Stencil Printing Machine

Abstract

The present application relates to a stencil printing machine, which comprises a first holding device 110, a moving device 121, two support tables 131, 132, and two driving devices 151, 152, wherein the first holding device 110 is capable of reciprocating horizontally in a vertical direction, the moving device 121 is attached to the first holding device 110 and is capable of reciprocating horizontally in a horizontal direction on the first holding device 110, and the two support tables 131, 132 are attached to the lower end of the moving device 121 and are driven by corresponding solder pastes. The two drive devices 151, 152 are mounted on a moving device 121 so that each of the two drive devices 151, 152 is positioned above a corresponding support table 131, 132 and is used to press the corresponding solder paste container 141, 142. The moving device 121 can drive the two support tables 131, 132 and the two drive devices 151, 152 to vertically reciprocate. Two standard solder paste containers 141, 142 can be assembled for the stencil printer provided by the present application. When one solder paste container 141, 142 is empty, the solder paste supply is switched to the other solder paste container 141, 142, and the stencil printer can continue to operate without stopping, thereby significantly improving the operating efficiency of the stencil printer.

Description

[Technical field]

[0001] [Related Applications] This international application claims priority to Chinese Patent Application No. 201811418182.9, entitled "A STENCIL PRINTER", filed on November 26, 2018, and Chinese Patent Application No. 201821959379.9, entitled "A STENCIL PRINTER", filed on November 26, 2018. Chinese Patent Application No. 201811418182.9 and Chinese Patent Application No. 201821959379.9 are hereby incorporated by reference in their entireties.

[0002] This application relates to stencil printers for manufacturing printed circuit boards, and more particularly to solder paste dispensing apparatus for stencil printers. [Background technology]

[0003] During the manufacture of surface mount printed circuit boards (PCBs), stencil printers can be used to print solder paste onto the PCB so that electronic components can be later deposited on the PCB. A PCB with a conductive surface is fed into the stencil printer, and one or more small holes or marks (called "benchmarks") on the PCB are aligned from below with the fine holes on the stencil of the stencil printer. The solder paste dispenser of the stencil printer descends from above the stencil to a height close to the stencil, and solder paste is forced out of a solder paste container onto the stencil. After the solder paste is dispensed onto the stencil, a scraper of the stencil printer moves close to the upper surface of the stencil to force the solder paste into the fine holes on the stencil so that it reaches the conductive surface of the PCB. The solder paste is usually dispensed onto the stencil from a standard solder paste container. The solder paste container contains a limited amount of solder paste. After the solder paste in the solder paste container is used up, the solder paste container needs to be replaced with a new solder paste container to dispense the solder paste. After the printing operation, the PCB leaves the stencil and is fed into the next processing unit in the production line. Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned operating procedures are repeated in a large-scale production line that manufactures large numbers of PCBs. An improved stencil printer is needed to continuously repeat the corresponding operating procedures more economically and efficiently.

[0005] After long-term observation and experiment, the inventor finds that the operation and time required to replace the exhausted solder paste container will affect the working efficiency of the stencil printer. A standard solder paste container usually contains 500g of solder paste and can be used to print multiple PCBs. After the solder paste in the solder paste container is exhausted, it is necessary to stop the stencil printer to replace the solder paste container with a new solder paste container. In a large-scale automatic production line, frequently stopping the stencil printer to replace the solder paste container will reduce the working efficiency of the stencil printer or even the entire production line. [Means for solving the problem]

[0006] Two standard solder paste containers can be assembled for the stencil printer provided by the present application. When one solder paste container is used up, the solder paste is switched to the other solder paste container, and the stencil printer can continue to operate without stopping, and after both solder paste containers are used up, they are replaced with new ones. In this way, the number of stops and the number of replacements are both reduced by half, and therefore the working efficiency of the stencil printer is significantly improved.

[0007] The stencil printer provided by the present application includes a first holding device, a moving device, two support tables, and two driving devices. The first holding device is horizontally reciprocable in a portrait orientation. The moving device is attached to the first holding device and horizontally reciprocable in a landscape orientation on the first holding device. Two support tables are attached to a lower end of the moving device, and each of the two support tables is used to support a corresponding solder paste container. The two driving devices are attached to the moving device such that each of the two driving devices is disposed above the corresponding support table and each of the two driving devices is used to press the corresponding solder paste container, and the moving device is drivable to vertically reciprocate the two support tables and the two driving devices.

[0008] According to the stencil printing machine, the two support tables are arranged on two opposite sides of the moving device so as to be arranged back-to-back, or the two support tables are arranged on the same side of the moving device so as to be arranged side-by-side.

[0009] According to the stencil printing machine, the two driving devices include a first driving device and a second driving device, each of the first driving device and the second driving device includes a cylinder, the cylinder including a cylinder body, a piston rod, and a pressure head. The cylinder body is fixed on the moving device, and the cylinder body has a chamber inside. The piston rod is disposed in the chamber and is vertically reciprocable in response to a change in air pressure in the chamber, and the piston rod extends downward to the outside of the cylinder body and forms a lower end of the piston rod. The pressure head is connected to the lower end of the piston rod so as to be vertically reciprocable together with the piston rod.

[0010] The stencil printer further includes two solder paste amount used detection devices, each of which is used to detect a stroke of a piston rod of a corresponding drive device and thus detects the amount of solder paste used in a corresponding solder paste container, and is configured to generate a solder paste amount used signal of the corresponding solder paste container when the piston rod moves to a predetermined position.

[0011] According to the stencil printer, the used solder paste amount detection device includes a magnet ring and a magnetic switch. The magnet ring is placed on the piston rod and can move with the piston rod. The magnetic switch is attached to the outside of the cylinder body, and the magnetic switch is capable of generating a used solder paste amount signal when the magnet ring moves to a position that is a predetermined distance away from the magnetic switch.

[0012] According to the stencil printing machine, each of the two support tables has a base and a support, the base is attached to the lower end of the moving device, the lower end of the support is attached to the base, the shape of the upper end of the support is configured to match the opening of the solder paste container and is used to support the solder paste container, the support has a through hole therein from bottom to top, and the through hole is used to extrude the solder paste into the solder paste container.

[0013] According to the stencil printer, the base has a recessed storage portion used to store the lower end of the support, the bottom of the storage portion has a circulation hole, and one side of the storage portion has an opening communicating with the storage portion. The base further includes a baffle, which is attached to the side of the storage portion and is used to open or close the opening.

[0014] The stencil printer further includes a second holding device, the moving device being attached to the first holding device via the second holding device, and the first holding device and the second holding device being detachably arranged such that the second holding device can be removed from the first holding device.

[0015] The stencil printing machine further includes a controller, the controller being capable of controlling the movements of the first holding device, the moving device, and the two drive devices.

[0016] According to the stencil printing machine, the two driving devices include a first driving device and a second driving device, and the first driving device and the second driving device are alternately set as working driving devices. When the first driving device is set as the working driving device, the controller receives a solder paste amount used signal from a solder paste amount used detection device corresponding to the first driving device, and is capable of selecting the second driving device as the working driving device according to the solder paste amount used signal.

[0017] According to the stencil printing machine, when a first drive unit is selected as the working drive unit, the controller is capable of controlling the working position of the first drive unit, and when a second drive unit is selected as the working drive unit, the controller is capable of adding a predetermined offset to the working position of the first drive unit to obtain the working position of the second drive unit.

[0018] According to the stencil printing machine, the offset is the distance between the centers of the circular holes of the two support tables.

[0019] The concept and specific structure of the present application, as well as the technical effects brought about by the present application, are described in combination with drawings to facilitate a complete understanding of the objectives, features, and effects of the present application.

[0020] A better understanding of the present application will be aided by reading the following detailed description in conjunction with the drawings, in which like reference numerals indicate like parts, and in which: [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 illustrates the structure of one embodiment of a stencil printer of the present application. [Figure 2A]2 is a diagram showing the rear structure of a second holding device and two solder paste supply devices in the embodiment of FIG. 1; [Figure 2B] 2 is a diagram showing a front structure of a second holding device and two solder paste supply devices in the embodiment of FIG. 1; FIG. [Figure 3A] FIG. 3 shows the structure of the embodiment of FIGS. 2A and 2B with the solder paste container removed. [Figure 3B] FIG. 3B shows the structure of the solder paste dispenser of the embodiment of FIG. 3A with the support removed. [Figure 3C] FIG. 3B shows the structure of the embodiment of FIG. 3A with the baffle open. [Figure 3D] FIG. [Figure 3E] 3D is a cross-sectional view of the support in the direction AA of FIG. 3C. [Figure 4A] FIG. 3 shows the structure of the cylinder body of the embodiment of FIGS. 2A and 2B with the drive mechanism removed. [Figure 4B] FIG. [Figure 4C] FIG. 4C is a cross-sectional view of the driving device in the BB direction of FIG. 4B. [Figure 4D] FIG. 3B shows the structure of the solder paste dispenser of FIG. 3A with the support removed. [Figure 5A] FIG. 2 illustrates an initial state in a solder paste extrusion process. [Figure 5B] 1 illustrates the solder paste extrusion process when the pressure head moves downward to contact the bottom surface of the solder paste container. FIG. [Figure 5C] FIG. 2 illustrates the solder paste extrusion process, in which a pressure head presses the solder paste container downward to extrude the solder paste. [Figure 5D] FIG. 2 illustrates the state of the solder paste in the solder paste container when it has been completely extruded during the solder paste extrusion process. [Figure 5E] FIG. 13 illustrates the reset state in the solder paste extrusion process. [Figure 6] FIG. 1 illustrates the structure of one embodiment of a magnetic switch. [Figure 7A] FIG. 2 is a diagram showing the structure of another embodiment of the stencil printer of the present application. [Figure 7B] 7B shows the structure of a second holding device and two solder paste supply devices of the embodiment of FIG. 7A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Various specific implementation modes of the present application are described below with reference to the drawings, which form a part of this specification. Although directional terms such as "front", "rear", "above", "below", "left", "right", "inside", "outside", "top", "bottom", "near end", "far end", "landscape", and "portrait" are used in the present application to describe various illustrated structural parts and components, it should be understood that these terms are used for convenience of illustration only and are determined based on the illustrated orientation in the drawings. Because the embodiments disclosed in the present application can be oriented in different directions, these directional terms are used only as illustrations, instead of limitations.

[0023] FIG. 1 shows the structure of one embodiment of the stencil printer 100 of the present application. As shown in FIG. 1, the stencil printer 100 includes an operating platform 101, a first holding device 110, a second holding device 250 (see FIG. 2A), and a moving device 121. The operating platform 101 is horizontally arranged and has a substantially rectangular shape, and a stencil (not shown) for printing on a PCB is placed in the center of the operating platform 101. The guide rails 102 are arranged on both sides of the operating platform 101 in a vertical direction. The first holding device 110 is attached to the operating platform 101 and can horizontally reciprocate on the guide rails 102 in a vertical direction. The guide rails 111 are arranged laterally on the first holding device 110. The second holding device 250 is attached to the first holding device 110 and can horizontally reciprocate on the guide rails 111 in a horizontal direction. The moving device 121 is attached to the first holding device 110 via the second holding device 250. The moving device 121 comprises a vertically reciprocating part. The moving device 121 is used to move the solder paste supply device. In the embodiment of FIG. 1, the moving device 121 is a cylinder, and the vertically reciprocating part is a piston rod of the cylinder. Through the above-mentioned settings, the moving device 121 can drive the solder paste supply device to move horizontally and vertically, so that the solder paste supply device can dispense solder paste to an expected position on the operating platform 101.

[0024] In the present application, two solder paste supplying devices are arranged for the stencil printing machine 100, the first solder paste supplying device includes a first support table 131 supporting a first solder paste container 141 and a first driving device 151 for pressing the first solder paste container 141, and the second solder paste supplying device includes a second support table 132 supporting a second solder paste container 142 and a second driving device 152 for pressing the second solder paste container 142. The first support table 131 and the first driving device 151 are fixed to one side of the moving device 121, and the second support table 132 and the second driving device 152 are fixed to the other side of the moving device 121, so that the two solder paste supplying devices are arranged back to back. The moving device 121 can drive the two solder paste supplying devices to vertically reciprocate.

[0025] The first support table 131 is attached to the lower end of the moving device 121. The first solder paste container 141 is placed on the first support table 131 with its opening facing downward and its bottom surface facing upward. The first driving device 151 is attached to the first support table 131 and equipped with a pressure head 423 that can vertically reciprocate with respect to the first support table 131 (see FIG. 5A to FIG. 5C). As the pressure head 423 of the first driving device 151 moves downward with respect to the first support table 131, the pressure head 423 can press the bottom surface of the first solder paste container 141 downward to push the solder paste downward from the first solder paste container 141. In the embodiment of FIG. 1, the first driving device 151 is a cylinder. The second solder paste supply device has the same structure as that of the first solder paste supply device, and the second solder paste supply device will not be described again here.

[0026] When a printing operation is performed, the moving device 121 lowers the solder paste dispenser to an appropriate height above the stencil to push the solder paste toward the stencil. When the moving device is in other states, for example when the moving device is moving horizontally or in a standby mode, the moving device 121 raises the solder paste dispenser to perform other operations.

[0027] In the embodiment of FIG. 1, the first holding device 110 and the second holding device 250 are removably arranged such that the second holding device 250 can be removed from the first holding device 110 to facilitate replacement of the solder paste container on the solder paste supply device.

[0028] The stencil printer 100 further includes a scraper 160 attached to the first holding device 110. After the solder paste is extruded onto the stencil, the scraper 160 is driven by the first holding device 110 to move close to the upper surface of the stencil so as to push the solder paste into the slots on the stencil to reach the conductive surface of the PCB, thus completing the printing operation.

[0029] The stencil printer 100 further includes a controller 170. The controller 170 is capable of controlling the movement and working positions of the first holding device 110, the second holding device 250, the moving device 121, the scraper 160, and the driving devices 151, 152, so that they can cooperate with each other to complete a printing operation for a PCB. The controller 170 can include any suitable control device or control component, such as one or more processors, memories, and programmable circuits.

[0030] 2A and 2B show the 3D structure of two solder paste dispensers of the embodiment of FIG. 1 from rear and front views respectively, with FIG. 2A further showing a second holding device 250. As shown in FIG.

[0031] 2A and 2B, the moving device 121 includes a first cylinder 221 and a second cylinder 222, which are used to drive the first solder paste supply device and the second solder paste supply device to vertically reciprocate, respectively. The first cylinder 221 and the second cylinder 222 are arranged side by side. The first cylinder 221 has a cylinder body 231 and a piston rod 241. The second cylinder 222 has a cylinder body 232 and a piston rod 242. The cylinder bodies 231 and 232 of the first cylinder 221 and the second cylinder 222 are attached to the first holding device 110 via the second holding device 250, and the piston rods 241 and 242 of the first cylinder 221 and the second cylinder 222 are vertically reciprocable relative to the cylinder bodies 231 and 232. The two solder paste supply devices are arranged back to back on both sides of the moving device 121, and the first support table 131 and the first driving device 151 are fixed and connected to the driving end of the piston rod 241 of the first cylinder 221 via a support plate 261, so that the first driving device can be driven to vertically reciprocate by the piston rod 241 of the first cylinder 221. The second support table 132 and the second driving device 152 are fixed and connected to the driving end of the piston rod 242 of the second cylinder 222 via a support plate 262, so that the second driving device can be driven to vertically reciprocate by the piston rod 242 of the second cylinder 222. In another embodiment, the moving device 121 may have only one cylinder, and the two solder paste supply devices may be fixed and attached to the same cylinder. It should be noted that in other embodiments, the second holding device 250 may not be provided, in which case the moving device 121 may be directly coupled to the first holding device 110 .

[0032] Figure 3A shows the structure of the embodiment of Figures 2A and 2B with solder paste reservoirs 141, 142 removed. Figure 3B shows the structure of the solder paste dispenser of the embodiment of Figure 3A with support 320 removed. Figure 3C shows the structure of the embodiment of Figure 3A with baffle 331 open. Figure 3D is a side view of support 320, and Figure 3E is a cross-sectional view of support 320 in direction AA of Figure 3C.

[0033] As shown in Figures 3A to 3E, the first support table 131 is attached to a support plate 261 on one side. The first support table 131 includes a base 310, a support 320, a vertically extending connecting plate 361, and a horizontally extending connecting plate 371. The base 310 is attached to the lower end of the connecting plate 361, and the connecting plate 371 is attached to the upper end of the connecting plate 361. The first driving device 151 is supported by the connecting plate 371. The support 320 has a through hole 323 therein that runs from bottom to top. The lower end of the support 320 is attached to the base 310, and the shape of the upper end 321 of the support 320 is configured to match the opening of the solder paste container such that the solder paste container 141, 142 can be inverted on the upper end 321 of the support 320 with the opening facing down, and the solder paste in the solder paste container 141, 142 can only flow out through the through hole 323 in the support 320. A seal ring 340 is further disposed around the upper end 321 of the support 320 such that a slipper seal is formed between the outer periphery of the upper end 321 and the inner wall of the solder paste container 141, 142 to prevent solder paste leakage. It should be noted that the first drive device 151 is supported by the first support table 131 in the above-mentioned embodiment, but in other embodiments, the horizontally extending connecting plate 371 may not be disposed on the first support table 131, and the first drive device 151 may be directly coupled to the support plate 261.

[0034] The base 310 has a recessed storage portion 311 that is used to store the lower end 322 of the support 320. The bottom of the storage portion 311 has a circulation hole 312 that communicates with a through hole 323 in the support 320 when the support 320 is attached to the base 310. The storage portion 311 has an opening 313 on the outside that communicates with the storage portion 311, and a baffle 331 is attached to the outside of the storage portion 311 and is used to open or close the opening 313. One end of the baffle 331 can be rotatably connected to one end of the opening 313, and the other end of the baffle 331 can be screwed or snapped to the other end of the opening 313.

[0035] When the solder paste container is placed in or removed from the base 310, it is typically placed in or removed together with the support 320. Specifically, when the solder paste container needs to be placed in the base 310, the upper end 321 of the support 320 is first inserted into the opening of the solder paste container, and then the lower end 322 of the support 320 is mounted in the recessed receiving portion 311 of the base 310. When the solder paste container needs to be removed from the base 310, the support 320, with the solder paste container placed upside down on the support 320, is removed from the base 310 for solder paste container replacement. With the opening 313 and the baffle 331 in place, when the baffle 331 is opened, the opening 313 is exposed, so that the support 320, together with the solder paste containers 141, 142 arranged on the support 320, can be placed in or removed from the base 310 via the opening 313 side of the base 310. Such a configuration ensures easier replacement and installation of the solder paste containers in a limited operating space (especially a vertically limited operating space). After the support 320 is attached to the base 310, the support 320 can be fixed by closing the baffle 331.

[0036] The second support table 132 has the same structure as that of the first support table 131, which will not be described again here.

[0037] 4A shows the structure of the cylinder body 410 of the embodiment of FIGS. 2A and 2B with the driving devices 151 and 152 removed, FIG. 4B is a side view of the driving devices 151 and 152, FIG. 4C is a cross-sectional view of the driving devices 151 and 152 in the BB direction of FIG. 5B, and FIG. 4D shows the structure of the solder paste supply device of FIG. 3A with the support 320 removed.

[0038] As shown in FIG. 4A-FIG. 4C, the driving devices 151, 152 are cylinders. The driving devices 151, 152 have the same structure, and the driving device 151 is taken as an example to describe the specific structure of the two driving devices. The driving device 151 includes a cylinder body 410, a piston rod 420, and a pressure head 423. The cylinder body 410 is supported by the connecting plate 371 of the first support table 131 with the opening facing downward. The opening through which the piston rod 420 passes is disposed on the connecting plate 371. The cylinder body 410 has a chamber 411 therein. The piston rod 420 is disposed in the chamber 411, and a slipper seal exists between the upper end 421 of the piston rod 420 and the inner wall of the cylinder body 410, and the piston rod can vertically reciprocate according to the change in the air pressure in the chamber 411. The piston rod 420 extends down to the outside of the cylinder body 410 to form a lower end 422 of the piston rod 420. The pressure head 423 is coupled to the lower end 422 of the piston rod 420 such that the pressure head 423 can vertically reciprocate together with the piston rod 420. The shape of the pressure head 423 is formed such that the pressure head conforms to the bottom surfaces of the solder paste containers 141, 142 to help press the bottom surfaces of the solder paste containers 141, 142 downward.

[0039] Each of the driving devices 151, 152 is correspondingly equipped with a solder paste quantity used detection device, which is used to detect the stroke of the piston rod 420 in the corresponding driving device 151, 152 and thus detect the amount of solder paste used in the corresponding solder paste container 141, 142. The solder paste quantity used detection device is configured to generate a corresponding solder paste quantity used signal when the piston rod 420 moves to a predetermined position, which indicates whether the solder paste in the corresponding solder paste container 141, 142 has been used up.

[0040] The used solder paste amount detection device includes a magnet ring 431 and a magnetic switch 432. The magnet ring 431 is placed on the piston rod 420 and can move together with the piston rod 420. The magnetic switch 432 is mounted on the outside of the cylinder body 410, and the magnetic switch 432 is capable of generating a corresponding used solder paste amount signal when the magnet ring 431 moves to a position that is a predetermined distance away from the magnetic switch 432.

[0041] The controller 170 is connected to the magnetic switch 432 and can receive a used solder paste amount signal from the magnetic switch 432. When the controller 170 receives a used solder paste amount signal from the corresponding magnetic switch 432 of the first driver 151 indicating that the solder paste in the first solder paste container 141 has been used up, the controller 170 selects the second driver 152 as the working driver to replace the first driver 151.

[0042] 4D, the distance between the center of the circulation hole 312 of the first support table 131 and the center of the circulation hole 312 of the second support table 132 is x. The distance x is also the distance between the centers of the through holes 323 in the two supports after the supports 320 on the first support table 131 and the supports 320 on the second support table 132 are mounted in place.

[0043] 4A , when the first solder paste supply device in the working position is aligned with the dispensing position P on the operating platform 101 to dispense solder paste, if the controller 170 receives a used solder paste amount signal from the corresponding magnetic switch 432 of the first actuator 151 indicating that the solder paste in the first solder paste container 141 is exhausted, the controller 170 selects the second actuator 152 as the working actuator to replace the first actuator 151. However, before the solder paste is dispensed through the second actuator 152 of the second solder paste supply device, the second solder paste supply device needs to move by a predetermined offset to align with the dispensing position P so that the first solder paste supply device can continue the uncompleted solder paste dispense. That is, the controller 170 needs to add a predetermined offset to the working position of the first actuator 151 to obtain the working position of the second actuator 152. The offset is the distance x (shown in FIG. 4D ) between the center of the circulation hole 312 of the first support table 131 and the center of the circulation hole 312 of the second support table 132. After the working drive is switched to the second drive 152, the stencil printer can continue the printing operation using the second solder paste container 142.

[0044] When the working position of the second driving device 152 is obtained by adding a predetermined offset to the working position of the first driving device 151, it is unnecessary to configure separate control programs for the two driving devices in the solder paste dispensing operation, and thus the control operation for solder paste dispensing is simplified.

[0045] 5A to 5E show the solder paste extrusion process of the first solder paste supplying device, where FIG. 5A shows the initial state, FIG. 5B shows the state when the pressure head 423 moves downward to contact the bottom surface of the solder paste container 141, FIG. 5C shows the state when the pressure head 423 presses the solder paste container 141 downward to extrude the solder paste, FIG. 5D shows the state when the solder paste in the solder paste container 141 has been completely extruded, and FIG. 5E shows the reset state.

[0046] 5A, initially, the solder paste container 141 filled with solder paste is placed upside down on the support 320 with the opening facing down and the bottom surface facing up. The upper end 321 of the support 320 is inserted into the opening of the solder paste container 141 and a slipper seal is formed between the upper end and the inner wall of the solder paste container 141.

[0047] As shown in FIG. 5B, pressure head 423 is driven by piston rod 420 to move downward and contact the bottom surface of solder paste container 141.

[0048] 5C, the pressure head 423 continues to move downward and presses the solder paste container 141. The solder paste in the solder paste container 141 is forced out from the bottom of the base 310 through the through hole 323 in the support 320 and the circulation hole 312 in the base 310. As the downward stroke of the piston rod 420 and the pressure head 423 increases continuously, the solder paste in the solder paste container 141 is continuously forced out, or the solder paste container 141 moves downward continuously under the pressure of the pressure head 423, so that the upper end 321 of the support 320 is inserted deeper into the solder paste container 141. Meanwhile, the magnet ring 431 on the piston rod 420 also moves downward.

[0049] 5D, when the solder paste in the solder paste container 141 is completely pushed out or only a very small amount remains, the piston rod 420 and the pressure head 423 move downward to the maximum stroke. At this point, the magnet ring 431 reaches a position close to the position of the magnetic switch 432, for example, at the same level as the magnetic switch 432. The magnetic switch 432 detects the magnet ring 431 and thus generates a corresponding solder paste usage signal, indicating that the solder paste in the solder paste container 141 has been used up.

[0050] As shown in FIG. 5E, after receiving the solder usage amount signal from the magnetic switch 432, the controller 170 resets the first driving device 151, switches the working driving device to the second driving device 152, and uses the second solder paste container 142 to continue the printing operation, and repeats the working process of FIGS. 5A to 5D.

[0051] FIG. 6 shows the structure of one embodiment of the magnetic switch 432. As shown in FIG. 6, the magnetic switch 432 comprises two elastic magnetic reeds 631 which constitute a pair of mechanical contacts in a circuit connection. There is a small gap between the two magnetic reeds 631. When the magnetic ring 431 moving with the piston rod 420 approaches the magnetic switch 432, the magnetic field generated by the magnetic ring 431 magnetizes and brings the two magnetic reeds 631 into contact, thus connecting the circuit and generating a corresponding electric signal. After the magnetic ring 431 moves far away from the magnetic switch 432, the magnetic field disappears, and the two magnetic reeds 631 are demagnetized and return to their original positions, thus disconnecting the circuit and also disappearing the electric signal.

[0052] FIG. 7A shows the structure of another embodiment of the stencil printer 700 of the present application, and FIG. 7B shows the structure of the second holding device 720 and two solder paste supply devices of the embodiment of FIG. 7A. As shown in FIG. 7A and FIG. 7B, the two solder paste supply devices are arranged side by side on the same side of the moving device 721, unlike the embodiment of FIG. 1. The moving device 721 can only include one cylinder that can move the two solder paste supply devices vertically at the same time. Of course, the moving device 721 can also include two cylinders that are used to move the two solder paste supply devices respectively.

[0053] Based on the software and hardware structure of the conventional stencil printer, a solder paste supply device is added and an offset is configured for the stencil printer provided by the present application. Without making major changes to the original operation mode or control mode, the solder paste container replacement frequency can be greatly reduced, thus improving the work efficiency.

[0054] Furthermore, if the stencil printer configuration allows the operating space to accommodate more solder paste dispensers, one or more solder paste dispensers can be added, thus further reducing the frequency of solder paste container replacement.

[0055] This application is disclosed by the use of examples, one or more of which are illustrated in the drawings. Each example is provided to explain the application, not to limit the application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the application without departing from the scope or spirit of the application. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still further embodiments. It is therefore intended that these features cover all modifications and variations within the scope of the appended claims and their equivalents. The present disclosure also includes the following aspects. [Aspect 1] A first holding device (110) that is horizontally reciprocable in the vertical direction; a moving device (121) attached to the first holding device (110) and capable of horizontally reciprocating on the first holding device (110); two support tables (131, 132) attached to the lower end of the moving device (121), each of the two support tables (131, 132) being used to support a corresponding solder paste container (141, 142); two driving devices (151, 152), each of which is attached to the moving device (121) so as to be positioned above a corresponding support table (131, 132), and each of which is used to press a corresponding solder paste container (141, 142); The stencil printing machine, wherein the moving device (121) is capable of driving the two support tables (131, 132) and the two drive devices (151, 152) to vertically reciprocate. [Aspect 2] The two support tables (131, 132) are arranged on both sides of the moving device (121) so as to be arranged back to back, or The stencil printing machine according to claim 1, characterized in that the two support tables (131, 132) are arranged on the same side of the moving device (121) so as to be arranged side by side. [Aspect 3] The two drive units (151, 152) include a first drive unit (151) and a second drive unit (152), each of the first drive unit (151) and the second drive unit (152) having a cylinder; The cylinder is A cylinder body (410) fixed on the moving device (121) and having a chamber (411) therein; a piston rod (420) disposed within the chamber (411), capable of vertically reciprocating in response to changes in air pressure within the chamber (411), and extending downward to the outside of the cylinder body (410) to form the lower end of the piston rod (420); and a pressure head (423) connected to the lower end of the piston rod (420) so as to be vertically reciprocable together with the piston rod (420). Aspect 4 The stencil printing machine of embodiment 3 further comprises two solder paste amount detection devices, each of which is used to detect the stroke of the piston rod (420) of the corresponding drive device (151, 152) and thus detect the amount of solder paste used in the corresponding solder paste container (141, 142), and is configured to generate a solder paste amount detection signal of the corresponding solder paste container (141, 142) when the piston rod (420) moves to a predetermined position. Aspect 5 The solder paste usage amount detection device is a magnet ring (431) disposed on the piston rod (420) and movable together with the piston rod (420); The stencil printing machine of embodiment 4, further comprising a magnetic switch (432) attached to the outside of the cylinder body (410) and capable of generating the solder paste usage amount signal when the magnet ring (431) moves to a position a predetermined distance away from the magnetic switch (432). Aspect 6 Each of the two support tables (131, 132) has a base (310) attached to the lower end of the moving device (121); The stencil printing machine of aspect 1 further comprises a support (320), the lower end of which is attached to the base (310), the shape of the upper end of which is configured to match the opening of the solder paste container (141, 142) and is used to support the solder paste container (141, 142), the support (320) having a through hole (323) therein from bottom to top, the through hole being used to extrude solder paste into the solder paste container (141, 142). Aspect 7 The base (310) has a recessed storage portion (311) for storing the lower end of the support (320), the bottom of the storage portion (311) has a circulation hole (312), and one side of the storage portion (311) has an opening (313) communicating with the storage portion (311); The stencil printing machine of claim 6, wherein the base (310) further comprises a baffle (331), the baffle (331) being attached to the side of the storage portion (311) and used to open or close the opening (313). Aspect 8 The stencil printing machine of embodiment 1 further comprises a second holding device (250), the moving device (121) is attached to the first holding device (110) via the second holding device (250), and the first holding device (110) and the second holding device (250) are removably arranged so that the second holding device (250) can be removed from the first holding device (110). Aspect 9 The stencil printing machine according to any one of aspects 1 to 8, further comprising a controller (170), the controller (170) being capable of controlling the movement of the first holding device (110), the moving device (121), and the two driving devices (151, 152). Aspect 10 the two driving devices (151, 152) include a first driving device (151) and a second driving device (152), the first driving device (151) and the second driving device (152) are alternately set as the working driving device, The stencil printing machine of aspect 9, characterized in that when the first driving device (151) is set as the working driving device, the controller (170) receives the solder paste amount used signal from the solder paste amount used detection device corresponding to the first driving device (151), and is capable of selecting the second driving device (152) as the working driving device in accordance with the solder paste amount used signal. Aspect 11 When the first driving device (151) is selected as the working driving device, the controller (170) is capable of controlling the working position of the first driving device (151); The stencil printing machine (200) of aspect 10, characterized in that when the second drive unit (152) is selected as the working drive unit, the controller (170) is capable of adding a predetermined offset to the working position of the first drive unit (151) to obtain the working position of the second drive unit (152). Aspect 12 The stencil printing machine according to claim 11, wherein the offset is the center-to-center distance between the circulation holes (312) of the two support tables (131, 132). [Explanation of symbols] [Explanation of symbols]

[0056] 100 Stencil Printing Machine 101 Operating Platform 102 Guide rail 110 First holding device 111 Guide rail 121 Mobile Device 131 First Support Table 132 Second Support Table 141 Paste container 142 Paste container 151 First Drive Unit 152 Second Drive Unit 160 Scraper 170 Controller 200 Stencil Printing Machine 221 First Cylinder 222 Second Cylinder 231 Cylinder body 232 Cylinder body 241 Piston rod 242 Piston rod 250 Second holding device 261 Support Plate 262 Support Plate 310 Base 311 Storage area 312 Circulation hole 313 Aperture 320 Support 321 Upper end 322 Bottom end 323 Through Hole 331 Baffle 340 Seal Ring 361 Connecting plate 371 Connecting plate 410 Cylinder body 411 Chamber 420 Piston rod 421 Upper end 422 Bottom end 423 Pressure Head 431 Magnet Ring 432 Magnetic Switch 631 Magnetic Reed 700 Stencil Printing Machine 720 Second holding device 721 Mobile Device

Claims

1. A first holding device (110) that is horizontally reciprocable in the vertical direction; a moving device (121) attached to the first holding device (110) and capable of horizontally reciprocating laterally on the first holding device (110); two support tables (131, 132) attached to the lower end of the moving device (121), each of the two support tables (131, 132) being used to support a corresponding solder paste container (141, 142); two driving devices (151, 152), each of which is attached to the moving device (121) so as to be positioned above a corresponding support table (131, 132), and each of which is used to press a corresponding solder paste container (141, 142); The moving device (121) is capable of driving the two support tables (131, 132) and the two drive devices (151, 152) to vertically reciprocate; a controller (170) capable of controlling the movements of the first holding device (110), the moving device (121), and the two driving devices (151, 152); The two drive devices (151, 152) include a first drive device (151) and a second drive device (152), and the first drive device (151) and the second drive device (152) are alternately set as working drive devices; When the first driving device (151) is set as the working driving device, the controller (170) receives the solder paste amount used signal from a solder paste amount used detection device corresponding to the first driving device (151), and is capable of selecting the second driving device (152) as the working driving device in accordance with the solder paste amount used signal.

2. The two support tables (131, 132) are disposed on both sides of the moving device (121), or 2. The stencil printing machine according to claim 1, characterized in that the two support tables (131, 132) are arranged on the same side of the moving device (121).

3. The two drive units (151, 152) include a first drive unit (151) and a second drive unit (152), each of the first drive unit (151) and the second drive unit (152) having a cylinder; The cylinder is A cylinder body (410) fixed on the moving device (121) and having a chamber (411) therein; a piston rod (420) disposed within the chamber (411), capable of vertically reciprocating in response to changes in air pressure within the chamber (411), and extending downward to the outside of the cylinder body (410) to form a lower end of the piston rod (420); 2. The stencil printing machine according to claim 1, further comprising a pressure head (423) connected to a lower end of the piston rod (420) so as to be vertically reciprocable together with the piston rod (420).

4. 4. The stencil printing machine of claim 3, further comprising two solder paste amount detection devices, each of which is used to detect the stroke of the piston rod (420) of the corresponding driving device (151, 152) and thus detect the amount of solder paste used in the corresponding solder paste container (141, 142), and is configured to generate a solder paste amount detection signal for the corresponding solder paste container (141, 142) when the piston rod (420) moves to a predetermined position.

5. The solder paste usage amount detection device is a magnet ring (431) placed on the piston rod (420) and movable with the piston rod (420); 5. The stencil printer of claim 4, further comprising a magnetic switch (432) attached to the outside of the cylinder body (410) and capable of generating the solder paste amount used signal when the magnet ring (431) moves to a position a predetermined distance away from the magnetic switch (432).

6. Each of the two support tables (131, 132) has A base (310) attached to the lower end of the moving device (121); 6. The stencil printer of claim 5, further comprising: a support (320), the lower end of which is attached to the base (310), the shape of the upper end of which is configured to match the opening of the solder paste container (141, 142) and is used to support the solder paste container (141, 142), the support (320) having a through hole (323) therein from bottom to top, the through hole being used to extrude solder paste from within the solder paste container (141, 142).

7. The base (310) has a recessed storage portion (311) used to store the lower end of the support (320), the bottom of the storage portion (311) has a hole (312), and one side of the storage portion (311) has an opening (313) communicating with the storage portion (311); 7. The stencil printer of claim 6, wherein the base (310) further comprises a baffle (331), the baffle (331) being attached to the side of the storage portion (311) and used to open or close the opening (313).

8. 2. The stencil printing machine according to claim 1, further comprising a second holding device (250), the moving device (121) being attached to the first holding device (110) via the second holding device (250), and the first holding device (110) and the second holding device (250) being removably arranged so that the second holding device (250) can be removed from the first holding device (110).

9. When the first driving device (151) is selected as the working driving device, the controller (170) is capable of controlling the working position of the first driving device (151); 8. The stencil printing machine of claim 7, characterized in that when the second drive unit (152) is selected as the working drive unit, the controller (170) is capable of adding a predetermined offset to the working position of the first drive unit (151) to obtain the working position of the second drive unit (152).

10. 10. The stencil printer of claim 9, wherein the offset is the center-to-center distance of the holes (312) of the two support tables (131, 132).

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