A method for improving the hole filling rate of printed circuit board

Abstract

The present invention discloses a method for improving the hole filling rate of a printed circuit board, which relates to the technical field of printed circuit board processing. The method comprises the following steps: placing a circuit board in a punching die to punch a through hole to be filled, placing the circuit board in a limiting frame in a conductive paste hole filling device, and fixing the circuit board in the limiting frame by a circuit board fixing component in the conductive paste hole filling device; placing a hole filling center column in the through hole of the circuit board in advance, and the bottom of the through hole of the circuit board can be tightly sealed, and conductive paste is injected into a limiting cover, so that the annular grouting gap can be quickly filled, and the pressure in the limiting cover can be combined to make the bubbles in the annular grouting gap overflow, and the conductive paste in the through hole will not be squeezed out by the second punching die of the second punching needle plate, and the conductive paste retained on the circuit board will not increase during the punching die, and the conductive paste in the annular grouting gap can be quickly cooled and solidified by the conductive paste cooling component, thereby improving the efficiency of the hole filling process. This method also ensures the hole filling rate of the printed circuit board.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit board processing, in particular to a method for improving the hole filling rate of a printed circuit board. Background Art

[0002] At present, double-sided and multi-layer printed circuit boards often need to conduct circuits between multiple surfaces. This is often achieved through the via filling process. The main purpose of via filling is to bridge different layers of the PCB board to form interconnection holes. Conductive paste via filling is a new process for making interconnection holes in printed circuit boards. It has many advantages such as short production cycle, low cost, and no three waste pollution. Therefore, this process has been widely used.

[0003] The filling rate refers to the proportion of successfully interconnected holes to all filled holes after the refilling process on the PCB board. The filling rate is related to the circuit quality of the PCB board. The higher the filling rate, the more stable and guaranteed the product performance.

[0004] To address the above issues, a Chinese invention patent with authorization announcement number CN107278055B discloses a method for improving the hole filling rate of PCB boards. By using a high-flow conductive paste to fill the holes, it is easier to fill the holes with the conductive paste.

[0005] Although this patent improves the hole filling rate, it still has the following defects: a second punching plate is required to squeeze out the conductive paste in the middle of the circuit board through-hole to achieve hole filling, which easily causes too much conductive paste to remain on the circuit board and is not easy to scrape off. In addition, the drying and solidification time of the conductive paste is long, which affects the efficiency of the hole filling process. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the existing defects and provide a method for improving the hole filling rate of printed circuit boards. A hole filling center column is placed in the through hole of the circuit board in advance, and the bottom of the through hole of the circuit board can be tightly sealed. Conductive paste is injected into the limiting cover, and the annular grouting gap can be quickly filled. The pressure in the limiting cover can make the bubbles in the annular grouting gap overflow, and the conductive paste in the through hole will not be squeezed out by the second punching needle plate. The conductive paste retained on the circuit board will not increase during the punching, and the conductive paste in the annular grouting gap can be quickly cooled and solidified by the conductive paste cooling component, thereby improving the efficiency of the hole filling process. This method also ensures the hole filling rate of the printed circuit board and can effectively solve the problems in the background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for improving the hole filling rate of a printed circuit board, comprising the following steps:

[0008] Step 1: Place the circuit board into a punching die to form a through hole to be filled;

[0009] Step 2: Place the circuit board into a limit frame in the conductive paste hole filling device, and fix the circuit board in the limit frame using a circuit board fixing component in the conductive paste hole filling device;

[0010] Step 3: The cleaning column of the through-hole grouting auxiliary unit in the conductive paste grouting device moves upward to push the impurities in the through-hole to the upper side of the circuit board, and then the impurities are blown into the debris collection component by the fan;

[0011] Step 4: The top of the cleaning column of the through-hole grouting auxiliary unit in the conductive slurry grouting device cooperates with the bottom sealing ring and the gasket to seal the bottom of the through-hole, leaving an annular grouting gap between the outer side of the grouting center column at the top center of the cleaning column and the inner wall of the through-hole;

[0012] Step 5: The lifting assembly in the conductive paste hole filling device drives the conductive paste limiting and pressurizing unit to descend, so that the conductive paste limiting and pressurizing unit covers the through hole;

[0013] Step 6: Add conductive slurry into the conductive slurry limiting and pressurizing unit so that the conductive slurry fills the annular grouting gap, and at the same time increase the air pressure in the conductive slurry limiting and pressurizing unit;

[0014] Step 7: The conductive paste cooling assembly in the conductive paste grouting device cools and solidifies the conductive paste in the annular grouting gap, and then the lifting assembly drives the conductive paste limiting and pressurizing unit to rise;

[0015] Step 8: The conductive paste scraping component in the conductive paste filling device scrapes off the solidified conductive paste on the upper side of the circuit board, and then blows the solidified conductive paste into the debris collection component through the fan;

[0016] In step nine, the through-hole grouting auxiliary unit in the conductive slurry grouting device descends, and a solidified annular conductive slurry sleeve of equal thickness is formed on the inner wall of the through-hole, completing the grouting operation.

[0017] Furthermore, the conductive slurry hole filling device includes a limit frame, a through-hole grouting auxiliary unit, a conductive slurry limit and pressure unit and a debris collection assembly. The bottom of the limit frame is fixedly connected to the circuit board edge support frame, the thickness of the limit frame is consistent with the thickness of the circuit board, and the four corners of the top of the limit frame are respectively installed with circuit board fixing assemblies. The bottom of the limit frame is provided with a through-hole grouting auxiliary unit, and the through-hole grouting auxiliary unit is installed with a conductive slurry cooling assembly. The front side of the limit frame is installed with a lifting assembly, and the rear side of the lifting assembly is installed with a conductive slurry limit and pressure unit. A fan is installed on the right side of the limit frame, a conductive slurry scraping assembly is installed on the left top of the limit frame, and a debris collection assembly is installed on the left side of the limit frame.

[0018] The circuit board is placed in the limit frame, and the edge bottom of the circuit board is supported by the circuit board edge support frame at the bottom. The circuit board fixing component fixes the top four corners of the circuit board to prevent the circuit board from being pushed out of the limit frame during operation. The through-hole grouting auxiliary unit can close the bottom of the through-hole and occupy the middle space in the through-hole. There is no need to pour too much conductive slurry into the through-hole, and only the conductive slurry is poured into the annular grouting gap. The conductive slurry cooling component can accelerate the cooling speed of the conductive slurry in the annular grouting gap and improve the efficiency of the hole filling process. The lifting component can drive the conductive slurry limiting and pressurizing unit to rise and fall. The conductive slurry limiting and pressurizing unit can cover the through-hole during the descent process, and then the conductive slurry limiting and pressurizing unit can pressurize the area where the through-hole is located so that the conductive slurry fully enters the annular grouting gap. The conductive slurry scraping component can scrape the cooled conductive slurry on the circuit board, and then blow the scraped conductive slurry to the debris collection component for collection through the fan.

[0019] Furthermore, the through-hole grouting auxiliary unit includes a lifting assembly, a movable support plate, a cleaning column and a grouting center column. The bottom of the limit frame is installed with a movable support plate through the lifting assembly. A cleaning column is provided on the upper side of the movable support plate at a position corresponding to the through hole. The diameter of the cleaning column is the same as the diameter of the through hole, and the height of the cleaning column is greater than the thickness of the circuit board. The top center of the cleaning column is connected to the bottom of the grouting center column. The diameter of the grouting center column is smaller than the diameter of the cleaning column, and the height of the grouting center column is equal to the thickness of the circuit board. An annular grouting gap is formed between the outer side of the grouting center column and the inner wall of the through hole.

[0020] As the lifting component rises, the cleaning column can push the debris retained on the inner wall of the through-hole during punching to the upper side of the circuit board. At this time, starting the fan can blow the lifted debris to the debris collection component for collection. Then the lifting component drives the movable support plate to descend, so that the top surface of the cleaning column is flush with the bottom surface of the circuit board. At this time, the top of the hole filling center column is flush with the top surface of the circuit board. After grouting in the annular grouting gap, the conductive paste scraping component is used to scrape the cooled conductive paste on the circuit board without touching the top of the hole filling center column. At the same time, it also ensures that the through-hole can be fully filled. This method occupies the middle part of the through-hole in advance, and does not require too much conductive paste to enter the through-hole, avoiding overflow of conductive paste caused by secondary punching, and reducing the conductive paste retained on the circuit board.

[0021] Furthermore, the through-hole grouting auxiliary unit also includes a spring and a bottom sealing ring. The outer peripheral side of the cleaning column is sleeved with a spring, the bottom of the spring is connected to the movable support plate, and the top of the spring is connected to the bottom sealing ring. The bottom sealing ring is vertically slidably connected to the outer peripheral side of the cleaning column, and the spring pushes the bottom sealing ring to slide vertically along the cleaning column. The spring pushes the bottom sealing ring to close the gap between the top of the cleaning column and the bottom of the through hole to prevent the conductive slurry from seeping out here, and when the cleaning column is extended into the through hole, the spring will be fully compressed and will not interfere with the cleaning column extending into the through hole.

[0022] Furthermore, the through-hole grouting auxiliary unit also includes a gasket. A gasket is provided on the upper side of the bottom sealing ring. The gasket adopts a high-temperature resistant silicone ring to improve the sealing degree of the gap between the top of the cleaning column and the bottom of the through-hole.

[0023] Furthermore, the conductive slurry limiting and pressurizing unit includes a limiting cover, a sealing square ring, a conductive slurry delivery pipe and a valve. The limiting cover is located above the through hole, and a sealing square ring is provided on the bottom edge of the limiting cover. The top of the limiting cover is connected to the bottom end of the conductive slurry delivery pipe, and a valve is connected in series in the middle of the conductive slurry delivery pipe. Conductive slurry can be poured into the bottom of the limiting cover through the conductive slurry delivery pipe, so that the conductive slurry penetrates into the annular grouting gap. The sealing square ring can improve the sealing between the bottom of the limiting cover and the upper side of the circuit board to prevent the conductive slurry from seeping out here. The sealing square ring is made of high-temperature resistant silicone square ring, and the valve can close the conductive slurry delivery pipe when pressurized in the limiting cover.

[0024] Furthermore, the conductive paste limiting and pressurizing unit also includes an observation window. The top through groove of the limiting cover is inlaid with an observation window, and the observation window adopts a transparent tempered glass plate, which can conveniently observe the state of the conductive paste in the limiting cover.

[0025] Furthermore, the conductive slurry limiting and pressurizing unit also includes a connecting sleeve and a pressurized air pipe. The top of the limiting cover is connected to one end of the pressurized air pipe through the connecting sleeve, and the other end of the pressurized air pipe is connected to the air outlet of the external air pump. The connecting sleeve is used to connect the limiting cover and the pressurized air pipe. The limiting cover is pressurized by the external air pump and the pressurized air pipe to ensure that the conductive slurry at the bottom of the limiting cover fully penetrates into the annular grouting gap, thereby improving the grouting rate and grouting effect of the circuit board.

[0026] Furthermore, the conductive paste limiting and pressurizing unit also includes an insulating heating wire, and the outer side of the conductive paste conveying pipe is wrapped with the insulating heating wire. The insulating heating wire heats and insulates the conductive paste conveying pipe to prevent the conductive paste from cooling down when flowing in the conductive paste conveying pipe and clogging the conductive paste conveying pipe.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. Place the circuit board into the limit frame, and support the edge and bottom of the circuit board through the circuit board edge support frame at the bottom. The circuit board fixing assembly fixes the top four corners of the circuit board to prevent the circuit board from being ejected from the limit frame during operation. The through-hole grouting auxiliary unit can seal the bottom of the through-hole and occupy the middle space in the through-hole at the same time. There is no need to pour too much conductive paste into the through-hole, and only the conductive paste is poured into the annular grouting gap;

[0029] 2. The conductive paste cooling component can accelerate the cooling rate of the conductive paste in the annular grouting gap and improve the efficiency of the hole filling process. The lifting component can drive the conductive paste limiting and pressurizing unit to rise and fall. The conductive paste limiting and pressurizing unit can cover the through-hole during the descent process. Then, the conductive paste limiting and pressurizing unit can pressurize the area where the through-hole is located, so that the conductive paste can fully enter the annular grouting gap. The conductive paste scraping component can scrape the cooled conductive paste on the circuit board, and then the fan blows the scraped conductive paste to the debris collection component for collection;

[0030] 3. A filling center column is placed in the through hole of the circuit board in advance, and the bottom of the through hole of the circuit board can be tightly sealed. Conductive paste is injected into the limit cover to quickly fill the annular grouting gap. The pressure in the limit cover can make the bubbles in the annular grouting gap overflow, and the conductive paste in the through hole will not be squeezed out by the second punching die of the second punching needle plate. The conductive paste left on the circuit board will not increase during the punching process, and the conductive paste in the annular grouting gap can be quickly cooled and solidified by the conductive paste cooling component, thereby improving the efficiency of the filling process. This method also ensures the filling rate of the printed circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of the conductive paste hole filling device of the present invention;

[0032] Figure 2 The conductive paste filling device of the present invention Figure 1 A schematic diagram of the partially enlarged structure at center A;

[0033] Figure 3 This is a schematic diagram of the rear side structure of the conductive paste hole filling device of the present invention;

[0034] Figure 4 This is a bottom view of the conductive paste hole filling device of the present invention;

[0035] Figure 5 The conductive paste filling device of the present invention Figure 4 A schematic diagram of the partially enlarged structure at point B in the middle;

[0036] Figure 6 It is a schematic diagram of the partial cross-sectional structure of the conductive paste hole filling device of the present invention.

[0037] In the figure: 1 limit frame, 2 through-hole grouting auxiliary unit, 21 base, 22 fixed seat, 23 hydraulic cylinder 1, 24 movable support plate, 25 cleaning column, 26 grouting center column, 27 spring, 28 bottom sealing ring, 29 gasket, 3 conductive slurry cooling assembly, 31 water inlet pipe, 32 water outlet pipe, 33 spiral cooling channel, 4 lifting assembly, 41 lifting bracket, 42 column, 43 screw, 44 lifting motor, 45 lifting plate, 5 conductive slurry limit pressure unit, 51 limit cover, 52 Sealing square ring, 53 observation window, 54 connecting sleeve, 55 pressurized air pipe, 56 conductive slurry delivery pipe, 57 valve, 58 thermal insulation heating wire, 6 circuit board fixing assembly, 61 motor fixing seat, 62 fixed motor, 63 rotary rod, 7 conductive slurry scraping assembly, 71 side frame, 72 hydraulic cylinder 2, 73 inclined plate, 74 blade, 8 debris collection assembly, 81 collection box, 82 arc frame, 83 arc baffle, 9 fan, 10 circuit board, 11 through hole, 12 circuit board edge support frame. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] For example 1, please refer to Figure 1-6 This embodiment provides a technical solution: a method for improving the hole filling rate of a printed circuit board, comprising the following steps:

[0040] Step 1: Place the circuit board 10 into a punching die to form a through hole 11 to be filled;

[0041] Step 2: Place the circuit board 10 into the limiting frame 1 in the conductive paste hole filling device, and fix the circuit board 10 in the limiting frame 1 using the circuit board fixing component 6 in the conductive paste hole filling device; the circuit board 10 and the limiting frame 1 have the same thickness;

[0042] Step 3: The cleaning column 25 of the through-hole grouting auxiliary unit 2 in the conductive paste grouting device moves upward to push the impurities in the through-hole 11 to the upper side of the circuit board 10, and then the impurities are blown into the debris collection assembly 8 by the fan 9;

[0043] Step 4: The top of the cleaning column 25 of the through-hole grouting auxiliary unit 2 in the conductive paste grouting device cooperates with the bottom sealing ring 28 and the gasket 29 to seal the bottom of the through-hole 11, leaving an annular grouting gap between the outer side of the grouting center column 26 at the top center of the cleaning column 25 and the inner wall of the through-hole 11;

[0044] Step 5: The lifting assembly 4 in the conductive paste filling device drives the conductive paste limiting and pressurizing unit 5 to descend, so that the conductive paste limiting and pressurizing unit 5 covers the through hole 11;

[0045] Step 6: Add conductive slurry into the conductive slurry limiting and pressurizing unit 5 so that the conductive slurry fills the annular grouting gap, and at the same time increase the air pressure in the conductive slurry limiting and pressurizing unit 5;

[0046] Step 7: The conductive paste cooling assembly 3 in the conductive paste grouting device cools and solidifies the conductive paste in the annular grouting gap, and then the lifting assembly 4 drives the conductive paste limiting and pressurizing unit 5 to rise;

[0047] Step 8: The conductive paste scraping assembly 7 in the conductive paste filling device scrapes off the solidified conductive paste on the upper side of the circuit board 10, and then blows the solidified conductive paste into the debris collection assembly 8 through the fan 9;

[0048] In step nine, the through-hole grouting auxiliary unit 2 in the conductive slurry grouting device descends, and a solidified annular conductive slurry sleeve of equal thickness is formed on the inner wall of the through-hole 11, completing the grouting operation.

[0049] The conductive slurry hole filling device includes a limit frame 1, a through-hole grouting auxiliary unit 2, a conductive slurry limit and pressure unit 5 and a debris collection component 8. The bottom of the limit frame 1 is fixedly connected to the circuit board edge support frame 12. The thickness of the limit frame 1 is consistent with the thickness of the circuit board 10. The four corners of the top of the limit frame 1 are respectively installed with circuit board fixing components 6. The bottom of the limit frame 1 is provided with a through-hole grouting auxiliary unit 2. The through-hole grouting auxiliary unit 2 is installed with a conductive slurry cooling component 3. The front side of the limit frame 1 is installed with a lifting component 4. The rear side of the lifting component 4 is installed with a conductive slurry limit and pressure unit 5. A fan 9 is installed on the right side of the limit frame 1. A conductive slurry scraping component 7 is installed on the top left side of the limit frame 1. A debris collection component 8 is installed on the left side of the limit frame 1.

[0050] The circuit board 10 is placed in the limit frame 1, and the edge and bottom of the circuit board 10 are supported by the circuit board edge support frame 12 at the bottom. The circuit board fixing component 6 fixes the top four corners of the circuit board 10 to prevent the circuit board 10 from being ejected from the limit frame 1 during operation. The through-hole grouting auxiliary unit 2 can close the bottom of the through-hole 11 and occupy the middle space in the through-hole 11 at the same time. There is no need to pour too much conductive paste into the through-hole 11, and only the conductive paste is poured into the annular grouting gap. The conductive paste cooling component 3 can speed up the annular grouting. The cooling speed of the conductive paste in the gap improves the efficiency of the hole filling process. The lifting component 4 can drive the conductive paste limiting and pressurizing unit 5 to rise and fall. The conductive paste limiting and pressurizing unit 5 can cover the through hole 11 during the descent process. Then, the conductive paste limiting and pressurizing unit 5 can pressurize the area where the through hole 11 is located, so that the conductive paste can fully enter the annular grouting gap. The conductive paste scraping component 7 can scrape the cooled conductive paste on the circuit board 10, and then the scraped conductive paste is blown to the debris collection component 8 for collection through the fan 9.

[0051] The through-hole grouting auxiliary unit 2 includes a lifting component, a movable support plate 24, a cleaning column 25 and a grouting center column 26. The bottom of the limit frame 1 is installed with a movable support plate 24 through the lifting component. A cleaning column 25 is provided on the upper side of the movable support plate 24 corresponding to the position of the through hole 11. The diameter of the cleaning column 25 is the same as the diameter of the through hole 11, and the height of the cleaning column 25 is greater than the thickness of the circuit board 10. The top center of the cleaning column 25 is connected to the bottom of the grouting center column 26. The diameter of the grouting center column 26 is smaller than the diameter of the cleaning column 25, and the height of the grouting center column 26 is equal to the thickness of the circuit board 10. An annular grouting gap is formed between the outer side of the grouting center column 26 and the inner wall of the through hole 11.

[0052] The lifting assembly includes a base frame 21, a fixed seat 22, and a hydraulic cylinder 23. The bottom two sides of the limit frame 1 are fixedly connected to the two ends of the U-shaped base frame 21. The middle part of the base frame 21 is fixedly connected to the bottom end of the hydraulic cylinder 23 through the fixed seat 22. The top of the hydraulic cylinder 23 is fixedly connected to the bottom center of the movable support plate 24. The hydraulic cylinder 23 is connected to the external hydraulic system through an oil pipe. The hydraulic cylinder 23 is extended and retracted to drive the movable support plate 24 to rise and fall.

[0053] As the lifting component rises, the cleaning column 25 can push the debris retained on the inner wall of the through hole 11 during punching to the upper side of the circuit board 10. At this time, starting the fan 9 can blow the lifted debris to the debris collection component 8 for collection, and then the lifting component drives the movable support plate 24 to descend, so that the top surface of the cleaning column 25 is flush with the bottom surface of the circuit board 10. At this time, the top of the hole filling center column 26 is flush with the top surface of the circuit board 10. After grouting in the annular grouting gap, the conductive paste scraping component 7 is used to scrape the cooled conductive paste on the circuit board 10 without touching the top of the hole filling center column 26. At the same time, it also ensures that the through hole 11 can be fully filled. This method occupies the middle part of the through hole 11 in advance, and does not require too much conductive paste to enter the through hole 11, avoiding overflow of conductive paste caused by secondary punching, and reducing the conductive paste retained on the circuit board 10.

[0054] The through-hole grouting auxiliary unit 2 also includes a spring 27 and a bottom sealing ring 28. The spring 27 is sleeved on the outer peripheral side of the cleaning column 25. The bottom of the spring 27 is connected to the movable support plate 24, and the top of the spring 27 is connected to the bottom sealing ring 28. The bottom sealing ring 28 is vertically slidably connected to the outer peripheral side of the cleaning column 25. The spring 27 pushes the bottom sealing ring 28 to slide vertically along the cleaning column 25. The spring 27 pushes the bottom sealing ring 28 to close the gap between the top of the cleaning column 25 and the bottom of the through hole 11 to prevent the conductive slurry from seeping out here, and when the cleaning column 25 is extended into the through hole 11, the spring 27 will be fully compressed and will not interfere with the cleaning column 25 extending into the through hole 11.

[0055] The through-hole grouting auxiliary unit 2 further includes a gasket 29 . The gasket 29 is provided on the upper side of the bottom sealing ring 28 . The gasket 29 is made of a high-temperature resistant silicone ring to improve the sealing degree of the gap between the top of the cleaning column 25 and the bottom of the through-hole 11 .

[0056] The conductive slurry cooling assembly 3 includes a water inlet pipe 31, a water outlet pipe 32, and a spiral cooling channel 33. The spiral cooling channel 33 is provided on the inner side of the grouting center column 26. One end of the spiral cooling channel 33 is connected to the water inlet pipe 31, and the other end of the spiral cooling channel 33 is connected to the water outlet pipe 32. The water inlet pipe 31 is connected to an external tap water pipe through a liquid pump. The liquid pump pumps water into the spiral cooling channel 33 to dissipate heat from the grouting center column 26, thereby increasing the cooling and solidification speed of the conductive slurry.

[0057] The conductive paste limiting and pressurizing unit 5 includes a limiting cover 51, a sealing square ring 52, a conductive paste delivery pipe 56 and a valve 57. The limiting cover 51 is located above the through hole 11, and a sealing square ring 52 is provided on the bottom edge of the limiting cover 51. The top of the limiting cover 51 is connected to the bottom end of the conductive paste delivery pipe 56, and a valve 57 is connected in series in the middle of the conductive paste delivery pipe 56. Conductive paste can be poured into the bottom of the limiting cover 51 through the conductive paste delivery pipe 56, so that the conductive paste penetrates into the annular grouting gap. The sealing square ring 52 can improve the sealing between the bottom of the limiting cover 51 and the upper side of the circuit board 10 to prevent the conductive paste from seeping out here. The sealing square ring 52 is made of high-temperature resistant silicone square ring. The valve 57 can close the conductive paste delivery pipe 56 when pressurized in the limiting cover 51.

[0058] The conductive paste limiting and pressurizing unit 5 further includes an observation window 53 . The top through groove of the limiting cover 51 is inlaid with the observation window 53 . The observation window 53 is made of a transparent tempered glass plate, which allows convenient observation of the state of the conductive paste in the limiting cover 51 .

[0059] The conductive paste limiting and pressurizing unit 5 also includes a connecting sleeve 54 and a pressurized air pipe 55. The top of the limiting cover 51 is connected to one end of the pressurized air pipe 55 through the connecting sleeve 54, and the other end of the pressurized air pipe 55 is connected to the air outlet of the external air pump. The connecting sleeve 54 is used to connect the limiting cover 51 and the pressurized air pipe 55. The limiting cover 51 is pressurized through the external air pump and the pressurized air pipe 55 to ensure that the conductive paste at the bottom of the limiting cover 51 fully penetrates into the annular grouting gap, thereby improving the grouting rate and grouting effect of the circuit board.

[0060] The conductive paste limiting and pressurizing unit 5 further includes a heat-insulating heating wire 58 , which is wound around the outside of the conductive paste delivery pipe 56 . The heat-insulating heating wire 58 heats and insulates the conductive paste delivery pipe 56 to prevent the conductive paste from cooling down while flowing in the conductive paste delivery pipe 56 and clogging the conductive paste delivery pipe 56 .

[0061] The lifting assembly 4 includes a lifting bracket 41, a column 42, a screw 43, a lifting motor 44, and a lifting plate 45. The front side of the limit frame 1 is fixedly connected to the bottom of the lifting bracket 41, the lifting bracket 41 is fixedly connected to the vertical column 42, and the lifting bracket 41 is rotatably connected to the vertical screw 43. The sliding hole at the end of the lifting plate 45 is vertically slidably connected to the column 42, the screw hole at the end of the lifting plate 45 is threadedly connected to the screw 43, and the top of the screw 43 is fixedly connected to the output shaft of the lifting motor 44. The lifting motor 44 is fixed to the top of the lifting bracket 41, and the end of the lifting plate 45 away from the screw 43 is fixedly connected to the front side of the limit cover 51. The lifting motor 44 drives the screw 43 to rotate when it works, and the lifting plate 45 is driven to move up and down along the column 42 through the threaded action of the screw 43 and the lifting plate 45, which can drive the limit cover 51 to move down and buckle on the circuit board 10 and cover the through hole 11;

[0062] For example 2, please refer to Figure 1-6 ,This embodiment provides a technical solution: a method for improving the hole filling rate of a printed circuit board. This embodiment is a further explanation of the first embodiment;

[0063] The circuit board fixing assembly 6 includes a motor fixing seat 61, a fixed motor 62 and a rotating rod 63. The fixed motor 62 is fixedly installed at the four corners of the top of the limit frame 1 through the motor fixing seat 61. The output shaft at the top of the fixed motor 62 is connected to the rotating rod 63. The bottom of the rotating rod 63 is flush with the bottom of the rotating rod 63. The fixed motor 62 can drive the rotating rod 63 to rotate, so that the end of the rotating rod 63 is placed on the upper side of the circuit board 10. At this time, the circuit board 10 is fixed in the limit frame 1.

[0064] For example three, please refer to Figure 1-6 ,This embodiment provides a technical solution: a method for improving the hole filling rate of a printed circuit board. This embodiment is a further explanation of the first embodiment;

[0065] The conductive paste scraping assembly 7 includes a side frame 71, a hydraulic cylinder 2 72, an inclined plate 73, and a blade 74. The left side of the limit frame 1 is fixedly connected to the bottom of the side frame 71, and the top of the side frame 71 is fixedly connected to the left end of the horizontal hydraulic cylinder 2 72. The right end of the hydraulic cylinder 2 72 is connected to the inclined plate 73. The inclined plate 73 is higher on the left and lower on the right, and the right end of the inclined plate 73 is provided with a blade 74, and the blade 74 is flush with the limit frame 1 and the upper side of the circuit board 10. The hydraulic cylinder 2 72 is connected to the external hydraulic source through an oil pipe. The extension of the hydraulic cylinder 2 72 can drive the inclined plate 73 to move to the right to scrape off the solidified conductive paste on the circuit board 10.

[0066] For example 4, please refer to Figure 1-6 ,This embodiment provides a technical solution: a method for improving the hole filling rate of a printed circuit board. This embodiment is a further explanation of the first embodiment;

[0067] The debris collection assembly 8 includes a collection box 81, an arc frame 82, and an arc-shaped baffle 83. The collection box 81 is arranged on the left side of the limit frame 1, and an arc frame 82 is arranged on the left top of the collection box 81. An arc-shaped baffle 83 is arranged in the arc frame 82. The fan 9 blows the conductive paste scraped off the circuit board 10 or the debris pushed out of the through hole 11 by the cleaning column 25 toward the arc-shaped baffle 83, and the debris is intercepted by the arc-shaped baffle 83 and falls into the collection box 81 for collection.

[0068] It is worth noting that the input ends of the fan 9, hydraulic cylinder 1 23, thermal insulation heating wire 58, lifting motor 44, fixed motor 62, and hydraulic cylinder 2 72 disclosed in the above embodiments are electrically connected to the output ends of the external power supply through an external PLC controller, and the lifting motor 44 and the fixed motor 62 both adopt servo motors, and the specific model and power are selected according to actual common use. The external PLC controller controls the operation of the fan 9, hydraulic cylinder 1 23, thermal insulation heating wire 58, lifting motor 44, fixed motor 62, and hydraulic cylinder 2 72 using methods commonly used in the prior art.

[0069] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for improving the hole filling rate of a printed circuit board, characterized in that: The following steps are involved: Step 1: placing the circuit board (10) into a punching die to punch out a through hole (11) to be filled; Step 2: placing the circuit board (10) into the limiting frame (1) in the conductive paste hole filling device, and fixing the circuit board (10) in the limiting frame (1) using the circuit board fixing component (6) in the conductive paste hole filling device; Step 3: The cleaning column (25) of the through-hole grouting auxiliary unit (2) in the conductive paste grouting device moves upward to push the impurities in the through-hole (11) to the upper side of the circuit board (10), and then the impurities are blown into the debris collection component (8) by the fan (9); Step 4: The top of the cleaning column (25) of the through-hole grouting auxiliary unit (2) in the conductive slurry grouting device cooperates with the bottom sealing ring (28) and the gasket (29) to seal the bottom of the through-hole (11), and an annular grouting gap is left between the outer side of the grouting center column (26) at the center of the top of the cleaning column (25) and the inner wall of the through-hole (11); Step 5: the lifting assembly (4) in the conductive paste hole filling device drives the conductive paste limiting and pressurizing unit (5) to descend, so that the conductive paste limiting and pressurizing unit (5) covers the through hole (11); Step six, adding conductive slurry into the conductive slurry limiting and pressurizing unit (5) so that the conductive slurry is poured into the annular grouting gap, and at the same time increasing the air pressure in the conductive slurry limiting and pressurizing unit (5); Step seven, the conductive paste cooling component (3) in the conductive paste grouting device cools and solidifies the conductive paste in the annular grouting gap, and then the lifting component (4) drives the conductive paste limiting and pressurizing unit (5) to rise; Step eight, the conductive paste scraping component (7) in the conductive paste hole filling device scrapes off the solidified conductive paste on the upper side of the circuit board (10), and then blows the solidified conductive paste into the debris collection component (8) through the fan (9); In step nine, the through-hole grouting auxiliary unit (2) in the conductive slurry grouting device descends, and a solidified annular conductive slurry sleeve of equal thickness is formed on the inner wall of the through-hole (11), completing the grouting operation.

2. The method for improving the hole filling rate of a printed circuit board according to claim 1, wherein: The conductive paste grouting device comprises a limit frame (1), a through-hole grouting auxiliary unit (2), a conductive paste limit pressurizing unit (5) and a debris collection component (8), wherein the bottom of the limit frame (1) is fixedly connected to a circuit board edge support frame (12), the thickness of the limit frame (1) is consistent with the thickness of the circuit board (10), the top four corners of the limit frame (1) are respectively installed with circuit board fixing components (6), the bottom of the limit frame (1) is provided with a through-hole grouting auxiliary unit (2), the through-hole grouting auxiliary unit (2) is installed with a conductive paste cooling component (3), the front side of the limit frame (1) is installed with a lifting component (4), the rear side of the lifting component (4) is installed with a conductive paste limit pressurizing unit (5), the right side of the limit frame (1) is installed with a fan (9), the left top of the limit frame (1) is installed with a conductive paste scraping component (7), and the left side of the limit frame (1) is installed with a debris collection component (8).

3. The method for improving the hole filling rate of a printed circuit board according to claim 1, wherein: The through-hole grouting auxiliary unit (2) includes a lifting component, a movable support plate (24), a cleaning column (25) and a grouting center column (26). The bottom of the limit frame (1) is installed with a movable support plate (24) through the lifting component. The cleaning column (25) is provided on the upper side of the movable support plate (24) at a position corresponding to the through-hole (11). The diameter of the cleaning column (25) is the same as the diameter of the through-hole (11), and the height of the cleaning column (25) is greater than the thickness of the circuit board (10). The top center of the cleaning column (25) is connected to the bottom of the grouting center column (26). The diameter of the grouting center column (26) is smaller than the diameter of the cleaning column (25), and the height of the grouting center column (26) is equal to the thickness of the circuit board (10). An annular grouting gap is formed between the outer side of the grouting center column (26) and the inner wall of the through-hole (11).

4. The method for improving the hole filling rate of a printed circuit board according to claim 3, wherein: The through-hole grouting auxiliary unit (2) further comprises a spring (27) and a bottom sealing ring (28); the outer peripheral side of the cleaning column (25) is sleeved with the spring (27); the bottom of the spring (27) is connected to the movable support plate (24); and the top of the spring (27) is connected to the bottom sealing ring (28); the bottom sealing ring (28) is vertically slidably connected to the outer peripheral side of the cleaning column (25).

5. The method for improving the hole filling rate of a printed circuit board according to claim 4, wherein: The through-hole grouting auxiliary unit (2) further comprises a gasket (29), and the gasket (29) is provided on the upper side of the bottom sealing ring (28).

6. The method for improving the hole filling rate of a printed circuit board according to claim 1, wherein: The conductive paste limiting and pressurizing unit (5) comprises a limiting cover (51), a sealing square ring (52), a conductive paste delivery pipe (56) and a valve (57). The limiting cover (51) is located above the through hole (11), and a sealing square ring (52) is provided on the bottom edge of the limiting cover (51). The top of the limiting cover (51) is connected to the bottom end of the conductive paste delivery pipe (56), and the middle of the conductive paste delivery pipe (56) is connected in series with the valve (57).

7. The method for improving the hole filling rate of a printed circuit board according to claim 6, characterized in that: The conductive paste limiting and pressurizing unit (5) further comprises an observation window (53), and the observation window (53) is embedded in the top through groove of the limiting cover (51).

8. The method for improving the hole filling rate of a printed circuit board according to claim 6, wherein: The conductive paste limiting and pressurizing unit (5) further comprises a connecting sleeve (54) and a pressurizing air pipe (55); the top of the limiting cover (51) is connected to one end of the pressurizing air pipe (55) via the connecting sleeve (54); and the other end of the pressurizing air pipe (55) is connected to the air outlet of an external air pump.

9. The method for improving the hole filling rate of a printed circuit board according to claim 6, wherein: The conductive paste limiting and pressurizing unit (5) further comprises a heat-insulating electric heating wire (58), and the outer side of the conductive paste delivery pipe (56) is wound with the heat-insulating electric heating wire (58).

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