacking cylinder 5 in the same direction, which can achieve precise tin plating of the chips. A conveyor belt is set parallel to one side of the chip loading workbench 3. The tin-plated chips are placed on the conveyor belt and transported to the next work station for production. The thermal resistance mechanism includes a frame 8, a lifting seat 9, a finger cylinder 10 and a cold plate 11. The lifting seat 9 is installed on the frame 8 and has the freedom to move along the height direction of the frame 8. A finger cylinder 10 is installed at one end of the lifting seat 9. A cold plate 11 is installed on each of the two grippers of the finger cylinder 10. Cold air is introduced into the cold plate 11. The upper part of the chip pin is clamped by the two cold plates 11 for tin plating. The cold plate blocks the heat of tin plating from being transferred to the chip.The four-way conveying mechanism includes a gantry 12, a three-way conveying mechanism, and a flipping plate 13. The three-way conveying mechanism is mounted on the gantry 12 and has three degrees of freedom of movement in the X, Y, and Z directions in the spatial coordinate system. The flipping plate 13 is rotatably mounted on the three-way conveying mechanism, and its deflection axis is horizontally set. A rotating disk 18 is rotatably mounted on the bottom of the flipping plate 13, and the rotation axis of the rotating disk 18 is perpendicular to the deflection axis of the flipping plate 13. A negative pressure suction cup 14 is provided on the rotating disk 18. The three-way conveying mechanism drives the negative pressure suction cup 14 to move directly above the chip stacking cylinder 5. The negative pressure suction cup 14 is connected to a negative pressure pump through a negative pressure pipe and clamps the chip by negative pressure. This is prior art and will not be described in detail. The negative pressure suction cup 14 extends from the top of the chip stacking cylinder 5 to adsorb the chip to be tinned, and then the three-way conveying mechanism transports the chip to the thermal resistance mechanism. During the transport process, the flipping plate 13 drives the negative pressure suction cup 14 to deflect 90°, causing the chip to flip 90°. The device is used to position the pins on one side of the chip downwards. The downward-facing pins are moved into the clamping range of the finger cylinder 10. The finger cylinder 10 is activated, causing two cold plates 11 to clamp the upper part of the chip pins. Then, the lifting seat 9 moves downwards towards the molten solder pool 1, immersing the lower part of the pins clamped by the cold plates 11 into the molten solder, thus completing the tinning operation of the pins. Since the cold plates 11 are filled with cold air, they can isolate the high temperature from being transferred to the chip, effectively protecting the chip from being affected during the tinning process. Secondly, they can also quickly solidify and cool the molten solder on the chip pins, preventing the molten solder from falling off and improving the tinning effect. After the pins on one side of the chip are tinned, the chip is again picked up by the negative pressure suction cup 14, and the rotating disk 18 drives the chip to rotate 90° or 180°, so that the remaining pins of the chip are positioned downwards. Then, the pins are clamped by the cold plates 11 again for tinning. This process is repeated until all the pins of the chip are tinned. The tinned chip is then placed on a conveyor belt and transported to the next workstation. Due to the different types of chips, the arrangement of pins on the chip sides varies, generally falling into two categories: First, pins are arranged on all four sides of the chip. In this case, the chip is rotated 90° each time by the rotating disk 18 to complete the tin plating of all four sets of pins. Second, pins are arranged on opposite sides of the chip. In this case, the chip is rotated 180° by the rotating disk 18 to complete the tin plating of two sets of pins. Since the area of ​​the chip pins closest to the chip is usually gold-plated to increase its conductivity and corrosion resistance, incomplete gold plating is done to reduce costs. Considering this, this invention uses partial tin plating to reduce the impact of the high temperature of tin plating on the chip. That is, only the lower area of ​​the chip pins is tin-plated. This area needs to be soldered to the solder holes on the circuit board. Tin plating in this area improves solderability. Furthermore, the isolation provided by the cold plate 11 further protects the chip's safety, ensuring that the tin plating operation does not affect the chip's performance.

[0030] Example 2: Based on Example 1, as follows Figures 1 to 6As shown, the three-way conveying mechanism includes a moving beam 42, a sliding plate 43, and a Z-axis slide block 44. Two sets of linear moving modules 45 are arranged in parallel on the moving beam 42. The two ends of the moving beam 42 are respectively connected to the slide blocks of the two sets of linear moving modules 45. A horizontal lead screw groove 46 is opened at the bottom of the moving beam 42. A second lead screw 47 is rotatably installed in the horizontal lead screw groove 46. A second lead screw slider is threaded on the second lead screw 47. The sliding plate 43 is connected to the second lead screw slider. The moving direction of the sliding plate 43 is perpendicular to the moving direction of the moving beam 42. A first motor 48 is installed at one end of the moving beam 42. The output shaft of the first motor 48 is connected to the second lead screw 47. A Z-axis cylinder 49 is vertically installed on the sliding plate 43. The telescopic shaft of the Z-axis cylinder 49 moves through the sliding plate 43 and connects to the Z-axis slide block. 44. The linear motion module 45 drives the moving beam 42 to move along the X-axis, thereby driving the negative pressure suction cup 14 to move along the X-axis. The first motor 48 drives the second lead screw 47 to rotate, causing the second lead screw slider to move linearly along the axis of the second lead screw 47, driving the sliding plate 43 on it to move along the Y-axis, thereby driving the negative pressure suction cup 14 to move along the X-axis. The Z-axis cylinder 49 drives the Z-axis slide block 44 to move along the Z-axis, thereby driving the negative pressure suction cup 14 to move along the Z-axis. Thus, the negative pressure suction cup 14 has three degrees of freedom of movement in the spatial coordinate system. Within the arrangement range of the four-way conveying mechanism, the negative pressure suction cup 14 can take out the chip from the chip stacking cylinder 5 and transport it to the working range of the thermal resistance mechanism, and then put the tin-plated chip onto the conveyor belt.

[0031] Furthermore, such as Figures 1 to 5 As shown, a flip mounting slot 50 is provided at the bottom of the Z-axis slide 44. A horizontal spindle 51 is rotatably mounted on the flip mounting slot 50. The flip plate 13 is inverted T-shaped, and the vertical plate of the flip plate 13 is fixedly mounted on the horizontal spindle 51. A second motor 52 is mounted on the side wall of the Z-axis slide 44. The output shaft of the second motor 52 is connected to the horizontal spindle 51. The second motor 52 drives the horizontal spindle 51 to rotate, and the horizontal spindle 51 drives the flip plate 13 to deflect 90°, thereby deflecting the chip from a horizontal state to a vertical state, so that the pins of the chip face downwards. To facilitate tin plating, the end of the rotating disk 18 away from the negative pressure suction cup 14 is rotatably connected to the flip plate 13 via a bearing. A large gear 53 is mounted on the rotating disk 18. A third motor 54 is installed on the horizontal plate of the flip plate 13. The output shaft of the third motor 54 is connected to a small gear 55. The small gear 55 meshes with the large gear 53. The third motor 54 drives the rotating disk 18 to rotate through the meshing of the small gear 55 and the large gear 53, thereby causing the negative pressure suction cup 14 to drive the chip on it to rotate, so as to deflect the pins at different positions of the chip to the bottom for tin plating.

[0032] Example 3: Based on Example 2, such as Figures 1 to 8As shown, a lifting cylinder 15 is vertically mounted on the frame 8. The telescopic shaft of the lifting cylinder 15 is connected to the lifting base 9. A cold air chamber 16 is provided inside the cold plate 11. One end of the cold plate 11 connected to the gripper is connected to a cold air cylinder through an air inlet pipe. The air inlet pipe connects to the cold air chamber 16. Several cold air holes 17 are opened at the bottom of the cold plate 11 along its own length direction. The cold air holes 17 are inclined towards the clamping center to allow cold air to be sprayed onto the lower part of the chip pins through the cold air holes 17. Cold air is introduced into the cold air chamber 16 of the cold plate 11 through the cold air cylinder to raise the temperature of the cold plate 11. The cooling system is designed to isolate the tin-plating area of ​​the chip from the chip itself, preventing high temperatures from affecting its performance. Cool air is discharged through the cooling vent 17. Since the cooling vent 17 is tilted towards the lower part of the chip pins, the discharged cool air contacts the soldering position of the chip pins, thereby cooling the molten solder on the pins and causing it to solidify quickly. This prevents the molten solder from falling and affecting the tin plating thickness. At the same time, after rapid cooling, the tin-plated chip can be directly transported onto the conveyor belt without waiting for the molten solder to cool naturally, thus improving the tin plating efficiency of the chip.

[0033] Example 4: To prevent the molten solder from overflowing the cold plate 11 and contacting the chip during tin plating, it is necessary to precisely control the height of the molten solder in the molten solder pool 1, while also controlling the tin plating height of the chip. Therefore, based on Example 3, as follows... Figures 1 to 6As shown, a solder surface positioning plate 19 is fixed inside the solder bath 1. The solder surface positioning plate 19 is located on the moving path of the cold chip 11. The height of the solder in the solder bath 1 is flush with the top surface of the solder surface positioning plate 19. The cold chip 11 is L-shaped, and its vertical plates are connected to grippers. During tin plating, the cold chip 11 contacts the solder surface positioning plate 19 to immerse the lower part of the chip in the solder. A liquid level sensor 20 is installed on the frame 8, located above the lifting seat 9. The liquid level sensor 20 is used to detect the liquid level in the solder bath 1. A solder replenishment pool 21 is provided on one side of the solder bath 1. The solder replenishment pool 21 is connected to the solder bath 1 through a solder replenishment pipe 22. A high-temperature valve is connected to the solder replenishment pipe 22. An electric heating rod 23 is installed inside the solder replenishment pool 21. The liquid level sensor 20 detects the liquid level in real time. The height of the molten solder in the molten solder pool 1 is detected. When the height of the molten solder is lower than the top surface of the molten solder positioning plate 19, the high-temperature valve on the molten solder replenishment tube 22 is opened, allowing the molten solder in the molten solder replenishment pool 21 to flow into the molten solder pool 1 through the molten solder replenishment tube 22. When the liquid level is flush with the top surface of the molten solder positioning plate 19, the high-temperature valve is closed, ensuring that the height of the molten solder in the molten solder pool 1 is always flush with the top surface of the molten solder positioning plate 19, thereby precisely controlling the height of the molten solder in the molten solder pool 1. During tin plating, the lifting seat 9 drives the cold plate 11 to directly contact the molten solder positioning plate 19. The molten solder positioning plate 19 precisely controls the tin plating height of the chip, allowing the lower part of the chip pins to be directly immersed in the molten solder for tin plating. The dual positioning method ensures that the tin plating position of the chip pins is consistent, resulting in high tin plating accuracy and meeting the tin plating length requirements of the pins. In practice, staff regularly add solder blocks to the solder replenishment pool 21. The solder blocks are heated and melted by electric heating rods 23 to form molten tin. Similarly, electric heating rods 23 are also installed in the molten tin pool 1 to ensure that the tin in the molten tin pool 1 is always in a liquid state.

[0034] Example 5: Because an oxide film forms on the surface of the molten tin, this film adheres to the pins during the tin plating process, preventing the molten tin from being plated onto the pins, resulting in insufficient tin plating or plating failure. Therefore, based on Example 4, as follows... Figures 1 to 9As shown, a solder scraping mechanism is provided in the solder bath 1. The solder scraping mechanism includes a crossbeam 24, a recessed plate 25, and a scraper 26. The crossbeam 24 is located above the solder surface positioning plate 19. Horizontal grooves 27 are formed on two opposite inner walls of the solder bath 1. The two ends of the crossbeam 24 protrude from the two horizontal grooves 27 respectively. Both ends of the crossbeam 24 are connected to a push cylinder 28, which is installed horizontally. The recessed plate 25 is fixedly sleeved on the crossbeam 24, and the scraper 26 passes through the bottom of the recessed plate 25. The scraper 26 has the freedom to move along the height of the molten tin pool 1. A rectangular mounting groove 29 is provided at the bottom of the sinking plate 25. A high-temperature resistant spring 30 is installed inside the rectangular mounting groove 29. The top of the scraper 26 slides within the rectangular mounting groove 29. The two ends of the high-temperature resistant spring 30 are connected to the sinking plate 25 and the scraper 26, respectively. Wedge-shaped surfaces 31 are provided on both sides of the bottom of the scraper 26. The tin surface positioning plate 19 is located on the moving path of the wedge-shaped surfaces 31. Before each tin plating, the chip pins are first... The oxide film on the surface of the molten solder is scraped off by the solder scraping mechanism. The specific process is as follows: the cylinder 28 drives the crossbeam 24 to move horizontally, and the crossbeam 24 drives the sink plate 25 and the scraper 26 to move horizontally. In order to ensure effective removal of the film, the scraper 26 must be inserted into the molten solder to move. This causes the scraper 26 to interfere with the solder surface positioning plate 19 during the movement. For this reason, the sink plate 25 is set, and the scraper 26 is slidably mounted on the sink plate 25. The wedge-shaped surface 31 of the scraper 26 contacts the surface of the solder. Guided by the wedge-shaped surface 31, the tin-side positioning plate 19 causes the scraper 26 to press against the high-temperature resistant spring 30 and move upward, allowing the scraper 26 to pass through the tin-side positioning plate 19. After passing through the tin-side positioning plate 19, the scraper 26 is re-immersed in the molten tin by the reaction force of the high-temperature resistant spring 30 to scrape off the thin film, thereby scraping the oxide film to both ends of the molten tin pool 1, keeping the oxide film away from the tin plating position of the chip, ensuring that it will not affect the tin plating of the pins, and making the tin plating effect better.

[0035] Example 6: Based on Example 5, such as Figures 1 to 7As shown, a top-feeding mechanism is provided on one side of the chip stacking cylinder 5. The top-feeding mechanism includes a column 32 and a top-feeding plate 33. The top-feeding plate 33 is located in the stacking groove 6. A lead screw groove 34 is provided on the side of the column 32 near the chip stacking cylinder 5. A first lead screw 39 is rotatably installed in the lead screw groove 34. A lead screw slider 35 is threaded onto the first lead screw 39. The lead screw slider 35 is connected to the top-feeding plate 33 through a horizontal connecting rod 36. A vertical clearance groove 37 is provided on the side wall of the chip stacking cylinder 5 for the horizontal connecting rod 36 to pass through. The vertical clearance groove 37 extends to the bottom of the chip stacking cylinder 5. A lead screw motor 38 is installed on the top of the column 32. The output shaft of the lead screw motor 38 is connected to the first lead screw 39. Two Z-shaped connecting rods are symmetrically fixed to the outer wall of the chip stacking cylinder 5. The Z-shaped connecting rods are connected to the chip loading worktable 3 by bolts. The lead screw motor 38 drives the first lead screw 39 to rotate, so that the lead screw slider 35 moves linearly along the axis of the first lead screw 39. The lead screw slider 35 drives the top plate 33 to move through the horizontal connecting rod 36. The top plate 33 lifts the chips in the chip stacking cylinder 5 upward in sequence, so that the chip loading position is consistent. The chip stacking cylinder 5 is detachably connected to the chip loading worktable 3 by the Z-shaped connecting rods. After the chips in the chip stacking cylinder 5 are tin-plated, the chip stacking cylinder 5 is removed and the chip stacking cylinder 5 full of chips is installed on the chip loading worktable 3 for tin plating operation.

Claims

1. An automatic tin plating device for soldering circuit board chips, comprising a tin bath (1), characterized in that, It also includes a chip loading workbench (3), a four-way conveying mechanism and a thermal resistance mechanism. A chip stacking cylinder (5) is vertically installed on the chip loading workbench (3). A stacking groove (6) is opened through the top of the chip stacking cylinder (5) along its own axial direction. A pin groove (7) is opened on the side wall of the stacking groove (6) along the axial direction of the chip stacking cylinder (5). The pin groove (7) extends to the top of the chip stacking cylinder (5). The chip is stacked in the stacking groove (6) along the axial direction of the chip stacking cylinder (5), and the pins of the chip are inserted into the pin groove (7). The thermal resistance mechanism includes a frame (8), a lifting seat (9), a finger cylinder (10), and a cold plate (11). The lifting seat (9) is mounted on the frame (8) and has the freedom to move along the height direction of the frame (8). The finger cylinder (10) is mounted on one end of the lifting seat (9). The cold plate (11) is mounted on both jaws of the finger cylinder (10). Cold air is introduced into the cold plate (11). The upper part of the chip pin is clamped by the two cold plates (11) for tin plating. The cold plate blocks the heat of tin plating from being transferred to the chip. The four-way conveying mechanism includes a gantry (12), a three-way conveying mechanism, and a tilting plate (13). The three-way conveying mechanism is installed on the gantry (12) and has three degrees of freedom of movement in the spatial coordinate system: X, Y, and Z. The tilting plate (13) is rotatably installed on the three-way conveying mechanism. The deflection axis of the tilting plate (13) is set horizontally. A rotating disk (18) is rotatably installed at the bottom of the tilting plate (13). The rotation axis of the rotating disk (18) is perpendicular to the deflection axis of the tilting plate (13). A negative pressure suction cup (14) is provided on the rotating disk (18). A lifting cylinder (15) is vertically mounted on the frame (8). The telescopic shaft of the lifting cylinder (15) is connected to the lifting seat (9). A cold air chamber (16) is provided inside the cold plate (11). One end of the cold plate (11) connected to the gripper is connected to the cold air bottle through the air inlet pipe. The air inlet pipe is connected to the cold air chamber (16). Several cold air holes (17) are opened at the bottom of the cold plate (11) along its own length direction. The cold air holes (17) are inclined towards the clamping center to allow cold air to be sprayed through the cold air holes (17) to the lower part of the chip pin. A tin surface positioning plate (19) is fixed inside the tin bath (1). The tin surface positioning plate (19) is located on the moving path of the cold sheet (11). The height of the tin liquid in the tin bath (1) is flush with the top surface height of the tin surface positioning plate (19). The cold sheet (11) is L-shaped. The vertical piece of the cold sheet (11) is connected to the clamp. During tin plating, the cold sheet (11) contacts the tin surface positioning plate (19) to immerse the lower part of the chip in the tin liquid.

2. The automatic tin plating device for circuit board chip soldering according to claim 1, characterized in that, A liquid level sensor (20) is installed on the frame (8). The liquid level sensor (20) is located above the lifting seat (9). The liquid level sensor (20) is used to detect the liquid level in the tin bath (1). A tin replenishment pool (21) is provided on one side of the tin bath (1). The tin replenishment pool (21) is connected to the tin bath (1) through a tin replenishment pipe (22). A high-temperature valve is connected to the tin replenishment pipe (22). An electric heating rod (23) is installed in the tin replenishment pool (21).

3. The automatic tin plating device for circuit board chip soldering according to claim 1, characterized in that, The tin bath (1) is equipped with a tin scraping mechanism, which includes a crossbeam (24), a sinking plate (25), and a scraper (26). The crossbeam (24) is located above the tin surface positioning plate (19). The two opposite inner walls of the tin bath (1) are provided with horizontal grooves (27). The two ends of the crossbeam (24) pass through the two horizontal grooves (27) respectively. Both ends of the crossbeam (24) are connected to a push cylinder (28). The push cylinder (28) is installed horizontally. The sinking plate (25) is fixedly sleeved on the crossbeam (24). The scraper (26) passes through the bottom of the sinking plate (25). The scraper (26) has the freedom to move along the height direction of the tin bath (1).

4. The automatic tin plating device for circuit board chip soldering according to claim 3, characterized in that, The bottom of the sinking plate (25) is provided with a rectangular mounting groove (29), and a high temperature resistant spring (30) is provided in the rectangular mounting groove (29). The top of the scraper (26) is slidably adapted to the rectangular mounting groove (29). The two ends of the high temperature resistant spring (30) are respectively connected to the sinking plate (25) and the scraper (26). Both sides of the bottom of the scraper (26) are provided with wedge-shaped surfaces (31), and the tin-side positioning plate (19) is located on the moving path of the wedge-shaped surfaces (31).

5. The automatic tin plating device for circuit board chip soldering according to claim 1, characterized in that, A top feeding mechanism is provided on one side of the chip stacking cylinder (5). The top feeding mechanism includes a column (32) and a top feeding plate (33). The top feeding plate (33) is located in the stacking groove (6). A screw slide groove (34) is provided on the side of the column (32) near the chip stacking cylinder (5). A first screw (39) is rotatably installed in the screw slide groove (34). A screw slider (35) is threaded on the first screw (39). The screw slider (35) is connected to the top feeding plate (33) through a horizontal connecting rod (36). A vertical clearance groove (37) is provided on the side wall of the chip stacking cylinder (5) for the horizontal connecting rod (36) to pass through. The vertical clearance groove (37) extends to the bottom of the chip stacking cylinder (5).

6. The automatic tin plating device for circuit board chip soldering according to claim 5, characterized in that, A lead screw motor (38) is installed on the top of the column (32). The output shaft of the lead screw motor (38) is connected to the first lead screw (39). Two Z-shaped connecting rods are symmetrically fixed on the outer side wall of the chip stacking cylinder (5). The Z-shaped connecting rods are connected to the chip loading workbench (3) by bolts.

7. The automatic tin plating device for circuit board chip soldering according to claim 1, characterized in that, The three-way conveying mechanism includes a moving beam (42), a sliding plate (43), and a Z-axis slide (44). Two sets of linear moving modules (45) are arranged in parallel on the moving beam (42). The two ends of the moving beam (42) are respectively connected to the slides of the two sets of linear moving modules (45). A horizontal screw groove (46) is provided at the bottom of the moving beam (42). A second screw (47) is rotatably installed in the horizontal screw groove (46). A second screw is threaded onto the second screw (47). The slider is connected to the second lead screw slider by the sliding plate (43). The moving direction of the sliding plate (43) is perpendicular to the moving direction of the moving beam (42). A first motor (48) is installed at one end of the moving beam (42). The output shaft of the first motor (48) is connected to the second lead screw (47). A Z-axis cylinder (49) is vertically installed on the sliding plate (43). The telescopic shaft of the Z-axis cylinder (49) moves through the sliding plate (43) and is connected to the Z-axis slide block (44).

8. The automatic tin plating device for circuit board chip soldering according to claim 7, characterized in that, The bottom of the Z-axis slide (44) is provided with a flip mounting groove (50), and a horizontal main shaft (51) is rotatably mounted in the flip mounting groove (50). The flip plate (13) is inverted T-shaped, and the vertical plate of the flip plate (13) is fixedly mounted on the horizontal main shaft (51). A second motor (52) is mounted on the side wall of the Z-axis slide (44), and the output shaft of the second motor (52) is connected to the horizontal main shaft (51). The end of the rotating disk (18) away from the negative pressure suction cup (14) is rotatably connected to the flip plate (13) through a bearing. A large gear (53) is mounted on the rotating disk (18). A third motor (54) is mounted on the horizontal plate of the flip plate (13), and the output shaft of the third motor (54) is connected to a small gear (55). The small gear (55) meshes with the large gear (53).

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