Automatic tin plating device for circuit board chip welding

Abstract

The invention discloses an automatic tin plating device for circuit board chip welding, and relates to the technical field of chip welding, the automatic tin plating device comprises a tin liquid pool, a chip feeding workbench, a four-way conveying mechanism and a thermal resistance mechanism, a chip stacking cylinder is vertically installed on the chip feeding workbench, the thermal resistance mechanism comprises a rack, a lifting seat, a finger air cylinder and a cold sheet, and the lifting seat is connected with the finger air cylinder. The lifting seat is installed on the rack, a finger air cylinder is installed at one end of the lifting seat, two clamping jaws of the finger air cylinder are each provided with a cold piece, cold air is introduced into the cold pieces, the four-way conveying mechanism comprises a portal frame, a three-way conveying mechanism and an overturning plate, and the three-way conveying mechanism is installed on the portal frame; the three-direction conveying mechanism has moving freedom degrees in the X direction, the Y direction and the Z direction in a space coordinate system, the overturning plate is rotationally installed on the three-direction conveying mechanism, a rotating disc is rotationally installed at the bottom of the overturning plate, and a negative pressure suction cup is arranged on the rotating disc. And the cold sheet can isolate high temperature from being transmitted to the chip, so that the chip can be well protected from being influenced in the tin plating process.

Description

Technical Field

[0001] The invention relates to the technical field of chip welding, in particular to an automatic tinning device for circuit board chip welding. Background Art

[0002] Soldering chips on circuit boards is a very important production step. Traditional production is done by manual welding, which has high production efficiency and labor costs. With the rapid development of the automation industry, welding robots are currently used for automatic chip welding. The chips are placed on the circuit board through a negative pressure feeding mechanism, and then the welding robot performs the welding operation, which greatly improves production efficiency. Before welding, the pins of the chip need to be tinned to improve the conductivity, corrosion resistance and solderability of the pins. Tinning is performed by immersing the pins of the chip in a tin pool. During this process, high temperature is easily transferred to the chip through the pins, affecting the performance of the chip. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an automatic tinning device for circuit board chip welding to solve the problems of the prior art.

[0004] The object of the present invention is achieved through the following technical scheme: an automatic tinning device for chip welding of a circuit board, comprising a tin liquid pool, a chip loading workbench, a four-way conveying mechanism and a thermal resistance mechanism, a chip stacking barrel is vertically installed on the chip loading workbench, a stacking groove is opened through the top of the chip stacking barrel along its own axial direction, a pin groove is opened on the side wall of the stacking groove along the axial direction of the chip stacking barrel, the pin groove extends to the top of the chip stacking barrel, the chip is stacked in the stacking groove along the axial direction of the chip stacking barrel, and the pins of the chip penetrate into the pin groove;

[0005] The thermal resistance mechanism includes a frame, a lifting seat, a finger cylinder and a cold plate. The lifting seat is installed on the frame and has the freedom to move along the height direction of the frame. The finger cylinder is installed at one end of the lifting seat. The cold plates are installed on the two clamping claws of the finger cylinder. Cold air is passed into the cold plate. The upper part of the chip pin is clamped by the two cold plates for tinning. The temperature of the tinning is blocked by the cold plate and transmitted to the chip;

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

[0007] Furthermore, a lifting cylinder is vertically installed on the frame, the telescopic shaft of the lifting cylinder is connected to the lifting seat, a cold air cavity is provided in the cold plate, one end of the cold plate connected to the clamp is connected to a cold air bottle through an air inlet pipe, the air inlet pipe is connected to the cold air cavity, a plurality of cold air holes are provided at the bottom of the cold plate along its length direction, the cold air holes are inclined toward the clamping center, so that the cold air can be sprayed toward the lower part of the chip pins through the cold air holes.

[0008] Furthermore, a tin surface positioning plate is fixed in the tin liquid pool, and the tin surface positioning plate is located on the moving path of the cold plate. The height of the tin liquid in the tin liquid pool is flush with the top surface height of the tin surface positioning plate. The shape of the cold plate is L-shaped, and the vertical plate of the cold plate is connected to the clamp. During tinning, the cold plate 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 tin liquid pool. A tin replenishment pool is provided on one side of the tin liquid pool, and the tin replenishment pool is connected to the tin liquid pool through a tin replenishment tube. A high-temperature valve is connected to the tin replenishment tube, and an electric heating rod is installed in the tin replenishment pool.

[0010] Furthermore, a tin scraping mechanism is arranged in the tin liquid pool, and the tin scraping mechanism includes a crossbeam, a sinking plate and a scraper. The crossbeam is located above the tin surface positioning plate, and horizontal slide grooves are provided on two opposite inner walls of the tin liquid pool. The two ends of the crossbeam respectively pass through the two horizontal slide grooves, and both ends of the crossbeam are connected to a pushing cylinder, which is installed horizontally. The sinking plate is fixedly mounted on the crossbeam, and the scraper is passed through the bottom of the sinking plate. The scraper has the freedom to move along the height direction of the tin liquid pool.

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

[0012] Furthermore, a lifting mechanism is provided on one side of the chip stacking barrel, and the lifting mechanism includes a column and a lifting plate, the lifting plate is located in the stacking groove, and a screw slide groove is provided on the side of the column close to the chip stacking barrel, a first screw is rotatably installed in the screw slide groove, a screw slider is threadedly mounted on the first screw, and the screw slider is connected to the lifting plate through a horizontal connecting rod, and a vertical avoidance groove is provided on the side wall of the chip stacking barrel for the horizontal connecting rod to pass through, and the vertical avoidance groove extends to the bottom of the chip stacking barrel.

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

[0014] Furthermore, the three-way conveying mechanism includes a moving beam, a sliding plate and a Z-axis slide seat, two groups of linear moving modules are arranged in parallel on the moving beam, two ends of the moving beam are respectively connected to the slide seats of the two groups of linear moving modules, a horizontal screw groove is opened at the bottom of the moving beam, a second screw is rotatably arranged in the horizontal screw groove, a second screw slider is threadedly mounted on the second screw, the sliding plate is connected to the second screw slider, and 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 transmission-connected to the second screw, a Z-axis cylinder is vertically installed on the sliding plate, and the telescopic shaft of the Z-axis cylinder movably passes through the sliding plate to connect to the Z-axis slide seat.

[0015] Furthermore, a flip mounting groove is provided at the bottom of the Z-axis slide, and a horizontal main shaft is rotatably arranged in the flip mounting groove. The flip plate is in an inverted T shape, and the vertical plate of the flip plate is fixedly mounted on the horizontal main shaft. A second motor is installed on the side wall of the Z-axis slide, and the output shaft of the second motor is connected to the horizontal main shaft through a transmission system. The end of the rotating disk away from the negative pressure suction cup is rotatably connected to the flip plate through a bearing, and a large gear is mounted on the rotating disk. A third motor is installed on the horizontal plate of the flip plate, and 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 the present invention are:

[0017] The upper part of the chip pins is clamped by two cold plates, and the chip pins are driven to immerse in the tin liquid pool to perform tin plating on the lower part of the chip pins. Cold air is passed through the inside of the cold plate, so that the cold plate can isolate the high temperature from being transmitted to the chip, which can well protect the chip from being affected during the tin plating process. Secondly, it can also make the tin liquid on the chip pins solidify and cool quickly, and the tin liquid will not fall off, thereby improving the tin plating effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The structure diagram of an automatic tinning device for soldering circuit board chips of the present invention is shown in FIG. Figure 1 ;

[0019] Figure 2 The structure diagram of an automatic tinning device for soldering circuit board chips of the present invention is shown in FIG. Figure 2 ;

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

[0021] Figure 4 The structure diagram of an automatic tinning device for soldering circuit board chips of the present invention is shown in FIG. Figure 3 ;

[0022] Figure 5 The structure diagram of an automatic tinning device for soldering circuit board chips of the present invention is shown in FIG. Figure 4 ;

[0023] Figure 6 The structure diagram of an automatic tinning device for soldering circuit board chips of the present invention is shown in FIG. Figure 5 ;

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

[0025] Figure 8 It is a partial cross-sectional view of a cold plate in an automatic tinning device for circuit board chip welding of the present invention;

[0026] Fig. 9 This is a schematic diagram of the internal structure of a sinking plate in an automatic tinning device for circuit board chip welding according to the present invention;

[0027] In the figure, 1-tin liquid pool, 3-chip loading workbench, 5-chip stacking cylinder, 6-stacking slot, 7-pin slot, 8-rack, 9-lifting seat, 10-finger cylinder, 11-cold sheet, 12-gantry, 13-flip plate, 14-negative pressure suction cup, 15-lifting cylinder, 16-cold air cavity, 17-cold air hole, 18-rotating disk, 19-tin surface positioning plate, 20-liquid level sensor, 21-tin replenishing pool, 22-tin replenishing tube, 23-electric heating rod, 24-beam, 25-sinking plate, 26-scraper, 27-horizontal slide, 28-pushing cylinder, 29-motor shaped mounting groove, 30-high temperature resistant spring, 31-wedge surface, 32-column, 33-top plate, 34-screw slide groove, 35-screw slider, 36-horizontal connecting rod, 37-vertical avoidance groove, 38-screw motor, 39-first screw, 42-moving beam, 43-slide plate, 44-Z-direction slide seat, 45-linear moving module, 46-horizontal screw groove, 47-second screw, 48-first motor, 49-Z-direction cylinder, 50-flip mounting groove, 51-horizontal spindle, 52-second motor, 53-large gear, 54-third motor, 55-small gear. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0029] Embodiment 1: Figures 1 to 9As shown, an automatic tinning device for circuit board chip welding comprises a tin liquid pool 1, a chip loading workbench 3, a four-way conveying mechanism and a thermal resistance mechanism. A chip stacking barrel 5 is vertically installed on the chip loading workbench 3. A stacking groove 6 is provided on the top of the chip stacking barrel 5 along its own axial direction. A pin groove 7 is provided on the side wall of the stacking groove 6 along the axial direction of the chip stacking barrel 5. The pin groove 7 extends to the top of the chip stacking barrel 5. The chips are stacked in the stacking groove 6 along the axial direction of the chip stacking barrel 5, and the pins of the chips are inserted into the pin groove 7. The chips to be tinned are stacked together along the axial direction of the chip stacking barrel 5. The pin groove 7 accommodates the pins of the chips. On the one hand, it prevents the pins from colliding with the side wall of the chip stacking barrel 5 to cause bending. On the other hand, it can position the chips so that the chips are neatly arranged. The chips are stacked in the chip stacking tube 5 so that the four-way conveying mechanism takes out the chips from the chip stacking tube 5 in the same direction, and the precise tinning of the chips can be achieved. A conveyor belt is arranged in parallel on one side of the chip loading workbench 3, and the tinned chips are placed on the conveyor belt, and the chips are transported to the next workstation for production through the conveyor belt; 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 the lifting seat 9 has the freedom to move along the height direction of the frame 8, and a finger cylinder 10 is installed at one end of the lifting seat 9, and cold plates 11 are installed on the two clamping claws of the finger cylinder 10, and cold air is passed into the cold plate 11, and the upper part of the chip pins is clamped by the two cold plates 11 for tinning, and the temperature of the tinning is blocked by the cold plate to be transmitted to the chip;The four-way conveying mechanism includes a gantry 12, a three-way conveying mechanism and a flip plate 13. The three-way conveying mechanism is installed on the gantry 12. The three-way conveying mechanism has the freedom of movement in the three directions of X, Y and Z in the spatial coordinate system. The flip plate 13 is rotatably installed on the three-way conveying mechanism. The deflection axis of the flip plate 13 is horizontally arranged. A rotating disk 18 is rotatably installed at the bottom of the flip plate 13. The rotation axis of the rotating disk 18 is perpendicular to the deflection axis of the flip plate 13. A negative pressure suction cup 14 is arranged on the rotating disk 18. The negative pressure suction cup 14 is driven by the three-way conveying mechanism to move to the top of the chip stacking tube 5. The negative pressure suction cup 14 is connected to the negative pressure pump through a negative pressure pipe to clamp the chip by negative pressure. This belongs to the prior art and will not be repeated. The negative pressure suction cup 14 extends from the top of the chip stacking tube 5 to absorb the chip to be tinned, and then the chip is transported to the thermal resistance mechanism through the three-way conveying mechanism. During the transportation process, the flip plate 13 drives the negative pressure suction cup 14 to deflect 90°, so that the chip is flipped 90° , which is used to arrange the pins on one side of the chip downward, and the pins of the chip facing downward are moved into the clamping range of the finger cylinder 10. The finger cylinder 10 is actuated to clamp the two cold plates 11 on the upper part of the chip pins, and then the lifting seat 9 moves downward close to the tin liquid pool 1, so that the lower part of the pins clamped by the cold plates 11 is immersed in the tin liquid, thereby completing the tinning operation of the pins. Since there is cold air inside the cold plate 11, the cold plate can isolate the high temperature from being transmitted to the chip, which can well protect the chip from being affected during the tinning process. Secondly, it can also make the tin liquid on the chip pins quickly solidify and cool, and the tin liquid will not fall, thereby improving the tinning effect; when the pins on one side of the chip are tinned, the negative pressure suction cup 14 adsorbs the chip again, and the rotating disk 18 drives the chip to rotate 90° or 180°, so that the remaining pins of the chip are arranged downward, and then the pins are clamped by the cold plate 11 again for tinning, and this is repeated to complete the tinning of all the pins of the chip. The tinned chip is placed on the transmission belt and transported to the next workstation. Due to the difference in chips, the arrangement of the pins on the side of the chip is also different, which can be roughly divided into two categories. First, the four sides of the chip are arranged with pins, and the rotating disk 18 rotates 90° each time to complete the tinning of four groups of pins; second, the two opposite sides of the chip are arranged with pins, and the rotating disk 18 drives the chip to rotate 180° to complete the tinning of two groups of pins; since the chip pins are generally gold-plated in the area close to the chip to increase its conductivity and corrosion resistance, the reason for not fully gold-plating is to reduce costs. Considering this, the present invention adopts a partial tinning method to reduce the impact of high temperature tinning on the chip, that is, only the lower area of ​​the chip pins is tinned, and this area needs to be welded with the soldering hole of the circuit board. Tinning in this area can improve solderability, and then through the isolation of the cold plate 11, the safety of the chip is further protected, so that the tinning operation will not affect the performance of the chip. ;

[0030] Embodiment 2: Based on Embodiment 1, Figures 1 to 6As shown, the three-way conveying mechanism includes a moving beam 42, a sliding plate 43 and a Z-direction slide 44. Two groups of linear moving modules 45 are arranged in parallel on the moving beam 42. Both ends of the moving beam 42 are respectively connected to the slides of the two groups of linear moving modules 45. A horizontal screw groove 46 is provided at the bottom of the moving beam 42. A second screw rod 47 is rotatably arranged in the horizontal screw groove 46. A second screw rod slider is threadedly mounted on the second screw rod 47. The sliding plate 43 is connected to the second screw rod 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 transmission-connected to the second screw rod 47. A Z-direction cylinder 49 is vertically installed on the sliding plate 43. The telescopic shaft of the Z-direction cylinder 49 movably passes through the sliding plate 43 to connect to the Z-direction slide. 44, the moving beam 42 is driven to move along the X-axis direction through the linear moving module 45, thereby driving the negative pressure suction cup 14 to move along the X-axis direction, the first motor 48 drives the second screw rod 47 to rotate, so that the second screw rod slider moves linearly along the axial direction of the second screw rod 47, driving the sliding plate 43 thereon to move along the Y-axis direction, thereby driving the negative pressure suction cup 14 to move along the X-axis direction, and the Z-axis slide seat 44 is driven to move along the Z-axis direction through the Z-axis cylinder 49, thereby driving the negative pressure suction cup 14 to move along the Z-axis direction, so that the negative pressure suction cup 14 has three degrees of freedom of movement in the spatial coordinate system, and within the arrangement range of the four-way conveying mechanism, the negative pressure suction cup 14 can take out the chips in the chip stacking tube 5 and convey them to the working range of the thermal resistance mechanism, and then put the tinned chips on the conveyor belt.

[0031] Furthermore, if Figures 1 to 5 As shown, a flip installation groove 50 is provided at the bottom of the Z-direction slide 44, and a horizontal spindle 51 is rotatably provided in the flip installation groove 50. The flip plate 13 is in an inverted T shape, and the vertical plate of the flip plate 13 is fixedly mounted on the horizontal spindle 51. A second motor 52 is installed on the side wall of the Z-direction slide 44, and 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 downward. It is convenient to carry out tinning operation; 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, and 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, and 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, so that the negative pressure suction cup 14 drives the chip thereon to rotate, so as to deflect the pins at different positions of the chip to the bottom for tinning.

[0032] Embodiment 3: Based on Embodiment 2, Figures 1 to 8As shown, a lifting cylinder 15 is vertically installed on the frame 8, and the telescopic shaft of the lifting cylinder 15 is connected to the lifting seat 9. A cold air cavity 16 is arranged in the cold plate 11. One end of the cold plate 11 connected to the clamping claw is connected to the cold air bottle through an air inlet pipe, and the air inlet pipe is connected to the cold air cavity 16. A plurality of 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 toward the clamping center, and are used to allow cold air to pass through the cold air holes 17 and spray to the lower part of the chip pins. Cold air is introduced into the cold air cavity 16 of the cold plate 11 through the cold air bottle to make the temperature of the cold plate 11 The temperature is relatively low, and the tin-plating position of the chip can be isolated from the chip to prevent high temperature from being transferred to the chip and affecting its performance. Cold air is discharged through the cold air hole 17. Since the cold air hole 17 is tilted toward the lower part of the chip pin, the discharged cold air contacts the welding position of the chip pin, thereby cooling the tin liquid on the pin and solidifying the tin liquid quickly, thereby preventing the tin liquid from falling and affecting the tin plating thickness. At the same time, after rapid cooling, the tin-plated chip can be directly transported to the conveyor belt without waiting for the tin liquid to cool naturally before being transported, thereby improving the tin-plating efficiency of the chip.

[0033] Embodiment 4: In order to prevent the tin liquid from crossing the cold plate 11 and contacting the chip during tin plating, it is necessary to accurately control the height of the tin liquid in the tin liquid pool 1 and the tin plating height of the chip. For this purpose, based on the embodiment 3, Figures 1 to 6As shown, a tin surface positioning plate 19 is fixed in the tin liquid pool 1, and the tin surface positioning plate 19 is located on the moving path of the cold plate 11. The height of the tin liquid in the tin liquid pool 1 is flush with the top surface height of the tin surface positioning plate 19. The shape of the cold plate 11 is L-shaped, and the vertical plate of the cold plate 11 is connected to the clamping claw. During tin plating, the cold plate 11 contacts the tin surface positioning plate 19 and is used to immerse the lower part of the chip in the tin liquid. A liquid level sensor 20 is installed on the frame 8, and 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 liquid pool 1. A tin replenishment pool 21 is provided on one side of the tin liquid pool 1. The tin replenishment pool 21 is connected to the tin liquid pool 1 through a tin replenishment tube 22. A high-temperature valve is connected to the tin replenishment tube 22. An electric heating rod 23 is installed in the tin replenishment pool 21. The liquid level sensor 20 is used to detect the liquid level in the tin liquid pool 1 in real time. The height of the tin liquid in the tin liquid pool 1 is detected. When the height of the tin liquid is lower than the top surface of the tin surface positioning plate 19, the high-temperature valve on the tin supplement tube 22 is opened to allow the tin liquid in the tin supplement pool 21 to flow into the tin liquid pool 1 through the tin supplement tube 22. When the liquid level is flush with the top surface of the tin surface positioning plate 19, the high-temperature valve is closed to ensure that the height of the tin liquid in the tin liquid pool 1 is always flush with the top surface of the tin surface positioning plate 19, thereby accurately controlling the tin surface height in the tin liquid pool 1. During tin plating, the lifting seat 9 drives the cold plate 11 to directly contact the tin surface positioning plate 19. The tin plating height of the chip is accurately controlled by the tin surface positioning plate 19, so that the lower part of the chip pins is directly immersed in the tin liquid for tin plating. The tin plating position of the chip pins is consistent through double positioning, the tin plating accuracy is high, and the tin plating length of the pins meets the requirements. During the specific implementation, the staff regularly adds tin blocks into the tin replenishment pool 21, and the tin blocks are heated and melted by the electric heating rod 23 to form tin liquid. Similarly, the electric heating rod 23 is also installed in the tin liquid pool 1 to ensure that the tin in the tin liquid pool 1 is always in a liquid state.

[0034] Embodiment 5: Since an oxide film is formed on the surface of the tin liquid, during the tinning process, the film will adhere to the pins, thereby preventing the tin liquid from being plated on the pins, resulting in insufficient tinning or tinning failure. Therefore, based on the embodiment 4, as Figures 1 to 9As shown, a scraping mechanism is provided in the tin liquid pool 1, and the scraping mechanism includes a crossbeam 24, a sinking plate 25 and a scraper 26. The crossbeam 24 is located above the tin surface positioning plate 19. Two opposite inner walls of the tin liquid pool 1 are provided with horizontal slide grooves 27. The two ends of the crossbeam 24 pass through the two horizontal slide grooves 27 respectively. Both ends of the crossbeam 24 are connected to a push cylinder 28, and the push cylinder 28 is installed horizontally. The sinking plate 25 is fixedly sleeved on the crossbeam 24, and the scraper 26 is passed through the bottom of the sinking plate 25. The scraper 26 has the freedom to move along the height direction of the tin liquid pool 1. A rectangular mounting groove 29 is provided at the bottom of the sinking plate 25. A high temperature resistant spring 30 is provided in the rectangular mounting groove 29. The top of the scraper 26 is slidably adapted in 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 surfaces 31. The tin surface positioning plate 19 is located on the moving path of the wedge surface 31. Before each tinning, the chip pins are first passed through the The scraping mechanism scrapes off the oxide film on the surface of the tin liquid. The specific process is: the cylinder 28 is pushed to drive the beam 24 to move horizontally, and the beam 24 drives the sinking plate 25 and the scraper 26 to move horizontally. In order to ensure that the film can be effectively scraped off, the scraper 26 must be extended into the tin liquid to move, resulting in the scraper 26 interfering with the tin surface positioning plate 19 during the movement. For this reason, a sinking plate 25 is set, and the scraper 26 is slidably installed on the sinking plate 25. The wedge-shaped surface 31 of the scraper 26 contacts The tin surface positioning plate 19, under the guidance of the wedge surface 31, makes the scraper 26 squeeze the high temperature resistant spring 30 and move upward, so that the scraper 26 can pass through the tin surface positioning plate 19. After the scraper 26 passes through the tin surface positioning plate 19, the reaction force of the high temperature resistant spring 30 makes the scraper 26 re-immerse in the tin liquid to scrape the film, so as to scrape the oxide film to both ends of the tin liquid pool 1, so that the oxide film is away from the tin-plating position of the chip, ensuring that the tin-plating of the pins will not be affected, so that the tin-plating effect is better.

[0035] Embodiment 6: Based on Embodiment 5, Figures 1 to 7As shown, a material ejection mechanism is provided on one side of the chip stacking barrel 5, and the material ejection mechanism includes a column 32 and a material ejection plate 33. The material ejection plate 33 is located in the stacking groove 6. A screw slide groove 34 is provided on the side of the column 32 close to the chip stacking barrel 5. A first screw 39 is rotatably installed in the screw slide groove 34. A screw slider 35 is threadedly mounted on the first screw 39. The screw slider 35 is connected to the material ejection plate 33 through a horizontal connecting rod 36. A vertical avoidance groove 37 is provided on the side wall of the chip stacking barrel 5 for the horizontal connecting rod 36 to pass through. The vertical avoidance groove 37 extends to the bottom of the chip stacking barrel 5. A screw motor 38 is installed on the top of the column 32. The output shaft of the screw motor 38 is connected to the first screw 39. Two Z-shaped connecting rods are symmetrically fixed to the outer wall of the chip stacking barrel 5, and the Z-shaped connecting rods are connected to the chip loading workbench 3 by bolts. The screw motor 38 drives the first screw 39 to rotate, so that the screw slider 35 moves linearly along the axial direction of the first screw 39, and the screw slider 35 drives the ejection plate 33 to move through the horizontal connecting rod 36. The ejection plate 33 lifts the chips in the chip stacking barrel 5 upward in turn to make the loading position of the chips consistent; the chip stacking barrel 5 is detachably connected to the chip loading workbench 3 through the Z-shaped connecting rod. When the chips in the chip stacking barrel 5 are tinned, the chip stacking barrel 5 is removed, and the chip stacking barrel 5 fully loaded with chips is installed on the chip loading workbench 3 for tinning operation.

Claims

1. An automatic tinning device for circuit board chip welding, comprising a tin liquid pool (1), characterized in that: It also comprises a chip loading workbench (3), a four-way conveying mechanism and a thermal resistance mechanism. A chip stacking barrel (5) is vertically mounted on the chip loading workbench (3). A stacking groove (6) is provided on the top of the chip stacking barrel (5) along its axial direction. A pin groove (7) is provided on the side wall of the stacking groove (6) along the axial direction of the chip stacking barrel (5). The pin groove (7) extends to the top of the chip stacking barrel (5). The chips are stacked in the stacking groove (6) along the axial direction of the chip stacking barrel (5), and the pins of the chips are inserted into the pin groove (7). The thermal resistance mechanism comprises 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); the lifting seat (9) has the freedom to move along the height direction of the frame (8); one end of the lifting seat (9) is mounted with the finger cylinder (10); two clamping jaws of the finger cylinder (10) are mounted with the cold plates (11); cold air is passed into the cold plates (11); the upper part of the chip pins is clamped by the two cold plates (11) for tinning; the temperature of the tinning is blocked from being transmitted to the chip by the cold plates; The four-way conveying mechanism comprises a gantry (12), a three-way conveying mechanism and a flip plate (13); the three-way conveying mechanism is mounted on the gantry (12); the three-way conveying mechanism has the freedom of movement in three directions, namely, X, Y and Z, in a spatial coordinate system; the flip plate (13) is rotatably mounted on the three-way conveying mechanism; the deflection axis of the flip plate (13) is horizontally arranged; a rotating disk (18) is rotatably mounted on the bottom of the flip plate (13); the rotating axis of the rotating disk (18) is perpendicular to the deflection axis of the flip plate (13); and a negative pressure suction cup (14) is arranged on the rotating disk (18).

2. The automatic tinning device for circuit board chip welding according to claim 1 is characterized in that: 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 cavity (16) is arranged in the cold plate (11), one end of the cold plate (11) connected to the clamp is connected to a cold air bottle via an air inlet pipe, the air inlet pipe is connected to the cold air cavity (16), a plurality of cold air holes (17) are provided at the bottom of the cold plate (11) along its length direction, the cold air holes (17) are inclined toward the clamping center, and are used to allow cold air to pass through the cold air holes (17) and spray toward the lower part of the chip pins.

3. The automatic tinning device for circuit board chip welding according to claim 2 is characterized in that: A tin surface positioning plate (19) is fixed in the tin liquid pool (1), and the tin surface positioning plate (19) is located on the moving path of the cold plate (11). The height of the tin liquid in the tin liquid pool (1) is flush with the top surface height of the tin surface positioning plate (19). The cold plate (11) is in an L-shape, and the vertical plate of the cold plate (11) is connected to the clamping claw. When tinning, the cold plate (11) contacts the tin surface positioning plate (19) to immerse the lower part of the chip in the tin liquid.

4. The automatic tinning device for circuit board chip welding according to claim 3 is characterized in that: A liquid level sensor (20) is installed on the frame (8), and 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 liquid pool (1). A tin replenishment pool (21) is provided on one side of the tin liquid pool (1). The tin replenishment pool (21) is connected to the tin liquid pool (1) via a tin replenishment tube (22). A high-temperature valve is connected to the tin replenishment tube (22). An electric heating rod (23) is installed in the tin replenishment pool (21).

5. The automatic tinning device for circuit board chip welding according to claim 1, characterized in that: A tin scraping mechanism is arranged in the tin liquid pool (1), and the tin scraping mechanism comprises a crossbeam (24), a sinking plate (25) and a scraper (26). The crossbeam (24) is located above the tin surface positioning plate (19). Two opposite inner walls of the tin liquid pool (1) are provided with horizontal slide grooves (27). The two ends of the crossbeam (24) respectively pass through the two horizontal slide grooves (27). Both ends of the crossbeam (24) are connected to a pushing cylinder (28), and the pushing cylinder (28) is installed horizontally. The sinking plate (25) is fixedly sleeved on the crossbeam (24), and the scraper (26) is passed through the bottom of the sinking plate (25). The scraper (26) has the freedom to move along the height direction of the tin liquid pool (1).

6. The automatic tinning device for circuit board chip welding according to claim 5, characterized in that: A rectangular mounting groove (29) is provided at the bottom of the sinking plate (25), a high temperature resistant spring (30) is arranged in the rectangular mounting groove (29), the top of the scraper (26) is slidably adapted in 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), wedge surfaces (31) are provided on both sides of the bottom of the scraper (26), and the tin surface positioning plate (19) is located on the moving path of the wedge surface (31).

7. The automatic tinning device for circuit board chip welding according to claim 1, characterized in that: A material ejection mechanism is arranged on one side of the chip stacking barrel (5), and the material ejection mechanism comprises a column (32) and a material ejection plate (33). The material ejection plate (33) is located in the stacking groove (6). A screw guide groove (34) is provided on the side of the column (32) close to the chip stacking barrel (5). A first screw (39) is rotatably installed in the screw guide groove (34). A screw slider (35) is threadedly mounted on the first screw (39). The screw slider (35) is connected to the material ejection plate (33) via a horizontal connecting rod (36). A vertical avoidance groove (37) for the horizontal connecting rod (36) to pass through is provided on the side wall of the chip stacking barrel (5). The vertical avoidance groove (37) extends to the bottom of the chip stacking barrel (5).

8. The automatic tinning device for circuit board chip welding according to claim 7, characterized in that: A screw motor (38) is installed on the top of the column (32), and the output shaft of the screw motor (38) is drivingly connected to the first screw (39). Two Z-shaped connecting rods are symmetrically fixed to the outer wall of the chip stacking cylinder (5), and the Z-shaped connecting rods are connected to the chip loading workbench (3) through bolts.

9. The automatic tinning device for circuit board chip welding according to claim 1, characterized in that: The three-way conveying mechanism comprises a moving beam (42), a sliding plate (43) and a Z-direction sliding seat (44); two groups of linear moving modules (45) are arranged in parallel on the moving beam (42); two ends of the moving beam (42) are respectively connected to the sliding seats of the two groups of linear moving modules (45); a horizontal screw rod groove (46) is provided at the bottom of the moving beam (42); a second screw rod (47) is rotatably arranged in the horizontal screw rod groove (46); a second screw rod (47) is threadedly sleeved on the second screw rod (47); A slider, the sliding plate (43) is connected to the second 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 screw (47), a Z-direction cylinder (49) is vertically installed on the sliding plate (43), and the telescopic shaft of the Z-direction cylinder (49) movably passes through the sliding plate (43) and is connected to the Z-direction slide seat (44).

10. The automatic tinning device for circuit board chip welding according to claim 9, characterized in that: A flip installation groove (50) is provided at the bottom of the Z-direction slide (44), and a horizontal main shaft (51) is rotatably arranged in the flip installation groove (50); the flip plate (13) is in an inverted T shape, and the vertical plate of the flip plate (13) is fixedly sleeved on the horizontal main shaft (51); a second motor (52) is installed on the side wall of the Z-direction slide (44), and the output shaft of the second motor (52) is connected to the horizontal main shaft (51) through a transmission; 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 sleeved on the rotating disk (18), and 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), and the small gear (55) meshes with the large gear (53).

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