An apparatus for detecting defects of a circuit board and a method thereof

Abstract

The application discloses a kind of equipment and method for detecting defects of circuit board, it is related to circuit board defect detection technical field, including base, the both sides of the base are equipped with support frame, the top of the support frame is equipped with visual detector, the inside of the positioning frame is equipped with angle adjusting connector.The application is limited to the maximum angle of the indicator swing by adjusting the position of the second limit pin through the setting angle adjusting connector, and the telescopic cylinder is started.In this process, the movable pin will drive the support connecting shaft to swing through the straight slot guide rail, so the inclination angle of the circuit board can be adjusted, and then the rotation of the positioning table drives the rotation of the circuit board, so that the circuit board in the inclined state is rotated, so the top of the circuit board can be detected from different angles, so that the blind area originally blocked is exposed in the shooting range of the visual detector, and the full coverage detection of the surface of the circuit board without dead angle is realized.

Description

Technical Field

[0001] This invention relates to the field of circuit board defect detection technology, specifically to a device and method for circuit board defect detection. Background Technology

[0002] Circuit boards are boards used to support electronic components and provide circuits to connect them. Currently, after production, circuit boards need to be inspected by defect detection devices to ensure their quality.

[0003] Circuit boards typically have components, pins, solder joints, and other structures soldered on their surface. Some components have height differences, and pins and solder joints can easily create shadows. If only the top of the circuit board in a horizontal position is photographed, it is difficult to capture defects in areas such as the bottom of components, pin gaps, and corners of the circuit board edges. As a result, defects such as cracks, cold solder joints, missing solder joints, and component misalignment may be missed due to the limited field of view. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that defects are easily missed during circuit board inspection due to the shadows of components, and to provide a device and method for circuit board defect inspection.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a device for detecting defects in circuit boards, comprising a base, support frames installed on both sides of the base, a visual detector installed on the top of the support frames, a positioning frame installed on the top of the base, an angle-adjusting connector provided on the inner side of the positioning frame, and a positioning platform located above the positioning frame connected to the inner side of the positioning frame via the angle-adjusting connector, the positioning platform being located between the positioning frame and the visual detector; The angle-adjusting connector includes a support shaft installed inside the positioning frame. Both ends of the support shaft are rotatably connected to the positioning frame via bearings. A U-shaped frame is installed on the top of the support shaft. A motor is installed inside the U-shaped frame. The output end of the motor is connected to a positioning platform located above the U-shaped frame.

[0006] As a further embodiment of the present invention: the angle-adjusting connector further includes a straight groove guide rail installed at the bottom of the support shaft and located inside the positioning frame. A telescopic cylinder is installed on one side of the positioning frame. The output end of the telescopic cylinder is connected to a second extension rod located inside the positioning frame. A movable pin is slidably connected to the inner side of the straight groove guide rail. A push block is fixedly connected to one end of the movable pin. The second extension rod passes through the push block. A partition is fixedly connected to the end of the second extension rod away from the telescopic cylinder. A telescopic spring connected to the push block and located outside the second extension rod is provided at one end of the partition. One end of the positioning frame is equipped with a ring protractor. The outer side of the ring protractor is rotatably connected to an outer ring via a bearing. The outer wall of the outer ring is provided with a positioning plate. A worm gear is provided on one side of the positioning plate. One end of the visual detector is connected to an indicator located on one side of the ring protractor. One end of the ring protractor is provided with a first limiting pin that abuts against the indicator. One end of the worm gear is connected to a positioning plate. A second limiting pin is provided on one side of the positioning plate. One end of the positioning frame is provided with a worm that meshes with the worm gear. Locking units are provided on both sides of the positioning frame.

[0007] As a further embodiment of the present invention: the center of the annular protractor and the center of the supporting shaft are coaxial, and the center of the worm gear and the center of the annular protractor are coaxial.

[0008] As a further aspect of the present invention: the distance from the center of the first limiting pin to the center of the annular protractor is equal to the distance from the center of the second limiting pin to the center of the annular protractor.

[0009] As a further embodiment of the present invention: the diameter of the movable pin is equal to the inner width of the straight groove guide rail, and the inner side of the push block is provided with a through hole that matches the second extension rod.

[0010] As a further embodiment of the present invention: the locking unit includes a first extension rod installed on the end of the partition away from the second extension rod; a connecting cylinder is installed on the side of the positioning frame away from the telescopic cylinder; one end of the first extension rod extends to the inner side of the connecting cylinder; a second contact piece is installed on the inner side of the connecting cylinder; a first contact piece flush with the second contact piece is installed on the inner wall of the connecting cylinder; a piston cylinder is provided at the bottom of the telescopic cylinder; a piston rod extending to the outer side of the piston cylinder is inserted into the inner side of the piston cylinder; one end of the piston rod is connected to the bottom of the push block; a solenoid valve is installed at the end of the piston cylinder away from the piston rod; a water tank located on one side of the positioning frame is installed on the top of the base; and a connecting pipe extending to the inner side of the water tank is provided at one end of the solenoid valve.

[0011] As a further embodiment of the present invention: the first contact is electrically connected to an external power supply via a wire, and the second contact is electrically connected to a solenoid valve via a wire.

[0012] As a further aspect of the present invention: the farthest distance between the first contact piece and the second contact piece is equal to the extendable length of the telescopic cylinder.

[0013] As a further aspect of the present invention, the internal volume of the water tank is greater than the internal volume of the piston cylinder.

[0014] This invention also discloses a method for detecting defects in printed circuit boards, using the aforementioned equipment for detecting defects in printed circuit boards, comprising the following steps: S1: First, place the circuit board to be tested on the top of the positioning table, and then use the operation of the positioning table to fix and limit the circuit board. S2: Activate the vision detector to detect the top of the circuit board. The vision detector takes a top view of the circuit board. S3: The operation of the angle adjustment connector is used to adjust the tilt angle of the positioning stage, so that the positioning stage is tilted relative to the top of the positioning frame. At this time, the visual detector can take pictures and detect the circuit board in the tilted state from above. S4: Start the motor. The motor's operation causes the positioning stage to rotate relative to the U-shaped frame. This allows the circuit board to rotate intermittently while tilted, enabling the top of the circuit board to be detected from different angles, exposing previously obscured blind spots to the visual detector's field of view.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. By setting up the angle adjustment connector, rotating the worm gear causes the worm wheel to rotate. The worm wheel, through the positioning plate, drives the second limit pin to rotate, thus allowing the second limit pin to rotate along the center of the annular protractor. Adjusting the position of the second limit pin limits the maximum angle of the indicator's swing. Activating the telescopic cylinder extends the second extension rod horizontally. The partition, through the telescopic spring, drives the push block to move. The push block and the second extension rod move synchronously. During this process, the movable pin swings along the straight groove guide rail, causing the indicator to separate from the first limit pin. The support shaft then drives the positioning... The platform swings, causing the positioning platform to tilt. When the indicator comes into contact with the second limit pin, the support shaft cannot rotate. At the same time, the telescopic cylinder continues to extend, and the second extension rod moves relative to the push block. Simultaneously, the telescopic spring extends, thus adjusting the tilt angle of the circuit board. Then, the positioning platform drives the circuit board to rotate, causing the tilted circuit board to rotate. This allows for inspection of the top of the circuit board from different angles, exposing previously obscured blind spots to the field of view of the vision detector. This achieves full coverage inspection of the circuit board surface without blind spots, avoiding the omission of defects such as cracks, cold solder joints, missing solder joints, and component misalignment due to limited viewing angle. 2. By setting a locking unit, when the push block moves relative to the positioning frame, it will drive the piston rod to move. At this time, the piston rod will move relative to the piston cylinder. When the piston rod moves away from the piston cylinder, the solution inside the water tank will enter the piston cylinder under the action of negative pressure. When the piston rod moves towards the piston cylinder, the solution inside the piston cylinder will enter the water tank through the connecting pipe under the compression of the piston rod. When the telescopic cylinder is fully extended, the second contact plate contacts the first contact plate. At this time, the solenoid valve is energized and closed, so that the solution inside the piston cylinder loses the flow space. At this time, the piston rod cannot move relative to the piston cylinder, thus fixing the moved push block and improving the stability of the positioning stage in the tilted state. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 For the present invention Figure 1 Enlarged view of point A in the middle; Figure 3 This is a schematic diagram showing the connection between the positioning frame and the positioning platform of the present invention; Figure 4 This is a schematic diagram showing the connection between the positioning platform and the support shaft of the present invention; Figure 5 This is a schematic diagram showing the connection between the telescopic cylinder and the push block of the present invention; Figure 6This is a schematic diagram of the internal structure of the connecting cylinder of the present invention; Figure 7 This is a schematic diagram showing the connection between the worm gear and the indicator of the present invention; Figure 8 This is a schematic diagram showing the connection between the piston cylinder and the push block of the present invention.

[0017] In the diagram: 1. Base; 2. Support frame; 3. Vision detector; 4. Positioning frame; 5. Positioning platform; 6. Water tank; 7. Outer connecting ring; 8. Worm gear; 9. Annular protractor; 10. First limit pin; 11. Indicator; 12. Connecting cylinder; 13. Support shaft; 14. U-shaped frame; 15. Second limit pin; 16. Motor; 17. Positioning plate; 18. Connecting pipe; 19. Worm gear; 20. Straight groove guide rail; 21. First extension rod; 22. Partition plate; 23. Telescopic spring; 24. Movable pin; 25. Piston cylinder; 26. Piston rod; 27. Solenoid valve; 28. Telescopic cylinder; 29. ​​Push block; 30. Second extension rod; 31. First contact piece; 32. Second contact piece; 33. Positioning connecting plate. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," and "set up" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The following describes embodiments of the invention based on its overall structure.

[0020] Please see Figures 1 to 8 In this embodiment of the invention, a device for detecting defects in circuit boards includes a base 1, support frames 2 are installed on both sides of the base 1, a visual detector 3 is provided on the top of the support frame 2, a positioning frame 4 is installed on the top of the base 1, an angle adjustment connector is provided on the inner side of the positioning frame 4, and a positioning platform 5 located above the positioning frame 4 is connected to the inner side of the positioning frame 4 through the angle adjustment connector. The positioning platform 5 is located between the positioning frame 4 and the visual detector 3. The angle adjustment connector includes a support shaft 13 installed inside the positioning frame 4. Both ends of the support shaft 13 are rotatably connected to the positioning frame 4 via bearings. A U-shaped frame 14 is installed on the top of the support shaft 13. A motor 16 is installed inside the U-shaped frame 14. The output end of the motor 16 is connected to a positioning platform 5 located above the U-shaped frame 14.

[0021] In this embodiment: First, the circuit board to be inspected is placed on top of the positioning platform 5. Then, the positioning platform 5 is used to fix and limit the circuit board. Next, the vision detector 3 is activated to inspect the top of the circuit board. At this time, the vision detector 3 captures a top view of the circuit board. Then, the tilt angle of the positioning platform 5 is adjusted by the operation of the angle adjustment connector, so that the positioning platform 5 is tilted relative to the top of the positioning frame 4. At this time, the vision detector 3 can capture and inspect the circuit board in the tilted state from above. Then, the motor 16 is activated to rotate the positioning platform 5 relative to the U-shaped frame 14. This allows the circuit board to rotate intermittently in the tilted state, so that the top of the circuit board can be inspected from different angles. This exposes the originally blocked blind areas to the field of view of the vision detector 3, achieving full coverage inspection of the circuit board surface without blind spots, avoiding the omission of defects such as cracks, cold solder joints, missing solder joints, and component misalignment caused by limited field of view.

[0022] Please refer to this carefully. Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 7The angle-adjusting connector also includes a straight groove guide rail 20 installed at the bottom of the support shaft 13 and located inside the positioning frame 4. A telescopic cylinder 28 is installed on one side of the positioning frame 4. The output end of the telescopic cylinder 28 is connected to a second extension rod 30 located inside the positioning frame 4. A movable pin 24 is slidably connected to the inner side of the straight groove guide rail 20. A push block 29 is fixedly connected to one end of the movable pin 24. The second extension rod 30 passes through the push block 29. A partition plate 22 is fixedly connected to the end of the second extension rod 30 away from the telescopic cylinder 28. A telescopic spring 23 connected to the push block 29 and located outside the second extension rod 30 is provided at one end of the partition plate 22. One end of the positioning frame 4 is equipped with an annular protractor 9. The outer side of the annular protractor 9 is rotatably connected to an outer connecting ring 7 via a bearing. The outer wall of the outer connecting ring 7 is provided with a positioning connecting plate 33. A worm gear 8 is provided on one side of the positioning connecting plate 33. One end of the visual detector 3 is connected to an indicator 11 located on one side of the annular protractor 9. One end of the annular protractor 9 is provided with a first limiting pin 10 that fits against the indicator 11. One end of the worm gear 8 is connected to a positioning plate 17. A second limiting pin 15 is provided on one side of the positioning plate 17. One end of the positioning frame 4 is provided with a worm 19 that meshes with the worm gear 8. Locking units are provided on both sides of the positioning frame 4.

[0023] Among them, the center of the annular protractor 9 is coaxial with the center of the supporting shaft 13, the center of the worm gear 8 is coaxial with the center of the annular protractor 9, the distance from the center of the first limiting pin 10 to the center of the annular protractor 9 is equal to the distance from the center of the second limiting pin 15 to the center of the annular protractor 9, the diameter of the movable pin 24 is equal to the inner width of the straight groove guide rail 20, and the inner side of the push block 29 is provided with a through hole that matches the second extension rod 30.

[0024] In this embodiment: Rotating the worm gear 19 causes the worm wheel 8 to rotate. The worm wheel 8, via the positioning plate 17, drives the second limiting pin 15 to rotate, thus allowing the second limiting pin 15 to rotate along the center of the annular protractor 9. Adjusting the position of the second limiting pin 15 limits the maximum swing angle of the indicator 11. Activating the telescopic cylinder 28 causes the second extension rod 30 to move horizontally. The partition plate 22, via the telescopic spring 23, drives the push block 29 to move. The push block 29 moves synchronously with the second extension rod 30. During this process, the movable pin 24 swings via the straight groove guide rail 20, actuating the support shaft 13. Simultaneously, the indicator 11 separates from the first limiting pin 10. The supporting shaft 13 drives the positioning stage 5 to swing, thereby tilting the positioning stage 5. When the indicator 11 contacts the second limit pin 15, the supporting shaft 13 can no longer rotate. At the same time, the telescopic cylinder 28 continues to extend, and the second extension rod 30 moves relative to the push block 29. Simultaneously, the telescopic spring 23 extends, thus adjusting the tilt angle of the circuit board. Then, the positioning stage 5 drives the circuit board to rotate, causing the tilted circuit board to rotate. This allows for inspection of the top of the circuit board from different angles, exposing previously obscured blind spots to the field of view of the vision detector 3. This achieves full coverage inspection of the circuit board surface without blind spots, avoiding missed defects such as cracks, cold solder joints, missing solder joints, and component misalignment caused by limited viewing angle.

[0025] Please refer to this carefully. Figure 3 , Figure 4 , Figure 6 , Figure 8 The locking unit includes a first extension rod 21 installed on the partition 22 away from the end of the second extension rod 30. A connecting cylinder 12 is installed on the side of the positioning frame 4 away from the telescopic cylinder 28. One end of the first extension rod 21 extends to the inside of the connecting cylinder 12. A second contact piece 32 located inside the connecting cylinder 12 is installed on one end of the first extension rod 21. A first contact piece 31 flush with the second contact piece 32 is installed on the inner wall of the connecting cylinder 12. A piston cylinder 25 is provided at the bottom of the telescopic cylinder 28. A piston rod 26 extending to the outside of the piston cylinder 25 is inserted into the inside of the piston cylinder 25. One end of the piston rod 26 is connected to the bottom of the push block 29. A solenoid valve 27 is installed at the end of the piston cylinder 25 away from the piston rod 26. A water tank 6 located on one side of the positioning frame 4 is installed on the top of the base 1. A connecting pipe 18 extending to the inside of the water tank 6 is provided at one end of the solenoid valve 27.

[0026] The first contact 31 is electrically connected to an external power source via a wire, and the second contact 32 is electrically connected to the solenoid valve 27 via a wire. The furthest distance between the first contact 31 and the second contact 32 is equal to the extendable length of the telescopic cylinder 28. The internal volume of the water tank 6 is greater than the internal volume of the piston cylinder 25.

[0027] In this embodiment: when the push block 29 moves relative to the positioning frame 4, it will drive the piston rod 26 to move. At this time, the piston rod 26 will move relative to the piston cylinder 25. When the piston rod 26 moves away from the piston cylinder 25, the solution inside the water tank 6 will enter the piston cylinder 25 under the action of negative pressure. When the piston rod 26 moves towards the piston cylinder 25, the solution inside the piston cylinder 25 will enter the water tank 6 through the connecting pipe 18 under the compression of the piston rod 26. When the telescopic cylinder 28 is fully extended, the second contact piece 32 contacts the first contact piece 31. At this time, the solenoid valve 27 is energized and closed, so that the solution inside the piston cylinder 25 loses its flow space. At this time, the piston rod 26 cannot move relative to the piston cylinder 25, thereby fixing the moved push block 29, thereby improving the stability of the positioning stage 5 in the tilted state.

[0028] The following describes a method for detecting defects in printed circuit boards, based on the aforementioned equipment, and includes the following steps: S1: First, place the circuit board to be tested on the top of the positioning stage 5, and then fix and limit the circuit board by the operation of the positioning stage 5. S2: Start the vision detector 3. The top of the circuit board is detected by the operation of the vision detector 3. At this time, the view captured by the vision detector 3 is a top view of the circuit board. S3: Rotate the worm gear 19, which in turn causes the worm wheel 8 to rotate. The worm wheel 8 then rotates the second limit pin 15 via the positioning plate 17, allowing the second limit pin 15 to rotate along the center of the annular protractor 9. Adjusting the position of the second limit pin 15 limits the maximum swing angle of the indicator 11. Activate the telescopic cylinder 28, which extends the second extension rod 30 horizontally. The partition plate 22 moves the push block 29 via the telescopic spring 23. The push block 29 moves synchronously with the second extension rod 30. During this process, the movable pin 24 moves the support shaft 13 via the straight groove guide rail 20, causing it to swing. Simultaneously, the indicator 11 separates from the first limit pin 10, and the support shaft 13 causes the positioning table 5 to swing, tilting it. When the indicator 11 contacts the second limit pin 15, the support shaft 13 cannot rotate, and the telescopic cylinder 28 continues to extend. The extension rod 30 moves relative to the push block 29, and the telescopic spring 23 extends, thus adjusting the tilt angle of the circuit board. When the push block 29 moves relative to the positioning frame 4, it drives the piston rod 26 to move. At this time, the piston rod 26 moves relative to the piston cylinder 25. When the piston rod 26 moves away from the piston cylinder 25, the solution inside the water tank 6 enters the piston cylinder 25 under negative pressure. When the piston rod 26 moves towards the piston cylinder 25, the solution inside the piston cylinder 25 enters the water tank 6 through the connecting pipe 18 under the pressure of the piston rod 26. When the telescopic cylinder 28 is fully extended, the second contact piece 32 contacts the first contact piece 31. At this time, the solenoid valve 27 is energized and closed, thus depriving the solution inside the piston cylinder 25 of flow space. At this time, the piston rod 26 cannot move relative to the piston cylinder 25, thereby fixing the moved push block 29 and improving the stability of the positioning stage 5 in the tilted state. S4: Start motor 16. The operation of motor 16 causes positioning stage 5 to rotate relative to U-shaped frame 14. This allows the circuit board to rotate intermittently when tilted, thus enabling detection of the top of the circuit board from different angles and exposing the originally obscured blind area to the shooting range of visual detector 3.

[0029] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A device for detecting defects in circuit boards, comprising a base (1), characterized in that, Support frames (2) are installed on both sides of the base (1). A visual detector (3) is installed on the top of the support frame (2). A positioning frame (4) is installed on the top of the base (1). An angle adjustment connector is provided on the inner side of the positioning frame (4). A positioning platform (5) located above the positioning frame (4) is connected to the inner side of the positioning frame (4) through the angle adjustment connector. The positioning platform (5) is located between the positioning frame (4) and the visual detector (3). The angle adjustment connector includes a support shaft (13) installed inside the positioning frame (4). Both ends of the support shaft (13) are rotatably connected to the positioning frame (4) via bearings. A U-shaped frame (14) is installed on the top of the support shaft (13). A motor (16) is provided inside the U-shaped frame (14). The output end of the motor (16) is connected to a positioning platform (5) located above the U-shaped frame (14).

2. The equipment for detecting defects in circuit boards according to claim 1, characterized in that, The angle-adjusting connector also includes a straight groove guide rail (20) installed at the bottom of the support shaft (13) and located inside the positioning frame (4). A telescopic cylinder (28) is installed on one side of the positioning frame (4). The output end of the telescopic cylinder (28) is connected to a second extension rod (30) located inside the positioning frame (4). A movable pin (24) is slidably connected to the inner side of the straight groove guide rail (20). A push block (29) is fixedly connected to one end of the movable pin (24). The second extension rod (30) passes through the push block (29). A partition plate (22) is fixedly connected to the end of the second extension rod (30) away from the telescopic cylinder (28). A telescopic spring (23) connected to the push block (29) and located outside the second extension rod (30) is provided at one end of the partition plate (22). One end of the positioning frame (4) is equipped with a ring protractor (9). The outer side of the ring protractor (9) is rotatably connected to an outer ring (7) via a bearing. The outer wall of the outer ring (7) is provided with a positioning plate (33). A worm gear (8) is provided on one side of the positioning plate (33). One end of the visual detector (3) is connected to an indicator (11) located on one side of the ring protractor (9). One end of the ring protractor (9) is provided with a first limiting pin (10) that fits against the indicator (11). One end of the worm gear (8) is connected to a positioning plate (17). A second limiting pin (15) is provided on one side of the positioning plate (17). One end of the positioning frame (4) is provided with a worm (19) that meshes with the worm gear (8). Locking units are provided on both sides of the positioning frame (4).

3. The equipment for detecting defects in circuit boards according to claim 2, characterized in that, The center of the annular protractor (9) and the center of the supporting shaft (13) are coaxial, and the center of the worm gear (8) and the center of the annular protractor (9) are coaxial.

4. The equipment for detecting defects in circuit boards according to claim 2, characterized in that, The distance from the center of the first limiting pin (10) to the center of the annular protractor (9) is equal to the distance from the center of the second limiting pin (15) to the center of the annular protractor (9).

5. The equipment for detecting defects in circuit boards according to claim 2, characterized in that, The diameter of the movable pin (24) is equal to the inner width of the straight groove guide rail (20), and the inner side of the push block (29) is provided with a through hole that matches the second extension rod (30).

6. The equipment for detecting defects in circuit boards according to claim 2, characterized in that, The locking unit includes a first extension rod (21) installed on the end of the partition (22) away from the second extension rod (30). A connecting cylinder (12) is installed on the side of the positioning frame (4) away from the telescopic cylinder (28). One end of the first extension rod (21) extends to the inside of the connecting cylinder (12). A second contact piece (32) located inside the connecting cylinder (12) is installed on one end of the first extension rod (21). A first contact piece (31) flush with the second contact piece (32) is installed on the inner wall of the connecting cylinder (12). A piston cylinder (25) is provided at the bottom of the compression cylinder (28). A piston rod (26) extending to the outside of the piston cylinder (25) is inserted into the inner side of the piston cylinder (25). One end of the piston rod (26) is connected to the bottom of the push block (29). A solenoid valve (27) is installed at the end of the piston cylinder (25) away from the piston rod (26). A water tank (6) located on one side of the positioning frame (4) is installed on the top of the base (1). A connecting pipe (18) extending to the inside of the water tank (6) is provided at one end of the solenoid valve (27).

7. The equipment for detecting defects in circuit boards according to claim 6, characterized in that, The first contact (31) is electrically connected to an external power supply via a wire, and the second contact (32) is electrically connected to the solenoid valve (27) via a wire.

8. The equipment for detecting defects in circuit boards according to claim 6, characterized in that, The furthest distance between the first contact piece (31) and the second contact piece (32) is equal to the extendable length of the telescopic cylinder (28).

9. The equipment for detecting defects in circuit boards according to claim 6, characterized in that, The internal volume of the water tank (6) is greater than the internal volume of the piston cylinder (25).

10. A method for detecting defects in a circuit board, characterized in that, The equipment for detecting defects in circuit boards according to any one of claims 1-9 includes the following steps: S1: First, place the circuit board to be tested on the top of the positioning table (5), and then fix and limit the circuit board by the operation of the positioning table (5). S2: Start the visual detector (3) to detect the top of the circuit board. At this time, the view captured by the visual detector (3) is a top view of the circuit board. S3: The operation of the angle adjustment connector is used to adjust the tilt angle of the positioning platform (5), so that the positioning platform (5) is tilted relative to the top of the positioning frame (4). At this time, the visual detector (3) can take pictures and detect the circuit board in the tilted state from above. S4: Start the motor (16) and rotate the positioning stage (5) relative to the U-shaped frame (14) by the operation of the motor (16). This allows the circuit board to rotate intermittently when it is tilted, so that the top of the circuit board can be detected from different angles, exposing the originally blocked blind area to the shooting range of the visual detector (3).

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