A paste coating structure of a solder paste printer

Abstract

The application discloses a tin paste printing machine's paste coating structure, relates to the tin paste printing technical field, including the tin paste jar being arranged below the moving frame, the hole site self-test assembly being arranged below the tin paste jar, the reversing range increasing assembly being arranged in the hole site self-test assembly, the sealing assembly being symmetrically arranged below the tin paste jar and controlling the tin paste discharging by the movement of the reversing range increasing assembly and the side changing assembly being arranged on both sides of the tin paste jar and being driven and controlled by two groups of scrapers to control the tin paste discharging direction. The tin paste feeding mode can more accurately inject sufficient tin paste into the opening. On the one hand, the tin paste amount of the non-opening area is greatly reduced, the tin paste use cost is reduced, and the difficulty of cleaning the equipment in the later period is reduced. On the other hand, especially in the long-period printing process, the tin paste gradually distributes unbalanced on the steel mesh surface due to the different tin paste amounts required by different openings, thereby reducing the occurrence of printing defects such as missing printing and tin amount loss.

Description

Technical Field

[0001] This invention relates to the field of solder paste printing technology, specifically to a solder paste printing machine's paste coating structure. Background Technology

[0002] With the rapid development of the electronics and information industry, electronic products are constantly moving towards miniaturization, multifunctionality, and high reliability, which places increasingly higher demands on electronic manufacturing processes. As a core component of electronic products, printed circuit boards (PCBs) are directly affected by every step of their manufacturing process, impacting the performance and quality of the final product. Solder paste printing is a crucial link in this process. Solder paste, also known as soldering paste, is a paste-like mixture composed of solder powder, flux, and other additives. At room temperature, it has a certain viscosity and shaping ability, allowing it to maintain a specific shape and position after printing. During high-temperature reflow soldering, the flux evaporates and removes oxides from the pads and component leads, while the solder powder melts and redistributes, ultimately achieving reliable soldering between the components and the PCB. In the PCB assembly process, accurately printing solder paste onto the PCB pads to form a solder paste pattern that meets design requirements is fundamental to achieving mechanical and electrical connections between surface-mount components and the PCB pads.

[0003] Currently, the traditional solder paste printing machine's coating structure basically consists of a squeegee and a stencil. During the coating process, solder paste is typically injected manually or by machine into specific areas of the stencil (usually the non-perforated areas on both sides) in a strip-like form. This stencil has precisely pre-drilled openings according to the circuit board pad pattern. The circuit board to be printed is then precisely aligned and pressed tightly against the bottom surface of the stencil. Next, the squeegee applies pressure to the stencil surface, and the solder paste, pushed and squeezed by the squeegee, is transferred through the openings in the stencil to the surface of the circuit board pads below, thus completing the solder paste coating process. This method relies on the synergy of manual feeding and mechanical squeegee printing, has a high degree of technological maturity, and allows for flexible adjustment of the initial solder paste distribution through manual intervention.

[0004] However, traditional solder paste application processes still have significant limitations in practical applications: although manual or automated feeding can achieve an initial strip distribution of solder paste, solder paste in non-perforated areas of the stencil is difficult to participate in printing due to the lack of a transfer path, resulting in continuous solder paste retention; furthermore, the diameter and shape of stencil openings vary due to differences in pad design, leading to inconsistent solder paste transfer amounts across different openings. As the squeegee cycle increases, the solder paste distribution on the stencil surface gradually becomes unbalanced: some areas accumulate solder paste due to continuous retention, while areas with dense openings or large apertures experience insufficient solder paste due to excessive consumption. At this point, production must be interrupted for manual equalization. If not handled promptly, insufficient solder paste in these areas can easily lead to printing defects such as missed pad printing and insufficient solder. In addition, regardless of whether manual or automated feeding is used, after the solder paste is concentrated and repeatedly squeegeed, irregular thin flakes of residue are easily formed on the stencil surface, causing not only ineffective solder paste loss but also increasing the difficulty and frequency of stencil cleaning, affecting the continuous operating efficiency of the equipment.

[0005] To address the aforementioned issues, there is an urgent need for innovative design based on the existing solder paste printing machine's paste application structure. Summary of the Invention

[0006] The present invention addresses the problem of overly simplistic solutions in existing technologies by providing a significantly different solution. Specifically, the present invention aims to provide a solder paste coating structure for a solder paste printer to solve the problem mentioned in the background art where the solder paste gradually becomes unevenly distributed on the stencil surface as the printing cycle increases.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a solder paste coating structure for a solder paste printing machine, comprising a printing machine tool, a movable frame movably mounted on the printing machine tool, and a scraper symmetrically and movable below the movable frame via an electromagnetic slide rail, further comprising:

[0008] Solder paste cans are set below the moving frame; hole position self-testing components are set in the middle of the bottom of the solder paste cans; reversing and range extender components are set in the middle of the hole position self-testing components; sealing components are symmetrically set below the solder paste cans and the reversing and range extender components control the solder paste feeding by motion; and reversing components are set on both sides of the solder paste cans and the solder paste feeding direction is controlled by two sets of scrapers.

[0009] The hole position self-testing component includes several sets of cylindrical shells fixed in the middle of the bottom of the solder paste can, a connector movably disposed inside the cylindrical shell, and a test ball that is rolled and locked in the lower end of the connector.

[0010] The reversing range extender assembly includes a movable plate movably disposed inside the cylindrical shell, reversing slots symmetrically opened on both sides of the cylindrical shell, a rotating rod slidably inserted in the reversing slots, and cams symmetrically disposed on both sides of the cylindrical shell.

[0011] The sealing assembly includes a sealing plug movably disposed inside the bottom of the solder paste can, a second long rod fixed to the bottom of the sealing plug, and a movable block fixed to the other end of the second long rod.

[0012] The switching assembly includes a second positioning plate fixed to the outer wall of the solder paste container, a limiting link that moves through the middle of the second positioning plate, and a rectangular frame fixed to one end of the limiting link.

[0013] Preferably, the lower end cross-section of the solder paste container is W-shaped;

[0014] The bottom of the solder paste container is provided with several sets of discharge ports, which are equidistantly and symmetrically arranged on both sides of the bottom of the solder paste container in a linear array.

[0015] Each set of discharge ports has a set of sealing plugs that are movably installed inside, and the bottom size of the sealing plugs is larger than the size of the discharge port.

[0016] Preferably, the hole position self-testing component further includes a No. 1 spring disposed inside the cylindrical shell;

[0017] The two ends of the first spring are fixedly connected to the bottom of the solder paste container and the top surface of the moving plate, respectively.

[0018] Preferably, the connector consists of a short rod fixed to the bottom surface of the movable plate, a disc fixed to the bottom end of the short rod, and a hemispherical shell fixed to the bottom surface of the disc;

[0019] The diameter of the disk is the same as the diameter of the inner wall of the cylinder, and the disk moves vertically within the cylinder.

[0020] The measuring ball rolls inside the hemispherical shell;

[0021] The lower end cross-section of the cylindrical shell is set as trapezoidal, and the maximum diameter of the lower end of the cylindrical shell is greater than the diameter of the hemispherical shell, while the minimum diameter is less than the diameter of the hemispherical shell.

[0022] A steel mesh is provided in the middle of the printing machine tool, and the measuring ball rolls on the surface of the steel mesh.

[0023] Preferably, the reversing range extender assembly further includes tie rods symmetrically fixed on both sides of the moving plate;

[0024] The pull rod is U-shaped, and the two sides of the cylindrical shell are provided with sliding grooves that are adapted to the size of the pull rod. One end of the pull rod passes through the sliding groove and extends to the outside of the cylindrical shell.

[0025] One end of the pull rod is movably inserted through the top of the insert rod;

[0026] One end of the insertion rod passes through the pull rod and is fixed to a square plate, and one side of the square plate is fixedly connected to one end of the rotating rod.

[0027] Preferably, a sleeve rod is movably sleeved on the outer surface of the other end of the insertion rod, and one end of the sleeve rod is fixedly connected to the cam;

[0028] A second spring is fixedly connected between the other end of the insertion rod and the inner wall of the sleeve rod.

[0029] The outer surface of the other end of the insertion rod is fixed with several sets of square sliders in proportion. The inside of the sleeve rod is provided with square sliding grooves that are adapted to the square sliders. The other end of the insertion rod and the square sliders are simultaneously slidably inserted into the inside of the sleeve rod.

[0030] Preferably, the width of the reversing slot is the same as the diameter of the rotating rod;

[0031] The reversing groove consists of two sets of symmetrical and longitudinally aligned vertical grooves and a semi-circular annular groove connecting the two sets of vertical grooves.

[0032] Preferably, the sealing assembly further includes a No. 1 positioning plate fixed to the outer wall of the solder paste container;

[0033] One end of the No. 1 positioning plate is movably inserted with a No. 1 long rod, and the bottom end of the No. 1 long rod is fixedly connected to the top surface of the moving block. A No. 3 spring is fixedly connected between the top of the No. 1 long rod and the top surface of the No. 1 positioning plate.

[0034] The sealing plug has a triangular cross-section, and a sealing rubber layer is glued and fixed to the bottom of the sealing plug.

[0035] The bottom surface of the moving block is arc-shaped, and both the surface of the moving block and the surface of the cam have been polished. The moving block is located above the cam.

[0036] Preferably, the side-changing assembly further includes push plates symmetrically arranged on both sides of each set of scrapers;

[0037] A T-shaped block is provided on one side of the push plate, and a T-shaped groove is fixed on one side of the scraper, with the T-shaped groove slidably inserted into the T-shaped block.

[0038] One side of the push plate is provided with an inclined surface, and one side of the push plate is attached to one side of the rectangular frame, but the two are not fixed.

[0039] The bottom of the push plate is polished and lubricated.

[0040] Preferably, a fourth spring is fixedly connected between the other end of the limiting link and the second positioning plate;

[0041] On the other side of the rectangular frame, there are several sets of ball-head columns distributed proportionally, and one end of each ball-head column is rounded and without sharp edges.

[0042] The axis of the ball joint and the axis of the insert are on the same horizontal line.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] 1. This invention eliminates the need to pre-pour solder paste onto the stencil surface before application. Instead, as the scraper moves, the probe ball rolls along the stencil surface. Since the probe ball always contacts the openings on the stencil before the scraper, it experiences a slight downward movement when encountering an opening. This downward movement is transferred by the reversing and range extender assembly, causing the cam to rotate significantly. This fully lifts the sealing plug, allowing the solder paste in the solder paste container to be transferred to the target area. The larger the opening size, the longer the probe ball stays in the opening, and the longer the sealing plug remains in the lifted state. Naturally, the amount of solder paste coming out of the solder paste container is also greater. The solder paste feeding method of the present invention can more accurately inject sufficient amount of solder paste into the openings. On the one hand, the amount of solder paste in non-opening areas is greatly reduced, the cost of solder paste use is reduced, and the difficulty of cleaning the equipment later is reduced. On the other hand, especially in long-cycle printing, it is less likely to cause the problem of uneven distribution of solder paste on the stencil surface due to different solder paste amounts required for different openings. This reduces the occurrence of printing defects such as missing prints and insufficient solder, and improves solder paste printing efficiency and finished product qualification rate.

[0045] 2. This invention retains the traditional dual-scraper alternating reciprocating solder paste application method. When the two sets of scrapers alternately rise and fall, the inclined surface of the push plate controls the distance between the ball-end post and the cam. When one set of scrapers moves upward and is not involved in the solder paste application, the cam is pushed to a position offset from the moving block. Conversely, when the other set of scrapers moves downward and needs to be applied, the ball-end post moves away from the cam, placing the cam directly below the moving block. During the large-scale rotation of the cam, one side of the moving block remains stationary, while the other side lifts the sealing plug, thus achieving solder paste feeding. This invention utilizes the rising and falling of the scrapers as the driving force. By controlling the alternating feeding on both sides, it ensures that the order of first detecting the hole position—then accurately feeding—and finally applying solder paste is not reversed or disordered, while also meeting the requirements of the dual-scraper alternating reciprocating solder paste application method. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the first three-dimensional structure of the present invention.

[0047] Figure 2 This is a partial structural diagram of the present invention.

[0048] Figure 3 This is a partial structural diagram of the present invention.

[0049] Figure 4 This is a partial structural diagram of the present invention.

[0050] Figure 5 This is a partial structural diagram of the present invention.

[0051] Figure 6 This is a partial cross-sectional structural diagram of the present invention.

[0052] Figure 7 This is a schematic diagram of the closed state structure of the discharge port of the present invention.

[0053] Figure 8 This is a schematic diagram of the single-sided discharge port of the present invention in the open state.

[0054] Figure 9 This is a schematic diagram of the cross-sectional structure of the cylindrical shell of the present invention.

[0055] Figure 10 This is a schematic diagram of the commutation range extender component of the present invention.

[0056] Figure 11 This is a schematic diagram of the cam rotation state structure of the present invention.

[0057] Figure 12 This is a schematic diagram of the structure of the insertion rod and sleeve rod of the present invention.

[0058] Figure 13 This is a front view schematic diagram of the measuring ball of the present invention located on the surface of the steel mesh.

[0059] Figure 14 This is a front view schematic diagram of the measuring ball of the present invention located inside the opening.

[0060] Figure 15 This is a front view structural diagram of the sealing component of the present invention.

[0061] Figure 16 This is a schematic diagram of the push plate and rectangular frame of the present invention.

[0062] Figure 17 This is a schematic diagram of the structure of the T-shaped block and T-shaped groove of the present invention.

[0063] In the diagram: 1. Printing machine tool; 2. Moving frame; 3. Squeegee; 4. Stencil; 5. Solder paste container; 6. Shell; 7. Moving plate; 8. Spring No. 1; 9. Connector; 10. Measuring ball; 11. Reversing groove; 12. Pull rod; 13. Insert rod; 14. Square plate; 15. Rotating rod; 16. Sleeve rod; 17. Spring No. 2; 18. Cam; 19. Positioning plate No. 1; 20. Long rod No. 1; 21. Spring No. 3; 22. Moving block; 23. Long rod No. 2; 24. Sealing plug; 25. Positioning plate No. 2; 26. Limiting link; 27. Spring No. 4; 28. Rectangular frame; 29. ​​Ball head column; 30. Push plate; 31. T-block; 32. T-slot. Detailed Implementation

[0064] 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.

[0065] Please see Figures 1 to 17 The present invention provides a technical solution: a solder paste printing machine's paste coating structure, including a printing machine 1, a movable frame 2 movably mounted on the printing machine 1, and a scraper 3 symmetrically and movable below the movable frame 2 via an electromagnetic slide rail, and further including:

[0066] Solder paste container 5 is set below the movable frame 2; hole position self-testing component is set in the middle below the solder paste container 5; reversing and range extender component is set in the middle of the hole position self-testing component; sealing component is symmetrically set below the solder paste container 5 and uses the motion of the reversing and range extender component to control the solder paste feeding; and side-changing component is set on both sides of the solder paste container 5 and is driven by two sets of scrapers 3 to control the solder paste feeding direction.

[0067] In specific implementation, as shown in the appendix Figure 1 To be continued Figure 4 As shown, the assembly relationship and operation mode between the printing machine tool 1, the moving frame 2, the squeegee 3, and the stencil 4 are consistent with the existing technology, and will not be elaborated on further here. It is important to note that if the solder paste used has good fluidity, a regular solder paste storage container can be used directly. If the solder paste has average fluidity, the solder paste container 5 must be a feeding container of, but not limited to, a pneumatic solder paste container type. The internal pressure of the solder paste container 5 should be adjusted to an appropriate range to ensure that the solder paste can flow down quickly when the outlet is opened. However, it should be noted that the internal pressure of the solder paste container 5 should not exceed the elastic force of the first spring 8 to prevent the cam 18 from being unable to lift the sealing plug 24. The specific model and type of solder paste container 5 can be freely selected according to requirements, and will not be elaborated on further here.

[0068] In addition, several sets of hole position self-testing components, reversing range extenders, and sealing components are required, and they are distributed proportionally and symmetrically in a linear array below the solder paste container 5. It should be noted that, in fact, because the stencil 4 is relatively thin and the circuit board to be printed is in close contact with the stencil 4, the downward movement of the hole testing ball 10 is very short in order to prevent damage to the surface of the circuit board when the stencil 4 moves downward. This invention relies on the reversing range extender to amplify the movement of the hole testing ball 10, so as to more fully lift the sealing plug 24 and ensure that the amount of solder paste falling is sufficient.

[0069] The hole position self-testing component includes several sets of cylindrical shells 6 fixed in the middle of the bottom of the solder paste can 5, a connector 9 movably disposed inside the cylindrical shell 6, and a hole measuring ball 10 that is rolled and locked in the lower end of the connector 9.

[0070] The reversing range extender assembly includes a movable plate 7 movably disposed inside the cylindrical shell 6, reversing grooves 11 symmetrically opened on both sides of the cylindrical shell 6, a rotating rod 15 slidably inserted in the reversing grooves 11, and cams 18 symmetrically disposed on both sides of the cylindrical shell 6.

[0071] In specific implementation, when the measuring ball 10 is located on the upper surface of the steel mesh 4, that is, when the measuring ball 10 has not moved to the opening, the rotating rod 15 should be at the top of the reversing groove 11, and the protruding part of the cam 18 should face downward. Conversely, when the measuring ball 10 moves to the opening and moves downward, the protruding part of the cam 18 should face upward.

[0072] The sealing assembly includes a sealing plug 24 that is movably disposed inside the bottom of the solder paste container 5, a second long rod 23 fixed to the bottom of the sealing plug 24, and a movable block 22 fixed to the other end of the second long rod 23.

[0073] The side-changing assembly includes a second positioning plate 25 fixed to the outer wall of the solder paste container 5, a limiting link 26 that moves through the middle of the second positioning plate 25, and a rectangular frame 28 fixed to one end of the limiting link 26.

[0074] The lower cross-section of solder paste container 5 is designed to be W-shaped;

[0075] In specific implementation, as shown in the appendix Figure 7 and attached Figure 8 As shown, the lower end of the solder paste container 5 is divided into two chambers, each of which is larger at the top and smaller at the bottom, and the side walls of both chambers are sloping. This helps the solder paste to be concentrated at the outlet.

[0076] The bottom of the solder paste container 5 is provided with several sets of discharge ports, which are equidistantly and symmetrically arranged on both sides of the bottom of the solder paste container 5 in a linear array.

[0077] Each set of discharge ports has a set of sealing plugs 24 that are movable inside. The bottom size of the sealing plugs 24 is larger than the size of the discharge port.

[0078] In practice, as the sealing plug 24 moves downwards, it gradually approaches the inner wall of the solder paste container 5 until the two side walls are completely in contact, thus effectively sealing the outlet. Conversely, as the sealing plug 24 moves upwards, it gradually moves away from the inner wall of the solder paste container 5, providing a transfer channel for the solder paste. It should be noted that, as shown in the attached... Figure 7 and attached Figure 8 As shown, the discharge ports of each group are not connected.

[0079] The hole position self-testing component also includes a No. 1 spring 8 disposed inside the cylindrical shell 6;

[0080] The two ends of spring 8 are fixedly connected to the bottom of solder paste container 5 and the top surface of movable plate 7, respectively.

[0081] The connector 9 consists of a short rod fixed to the bottom surface of the movable plate 7, a disc fixed to the bottom end of the short rod, and a hemispherical shell fixed to the bottom surface of the disc;

[0082] The diameter of the disk is the same as the inner wall diameter of the cylindrical shell 6, and the disk moves vertically within the cylindrical shell 6.

[0083] In practice, the main function of the disc is to maintain the stability and directional certainty of the movement of the measuring ball 10 and the moving plate 7.

[0084] The measuring ball 10 rolls inside the hemispherical shell;

[0085] The lower end cross-section of the cylindrical shell 6 is set as trapezoidal, and the maximum diameter of the lower end of the cylindrical shell 6 is greater than the diameter of the hemispherical shell, while the minimum diameter is less than the diameter of the hemispherical shell.

[0086] In practice, the measuring ball 10 and the hemispherical shell have a certain amount of room to move inside the lower end of the cylindrical shell 6, as shown in the attached diagram. Figure 13 and attached Figure 14 As shown, when the measuring ball 10 rolls to the opening on the surface of the steel mesh 4, it will move down under the push of the spring 8 and a small part of it will be inserted into the opening. However, the downward space of the measuring ball 10 and the hemispherical shell is limited, and the hemispherical shell will not come out of the inside of the cylinder shell 6 to prevent the measuring ball 10 from getting stuck when it rolls out of the opening.

[0087] A steel mesh 4 is set in the middle of the printing machine tool 1, and the measuring ball 10 rolls on the upper surface of the steel mesh 4.

[0088] In practice, when the measuring ball 10 rolls on the upper surface of the steel mesh 4, the first spring 8 should be in a compressed state. When the measuring ball 10 is suspended, the first spring 8 should be in a relatively relaxed state. At this time, the first spring 8 should not be forcibly compressed to prevent it from pushing the measuring ball 10 downwards, causing the hemispherical shell to become too firmly stuck at the lower end of the cylindrical shell 6. This would result in excessive resistance when the measuring ball 10 moves upwards again, damaging the structure. In addition, the cylindrical shell 6 does not contact the steel mesh 4 to prevent the cylindrical shell 6 from scratching the surface of the steel mesh 4.

[0089] The commutation range extender also includes tie rods 12 symmetrically fixed on both sides of the movable plate 7;

[0090] The pull rod 12 is U-shaped, and the two sides of the cylindrical shell 6 are provided with sliding grooves that are adapted to the size of the pull rod 12. One end of the pull rod 12 extends through the sliding groove to the outside of the cylindrical shell 6.

[0091] A rod 13 is movably inserted through the top of one end of the pull rod 12;

[0092] One end of the insertion rod 13 passes through the pull rod 12 and is fixed to a square plate 14, and one side of the square plate 14 is fixedly connected to one end of the rotating rod 15.

[0093] In specific implementation, as shown in the appendix Figure 11 and attached Figure 12 As shown, when the rotating rod 15 moves down, it will rotate 180 degrees due to the influence of the reversing groove 11 trajectory. When the square plate 14 rotates, there will be no motion interference between it and the pull rod 12. The rotating rod 15 is forced to rotate when it moves down, which drives the cam 18 to rotate.

[0094] The other end of the insertion rod 13 is movably fitted with a sleeve rod 16, and one end of the sleeve rod 16 is fixedly connected to the cam 18;

[0095] A second spring 17 is fixedly connected between the other end of the insertion rod 13 and the inner wall of the sleeve rod 16;

[0096] Several sets of square sliders are fixed proportionally on the outer surface of the other end of the insertion rod 13. A square groove adapted to the square slider is opened inside the sleeve rod 16. The other end of the insertion rod 13 and the square slider are simultaneously slidably inserted into the inside of the sleeve rod 16.

[0097] In practice, the lateral position of the cam 18 can be adjusted independently of the insert rod 13. Regardless of its lateral position, the cam 18 will rotate with the insert rod 13. Thus, when the cam 18 rotates, it is possible to select whether the lifting moving block 22 is needed.

[0098] The width of the reversing slot 11 is the same as the diameter of the rotating rod 15;

[0099] The reversing slot 11 consists of two sets of symmetrical and longitudinally aligned vertical slots and a semi-circular annular slot connecting the two sets of vertical slots.

[0100] In specific implementation, the horizontal height of the semi-circular groove should be consistent with the travel length of the measuring ball 10. After the measuring ball 10 moves one stroke in one direction, the rotating rod 15 slides one stroke along the inside of the reversing groove 11. Simply put, when the measuring ball 10 drives the rotating rod 15 to move down, after the measuring ball 10 moves to the bottom, the rotating rod 15 also moves to the lowest end of the reversing groove 11. Conversely, when the measuring ball 10 drives the rotating rod 15 to move up, after the measuring ball 10 moves to the top, the rotating rod 15 also moves to the top of the reversing groove 11. In this way, the cam 18 can rotate 180 degrees when the measuring ball 10 moves.

[0101] The sealing assembly also includes a No. 1 positioning plate 19 fixed to the outer wall of the solder paste container 5;

[0102] One end of the positioning plate 19 is movably inserted with a long rod 20, and the bottom end of the long rod 20 is fixedly connected to the top surface of the moving block 22. A spring 21 is fixedly connected between the top of the long rod 20 and the top surface of the positioning plate 19.

[0103] In specific implementation, as shown in the appendix Figure 15 As shown, the first long rod 20 is composed of a large-diameter cylinder at the top and a small-diameter cylinder fixed at the bottom of the large-diameter cylinder. One end of the third spring 21 is fixed to the bottom surface of the large-diameter cylinder, and the third spring 21 is movably sleeved on the outside of the small-diameter cylinder. When the first long rod 20 is lifted, the third spring 21 will be stretched. When the proximal end of the cam 18 rotates to correspond with the moving block 22, the moving block 22 loses its obstruction. The rebound of the third spring 21 can drive the moving block 22 to move down back to its original position, so that the sealing plug 24 re-seals the discharge port.

[0104] The cross-section of the sealing plug 24 is triangular, and a sealing rubber layer is glued and fixed to the bottom of the sealing plug 24;

[0105] In practice, solder paste is less likely to accumulate on the top of the sealing plug 24, allowing it to flow down more smoothly. At the same time, the sealing rubber layer should be in an interference fit against the inner wall of the solder paste container 5 to enhance the sealing effect on the outlet.

[0106] The bottom surface of the movable block 22 is set to be arc-shaped, and both the surface of the movable block 22 and the surface of the cam 18 have been polished. The movable block 22 is located above the cam 18.

[0107] In practice, when the cam 18 is located directly below the moving block 22, the rotation of the cam 18 will cause its distal end protrusion to lift the moving block 22, and the cam 18 is not prone to jamming with the moving block 22 when it rotates.

[0108] The side-changing assembly also includes push plates 30 that are symmetrically arranged on both sides of each set of scrapers 3;

[0109] A T-shaped block 31 is provided on one side of the push plate 30, and a T-shaped groove 32 is fixed on one side of the scraper 3, and the T-shaped groove 32 is slidably inserted into the T-shaped block 31.

[0110] In practical implementation, if the scraper 3 causes the push plate 30 to contact the steel mesh 4 before the scraper 3 due to differences in equipment space dimensions, the continued downward movement of the scraper 3 will inevitably lead to damage to the push plate 30 and the steel mesh 4. Therefore, this invention uses a T-shaped block 31 and a T-shaped groove 32 to make the push plate 30 and the scraper 3 a movable connection, so that when the push plate 30 contacts the steel mesh 4 first, the scraper 3 continues to move downward, allowing the T-shaped groove 32 to slide along the inside of the T-shaped block 31, to prevent the push plate 30 from continuously pressing down on the steel mesh 4.

[0111] One side of the push plate 30 is provided with a slope, and one side of the push plate 30 is attached to one side of the rectangular frame 28, but the two are not fixed.

[0112] The bottom of the push plate 30 is polished and lubricated.

[0113] In specific implementation, as shown in the appendix Figure 16 As shown, when the push plate 30 moves upward, it pushes the rectangular frame 28, causing the cam 18 to separate from the moving block 22. When the push plate 30 moves downward, the rectangular frame 28 returns to its original position, and the cam 18 also returns to directly below the moving block 22. Thus, when one set of scrapers 3 does not participate in the paste application operation, after one set of scrapers 3 moves upward, the corresponding discharge port on one side remains blocked.

[0114] A fourth spring 27 is fixedly connected between the other end of the limiting link 26 and the second positioning plate 25.

[0115] On the other side of the rectangular frame 28, there are several sets of ball-head columns 29 distributed proportionally, and one end of the ball-head column 29 is rounded and without sharp corners;

[0116] The axis of the ball joint 29 and the axis of the insert rod 13 are on the same horizontal line.

[0117] In practice, when the ball joint 29 pushes the cam 18 and remains pressed against the surface of the cam 18, even though the cam 18 rotates, there will be no motion interference between the ball joint 29 and the cam 18, and the friction between the two is relatively small.

[0118] Working principle: When using the solder paste printing machine's paste coating structure, first, fill the solder paste container 5 with a sufficient amount of solder paste, then place the circuit board tightly against the lower surface of the stencil 4, and turn on the printing machine tool 1 to make the moving frame 2 move back and forth, and the two sets of squeegees 3 alternately rise and fall. The specific steps mentioned above are consistent with the existing technology, and will not be elaborated on further here. It is important to note that when one of the scrapers 3 moves downward, two sets of push plates 30 follow the scraper 3 downward. After the push plates 30 contact the steel mesh 4, the scraper 3 continues to move downward, causing the T-groove 32 to slide inside the T-block 31. When the two sets of push plates 30 move downward, the fourth spring 27 rebounds, pushing the limiting link 26 and the rectangular frame 28 away from the cam 18. After the cam 18 loses the obstruction of the ball head post 29, it moves downward under the rebound of the second spring 17 to a position directly below the moving block 22. At this time, the scraper 3 on the other side moves upward, driving the other two sets of push plates 30 to move upward. The other two sets of push plates 30 push the rectangular frame 28, causing the ball head post 29 to push the cam 18 on the other side to a position aligned with the moving block 22 on the other side. When the moving frame 2 moves, the measuring ball 10 rolls along the surface of the steel mesh 4. When the measuring ball 10 rolls to the opening, under the rebound of the first spring 8, the moving plate 7 and the measuring ball 10 are pushed down slightly. The moving plate 7 drives the pull rod 12 and the rotating rod 15 to move down slightly. The rotating rod 15 slides along the inside of the reversing groove 11 and is forced to rotate 180 degrees due to the trajectory of the reversing groove 11. The square plate 14 and the cam 18 rotate 180 degrees synchronously. The distal end protrusion rotates upwards, and the moving block 22 located directly above the cam 18 is lifted, while the moving block 22 offset from the cam 18 remains stationary. The moving block 22 on one side pushes the first long rod 20 and the sealing plug 24 upwards, stretching the third spring 21. The side wall of the sealing plug 24 creates a space for the solder paste to fall onto the inner wall of one side of the solder paste container 5. After the solder paste falls onto the surface of the stencil 4, it is scraped by the scraper on one side. 3. The paste is smoothed and squeezed by the scraper 3, then injected into the circuit board surface through the opening to complete the paste application. As the probe ball 10 continues to move and leaves the opening to return to the upper surface of the stencil 4, the probe ball 10 moves upward, and the first spring 8 is slightly compressed. Similarly, the moving plate 7 and the rotating rod 15 move upward slightly. The rotating rod 15 slides again along the inside of the reversing groove 11 and drives the cam 18 to rotate 180 degrees in the opposite direction. The proximal end of the cam 18 rotates to the position corresponding to the moving block 22. Previously, the moving block 22 on one side moved downward under the rebound action of the third spring 21, and the sealing plug 24 re-sealed the outlet until the probe ball 10 rolls to the next set of openings. Similarly, when the scraper 3 on the other side is applying paste, the cam 18 on the other side returns to the position directly below the moving block 22 on the other side. When the probe ball 10 rolls to the opening, the solder paste is released from the outlet on the other side of the solder paste container 5, while one side remains sealed.

[0119] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solder paste coating structure for a solder paste printing machine, comprising a printing machine (1), a movable frame (2) movably mounted on the printing machine (1), and a scraper (3) symmetrically and movably mounted below the movable frame (2) via an electromagnetic slide rail, characterized in that, Also includes: Solder paste container (5) is set below the moving frame (2), hole position self-testing component is set in the middle of the bottom of the solder paste container (5), reversing range extender component is set in the middle of the hole position self-testing component, sealing component symmetrically set below the solder paste container (5) and using the reversing range extender component to control the solder paste feeding direction, and side-changing component set on both sides of the solder paste container (5) and driven by two sets of scrapers (3) to control the solder paste feeding direction; The hole position self-testing component includes several sets of cylindrical shells (6) fixed in the middle of the bottom of the solder paste can (5), a connector (9) movably disposed inside the cylindrical shell (6), and a hole measuring ball (10) that is rolled and locked in the lower end of the connector (9). The reversing range extender assembly includes a movable plate (7) movably disposed inside the cylindrical shell (6), reversing grooves (11) symmetrically opened on both sides of the cylindrical shell (6), a rotating rod (15) slidably inserted in the reversing grooves (11), and cams (18) symmetrically disposed on both sides of the cylindrical shell (6). The reversing range extender also includes tie rods (12) symmetrically fixed on both sides of the moving plate (7). The tie rods (12) are U-shaped. The cylindrical shell (6) has grooves on both sides that are adapted to the size of the tie rods (12). One end of the tie rods (12) extends through the grooves to the outside of the cylindrical shell (6). One end of the pull rod (12) is movably inserted with a rod (13). One end of the rod (13) passes through the pull rod (12) and is fixed with a square plate (14). One side of the square plate (14) is fixedly connected to one end of the rotating rod (15). The other end of the rod (13) is movably fitted with a sleeve rod (16). One end of the sleeve rod (16) is fixedly connected to a cam (18). The other end of the rod (13) is fixedly connected to the inner wall of the sleeve rod (16) with a second spring (17). The other end of the rod (13) is fixedly fixed with several sets of square sliders in proportion. The inside of the sleeve rod (16) is provided with a square groove that matches the square slider. The other end of the rod (13) and the square slider are simultaneously slidably inserted into the inside of the sleeve rod (16). The sealing assembly includes a sealing plug (24) movably disposed inside the bottom of the solder paste can (5), a second long rod (23) fixed to the bottom of the sealing plug (24), and a moving block (22) fixed to the other end of the second long rod (23). The moving block (22) is located above the cam (18). The switching assembly includes a second positioning plate (25) fixed to the outer wall of the solder paste can (5), a limiting link (26) that moves through the middle of the second positioning plate (25), and a rectangular frame (28) fixed to one end of the limiting link (26).

2. The solder paste coating structure of a solder paste printing machine according to claim 1, characterized in that: The lower cross-section of the solder paste container (5) is W-shaped; The bottom of the solder paste container (5) is provided with several sets of discharge ports, which are equidistantly and symmetrically arranged on both sides of the bottom of the solder paste container (5) in a linear array. Each set of discharge ports is equipped with a set of sealing plugs (24) inside, and the bottom size of the sealing plugs (24) is larger than the size of the discharge port.

3. The solder paste coating structure of a solder paste printing machine according to claim 1, characterized in that: The hole position self-testing component also includes a No. 1 spring (8) disposed inside the cylindrical shell (6); The two ends of the first spring (8) are fixedly connected to the bottom of the solder paste container (5) and the top surface of the movable plate (7), respectively.

4. The solder paste coating structure of a solder paste printing machine according to claim 1, characterized in that: The connector (9) consists of a short rod fixed to the bottom surface of the movable plate (7), a disc fixed to the bottom end of the short rod, and a hemispherical shell fixed to the bottom surface of the disc; The diameter of the disk is the same as the inner wall diameter of the cylindrical shell (6), and the disk moves in the longitudinal vertical direction inside the cylindrical shell (6); The measuring ball (10) rolls inside the hemispherical shell; The lower end cross section of the cylindrical shell (6) is set as trapezoidal, and the maximum diameter of the lower end of the cylindrical shell (6) is greater than the diameter of the hemispherical shell, while the minimum diameter is less than the diameter of the hemispherical shell. A steel mesh (4) is provided in the middle of the printing machine (1), and the measuring ball (10) rolls on the upper surface of the steel mesh (4).

5. The solder paste coating structure of a solder paste printing machine according to claim 1, characterized in that: The width of the reversing groove (11) is the same as the diameter of the rotating rod (15); The reversing groove (11) consists of two sets of vertical grooves that are symmetrical and longitudinally aligned, and a semi-circular annular groove that connects the two sets of vertical grooves.

6. The solder paste coating structure of a solder paste printing machine according to claim 1, characterized in that: The sealing assembly also includes a No. 1 positioning plate (19) fixed on the outer wall of the solder paste can (5). One end of the No. 1 positioning plate (19) is movably inserted with a No. 1 long rod (20), and the bottom end of the No. 1 long rod (20) is fixedly connected to the top surface of the moving block (22). A No. 3 spring (21) is fixedly connected between the top of the No. 1 long rod (20) and the top surface of the No. 1 positioning plate (19). The cross-section of the sealing plug (24) is set as a triangle, and a sealing rubber layer is glued and fixed to the bottom of the sealing plug (24); The bottom surface of the moving block (22) is set to be arc-shaped, and the surfaces of the moving block (22) and the cam (18) have been polished.

7. The solder paste coating structure of a solder paste printing machine according to claim 1, characterized in that: The side-changing assembly also includes push plates (30) that are symmetrically arranged on both sides of each set of scrapers (3); A T-shaped block (31) is provided on one side of the push plate (30), and a T-shaped groove (32) is fixed on one side of the scraper (3), and the T-shaped groove (32) is slidably inserted into the T-shaped block (31); One side of the push plate (30) is provided with an inclined surface, and one side of the push plate (30) is attached to one side of the rectangular frame (28), but the two are not fixed. The bottom of the push plate (30) is polished and lubricated.

8. The solder paste coating structure of a solder paste printing machine according to claim 1, characterized in that: A fourth spring (27) is fixedly connected between the other end of the limiting link (26) and the second positioning plate (25). On the other side of the rectangular frame (28), there are several sets of ball-head columns (29) distributed in equal proportions, and one end of the ball-head column (29) is rounded and without sharp edges; The axis of the ball head (29) and the axis of the insert (13) are on the same horizontal line.

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