A double-sided AOI detection device for circuit board production and a detection method thereof

Abstract

The application discloses a double-sided AOI detection equipment and method for circuit board production, and belongs to the technical field of optical detection of circuit boards. The equipment comprises a main body frame, an optical imaging system, a feeding conveying mechanism and a material returning conveying mechanism arranged side by side along the front and back of the main body frame, a circuit board positioning mechanism arranged at the head of the feeding conveying mechanism and used for pre-fixing one side of the edge of the circuit board and adjusting the circuit board from an inclined state to a horizontal state, and a turnover mechanism arranged between the tail end of the feeding conveying mechanism and the head end of the material returning conveying mechanism and used for turning over the circuit board after front face detection and transferring the circuit board to the material returning conveying mechanism. The application realizes automatic alignment of the circuit board through an inclined gravity positioning mechanism, reduces the operation threshold, realizes lightweight turnover through the parallel layout of the double conveying belts and the single-side positioning turnover mechanism, avoids the structural complexity of the overall turnover plate, ensures the stability of the circuit board through horizontal posture detection, and has the advantages of simple structure, convenient operation and controllable cost.

Description

Technical Field

[0001] This invention belongs to the field of automatic optical inspection (AOI) technology for circuit boards, and particularly relates to a double-sided AOI inspection device and its inspection method for circuit board production. Background Technology

[0002] Automated Optical Inspection (AOI) is a widely used circuit board quality inspection technology in the electronics manufacturing industry. It uses an optical imaging system to scan the surface of the circuit board and compare it with a standard image to identify problems such as missing components, misalignment, incorrect polarity, and soldering defects. As electronic components become increasingly miniaturized and high-density, the demand for double-sided inspection of circuit boards is growing.

[0003] Traditional solutions use single-sided AOI equipment, which first inspects one side of the circuit board, then manually or with a robotic arm flips the board over and puts it back into the equipment for inspection of the other side. The disadvantages of this solution are: it requires two feeding operations, resulting in low inspection efficiency; manual flipping can easily cause damage to the circuit board; and it requires additional loading and unloading operations.

[0004] For example, Chinese patent CN201410168813.1 discloses a double-sided inspection device for circuit boards. This solution sets up camera devices and light source components on the upper and lower sides of the circuit board transmission path, respectively, and simultaneously acquires images of both the front and back sides of the circuit board in one transmission. Although this solution solves the flipping problem, the upper and lower light sources of the two independent optical imaging systems need to be staggered and light shields need to be set to prevent optical interference, resulting in a complex structure and high debugging difficulty.

[0005] For example, Chinese patent CN202511714524.1 discloses a double-sided inspection device for circuit boards. This solution uses two sets of conveyor belts to clamp the edges of the circuit board, allowing it to pass through recognition cameras on both sides in an upright position, thus achieving simultaneous double-sided inspection. The drawbacks of this solution are: when the circuit board is transported in an upright position, larger components are prone to displacement or detachment due to gravity, making it particularly unsuitable for inspection processes before reflow soldering; furthermore, vertical transport is highly sensitive to board warping, posing a risk of board jamming.

[0006] In addition, the feeding methods for circuit boards into the testing equipment in the above-mentioned prior art generally have the following problems: operators need to place the circuit boards precisely on the conveyor belt or positioning mechanism, which requires high operator skills; even a slight deviation in the placement position may cause the circuit board to be misaligned with the conveyor belt, resulting in jamming or deviation of the testing area. Summary of the Invention

[0007] The purpose of this invention is to solve the technical problems of inconvenient feeding operation, complex flipping mechanism, high equipment cost or insufficient detection reliability in the prior art, and to propose a double-sided AOI inspection equipment and its inspection method for circuit board production.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a double-sided AOI inspection device for circuit board production, comprising a main frame, an optical imaging system disposed within the main frame for acquiring circuit board information, and a feeding conveyor mechanism and a return conveyor mechanism for transmitting the circuit board. The feeding conveyor mechanism and the return conveyor mechanism are arranged side by side along the front and rear of the main frame. A circuit board positioning mechanism is provided at the mounting position at the front end of the feeding conveyor mechanism. An installation notch is provided between the unloading position at the rear end of the feeding conveyor mechanism and the mounting position at the front end of the return conveyor mechanism. A flipping mechanism is provided at the aforementioned position. The circuit board positioning mechanism is used to pre-fix one side of the edge of the circuit board and adjust the circuit board from an inclined state to a horizontal state to adapt it to the feeding conveyor mechanism. The flipping mechanism flips the circuit board after the front-side inspection is completed and transfers it from the feeding conveyor mechanism to the return conveyor mechanism.

[0009] As a further description of the above technical solution: the feeding and conveying mechanism and the return material conveying mechanism have the same structure, both including two mounting plates symmetrically arranged front and back, a synchronous wheel set on the mounting plate and a synchronous belt wound around the synchronous wheel. The synchronous belt is used to convey the circuit board, and multiple actuating blocks are evenly spaced along the length direction of the synchronous belt. The distance between two adjacent actuating blocks is greater than the length of the circuit board along the conveying direction.

[0010] As a further description of the above technical solution: a drive motor is provided on the rear mounting plate of the feeding and conveying mechanism, and the output shaft of the drive motor is coaxially and fixedly connected to the rotating shaft of the synchronous wheel on the feeding and conveying mechanism; the rotating shaft of the synchronous wheel on the feeding and conveying mechanism and the rotating shaft of the synchronous wheel on the return material conveying mechanism are connected by a gear set, and the gear set is mounted on the main frame.

[0011] As a further description of the above technical solution: a limiting strip is provided on the mounting plate, the limiting strip is located above the synchronous belt, and the limiting strip extends along the conveying path between the mounting position and the unloading position of the feeding conveyor or the return conveyor, for limiting the upper part of the circuit board.

[0012] As a further description of the above technical solution: the end of the limiting strip on the mounting plate of the feeding / returning conveyor mechanism is provided with a side guide arc plate and an end guide arc plate, which are used to guide the circuit board into the conveying channel between the limiting strip and the synchronous belt.

[0013] As a further description of the above technical solution: the front mounting plate of the feeding conveying mechanism is provided with an arc-shaped guide side plate at the position corresponding to the mounting position, and the front mounting plate of the return material conveying mechanism is also provided with an arc-shaped guide side plate at the position corresponding to the mounting position.

[0014] As a further description of the above technical solution: the circuit board positioning mechanism includes a first mounting base, a fixed clamping plate, and a movable clamping plate. The first mounting base is provided with ear plates at both ends. The ear plates are rotatably mounted on the rear mounting plate. A torsion spring is provided at the rotation axis of the ear plates. The fixed clamping plate is fixedly mounted on the side of the first mounting base facing the mounting position. The first mounting base is provided with mounting holes along the front-back direction. The movable clamping plate slides back and forth through the mounting holes. The movable clamping plate is located below the fixed clamping plate. A support rod is provided between the two ear plates, the support rod is located behind the first mounting base, a guide rod is provided between the first mounting base and the support rod, a positioning plate is provided at the end of the movable clamp away from the mounting position, the positioning plate slides through the guide rod, a spring is sleeved on the guide rod, and the spring abuts between the positioning plate and the support rod; The ear plate is provided with a guide hole, and the end face of the positioning plate is provided with an L-shaped rod. The L-shaped rod slides through the guide hole, and the two L-shaped rods are connected by a toggle shaft. The rear mounting plate is provided with an electric push rod, and the output end of the electric push rod is provided with a drive block. The drive block is corresponding to the toggle shaft. When the drive block moves upward, it drives the toggle shaft to move the positioning plate and the movable clamping plate away from the mounting position and compress the spring. A distance sensor is installed below the mounting position to detect the distance between the sensor and the circuit board.

[0015] As a further description of the above technical solution: the flipping mechanism includes a second mounting base, a servo motor, and two U-shaped limiting seats. The second mounting base is fixedly disposed between the unloading position of the feeding conveying mechanism and the mounting position of the return conveying mechanism. The servo motor is fixedly mounted on the second mounting base. The two U-shaped limiting seats are fixedly disposed on the output shaft of the servo motor, and the two U-shaped limiting seats are symmetrically arranged about the output shaft of the servo motor. A guide plate is provided at one end of the U-shaped limiting seat facing the mounting position of the feeding conveying mechanism.

[0016] As a further description of the above technical solution: The optical imaging system is also equipped with a counter at the position corresponding to the feeding conveyor and the return conveyor. The optical imaging system counts the objects being photographed and is also equipped with an alarm. The counter records the circuit boards with defects. When the circuit board with defects moves to the unloading position of the return conveyor, the alarm sounds.

[0017] A method for inspecting a double-sided AOI inspection device for circuit board manufacturing, using the aforementioned double-sided AOI inspection device for circuit board manufacturing, includes the following steps: Step S1: Place the circuit board to be tested on the circuit board positioning mechanism. The circuit board positioning mechanism pre-fixes one side of the edge of the circuit board. Under the action of gravity, the circuit board automatically adjusts from an inclined state to a horizontal state. Step S2: The circuit board positioning mechanism releases the restriction on the lower part of the circuit board, allowing the circuit board to fall into the mounting position at the beginning of the feeding and conveying mechanism, with the two side edges of the circuit board being engaged with the feeding and conveying mechanism. Step S3: The feeding and conveying mechanism transports the circuit board from the mounting position to the detection area of ​​the optical imaging system, and the optical imaging system performs image acquisition and defect detection on the front side of the circuit board; Step S4: After completing the front detection, the feeding and conveying mechanism transports the circuit board to the unloading position at its tail end; Step S5: The flipping mechanism positions one side of the circuit board located at the unloading position and flips the circuit board 180° so that the reverse side of the circuit board faces upward. Step S6: The flipping mechanism transfers the flipped circuit board to the mounting position at the beginning of the return material conveying mechanism, and the side edge of the circuit board away from the flipping mechanism is embedded in the return material conveying mechanism; Step S7: The return material conveying mechanism transports the circuit board from the mounting position to the detection area of ​​the optical imaging system, and the optical imaging system performs image acquisition and defect detection on the reverse side of the circuit board; Step S8: After the reverse side inspection is completed, the return material conveying mechanism conveys the circuit board to the discharge end.

[0018] In summary, due to the adoption of the above technical solutions, the beneficial effects of this invention are as follows: 1. By setting up an inclined gravity positioning mechanism (circuit board positioning mechanism), the operator only needs to place the edge of the circuit board between the fixed clamping plate and the movable clamping plate, and the circuit board will automatically adjust from an inclined state to a horizontal state under the action of gravity, achieving "positioning with a single touch". Combined with the automatic feeding mechanism controlled by a distance sensor and an electric push rod, the "placement → positioning → feeding" process is fully automated, requiring no secondary manual intervention. This avoids the risk of misalignment or jamming that may occur with manual board placement, significantly reduces the skill requirements for operators, shortens the single feeding time, and improves testing efficiency.

[0019] 2. A dual conveyor belt layout (feeding conveyor and return conveyor) is adopted, with an independent single-sided positioning and flipping mechanism between them. During flipping, only one edge of the circuit board is clamped and flipped, resulting in minimal change in the circuit board's center of gravity and low torque requirements for the servo motor. The U-shaped limit seat is symmetrically arranged about the output shaft, ensuring precise alignment of the circuit board with the mounting position of the return conveyor mechanism after a 180° flip, eliminating the need for secondary positioning. This solution avoids the problems of high load, large space occupation, and high cumulative error of traditional integral flipping mechanisms, and has the advantages of simple structure, reliable operation, and low maintenance cost.

[0020] 3. The circuit board is inspected while maintaining a horizontal posture on both the feeding and return conveying mechanisms, completely avoiding the risk of large components shifting or falling off due to gravity in vertical clamping and conveying schemes. This is especially suitable for inspecting circuit boards containing unsecured components, such as before reflow soldering. Simultaneously, limiting strips restrict movement above the circuit board, and the actuating blocks on the synchronous belt push the circuit board to move, ensuring positional stability and repeatability during transport. This benefits the optical imaging system by providing clear and consistent images.

[0021] 4. The feeding and return conveying mechanisms are connected by a gear set, and can achieve synchronous reverse operation at the same speed by sharing a single drive motor, reducing the hardware cost and control complexity of the drive system. Simultaneously, the two conveyor belts share the same optical imaging system to complete front and back detection in a time-sharing manner, eliminating the need for two independent imaging units and further controlling the overall equipment cost.

[0022] 5. The optical imaging system is equipped with counters at the feeding and return stations, which can record circuit boards with defects on the front or back. When the defective board moves to the discharge station, an alarm will be issued to issue a differentiated alarm (e.g., one alarm for front defects, two alarms for back defects). This facilitates quick sorting by operators and can accurately distinguish between front and back defects, improving the efficiency and accuracy of post-inspection processing.

[0023] 6. By adjusting the spacing of the toggle blocks on the timing belt and the position of the limit strips, it can accommodate circuit boards of different sizes and thicknesses. The equipment has a compact overall structure and is easy to debug, making it especially suitable for small-batch, multi-variety circuit board production lines with frequent line changes. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is another perspective of the three-dimensional structure of the present invention; Figure 3 This is a three-dimensional structural diagram of the circuit board when it is initially installed in the circuit board positioning mechanism during the operation of the present invention. Part of the main frame structure is not shown. Figure 4 This is a three-dimensional structural diagram of the circuit board being positioned from the circuit board positioning mechanism to the feeding and conveying mechanism in the working state of the present invention. Figure 5 This is a three-dimensional structural diagram of the present invention, showing the circuit board mounted on the circuit board positioning mechanism and the flipping mechanism flipping another circuit board in the working state. Figure 6 This is an exploded structural diagram of the flipping mechanism, feeding and conveying mechanism, and return material conveying mechanism of the present invention; Figure 7 for Figure 6 Enlarged view of point A in the middle; Figure 8 This is a schematic diagram of the internal structure of the main frame of the present invention. The optical imaging system is not shown, and the limiting strip and the feeding / returning conveyor are in an exploded state. Figure 9 for Figure 8 Enlarged view at point B in the middle; Figure 10 for Figure 8 Enlarged view at point C; Figure 11 For the present invention Figure 10 The cross-sectional view of the circuit board positioning mechanism shows the state of the circuit board at the moment it is placed in the mounting position; Figure 12 This is a three-dimensional structural diagram of the circuit board positioning mechanism of the present invention in the state where the circuit board is not clamped. Figure 13 for Figure 12 Sectional view in; Figure 14 This is a schematic diagram of the flipping mechanism of the present invention.

[0025] Legend: 100. Circuit board; 1. Main frame; 2. Optical imaging system; 3. Feeding and conveying mechanism; 31. Mounting plate; 32. Synchronous pulley; 33. Synchronous belt; 34. Actuating block; 35. Drive motor; 36. Limiting strip; 361. Side guide arc plate; 362. End face guide arc plate; 363. Arc-shaped guide side plate; 37. Mounting position; 38. Unloading position; 39. Mounting notch. 4. Return material conveying mechanism; 5. Circuit board positioning mechanism; 51. First mounting base; 511. Mounting hole; 52. Fixed clamping plate; 53. Movable clamping plate; 54. Ear plate; 541. Guide hole; 55. Support rod; 56. Guide rod; 57. Positioning plate; 58. Spring; 59. L-shaped rod; 591. Actuating shaft; 6. Electric push rod; 7. Drive block; 8. Tilting mechanism; 81. Second mounting base; 82. Servo motor; 83. U-shaped limit seat; 831. Guide plate. Detailed Implementation

[0026] 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.

[0027] Please see Figure 1-14 The present invention provides a double-sided AOI inspection equipment for circuit board production, including a main frame 1, an optical imaging system 2 disposed in the main frame 1 to collect information of the circuit board 100, and a feeding conveying mechanism 3 and a return conveying mechanism 4 for transmitting the circuit board 100.

[0028] Reference Figure 3 and Figure 5 The optical imaging system 2 is fixedly installed inside the upper part of the main frame 1. The optical imaging system 2 includes an industrial camera, a lens, and a light source assembly. The industrial camera can be a linear CCD camera or an area-array CMOS camera, the lens can be a fixed-focus or zoom lens, and the light source assembly can be a ring LED light source or a coaxial light source, used to provide uniform illumination to the surface of the circuit board 100. The optical imaging system 2 is used for image acquisition and defect detection on the surface of the circuit board 100, and its specific structure can adopt an AOI imaging system known in the art, which will not be described in detail here.

[0029] The feeding conveyor 3 and the return conveyor 4 are arranged side by side along the front and rear direction of the main frame 1. The feeding conveyor 3 is used to convey the circuit board 100 to be inspected from the feeding end to the detection area of ​​the optical imaging system 2 to complete the front detection, and then convey the inspected circuit board 100 to the unloading position 38; the return conveyor 4 is used to convey the flipped circuit board 100 back to the detection area of ​​the optical imaging system 2 to complete the reverse detection, and then convey the circuit board 100 that has completed double-sided detection to the discharge end.

[0030] Specifically, the optical imaging system 2 can simultaneously capture images of the front of one circuit board 100 located below it and the back of another circuit board 100.

[0031] The optical imaging system 2 is also equipped with a counter at the position corresponding to the feeding conveyor 3 and the return conveyor 4. The optical imaging system 2 counts the objects being photographed and is also equipped with an alarm. The counter records the circuit boards 100 with defects. When the defective circuit board 100 moves to the unloading position 38 of the return conveyor 4, the alarm sounds to indicate that the circuit board 100 is defective. It can be set that one alarm sound indicates that there is a defect on the front of the circuit board 100, and two alarm sounds indicate that there is a defect on the back of the circuit board 100.

[0032] In this embodiment, when the first circuit board 100 moves from the mounting position 37 of the feeding conveyor 3 to directly below the optical imaging system 2, the optical imaging system 2 acquires a front image of the first circuit board 100 and detects the front of the circuit board 100. Since there is no circuit board 100 at the position directly below the return conveyor 4, the area acquired is a blank image. When the first circuit board moves to directly below the return conveyor 4, the optical imaging system 2 acquires a back image of the first circuit board 100 directly below the return conveyor 4, and simultaneously acquires a front image of the ninth circuit board 100 directly below the feeding conveyor 3. At this time, the optical imaging system 2 can simultaneously detect the back of the first circuit board 100 and the front of the ninth circuit board.

[0033] A circuit board positioning mechanism 5 is provided at the mounting position 37 at the first end (i.e., the infeed end) of the feeding and conveying mechanism 3. A flipping mechanism 8 is provided between the unloading position 38 at the tail end (i.e., the discharge end) of the feeding and conveying mechanism 3 and the mounting position 37 at the first end of the return material conveying mechanism 4.

[0034] Reference Figure 3 , Figure 4 and Figure 6In this embodiment, the feeding conveyor mechanism 3 and the return conveyor mechanism 4 have the same structure and are arranged symmetrically front to back. Taking the feeding conveyor mechanism 3 as an example, it includes two mounting plates 31 arranged symmetrically front to back, a synchronous wheel 32 disposed on the mounting plate 31, and a synchronous belt 33 wound around the synchronous wheel 32. Specifically, each mounting plate 31 is provided with a synchronous belt 33, and the cutout between the two synchronous belts 33 is provided to provide non-interfering accommodation space for the components on the circuit board 100. The discharge end of the front mounting plate 31 of the feeding conveyor mechanism 3 is provided with a mounting notch 39, and the length of the synchronous belt 33 disposed thereon is less than that of the synchronous belt 33 on the rear mounting plate 31 of the feeding conveyor mechanism 3, and the length difference is the width of the circuit board 100.

[0035] The timing belt 33 is used to carry and transport the circuit board 100. The surface of the timing belt 33 is provided with a plurality of actuating blocks 34 at equal intervals along its length. The distance between two adjacent actuating blocks 34 is greater than the length of the circuit board 100 along the transport direction, so that the circuit board 100 can be located between two adjacent actuating blocks 34 and the circuit board 100 is pushed forward by the actuating blocks 34.

[0036] Reference Figure 5 and Figure 6 A drive motor 35 is mounted on the rear mounting plate 31 of the feeding and conveying mechanism 3. The output shaft of the drive motor 35 is coaxially and fixedly connected to the rotation shaft of the synchronous wheel 32 on the feeding and conveying mechanism 3, and is used to drive the synchronous wheel 32 to rotate. The rotation shaft of the synchronous wheel 32 on the feeding and conveying mechanism 3 and the rotation shaft of the synchronous wheel 32 on the return material conveying mechanism 4 are connected by a gear set (not shown in the figure), and the gear set is mounted on the main frame 1. Specifically, the rotation shaft of the synchronous wheel 32 on the feeding conveying mechanism 3 and the rotation shaft of the synchronous wheel 32 on the return conveying mechanism 4 are driven by two meshing external gears. That is, the axis of the rotation shaft of the synchronous wheel 32 on the feeding conveying mechanism 3 is parallel to and spaced apart from the axis of the rotation shaft of the synchronous wheel 32 on the return conveying mechanism 4. The two rotation shafts and their corresponding gears are coaxially fixed. With this configuration, only one drive motor 35 is needed to drive the feeding conveying mechanism 3 and the return conveying mechanism 4 to run synchronously. The feeding conveying mechanism 3 and the return conveying mechanism 4 have opposite transmission directions and the same conveying speed. This ensures that the circuit board 100 enters the main frame 1 from the feeding conveying mechanism 3 and is then output from the return conveying mechanism 4, reducing equipment costs and control system complexity.

[0037] A limiting strip 36 is provided on the mounting plate 31. The limiting strip 36 is located above the synchronous belt 33 and extends along the conveying path between the mounting position 37 and the unloading position 38 of the feeding and conveying mechanism 3. The limiting strip 36 is used to limit the upper part of the circuit board 100 to prevent the circuit board 100 from tilting or shifting due to vibration during the conveying process, and to ensure that the circuit board 100 passes smoothly through the detection area of ​​the optical imaging system 2.

[0038] The feeding conveying mechanism 3 has a side guide arc plate 361 and an end guide arc plate 362 at the end of the limiting strip 36 facing the mounting position 37. The return conveying mechanism 4 has an end guide arc plate 362 at the end of the limiting strip 36 facing the mounting position 37. The side guide arc plate 361 is used to guide the side edge of the circuit board 100 into the conveying channel, and the end guide arc plate 362 is used to guide the front end of the circuit board 100 into the space below the limiting strip 36, so as to avoid the circuit board 100 colliding with the limiting strip 36 during feeding.

[0039] The front mounting plate 31 of the feeding conveying mechanism 3 is provided with an arc-shaped guide side plate 363 at the mounting position 37, and the front mounting plate 31 of the return conveying mechanism 4 is also provided with an arc-shaped guide side plate 363 at the mounting position 37. The arc-shaped guide side plate 363 is used to guide the side of the circuit board 100 when it falls into the mounting position 37, ensuring that the circuit board 100 is accurately embedded between the two limiting strips 36.

[0040] Reference Figures 10-13 The circuit board positioning mechanism 5 includes a first mounting base 51, a fixed clamping plate 52, and a movable clamping plate 53. Ear plates 54 are provided at both ends of the first mounting base 51, and the ear plates 54 are rotatably mounted on the rear mounting plate 31 of the feeding and conveying mechanism 3. A torsion spring (not shown in the figure) is provided at the rotation axis of the ear plates 54, and the torsion spring is used to maintain the first mounting base 51 in an inclined posture in the initial state (e.g., Figure 2 (As shown).

[0041] like Figure 11 and Figure 13 As shown, the fixed clamping plate 52 is fixedly disposed on the side of the first mounting base 51 facing the mounting position 37. The first mounting base 51 has a mounting hole 511 in the front-back direction, and the movable clamping plate 53 slides through the mounting hole 511. The movable clamping plate 53 is located below the fixed clamping plate 52, and a clamping gap is formed between the two for clamping the edge of the circuit board 100.

[0042] A support rod 55 is provided between the two ear plates 54, and the support rod 55 is located behind the first mounting base 51. A guide rod 56 is provided between the first mounting base 51 and the support rod 55. A positioning plate 57 is provided at the end of the movable clamping plate 53 away from the mounting position 37, and the positioning plate 57 slides through the guide rod 56. A spring 58 is sleeved on the guide rod 56, and the spring 58 abuts against the positioning plate 57 and the support rod 55.

[0043] A guide hole 541 is provided on the ear plate 54. An L-shaped rod 59 is provided on the end face of the positioning plate 57, and the L-shaped rod 59 slides through the guide hole 541. The two L-shaped rods 59 are connected by a toggle shaft 591. An electric push rod 6 is provided on the rear mounting plate 31, and a drive block 7 is provided at the output end of the electric push rod 6. The drive block 7 corresponds to the toggle shaft 591. Specifically, the drive slope of the drive block 7 corresponds to the toggle shaft 591. When the toggle shaft 591 rotates with the ear plate 54 under the action of the torsion spring, the toggle shaft 591 and the drive block 7 do not interfere with each other.

[0044] When the drive block 7 moves upward, the drive block 7 pushes the actuating shaft 591 to move upward. The actuating shaft 591 drives the positioning plate 57 and the movable clamping plate 53 to move away from the mounting position 37 through the L-shaped rod 59, thereby compressing the spring 58 and causing the movable clamping plate 53 to slide away from the circuit board 100, thus releasing the restriction on the lower part of the circuit board 100.

[0045] A distance sensor (not shown in the figure) is installed below the mounting position 37 to detect the distance between itself and the circuit board 100, thereby determining whether the circuit board 100 has been adjusted to a horizontal position. The distance sensor can be an infrared distance sensor or a laser displacement sensor.

[0046] When the circuit board 100 to be tested is in a horizontal position, the circuit board positioning mechanism 5 cannot continue to rotate due to the limitation imposed by the side of the lower surface of the ear plate 54.

[0047] Please refer to Figure 6 and Figure 14The flipping mechanism 8 includes a second mounting base 81, a servo motor 82, and two U-shaped limiting seats 83. The flipping mechanism 8 is installed in the mounting notch 39 between the unloading position 38 of the feeding conveyor 3 and the mounting position 37 of the return conveyor 4, ensuring that the flipping mechanism 8 does not interfere with rotation. The second mounting base 81 is fixedly positioned between the unloading position 38 of the feeding conveyor 3 and the mounting position 37 of the return conveyor 4. The servo motor 82 is fixedly mounted on the second mounting base 81. The two U-shaped limiting seats 83 are fixedly positioned on the output shaft of the servo motor 82, and are symmetrically arranged about the front and rear of the output shaft of the servo motor 82. A guide plate 831 is provided at the end of the U-shaped limiting seat 83 facing the feeding conveyor 3 to guide the edge of the circuit board 100 into the interior of the U-shaped limiting seat 83.

[0048] Working principle: The working process of the circuit board double-sided inspection equipment provided in this embodiment is as follows: (a) Feeding and positioning stage The operator places the circuit board 100 to be tested onto the circuit board positioning mechanism 5, positioning one edge of the circuit board 100 between the fixed clamping plate 52 and the movable clamping plate 53. The movable clamping plate 53 and the fixed clamping plate 52 limit the edge of the circuit board 100, achieving pre-fixation of the edge of the circuit board 100. Before placing the circuit board 100, the first mounting base 51 is kept in an inclined state under the action of the torsion spring. After the circuit board 100 is placed, under its own weight, the circuit board 100 drives the first mounting base 51 to rotate downward against the elastic force of the torsion spring until the circuit board 100 is in a horizontal state. During this process, the feeding conveyor mechanism 3 and the return conveyor mechanism 4 are both kept in an intermittent stopped state.

[0049] When the distance sensor detects that the circuit board 100 has been adjusted to a horizontal position, the controller controls the electric push rod 6 to move. The drive block 7 of the electric push rod 6 moves upward and pushes the actuating shaft 591. The actuating shaft 591 drives the positioning plate 57 and the movable clamping plate 53 to move backward through the L-shaped rod 59, causing the movable clamping plate 53 to be pulled away from the bottom of the circuit board 100, releasing the clamping of the circuit board 100. Under the action of gravity, the circuit board 100 falls into the mounting position 37 of the feeding and conveying mechanism 3. Guided by the arc-shaped guide side plate 363, the front and rear edges of the circuit board 100 are located between the arc-shaped guide side plate 363 and the first mounting seat 51. Subsequently, the distance sensor detects that the distance to the circuit board 100 has decreased, and the controller controls the electric push rod 6 to reset. Under the action of the torsion spring and the spring 58, the circuit board positioning mechanism 5 returns to the tilted state to await the installation of the next circuit board 100 to be tested.

[0050] (II) Frontal Inspection Phase Subsequently, the drive motor 35 starts, driving the synchronous belt 33 of the feeding and conveying mechanism 3 to run, and the actuating block 34 pushes the circuit board 100 forward. The circuit board 100 is guided by the side guide arc plate 361 and the end face guide arc plate 362 into the area below the limiting strip 36. The limiting strip 36 limits the upper part of the circuit board 100 to prevent the circuit board 100 from tilting. The circuit board 100 smoothly enters the detection area of ​​the optical imaging system 2, and the optical imaging system 2 performs image acquisition and defect detection on the front of the circuit board 100. Then it continues to move to the unloading position 38 at the rear end of the feeding and conveying mechanism 3. During this process, when the forward side of the circuit board 100 enters the unloading position, its lower end is no longer supported by the shorter stroke synchronous belt 33 on the feeding and conveying mechanism 3, but enters the U-shaped limiting seat of the flipping mechanism 8.

[0051] (III) Flipping Phase After the front-side inspection is completed, the feeding conveyor 3 continues to convey the circuit board 100 to its unloading position 38 at the end. During this process, the synchronous belts of the feeding conveyor 3 and the return conveyor 4 intermittently drive the circuit board 100 to move, and each movement distance is the width of one circuit board. At the same time as the movement stops, the flipping mechanism flips 180 degrees, transferring the circuit board 100 located at the unloading position 38 of the feeding conveyor 3 to the mounting position 37 on the return conveyor 4. During the flipping process, the circuit board 100 positioned in the U-shaped limiting seat 83 corresponding to the unloading position 38 of the feeding conveying mechanism 3 flips upward to a vertical state and then flips downward to a horizontal state at the mounting position on the return conveying mechanism 4. During this process, the arc-shaped guide side plate 363 on the return conveying mechanism 4 guides and limits the end of the circuit board 100 away from the U-shaped limiting seat 83. At the same time, the U-shaped limiting seat 83 corresponding to the mounting position 37 on the return conveying mechanism 4 rotates downward to a vertical state and then rotates to a horizontal state corresponding to the unloading position 38 of the feeding conveying mechanism 3.

[0052] (iv) Reverse inspection stage After the flipping is completed, the servo motor 82 stops rotating, and the U-shaped limit seat 83 is aligned with the mounting position 37 of the return material conveying mechanism 4. Guided by the arc-shaped guide side plate 363, the edge of the circuit board 100 away from the flipping mechanism 8 is engaged between two adjacent toggle blocks 34 of the return material conveying mechanism 4.

[0053] Driven by the drive motor 35, the return material conveying mechanism 4 operates synchronously, conveying the circuit board 100 from the mounting position 37 to the detection area of ​​the optical imaging system 2. The optical imaging system 2 performs image acquisition and defect detection on the reverse side of the circuit board 100. During this process, the agitator block 34 on the synchronous belt 33 on the mounting plate 31 at the front of the return material conveying mechanism 4 pushes the circuit board 100. During the pushing process, the edge of the circuit board 100 located on one side of the U-shaped limiting seat 83 is supported by the U-shaped limiting seat 83 and slides along it. Only after it is completely separated from the U-shaped limiting seat 83 can the agitator block 34 on the two synchronous belts 33 on the return material conveying mechanism 4 synchronously push the circuit board 100.

[0054] After the reverse side inspection is completed, the return material conveying mechanism 4 transports the circuit board 100 to the discharge end, completing the entire double-sided inspection process.

[0055] It should be noted that the drive motor 35 in this embodiment adopts an intermittent working mode: when no circuit board 100 is accurately positioned at the mounting position 37 of the feeding conveyor mechanism 3, the drive motor 35 stops working, and the synchronous belt 33 stops conveying; when the circuit board 100 falls into the mounting position 37 and is located between two adjacent toggle blocks 34, the drive motor 35 starts, driving the circuit board 100 to move one station (i.e., the distance between two adjacent toggle blocks 34 along the conveying direction), and then the drive motor 35 stops again, waiting for the next circuit board 100 to be positioned. During the interval when the drive motor 35 stops working, the servo motor 82 of the flipping mechanism 8 starts, completing a 180° flipping action.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention, and all such substitutions or changes should be covered within the scope of protection of the present invention.

Claims

1. A double-sided AOI inspection device for circuit board production, comprising a main frame (1), an optical imaging system (2) disposed within the main frame (1) for acquiring information of circuit boards (100), and a feeding conveyor mechanism (3) and a return conveyor mechanism (4) for transmitting the circuit boards (100), characterized in that: The feeding conveyor (3) and the return conveyor (4) are arranged side by side along the main frame (1). The mounting position (37) at the beginning of the feeding conveyor (3) is provided with a circuit board positioning mechanism (5). The unloading position (38) at the end of the feeding conveyor (3) and the mounting position (37) at the beginning of the return conveyor (4) are provided with a mounting notch (39). A flipping mechanism (8) is provided at the position. The circuit board positioning mechanism (5) is used to pre-fix one side of the edge of the circuit board (100) and adjust the circuit board (100) from the inclined state to the horizontal state to adapt to the feeding conveyor (3). The flipping mechanism (8) flips the circuit board (100) after the front detection is completed and transfers it from the feeding conveyor (3) to the return conveyor (4).

2. The testing equipment according to claim 1, characterized in that: The feeding and conveying mechanism (3) has the same structure as the return material conveying mechanism (4), both including two mounting plates (31) arranged symmetrically front and rear, a synchronous wheel (32) set on the mounting plate (31), and a synchronous belt (33) wound around the synchronous wheel (32). The synchronous belt (33) is used to convey the circuit board (100). Multiple actuating blocks (34) are evenly spaced along the length direction on the surface of the synchronous belt (33). The distance between two adjacent actuating blocks (34) is greater than the length of the circuit board (100) along the conveying direction.

3. The testing equipment according to claim 2, characterized in that: A drive motor (35) is provided on the rear mounting plate (31) of the feeding and conveying mechanism (3). The output shaft of the drive motor (35) is coaxially and fixedly connected to the rotating shaft of the synchronous wheel (32) on the feeding and conveying mechanism (3). The rotating shaft of the synchronous wheel (32) on the feeding and conveying mechanism (3) and the rotating shaft of the synchronous wheel (32) on the return material conveying mechanism (4) are connected by a gear set. The gear set is installed on the main frame (1).

4. The detection device according to claim 2, characterized in that: The mounting plate (31) is provided with a limiting strip (36), which is located above the synchronous belt (33) and extends along the conveying path between the mounting position (37) and the unloading position (38) of the feeding conveying mechanism (3) or the return conveying mechanism (4) to limit the upper part of the circuit board (100).

5. The detection device according to claim 4, characterized in that: The limiting strip (36) on the mounting plate (31) of the feeding conveying mechanism (3) / returning conveying mechanism (4) is provided with a side guide arc plate (361) and an end guide arc plate (362) facing the mounting position (37), which are used to guide the circuit board (100) into the conveying channel between the limiting strip (36) and the synchronous belt (33).

6. The detection device according to claim 4, characterized in that: The front mounting plate (31) of the feeding conveying mechanism (3) is provided with an arc-shaped guide side plate (363) at the position corresponding to the mounting position (37), and the front mounting plate (31) of the return material conveying mechanism (4) is also provided with an arc-shaped guide side plate (363) at the position corresponding to the mounting position (37).

7. The detection device according to claim 1, characterized in that: The circuit board positioning mechanism (5) includes a first mounting base (51), a fixed clamping plate (52), and a movable clamping plate (53). The first mounting base (51) is provided with ear plates (54) at both ends. The ear plates (54) are rotatably mounted on the rear mounting plate (31). A torsion spring is provided at the rotation axis of the ear plates (54). The fixed clamping plate (52) is fixedly mounted on the side of the first mounting base (51) facing the mounting position (37). The first mounting base (51) is provided with a mounting hole (511) in the front-back direction. The movable clamping plate (53) slides through the mounting hole (511) in the front-back direction. The movable clamping plate (53) is located below the fixed clamping plate (52). A support rod (55) is provided between the two ear plates (54). The support rod (55) is located behind the first mounting base (51). A guide rod (56) is provided between the first mounting base (51) and the support rod (55). A positioning plate (57) is provided at the end of the movable clamp (53) away from the mounting position (37). The positioning plate (57) slides through the guide rod (56). A spring (58) is sleeved on the guide rod (56). The spring (58) abuts against the positioning plate (57) and the support rod (55). The ear plate (54) is provided with a guide hole (541), and the end face of the positioning plate (57) is provided with an L-shaped rod (59). The L-shaped rod (59) slides through the guide hole (541). The two L-shaped rods (59) are connected by a toggle shaft (591). The rear mounting plate (31) is provided with an electric push rod (6). The output end of the electric push rod (6) is provided with a drive block (7). The drive block (7) corresponds to the toggle shaft (591). When the drive block (7) moves upward, it drives the toggle shaft (591) to move the positioning plate (57) and the movable clamping plate (53) away from the mounting position (37) and compress the spring (58). A distance sensor is provided below the mounting position (37) to detect the distance between the sensor and the circuit board (100).

8. The testing equipment according to claim 1, characterized in that: The flipping mechanism (8) includes a second mounting base (81), a servo motor (82), and two U-shaped limiting seats (83). The second mounting base (81) is fixedly disposed between the unloading position (38) of the feeding conveying mechanism (3) and the mounting position (37) of the return conveying mechanism (4). The servo motor (82) is fixedly mounted on the second mounting base (81). The two U-shaped limiting seats (83) are fixedly disposed on the output shaft of the servo motor (82), and the two U-shaped limiting seats (83) are symmetrically arranged about the output shaft of the servo motor (82). A guide plate (831) is provided at one end of the U-shaped limiting seat (83) facing the mounting position (37) of the feeding conveying mechanism (3).

9. The detection device according to claim 1, characterized in that: The optical imaging system (2) is also equipped with a counter at the position corresponding to the feeding conveyor (3) and the return conveyor (4). The optical imaging system (2) counts the objects being photographed and is also equipped with an alarm. The counter records the circuit boards (100) with defects. When the circuit board (100) with defects moves to the unloading position (38) of the return conveyor (4), the alarm sounds.

10. A method for testing a double-sided AOI inspection device for circuit board manufacturing, comprising using the double-sided AOI inspection device for circuit board manufacturing as described in any one of claims 1-9, characterized in that: Includes the following steps: Step S1: Place the circuit board (100) to be tested on the circuit board positioning mechanism (5). The circuit board positioning mechanism (5) pre-fixes one side of the edge of the circuit board (100). Under the action of gravity, the circuit board (100) automatically adjusts from an inclined state to a horizontal state. Step S2: The circuit board positioning mechanism (5) releases the restriction on the lower part of the circuit board (100), so that the circuit board (100) falls into the mounting position (37) at the first end of the feeding and conveying mechanism (3), and the two side edges of the circuit board (100) are embedded in the feeding and conveying mechanism (3). Step S3: The feeding and conveying mechanism (3) transports the circuit board (100) from the mounting position (37) to the detection area of ​​the optical imaging system (2), and the optical imaging system (2) performs image acquisition and defect detection on the front side of the circuit board (100); Step S4: After the front detection is completed, the feeding and conveying mechanism (3) transports the circuit board (100) to the unloading position (38) at its tail end; Step S5: The flipping mechanism (8) positions one side of the edge of the circuit board (100) located at the unloading position (38) and flips the circuit board (100) 180° so that the reverse side of the circuit board (100) faces upward. Step S6: The flipping mechanism (8) transfers the flipped circuit board (100) to the mounting position (37) at the beginning of the return material conveying mechanism (4), and the side edge of the circuit board (100) away from the flipping mechanism (8) is embedded in the return material conveying mechanism (4). Step S7: The return material conveying mechanism (4) conveys the circuit board (100) from the mounting position (37) to the detection area of ​​the optical imaging system (2), and the optical imaging system (2) performs image acquisition and defect detection on the reverse side of the circuit board (100); Step S8: After the reverse side inspection is completed, the return material conveying mechanism (4) conveys the circuit board (100) to the discharge end.

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