Solder paste printing machine for PCB (Printed Circuit Board)

Abstract

The invention belongs to the technical field of circuit board printing equipment, and particularly relates to a solder paste printing machine for a PCB (printed circuit board), which comprises a solder paste printing device, the solder paste printing device comprises a support frame, a transmission frame is fixedly connected in the support frame, a placing plate is fixedly connected to the top of the transmission frame, and a steel mesh is detachably connected to the top of the transmission frame. An electric guide rail is fixedly connected to the top of the supporting frame, an electric air cylinder is fixedly connected to the bottom of an electric guide rail sliding block, solder paste placed on the steel mesh can be limited through the two first limiting plates, repeated coating work caused by diffusion of the solder paste is avoided, and then the coating work efficiency can be improved; meanwhile, circuit boards of different sizes can be adapted to be coated through movement of a displacement block, and then solder paste stacked on the side face of a second limiting plate can be scraped to the middle of a steel mesh through overturning and moving of a scraping plate, so that the situation that the solder paste is too much or too little in some areas can be avoided; and the uniformity of the solder paste on the steel mesh is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of circuit board printing equipment, in particular to a solder paste printer for a PCB circuit board. Background Art

[0002] The solder paste printer is an automated printing device that is mainly used to accurately print solder paste on the pads of printed circuit boards (PCBs). It achieves efficient and accurate solder paste printing through precise mechanical systems and advanced control technology, providing a reliable foundation for the connection of electronic components, and is an indispensable and important equipment in the electronics manufacturing industry.

[0003] In the prior art, when the solder paste printer is working, the PCB (printed circuit board) is first transported to the printing work area through a track and fixed. Then, the steel mesh will descend and fit tightly with the PCB. The hole positions of the steel mesh correspond to the pad positions on the PCB where the solder paste needs to be printed. Then, the scraper scrapes the solder paste from the solder paste storage area across the surface of the steel mesh. Under the pressure of the scraper, the solder paste is squeezed through the small holes of the steel mesh to the corresponding pads of the PCB. After that, the steel mesh rises, and the PCB board printed with solder paste is transported to the next process through the track, completing a solder paste printing process.

[0004] There are still some problems in the actual application of the above scheme. When using a scraper to coat the solder paste on the steel mesh, when the pressure applied by the scraper to the solder paste is too great, the solder paste will be squeezed and easily accumulate on both sides of the scraper, which will cause the distribution of the solder paste on the circuit board to become uneven, with too much solder paste in some areas and too little or no solder paste in some areas. This will require repeated coating operations during the coating process to correct the uneven coating effect, which will reduce production efficiency and increase production costs. Secondly, when the solder paste is limited by the added reciprocating limit mechanism, the flow range of the solder paste is limited, and the scraper will apply greater pressure on the solder paste when moving, trying to push it into the restricted area. This enhanced interaction will cause the solder paste to accumulate at the edge of the scraper or the edge of the restricted area, causing the solder paste to appear uneven during the coating process, which will reduce the welding quality.

[0005] To this end, the present invention provides a solder paste printer for a PCB circuit board. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows: a solder paste printer for a PCB circuit board described in the present invention comprises a solder paste printing device, the solder paste printing device comprises a support frame, a transmission frame is fixedly connected inside the support frame, a placement plate is fixedly connected to the top of the transmission frame, a steel mesh is detachably connected to the top of the transmission frame, an electric guide rail is fixedly connected to the top of the support frame, the electric guide rail comprises a slider, an electric cylinder is fixedly connected to the bottom of the electric guide rail slider, a scraper is fixedly connected to the output end of the electric cylinder, and a reciprocating limit mechanism is arranged inside the solder paste printing device;

[0008] The reciprocating limiting mechanism includes a protective frame fixedly arranged on the side of the scraper, two sets of displacement blocks are slidably arranged inside the protective frame, and a first limiting plate is fixedly arranged at the bottom of the displacement block. The relative movement of the two sets of displacement blocks can drive the two sets of first limiting plates to move relative to each other, thereby limiting the solder paste placed on the upper surface of the steel mesh to avoid too little or no solder paste in some areas, thereby reducing the number of reciprocating coating times and improving production efficiency.

[0009] Preferably, a driving motor is fixedly connected to the side of the protection frame, a bidirectional screw is fixedly connected to the output end of the driving motor, the displacement block is threadedly connected to the outer ring surface of the bidirectional screw, a connecting rod is fixedly connected to the bottom of the displacement block, and the first limit plate is fixedly connected to the bottom of the connecting rod.

[0010] Preferably, the rotation of the bidirectional screw rod can drive the two groups of displacement blocks to move synchronously, and then drive the two groups of first limit plates to move synchronously through the connecting rod.

[0011] Preferably, an inner cavity is opened inside the protection frame, a guide rod is fixedly connected to the side wall of the inner cavity of the protection frame, a guide plate is arranged on one side of the first limiting plate, and the first limiting plate slides in a groove body opened on the side of the guide plate.

[0012] Preferably, the guide rod can limit the two groups of displacement blocks so that they can perform relative linear motion along the guidance of the guide rod, and then drive the two groups of first limiting plates to perform relative linear motion, so that they can adapt to the coating work of circuit boards of different sizes. The two groups of the first limiting plates can limit the solder paste to prevent the solder paste from diffusing outward and causing repeated coating work, thereby improving production efficiency.

[0013] Preferably, a reciprocating smoothing mechanism for smoothing is arranged on the upper part of the reciprocating limiting mechanism, the reciprocating smoothing mechanism includes a micro motor, a fixed frame is fixedly connected to the side of the micro motor, the output shaft of the micro motor passes through the side wall of the fixed frame, the output end of the fixed frame is fixedly connected to a first rotating gear, the outer ring surface of the first rotating gear is meshed with a first movable rack, the outer ring surface of the first rotating gear is meshed with a second movable rack, and a guide groove is opened on the side of the fixed frame.

[0014] Preferably, the second movable rack and the first movable rack are oppositely distributed with respect to the first rotating gear, and two groups of guide grooves are oppositely distributed with respect to the first rotating gear, and the rotation of the first rotating gear can drive the second movable rack and the first movable rack to move relative to each other.

[0015] Preferably, an L-shaped fixing rod is fixedly connected to the side of the guide groove, the L-shaped fixing rod is slidably connected in the guide groove, the L-shaped fixing rod consists of a vertical plate and a horizontal plate, and a scraper is rotatably connected to the bottom of the vertical plate of the L-shaped fixing rod.

[0016] Preferably, the side of the L-shaped fixed rod is rotatably connected to a rotating ratchet, the outer ring surface of the rotating ratchet is meshed with a ratchet strip, the ratchet strip is fixedly connected to the side of the first limiting plate, the side of the L-shaped fixed rod is fixedly connected to a support rod, the outer ring surface of the support rod is rotatably provided with ratchet teeth, the outer arc surface of the ratchet teeth is fixedly connected to a reciprocating spring, the other end of the reciprocating spring is fixedly connected to a fixing plate, one side of the fixing plate is fixedly connected to the first limiting plate, the top of the fixing frame is fixedly connected to a fixing frame, the fixing frame is fixedly connected to the side of the protective frame, the ratchet strip and the rotating shaft in the middle of the rotating ratchet are fixedly connected to the middle of the scraper.

[0017] Preferably, the scraper can evenly coat the solder paste placed on the surface of the steel mesh, the ratchet teeth can fix the rotating ratchet to prevent the scraper from rotating when moving, and the ratchet bar can drive the scraper to flip over, thereby pushing the solder paste accumulated on the side of the first limiting plate back to the middle of the steel mesh, thereby improving the uniformity of the solder paste coating.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. In the solder paste printer for PCB circuit boards described in the present invention, while the bidirectional lead screw drives the displacement blocks to move, since the guide rod passes through the two groups of displacement blocks, when the bidirectional lead screw rotates, the two groups of displacement blocks will move in a straight line toward each other along the guidance of the guide rod, and drive the first limit plate to move synchronously while moving. The two groups of first limit plates can limit the solder paste placed on the steel mesh to prevent its diffusion and multiple coating work, thereby improving the coating work efficiency. At the same time, the movement of the displacement block can adapt to the coating work of circuit boards of different sizes.

[0020] 2. A solder paste printer for a PCB circuit board described in the present invention, when the rotating ratchet rotates, the scraper is driven to flip through the rotating shaft in the middle thereof, at which time the ratchet teeth rotate around the support rod, and the reciprocating spring fixed on the outer arc surface of the ratchet teeth is compressed. Since the distance between the bottom of the scraper and the upper part of the steel mesh is fixed, the solder paste accumulated on the side of the first limiting plate will be scraped toward the middle of the steel mesh during the flipping of the scraper. At this time, the solder paste accumulated on the side of the first limiting plate will be flipped by the scraper to the opposite side of the two groups of scrapers, and move in a straight line under the drive of the L-shaped fixed rod. Since the rotating ratchet and the ratchet bar are both ratchet tooth structures, the ratchet bar will not block the movement of the scraper. At the same time, since the rotating ratchet will be stuck due to the influence of the ratchet teeth, it will not be affected by the force of the solder paste and flip during the movement. The solder paste accumulated on the side of the second limiting plate can be scraped toward the middle of the steel mesh through the flipping and movement of the scraper, thereby avoiding the situation of too much or too little solder paste in some areas, thereby improving the uniformity of the solder paste on the steel mesh. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] Figure 1 It is a schematic diagram of the overall structure of a preferred embodiment of the present invention;

[0023] Figure 2 It is a rear-view stereoscopic structural schematic diagram of the device shown in the present invention;

[0024] Figure 3 It is a schematic diagram of the position structure of the solder paste printing device and the reciprocating limit mechanism shown in the present invention;

[0025] Figure 4 It is a schematic diagram of the three-dimensional structure of the reciprocating limiting mechanism shown in the present invention;

[0026] Figure 5 It is a schematic diagram of the internal structure of the protection frame shown in the present invention;

[0027] Figure 6 It is a schematic diagram of the position structure of the reciprocating limiting mechanism and the reciprocating smoothing mechanism shown in the present invention;

[0028] Figure 7 The present invention shows Figure 6 The enlarged structural diagram at A in the middle;

[0029] Figure 8 It is a schematic diagram of the internal structure of the fixed frame shown in the present invention;

[0030] In the figure: 1. solder paste printing device; 101. support frame; 102. transmission frame; 103. placement plate; 104. steel mesh; 105. electric guide rail; 106. electric cylinder; 107. scraper;

[0031] 2. Reciprocating limit mechanism; 201. Protection frame; 202. Driving motor; 203. Bidirectional screw rod; 204. Displacement block; 205. Connecting rod; 206. Guide rod; 207. First limit plate; 208. Guide plate; 209. Second limit plate;

[0032] 3. Reciprocating smoothing mechanism; 301. Micro motor; 302. Fixed frame; 303. First rotating gear; 304. First moving rack; 305. Guide groove; 306. Second moving rack; 307. L-shaped fixed rod; 308. Scraper; 309. Rotating ratchet; 310. Ratchet bar; 311. Ratchet teeth; 312. Support rod; 313. Reciprocating spring; 314. Fixed plate; 315. Fixed frame. DETAILED DESCRIPTION

[0033] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0034] Embodiment 1

[0035] like Figures 1 to 8 As shown, a solder paste printer for a PCB circuit board described in an embodiment of the present invention includes a solder paste printing device 1, wherein the solder paste printing device 1 includes a support frame 101, a transmission frame 102 is fixedly connected inside the support frame 101, a placement plate 103 is fixedly connected to the top of the transmission frame 102, a steel mesh 104 is detachably connected to the top of the transmission frame 102, an electric guide rail 105 is fixedly connected to the top of the support frame 101, the electric guide rail 105 includes a slider, an electric cylinder 106 is fixedly connected to the bottom of the slider of the electric guide rail 105, a scraper 107 is fixedly connected to the output end of the electric cylinder 106, and a reciprocating limit mechanism 2 is arranged inside the solder paste printing device 1;

[0036] The reciprocating limiting mechanism 2 includes a protective frame 201 fixedly arranged on the side of the scraper 107, two groups of displacement blocks 204 are slidably arranged inside the protective frame 201, and a first limiting plate 207 is fixedly arranged at the bottom of the displacement block 204. The relative movement of the two groups of displacement blocks 204 can drive the two groups of first limiting plates 207 to move relative to each other, so as to limit the solder paste placed on the upper surface of the steel mesh 104, avoiding too little or no solder paste in some areas, thereby reducing the number of reciprocating coating times and improving production efficiency.

[0037] Specifically, when the scraper 107 is used to coat the solder paste on the steel mesh 104, the solder paste will be squeezed, and it is easy to form accumulation on both sides of the scraper 107, which will cause the distribution of the solder paste on the circuit board to become uneven, with too much solder paste in some areas and too little or no solder paste in some areas. This will cause the coating process to require repeated coating operations to correct the uneven coating effect, thereby reducing production efficiency and increasing production costs;

[0038] Therefore, the present invention solves this problem by setting up a corresponding structure. In the solder paste printer for a PCB circuit board described in the present invention, when it is necessary to coat the circuit board with solder paste, the circuit board is first placed on the placement plate 103 on the upper part of the transmission frame 102, and the steel mesh 104 is detachably restricted on the top of the transmission frame 102. At this time, the electric guide rail 105 fixed on the top of the support frame 101 is started, and the electric guide rail 105 will drive the sliding slider inside it to move, and during the movement, it will drive the electric cylinder 106 fixed at the bottom to move synchronously. Since the solder paste is placed on the upper surface of the steel mesh 104, and the scraper 107 will be driven by the electric cylinder 106 to fit the upper part of the steel mesh 104, the solder paste placed on the upper part of the steel mesh 104 driven by the electric guide rail 105 will be pressed by the scraper 107 into the groove opened inside the steel mesh 104, The coating work on the circuit board is completed, but when the scraper 107 is used to coat the solder paste on the steel mesh 104, the solder paste will be squeezed, and it is easy to form accumulation on both sides of the scraper 107, which will cause the distribution of the solder paste on the circuit board to become uneven, with too much solder paste in some areas and too little or no solder paste in some areas. This will require repeated coating operations during the coating process to correct the uneven coating effect, which will reduce production efficiency and increase production costs. At this time, the displacement block 204 inside the protective frame 201 fixed on the side of the scraper 107 will perform relative linear motion, and at the same time drive the displacement block 204 and the first limiting plate 207 to move synchronously, so that the solder paste placed on the upper surface of the steel mesh 104 can be limited to avoid too little or no solder paste in some areas, thereby reducing the number of reciprocating coating times and improving production efficiency.

[0039] Embodiment 2

[0040] like Figures 2 to 8 As shown in Comparative Example 1, another embodiment of the present invention is:

[0041] like Figure 5 As shown, the protection frame 201 described in this embodiment is fixedly connected to a driving motor 202 on its side, the output end of the driving motor 202 is fixedly connected to a bidirectional screw rod 203, the outer ring surface of the bidirectional screw rod 203 is threadedly connected to a displacement block 204, the bottom of the displacement block 204 is fixedly connected to a connecting rod 205, and the bottom of the connecting rod 205 is fixedly connected to a first limit plate 207.

[0042] Specifically, when the solder paste falls onto the steel mesh 104 through the paste discharge device on the top of the scraper 107, the drive motor 202 is started according to the size of the circuit board. At this time, the output shaft of the drive motor 202 will drive the bidirectional screw 203 fixed thereto to rotate synchronously and drive the displacement block 204 to move synchronously while rotating. When the displacement block 204 rotates, it will drive the connecting rod 205 and the first limit plate 207 to move synchronously, and the bidirectional screw 203 can provide power support for subsequent components.

[0043] like Figure 5 As shown, the protection frame 201 of this embodiment has an inner cavity, and the side wall of the inner cavity of the protection frame 201 is fixedly connected to a guide rod 206. A guide plate 208 is provided on one side of the first limiting plate 207, and the first limiting plate 207 slides in a groove body opened on the side of the guide plate 208.

[0044] Specifically, while the bidirectional screw 203 drives the displacement block 204 to move, since the guide rod 206 passes through the two groups of displacement blocks 204, when the bidirectional screw 203 rotates, the two groups of displacement blocks 204 will move in a straight line towards each other along the guidance of the guide rod 206, and at the same time drive the first limit plate 207 to move synchronously. The two groups of first limit plates 207 can limit the solder paste placed on the steel mesh 104 to prevent its diffusion and cause multiple coating work, thereby improving the coating work efficiency. At the same time, the movement of the displacement block 204 can adapt to the coating work of circuit boards of different sizes.

[0045] like Figure 8As shown, in this embodiment, a reciprocating smoothing mechanism 3 for smoothing is arranged on the upper part of the reciprocating limiting mechanism 2, and the reciprocating smoothing mechanism 3 includes a micro motor 301, and a fixed frame 302 is fixedly connected to the side of the micro motor 301, and the output shaft of the micro motor 301 passes through the side wall of the fixed frame 302, and the output end of the fixed frame 302 is fixedly connected to a first rotating gear 303, and the outer ring surface of the first rotating gear 303 is meshed with a first movable rack 304, and the outer ring surface of the first rotating gear 303 is meshed with a second movable rack 306, and a guide groove 305 is opened on the side of the fixed frame 302.

[0046] Specifically, when the reciprocating limit mechanism 2 completes its work, the micro motor 301 will start and drive the first rotating gear 303 to rotate synchronously through its output shaft. When the first rotating gear 303 rotates, it will drive the first moving rack 304 and the second moving rack 306 engaged on its outer ring surface to move linearly along the guide block in the inner cavity of the fixed frame 302. The first moving rack 304 and the second moving rack 306 can provide power support for subsequent equipment operation.

[0047] like Figure 8 As shown, in this embodiment, the guide groove 305 is fixedly connected to the side with an L-shaped fixing rod 307, and the L-shaped fixing rod 307 is slidably connected in the guide groove 305. The L-shaped fixing rod 307 is composed of a vertical plate and a horizontal plate. The bottom of the vertical plate of the L-shaped fixing rod 307 is rotatably connected with a scraper 308.

[0048] Specifically, when the second moving rack 306 and the first moving rack 304 perform linear motion, the L-shaped fixed rod 307 fixed on the sides of the second moving rack 306 and the first moving rack 304 will also perform linear motion along the guidance of the two sets of guide grooves 305. Since the scraper 308 rotates inside the vertical plate of the L-shaped fixed rod 307, when the L-shaped fixed rod 307 moves, the scraper 308 will also move synchronously and push the solder paste accumulated in the middle to both sides.

[0049] like Figure 6 and Figure 7As shown, in this embodiment, the L-shaped fixed rod 307 is rotatably connected to a rotating ratchet 309 on the side, and the outer annular surface of the rotating ratchet 309 is meshed with a ratchet strip 310, and the ratchet strip 310 is fixedly connected to the side of the first limiting plate 207, and the L-shaped fixed rod 307 is fixedly connected to a support rod 312 on the side, and the outer annular surface of the support rod 312 is rotatably provided with ratchet teeth 311, and the outer arc surface of the ratchet teeth 311 is fixedly connected to a reciprocating spring 313, and the other end of the reciprocating spring 313 is fixedly connected to a fixed plate 314, and one side of the fixed plate 314 is fixedly connected to the first limiting plate 207, and a fixed frame 315 is fixedly connected to the top of the fixed frame 302, and the fixed frame 315 is fixedly connected to the side of the protective frame 201, and the ratchet strip 310 and the rotating shaft in the middle of the rotating ratchet 309 are fixedly connected to the middle of the scraper 308.

[0050] Specifically, during the coating process, solder paste will accumulate on the side of the two groups of first limiting plates 207 facing each other, and the L-shaped fixing rod 307 will also move toward the side of the first limiting plate 207. At this time, the rotating ratchet 309 will engage with the ratchet bar 310 and rotate. When the rotating ratchet 309 rotates, the scraper 308 will be driven to flip through the rotating shaft in the middle. At this time, the ratchet teeth 311 will rotate around the support rod 312, and the reciprocating spring 313 fixed on the outer arc surface of the ratchet teeth 311 will be compressed. Since the distance between the bottom of the scraper 308 and the upper part of the steel mesh 104 is fixed, the solder paste accumulated on the side of the first limiting plate 207 will be scraped toward the middle of the steel mesh 104 during the flipping process of the scraper 308. The solder paste on the side of the first limiting plate 207 will be flipped by the scraper 308 to the opposite side of the two groups of scrapers 308, and moved in a straight line under the drive of the L-shaped fixing rod 307. Since the rotating ratchet 309 and the ratchet bar 310 are both ratchet tooth structures, the ratchet bar 310 will not block the movement of the scraper 308. At the same time, since the rotating ratchet 309 will be stuck due to the influence of the ratchet teeth 311, it will not be affected by the force of the solder paste and will not flip during the movement. The flipping and movement of the scraper 308 can scrape the solder paste accumulated on the side of the second limiting plate 209 to the middle of the steel mesh 104, thereby avoiding excessive or insufficient solder paste in certain areas, thereby improving the uniformity of the solder paste on the steel mesh 104.

[0051] Working principle: when the solder paste falls onto the steel mesh 104 through the paste discharge device on the top of the scraper 107, the drive motor 202 is started according to the size of the circuit board. At this time, the output shaft of the drive motor 202 will drive the bidirectional lead screw 203 fixed thereto to rotate synchronously and drive the displacement block 204 to move synchronously while rotating. When the displacement block 204 rotates, it will drive the connecting rod 205 and the first limit plate 207 to move synchronously. The bidirectional lead screw 203 can provide power support for subsequent components.

[0052] While the bidirectional lead screw 203 drives the displacement block 204 to move, since the guide rod 206 passes through the two groups of displacement blocks 204, the two groups of displacement blocks 204 will move in a straight line towards each other along the guidance of the guide rod 206 when the bidirectional lead screw 203 rotates, and at the same time drive the first limit plate 207 to move synchronously. The two groups of first limit plates 207 can limit the solder paste placed on the steel mesh 104 to prevent its diffusion and cause multiple coating work, thereby improving the coating work efficiency. At the same time, the movement of the displacement block 204 can adapt to the coating work of circuit boards of different sizes.

[0053] When the reciprocating limit mechanism 2 completes its work, the micro motor 301 will start and drive the first rotating gear 303 to rotate synchronously through its output shaft. When the first rotating gear 303 rotates, it will drive the first moving rack 304 and the second moving rack 306 meshing on its outer ring surface to move linearly along the guide block in the inner cavity of the fixed frame 302. The first moving rack 304 and the second moving rack 306 can provide power support for subsequent equipment operation.

[0054] When the second movable rack 306 and the first movable rack 304 perform linear motion, the L-shaped fixed rod 307 fixed on the sides of the second movable rack 306 and the first movable rack 304 will also perform linear motion along the guidance of the two sets of guide grooves 305. Since the scraper 308 rotates inside the vertical plate of the L-shaped fixed rod 307, when the L-shaped fixed rod 307 moves, the scraper 308 will also move synchronously and push the solder paste accumulated in the middle to both sides.

[0055] During the coating process, solder paste will accumulate on the side of the two sets of first limiting plates 207 facing each other, and the L-shaped fixing rod 307 will also move toward the side of the first limiting plate 207. At this time, the rotating ratchet 309 will mesh with the ratchet bar 310 and rotate. When the rotating ratchet 309 rotates, the scraper 308 will be driven to flip through the rotating shaft in the middle. At this time, the ratchet teeth 311 will rotate around the support rod 312, and the reciprocating spring 313 fixed on the outer arc surface of the ratchet teeth 311 will be compressed. Since the distance between the bottom of the scraper 308 and the upper part of the steel mesh 104 is fixed, the solder paste accumulated on the side of the first limiting plate 207 will be scraped toward the middle of the steel mesh 104 during the flipping process of the scraper 308. The solder paste on the side of the limiting plate 207 will be flipped by the scraper 308 to the opposite side of the two groups of scrapers 308, and moved in a straight line under the drive of the L-shaped fixing rod 307. Since the rotating ratchet 309 and the ratchet bar 310 are both ratchet tooth structures, the ratchet bar 310 will not prevent the scraper 308 from moving. At the same time, since the rotating ratchet 309 will be stuck due to the influence of the ratchet teeth 311, it will not be affected by the force of the solder paste and flipped during the movement. The flipping and movement of the scraper 308 can scrape the solder paste accumulated on the side of the second limiting plate 209 to the middle of the steel mesh 104, thereby avoiding too much or too little solder paste in certain areas, thereby improving the uniformity of the solder paste on the steel mesh 104.

[0056] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A solder paste printer for a PCB circuit board, comprising a solder paste printing device (1), the solder paste printing device (1) comprising a support frame (101), the support frame (101) is fixedly connected to a transmission frame (102) inside, the top of the transmission frame (102) is fixedly connected to a placement plate (103), the top of the transmission frame (102) is detachably connected to a steel mesh (104), the top of the support frame (101) is fixedly connected to an electric guide rail (105), the electric guide rail (105) comprises a slider, the bottom of the slider of the electric guide rail (105) is fixedly connected to an electric cylinder (106), and the output end of the electric cylinder (106) is fixedly connected to a scraper (107), characterized in that: The solder paste printing device (1) is provided with a reciprocating limiting mechanism (2) inside; The reciprocating limiting mechanism (2) comprises a protection frame (201) fixedly arranged on the side of the scraper (107), two groups of displacement blocks (204) are slidably arranged inside the protection frame (201), and a first limiting plate (207) is fixedly arranged at the bottom of the displacement block (204). The relative movement of the two groups of displacement blocks (204) can drive the two groups of first limiting plates (207) to move relative to each other, thereby limiting the solder paste placed on the upper surface of the steel mesh (104), avoiding too little or no solder paste in some areas, thereby reducing the number of reciprocating coatings and improving production efficiency.

2. The solder paste printer for a PCB circuit board according to claim 1, characterized in that: The side of the protection frame (201) is fixedly connected to a driving motor (202); the output end of the driving motor (202) is fixedly connected to a bidirectional screw rod (203); the displacement block (204) is threadedly connected to the outer ring surface of the bidirectional screw rod (203); the bottom of the displacement block (204) is fixedly connected to a connecting rod (205); and the first limiting plate (207) is fixedly connected to the bottom of the connecting rod (205).

3. A solder paste printer for a PCB circuit board according to claim 2, characterized in that: The rotation of the bidirectional screw rod (203) can drive the two groups of displacement blocks (204) to move synchronously, and then drive the two groups of first limit plates (207) to move synchronously through the connecting rod (205).

4. The solder paste printer for a PCB circuit board according to claim 2, characterized in that: An inner cavity is provided inside the protection frame (201), a guide rod (206) is fixedly connected to the side wall of the inner cavity of the protection frame (201), a guide plate (208) is provided on one side of the first limiting plate (207), and the first limiting plate (207) slides in a groove body provided on the side of the guide plate (208).

5. A solder paste printer for a PCB circuit board according to claim 4, characterized in that: The guide rod (206) can limit the two groups of displacement blocks (204) so ​​that they can perform relative linear motion along the guide of the guide rod (206), thereby driving the two groups of first limiting plates (207) to perform relative linear motion so that they can adapt to the coating work of circuit boards of different sizes. The two groups of the first limiting plates (207) can limit the solder paste to prevent the solder paste from diffusing outwards and causing repeated coating work, thereby improving production efficiency.

6. The solder paste printer for a PCB circuit board according to claim 1, characterized in that: A reciprocating smoothing mechanism (3) for smoothing is arranged on the upper part of the reciprocating limiting mechanism (2), and the reciprocating smoothing mechanism (3) comprises a micro motor (301), a fixed frame (302) is fixedly connected to the side of the micro motor (301), an output shaft of the micro motor (301) passes through the side wall of the fixed frame (302), a first rotating gear (303) is fixedly connected to the output end of the fixed frame (302), a first moving rack (304) is meshed on the outer ring surface of the first rotating gear (303), a second moving rack (306) is meshed on the outer ring surface of the first rotating gear (303), and a guide groove (305) is provided on the side of the fixed frame (302).

7. A solder paste printer for a PCB circuit board according to claim 6, characterized in that: The second movable rack (306) and the first movable rack (304) are arranged opposite to each other with respect to the first rotating gear (303), and two groups of guide grooves (305) are arranged opposite to each other with respect to the first rotating gear (303). The rotation of the first rotating gear (303) can drive the second movable rack (306) and the first movable rack (304) to move relative to each other.

8. The solder paste printer for a PCB circuit board according to claim 6, characterized in that: An L-shaped fixing rod (307) is fixedly connected to the side of the guide groove (305), and the L-shaped fixing rod (307) is slidably connected in the guide groove (305). The L-shaped fixing rod (307) is composed of a vertical plate and a horizontal plate, and a scraper (308) is rotatably connected to the bottom of the vertical plate of the L-shaped fixing rod (307).

9. A solder paste printer for a PCB circuit board according to claim 8, characterized in that: The side of the L-shaped fixed rod (307) is rotatably connected to a rotating ratchet (309), the outer annular surface of the rotating ratchet (309) is meshed with a ratchet bar (310), the ratchet bar (310) is fixedly connected to the side of the first limit plate (207), the side of the L-shaped fixed rod (307) is fixedly connected to a support rod (312), the outer annular surface of the support rod (312) is rotatably provided with ratchet teeth (311), and the outer arc surface of the ratchet teeth (311) is fixedly connected to a reciprocating spring. A spring (313) is provided, the other end of the reciprocating spring (313) is fixedly connected to a fixed plate (314), one side of the fixed plate (314) is fixedly connected to the first limit plate (207), the top of the fixed frame (302) is fixedly connected to a fixed frame (315), the fixed frame (315) is fixedly connected to the side of the protection frame (201), and the ratchet bar (310) and the rotating shaft in the middle of the rotating ratchet (309) are fixedly connected to the middle of the scraper (308).

10. The solder paste printer for a PCB circuit board according to claim 9, characterized in that: The scraper (308) can evenly coat the solder paste placed on the upper surface of the steel mesh (104); the ratchet teeth (311) can fix the rotating ratchet (309) to prevent the scraper (308) from rotating when moving; the ratchet bar (310) can drive the scraper (308) to flip, thereby pushing the solder paste accumulated on the side of the first limiting plate (207) back to the middle of the steel mesh (104), thereby improving the uniformity of the solder paste coating.

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