AOI equipment that inspects conformal coating on circuit boards through a flip-panel system

Abstract

The invention discloses an AOI device for detecting conformal coating of a circuit board through a flipping system, and relates to the field of PCB production equipment, comprising a machine platform, on which a fixed-track motor bracket and a movable-track moving mechanism are fixedly installed; a flipping mechanism is fixedly installed on both the fixed-track motor bracket and the movable-track moving mechanism, and a flipping frame is driven and connected to the inner side of the flipping mechanism, and a board conveyor is fixedly installed on the flipping frame; the board conveyor comprises a first chain group and a second chain group, the first chain group is arranged above the second chain group, and a circuit board is driven and connected between the first chain group and the second chain group; compared with the prior art, the invention is applicable to the conveying of circuit boards of different widths; the first chain group and the second chain group which are operated synchronously can be used to clamp the circuit board to ensure that no sliding occurs during the conveying of the circuit board; the flipping mechanism on both sides is used to drive the flipping frame to realize the synchronous flipping of two board conveyors, and the stability is high and the load-bearing capacity is strong.

Description

Technical Field

[0001] The present invention relates to the field of PCB production equipment, and in particular to an AOI device for detecting conformal coatings of circuit boards through a board turning system. Background Art

[0002] Under the chemical, vibration, high dust, salt spray, humidity and high temperature environment of industrial sites, PCB may produce corrosion, softening, deformation, mildew and other problems, leading to circuit failure of circuit board. Conformal coating is a specially formulated transparent coating that forms a protective film with three protections (moisture-proof, salt spray-proof and mildew-proof) on the surface of the circuit board, thereby improving the reliability of the circuit board, increasing its safety factor and ensuring its service life.

[0003] At present, the quality inspection of PCB conformal coating mainly relies on manual observation under ultraviolet light. This method is easily affected by the subjective factors of the inspectors and cannot guarantee the efficiency and accuracy of the inspection. At the same time, the inspectors are in an ultraviolet light environment for a long time, which poses a threat to their health. Therefore, it is necessary to design a system that can detect the quality of PCB double-sided conformal coating.

[0004] The prior art (Announcement No.: CN108982539A, Announcement Date: 2018.12.11) discloses a PCB double-sided conformal coating quality inspection system and method, which realizes the automatic inspection of conformal coating quality, and realizes double-sided inspection through a flip module, shortens the assembly line length, and reduces costs; and compared with the manual visual inspection method, it can well eliminate the influence of subjective factors of the inspection personnel, ensuring efficiency and accuracy.

[0005] However, in the above scheme, the distance between the two side tracks inside the equipment cannot be changed, and it can only be applied to circuit boards of a single width. The scope of application is small, and the equipment needs to be customized according to circuit boards of different widths, which is costly. Secondly, the above scheme only transports PCBs through guide rails, without any clamping components, which causes the side of the circuit board to slide on the guide rails easily, thereby affecting the accuracy of automatic detection. Furthermore, it only uses a single-sided flipping mechanism to flip the circuit board. Due to the poor load-bearing capacity of a single flipping mechanism, the equipment will bend and deform to one side after long-term use, which will seriously affect the service life of the equipment. Summary of the invention

[0006] In order to overcome the above-mentioned shortcomings, the present invention provides a technical solution that can solve the above-mentioned problems.

[0007] The AOI equipment for inspecting the conformal coating of circuit boards through a flipping system includes a machine platform, on which a fixed-rail motor bracket and a moving rail mechanism are fixedly installed; a flipping mechanism is fixedly installed on both the fixed-rail motor bracket and the moving rail mechanism, and the two flipping mechanisms operate synchronously with each other. The inner side of the flipping mechanism is driven and connected with a flipping frame, and a board transporter is fixedly installed on the flipping frame.

[0008] Furthermore: the plate conveyors of the front and rear flip frames are symmetrically arranged front and back, the plate conveyors include side plates, a first motor, a first reducer, a first chain group and a second chain group, the side plates are fixedly mounted on the flip frames, the first motors of the two plate conveyors operate synchronously with each other, the first motor and the first reducer are fixedly mounted on the side plates, the first motor drives the first chain group and the second chain group to operate synchronously through the first reducer, the rotation directions of the first chain group and the second chain group are oppositely arranged, and the first chain group and the second chain group drive and are connected to a circuit board.

[0009] Furthermore: the first chain group is arranged above the second chain group, and the first chain group and the second chain group have the same structure, both including a chain, two sprockets and a plurality of clamping frames, the two sprockets are rotatably mounted on the two ends of the side plate in a one-to-one manner, the chain is mounted between the two sprockets, and a plurality of clamping frames are fixedly mounted on the joints of the chains in a one-to-one manner, and the first chain group and the second chain group press the outer edge of the circuit board through the clamping frames on the joints for conveying.

[0010] Further: the pressing frame is of a circular structure and is made of eutectic rubber.

[0011] Further: a belt transmission is fixedly installed on the side panel, and the belt transmission includes a first pulley, a second pulley and a transmission belt. The output shaft of the first reducer drives the first pulley and one of the sprockets of the second chain group to rotate. The second pulley is rotatably installed on the side panel, and the transmission belt is installed between the first pulley and the second pulley. A first gear is fixedly installed on the rotor of the second pulley, and a second gear is rotatably installed on the side panel. The first gear and the second gear are meshed with each other, and one of the sprockets of the first chain group is fixedly installed on the rotating shaft of the second gear.

[0012] Further: a pressure wheel is rotatably mounted on the side plate, and the pressure wheel presses on the outer side of the transmission belt.

[0013] Further: the flipping mechanism includes a second motor and a second reducer, the second motor drives the flipping frame to rotate through the second reducer, and the flipping frame is fixedly installed in the middle part of the outer side of the side plate.

[0014] Furthermore: the movable rail moving mechanism includes a connecting plate, two width-adjusting slide rails and two third motors, the two third motors are respectively fixedly mounted on the left and right ends of the upper side of the connecting plate, and the left and right ends of the bottom side of the connecting plate are respectively fixedly mounted with sliders, the sliders are slidably mounted on the width-adjusting slide rails in a one-to-one correspondence, a rack is fixedly mounted on the side of the width-adjusting slide rail, a third gear is fixedly mounted on the rotor of the third motor, the third gear is meshingly mounted on the rack, and the third motors on the left and right sides operate synchronously with each other.

[0015] Further: a moving rail motor bracket is fixedly installed in the middle of the upper side of the connecting plate, and the flip mechanism is fixedly installed on the moving rail motor bracket.

[0016] Furthermore: the connecting plate and the side plate are arranged parallel to each other.

[0017] Further: a first limit block is fixedly installed at one end of the front side panel, and first rubber columns are fixedly installed at both left and right ends of the upper side of the connecting plate. The first limit block is flipped and rests on one of the first rubber columns to complete the flip positioning.

[0018] Furthermore: a second limit block is fixedly installed at one end of the rear side panel, and second rubber columns are fixedly installed on the upper sides of the rear ends of the two width-adjusting slide rails. The second limit block is flipped and rests on one of the second rubber columns to complete the flip positioning.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The moving rail mechanism can be used to adjust the distance between the two board conveyors, which can be used to transport circuit boards of different widths and perform visual inspection during the transportation process;

[0021] 2. When the circuit board is being transported, the first chain group and the second chain group running synchronously can be used to clamp the outer edge of the circuit board, and the circuit board can be stably transported through two conveyors to ensure that the circuit board will not slip during transportation, and the circuit board will not fall off when flipping, and its load-bearing capacity is strong;

[0022] 3. The turning mechanism on both sides is used to drive the turning frame to realize the synchronous turning of the two plate conveyors, which has high stability and strong load-bearing capacity, thereby ensuring the service life of the equipment.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 It is a schematic diagram of the structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the present invention after the machine is hidden;

[0027] Figure 3 yes Figure 2 A schematic diagram of the enlarged structure at point A;

[0028] Figure 4 yes Figure 2 A schematic diagram of the enlarged structure at B;

[0029] Figure 5 yes Figure 2 A schematic diagram of the structure from another perspective;

[0030] Figure 6 yes Figure 2 A structural diagram from another perspective;

[0031] Figure 7 It is a structural schematic diagram of the moving rail moving mechanism;

[0032] Figure 8 It is a structural schematic diagram of another perspective of the present invention;

[0033] Fig. 9 yes Figure 8 Enlarged structural diagram at C.

[0034] As shown in the figure: 01, moving rail motor bracket; 1, fixed rail motor bracket; 2, moving rail moving mechanism; 2.1, connecting plate; 2.2, width-adjusting slide rail; 2.3, third motor; 3, flipping mechanism; 31, second motor; 32, second reducer; 4, flipping frame; 5, clamping wheel; 6, plate transporter; 61, side plate; 62, first motor; 63, first reducer; 64, first chain group; 65, second chain group; 7, circuit board; 8, chain; 9. Sprocket; 10. Pressing frame; 11. Belt driver; 111. First pulley; 112. Second pulley; 113. Driving belt; 12. First gear; 13. Second gear; 14. Slider; 15. Rack; 16. Third gear; 17. First limit block; 18. First rubber column; 19. Second limit block; 20. Second rubber column; 21. Machine table; 22. Upper bracket; 23. Lower bracket; 24. Thickness adjustment frame. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0036] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0037] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] like Figure 1-9 As shown, the AOI equipment for detecting conformal coating of circuit boards through a flipping system of the present invention comprises a machine platform 21, on which a fixed rail motor bracket 1 and a moving rail moving mechanism 2 are fixedly mounted;

[0041] The fixed track motor bracket 1 is arranged behind the movable track moving mechanism 2. The fixed track motor bracket 1 and the movable track moving mechanism 2 are both fixedly mounted with a turning mechanism 3. The two turning mechanisms 3 operate synchronously with each other. The inner side of the turning mechanism 3 is driven and connected with a turning frame 4, and a plate conveyor 6 is fixedly mounted on the turning frame 4.

[0042] The principle is as follows: the movable rail moving mechanism 2 can be used to adjust the distance between the two flipping mechanisms 3, so that it can be suitable for the transportation of circuit boards 7 of different widths, and component plug-in detection, three-proof paint coating detection or appearance defect detection can be performed during the transportation process; when the circuit board 7 is being transported, the board conveyor 6 can be used to stably convey the circuit board 7, so as to ensure that the circuit board 7 will not slip during the transportation process, and the circuit board 7 will not separate from the board conveyor 6 when flipping; the flipping mechanisms 3 on both sides are used to drive the flipping frames 4 to realize the synchronous flipping of the two board conveyors 6, which has high stability and strong load-bearing capacity.

[0043] Further: the plate conveyors 6 of the front and rear flip frames 4 are symmetrically arranged front and back, and the plate conveyors 6 include a side plate 61, a first motor 62, a first reducer 63, a first chain group 64 and a second chain group 65. The side plate 61 is fixedly mounted on the flip frame 4, and the first motors 62 of the two plate conveyors 6 operate synchronously with each other. The first motor 62 and the first reducer 63 are fixedly mounted on the side plate 61. The first motor 62 drives the first chain group 64 and the second chain group 65 to operate synchronously through the first reducer 63. The rotation directions of the first chain group 64 and the second chain group 65 are oppositely arranged. The first chain group 64 and the second chain group 65 drive the circuit board 7 connected thereto; it can be used The movable rail moving mechanism 2 is used to adjust the distance between the two side plate conveyors 6, so that it can be suitable for the transportation of circuit boards 7 with different widths; when the circuit board 7 is being transported, the first chain group 64 and the second chain group 65 that operate synchronously can be used to clamp the outer edge of the circuit board 7, and the two plate conveyors 6 can be used to stably transport the circuit board 7, so that the circuit board 7 will not fall out of the equipment when turning over, thereby ensuring that the circuit board 7 will not slip during the transportation process, and the circuit board 7 will not separate from the plate conveyor 6 when turning over; the turning mechanism 3 on both sides is used to drive the turning frame 4 to realize the synchronous turning of the two plate conveyors 6, which has high stability and strong load-bearing capacity, thereby ensuring the service life of the equipment.

[0044] Further: the side plate 61 includes an upper bracket 22, a lower bracket 23 and a thickness adjustment frame 24, the first chain group 64 is installed on the inner side of the upper bracket 22, the second chain group 65 is installed on the inner side of the lower bracket 23, the thickness adjustment frame 24 is fixedly installed between the upper bracket 22 and the lower bracket 23, the cross-section of the thickness adjustment frame 24 is an "I"-shaped structure, the upper bracket 22 and the lower bracket 23 are respectively fixedly installed in the "I"-shaped structure on the upper and lower sides of the thickness adjustment frame 24 by screws; the "I"-shaped thickness adjustment frame 24 can ensure the stable installation of the upper bracket 22 and the lower bracket 23. When conveying circuit boards 7 of different thicknesses, the thickness adjustment frame 24 of appropriate thickness can be replaced, so that the equipment can be suitable for circuit boards 7 of different thicknesses, which can ensure its stability during transportation and will not slide or shift.

[0045] Furthermore: the first chain group 64 is arranged above the second chain group 65. The first chain group 64 and the second chain group 65 have the same structure, both of which include a chain 8, two sprockets 9 and a plurality of clamping frames 10. The two sprockets 9 are rotatably mounted on the two ends of the side plate 61 in a one-to-one manner, the chain 8 is mounted between the two sprockets 9, and a plurality of clamping frames 10 are fixedly mounted on the joints of the chain 8 in a one-to-one manner. The first chain group 64 and the second chain group 65 press the outer edge of the circuit board 7 for conveyance through the clamping frames 10 on the joints; the clamping frames 10 are arranged on the joints of the chain 8 to press the outer edge of the circuit board 7 for conveyance, so that the circuit board 7 will not slide on the chain 8 during conveyance, and the accuracy is higher.

[0046] Furthermore, the pressing frame 10 is of a circular structure and is made of PU. It has the characteristics of wear resistance and anti-slip, and has slight elasticity, and can be applied to circuit boards 7 of different thicknesses.

[0047] Further: a belt transmission device 11 is fixedly installed on the side plate 61, and the belt transmission device 11 includes a first pulley 111, a second pulley 112 and a transmission belt 113. The output shaft of the first reducer 63 drives the first pulley 111 and one of the sprockets 9 of the second chain group 65 to rotate, and the second pulley 112 is rotatably mounted on the side plate 61, and the transmission belt 113 is mounted between the first pulley 111 and the second pulley 112. A first gear 12 is fixedly installed on the rotor of the second pulley 112, and a second gear 13 is rotatably mounted on the side plate 61. The first gear 12 and the second gear 13 are meshed with each other, and one of the sprockets 9 of the first chain group 64 is fixedly mounted on the rotating shaft of the second gear 13; it can ensure stable transmission between the first chain group 64 and the second chain group 65, and the transmission speed can be kept consistent under the premise that their running directions are opposite.

[0048] Furthermore, a pressure wheel 5 is rotatably mounted on the side plate 61 , and the pressure wheel 5 presses on the outside of the transmission belt 113 , thereby improving the transmission accuracy of the belt transmission device 11 .

[0049] Furthermore: the flipping mechanism 3 includes a second motor 31 and a second reducer 32. The second motor 31 drives the flipping frame 4 to rotate through the second reducer 32. The flipping frame 4 is fixedly installed in the middle of the outer side of the side plate 61; the second reducer 32 can effectively decelerate the second motor 31, thereby preventing the flipping from being too fast and causing a collision, which can effectively avoid damage to the equipment.

[0050] Furthermore: the movable rail moving mechanism 2 includes a connecting plate 2.1, two width-adjusting slide rails 2.2 and two third motors 2.3, the two third motors 2.3 are respectively fixedly mounted on the left and right ends of the upper side of the connecting plate 2.1, and sliders 14 are respectively fixedly mounted on the left and right ends of the bottom side of the connecting plate 2.1, and the sliders 14 are slidably mounted on the width-adjusting slide rails 2.2 in a one-to-one corresponding manner, and a rack 15 is fixedly mounted on the side of the width-adjusting slide rail 2.2, and a third gear 16 is fixedly mounted on the rotor of the third motor 2.3, and the third gear 16 is meshingly mounted on the rack 15, and the third motors 2.3 on the left and right sides operate synchronously with each other; it can ensure the stability of the movable rail moving mechanism 2 during width adjustment, and thus it is suitable for circuit boards 7 of different widths, and at the same time it will not affect the flipping movement, and the movable rail moving mechanism 2 is arranged on the bottom side of the circuit board 7 to effectively avoid visual detection from being blocked, thereby ensuring its detection effect.

[0051] Furthermore: a moving rail motor bracket 01 is fixedly installed in the middle of the upper side of the connecting plate 2.1, and the flipping mechanism 3 is fixedly installed on the moving rail motor bracket 01; thus, the stable installation of the flipping mechanism 3 on the moving rail moving mechanism 2 can be ensured.

[0052] Furthermore: the connecting plate 2.1 and the side plate 61 are arranged parallel to each other.

[0053] Furthermore: a first limit block 17 is fixedly installed at one end of the front side panel 61, and first rubber columns 18 are fixedly installed at both left and right ends of the upper side of the connecting plate 2.1. The first limit block 17 is flipped and abuts against one of the first rubber columns 18 to complete the flipping positioning; when flipped into place, the first rubber column 18 will abut against the first limit block 17, thereby achieving precise positioning and flipping.

[0054] Furthermore: a second limit block 19 is fixedly installed on one end of the rear side side panel 61, and a second rubber column 20 is fixedly installed on the upper side of the rear ends of the two width-adjusting slide rails 2.2. The second limit block 19 is flipped and abuts against one of the second rubber columns 20 to complete the flipping positioning; when flipped to the other side and in place, the second rubber column 20 will abut against the second limit block 19, thereby achieving precise positioning and flipping. Embodiment 1

[0055] AOI equipment for testing the conformal coating of circuit boards through a flipping system includes a fixed rail motor bracket 1 and a moving rail moving mechanism 2:

[0056] The fixed track motor bracket 1 is arranged behind the movable track moving mechanism 2. The fixed track motor bracket 1 and the movable track moving mechanism 2 are both fixedly mounted with a turning mechanism 3. The two turning mechanisms 3 operate synchronously with each other. The inner side of the turning mechanism 3 is driven and connected with a turning frame 4, and a plate conveyor 6 is fixedly mounted on the turning frame 4.

[0057] The plate conveyors 6 of the front and rear flip frames 4 are symmetrically arranged front and back, and the plate conveyors 6 include a side plate 61, a first motor 62, a first reducer 63, a first chain group 64 and a second chain group 65. The side plate 61 is fixedly mounted on the flip frame 4, and the first motors 62 of the two plate conveyors 6 are synchronously operated. The first motor 62 and the first reducer 63 are fixedly mounted on the side plate 61. The first motor 62 drives the first chain group 64 and the second chain group 65 to operate synchronously through the first reducer 63. The rotation directions of the first chain group 64 and the second chain group 65 are oppositely arranged, and the first chain group 64 and the second chain group 65 drive the circuit board 7 connected thereto;

[0058] The first chain group 64 is arranged above the second chain group 65. The first chain group 64 and the second chain group 65 have the same structure, both of which include a chain 8, two sprockets 9 and a plurality of clamping frames 10. The two sprockets 9 are rotatably mounted on both ends of the side plate 61 in a one-to-one manner, the chain 8 is mounted between the two sprockets 9, and a plurality of clamping frames 10 are fixedly mounted on the joints of the chain 8 in a one-to-one manner. The first chain group 64 and the second chain group 65 press the outer edge of the circuit board 7 through the clamping frames 10 on the joints for conveying.

[0059] The pressing frame 10 has a circular structure and is made of elastomeric rubber.

[0060] The movable rail moving mechanism 2 includes a connecting plate 2.1, two width-adjusting slide rails 2.2 and two third motors 2.3. The two third motors 2.3 are respectively fixedly mounted on the left and right ends of the upper side of the connecting plate 2.1. Slide blocks 14 are respectively fixedly mounted on the left and right ends of the bottom side of the connecting plate 2.1. The slide blocks 14 are slidably mounted on the width-adjusting slide rails 2.2 in a one-to-one corresponding manner. A rack 15 is fixedly mounted on the side of the width-adjusting slide rail 2.2. A third gear 16 is fixedly mounted on the rotor of the third motor 2.3. The third gear 16 is meshingly mounted on the rack 15. The third motors 2.3 on the left and right sides operate synchronously with each other.

[0061] A first limit block 17 is fixedly installed at one end of the front side panel 61, and first rubber columns 18 are fixedly installed at both left and right ends of the upper side of the connecting plate 2.1. The first limit block 17 is flipped and pressed against one of the first rubber columns 18 to complete the flipping positioning; a second limit block 19 is fixedly installed at one end of the rear side panel 61, and second rubber columns 20 are fixedly installed on the upper sides of the rear ends of the two width-adjusting slide rails 2.2. The second limit block 19 is flipped and pressed against one of the second rubber columns 20 to complete the flipping positioning.

[0062] In the first embodiment, the clamping frame 10 is installed on the chain 8 of the first chain group 64 and the second chain group 65 to stably clamp and convey the circuit board 7, which can ensure that the outer edge of the circuit board 7 is stably clamped for conveying. When it is flipped, the front and rear two flipping mechanisms 3 are used to operate synchronously. When flipped into place, the first limit block 17 abuts against one of the first rubber columns 18, and the second limit block 19 abuts against the second rubber column 20, thereby achieving precise positioning after flipping. The setting of the rubber column can effectively avoid collision of the equipment and thus prevent damage to the equipment. In addition, the movable rail moving mechanism 2 can adjust the distance between the two board conveyors 6, so as to be suitable for conveying circuit boards 7 of different widths. There is no need to customize the equipment according to the circuit board 7 for coating inspection, thereby reducing costs.

[0063] In addition to being applicable to detecting the three-proof paint coating effect on both sides of the circuit board 7, the present invention can also be used to detect the plug-in status, pin soldering status, surface integrity, scratch detection, etc. on both sides of the circuit board 7. In short, all devices with width adjustment and double-sided detection through flip-plate equipment are within the protection scope of the present invention.

[0064] This embodiment does not impose any formal limitation on the shape, material, structure, etc. of the present invention. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. AOI equipment that detects conformal coating on circuit boards through a flip-up system, characterized by: The machine comprises a machine platform (21), on which a fixed-rail motor bracket (1) and a movable-rail moving mechanism (2) are fixedly mounted; A turning mechanism (3) is fixedly mounted on both the fixed rail motor bracket (1) and the movable rail moving mechanism (2). The two turning mechanisms (3) operate synchronously with each other. The inner side of the turning mechanism (3) is connected to a turning frame (4), and a plate conveyor (6) is fixedly mounted on the turning frame (4). The board conveyor (6) comprises a first chain group (64) and a second chain group (65); the first chain group (64) is arranged above the second chain group (65); a circuit board (7) is driven and connected between the first chain group (64) and the second chain group (65); The plate conveyors (6) of the front and rear flip frames (4) are symmetrically arranged front and rear, and the plate conveyors (6) further include a side plate (61), a first motor (62) and a first reducer (63). The side plate (61) is fixedly mounted on the flip frame (4). The first motors (62) of the two plate conveyors (6) operate synchronously with each other. The first motor (62) and the first reducer (63) are fixedly mounted on the side plate (61). The first motor (62) drives the first chain group (64) and the second chain group (65) to operate synchronously through the first reducer (63). The first chain group (64) and the second chain group (65) are arranged to rotate in opposite directions. The first chain group (64) and the second chain group (65) have the same structure, and both include a chain (8), two sprockets (9) and a plurality of pressing frames (10). The two sprockets (9) are rotatably mounted on both ends of the side plate (61) in a one-to-one manner. The chain (8) is mounted between the two sprockets (9). The plurality of pressing frames (10) are fixedly mounted on the joints of the chain (8) in a one-to-one manner. The first chain group (64) and the second chain group (65) press the outer edge of the circuit board (7) through the pressing frames (10) on the plurality of joints for conveyance. A belt transmission device (11) is fixedly mounted on the side plate (61), and the belt transmission device (11) comprises a first pulley (111), a second pulley (112) and a transmission belt (113). The output shaft of the first reducer (63) drives the first pulley (111) and one of the sprockets (9) of the second chain group (65) to rotate. The second pulley (112) is rotationally mounted on the side plate (61). The transmission belt (113) is rotationally mounted between the first pulley (111) and the second pulley (112). A first gear (12) is fixedly mounted on the rotor of the second pulley (112). A second gear (13) is rotationally mounted on the side plate (61). The first gear (12) and the second gear (13) are meshed with each other. One of the sprockets (9) of the first chain group (64) is fixedly mounted on the rotating shaft of the second gear (13).

2. The AOI equipment for inspecting conformal coating of circuit boards through a flipping system according to claim 1, characterized in that: The turning mechanism (3) comprises a second motor (31) and a second reducer (32). The second motor (31) drives the turning frame (4) to rotate via the second reducer (32). The turning frame (4) is fixedly mounted on the middle part of the outer side of the side plate (61).

3. The AOI equipment for inspecting conformal coating of circuit boards through a flipping system according to claim 1, characterized in that: The movable rail moving mechanism (2) comprises a connecting plate (2.1), two width-adjusting slide rails (2.2) and two third motors (2.3); the two third motors (2.3) are respectively fixedly mounted on the left and right ends of the upper side of the connecting plate (2.1); sliders (14) are respectively fixedly mounted on the left and right ends of the bottom side of the connecting plate (2.1); the sliders (14) are slidably mounted on the width-adjusting slide rails (2.2) in a one-to-one correspondence; racks (15) are fixedly mounted on the sides of the width-adjusting slide rails (2.2); third gears (16) are fixedly mounted on the rotors of the third motors (2.3); the third gears (16) are meshedly mounted on the racks (15); and the third motors (2.3) on the left and right sides operate synchronously with each other.

4. The AOI equipment for inspecting conformal coating of circuit boards by means of a flipping system according to claim 3, characterized in that: A first limiting block (17) is fixedly mounted on one end of the front side plate (61), and first rubber columns (18) are fixedly mounted on both left and right ends of the upper side of the connecting plate (2.1), and the first limiting block (17) is turned over and abutted against one of the first rubber columns (18) to complete the turning positioning.

5. The AOI equipment for inspecting conformal coating of circuit boards through a flipping system according to any one of claims 3 or 4, characterized in that: A second limiting block (19) is fixedly mounted on one end of the rear side side plate (61), and a second rubber column (20) is fixedly mounted on the upper side of the rear ends of the two width-adjusting slide rails (2.2), and the second limiting block (19) is turned over and abutted against one of the second rubber columns (20) to complete the turning positioning.

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