An online continuous vacuum defoaming method

Abstract

The application provides an online continuous vacuum defoaming method, which is used for receiving printed circuit boards after solder mask printing is completed by a screen printer and conveying the defoamed printed circuit boards to a baking process; the method comprises the following steps: a layered storage mechanism is used to send the printed circuit boards into at least one vacuum storage chamber in a plurality of vacuum storage chambers one by one, so that the printed circuit boards are stored in the vertical direction and are spaced from each other; after the vacuum storage chamber is filled by the layered storage mechanism, the vacuum storage chamber is controlled to stop feeding and be closed, and is switched to execute a defoaming process; when the vacuum storage chamber executing the defoaming process is completed, the vacuum storage chamber is controlled to be switched to execute a discharging process; when the printed circuit boards in the vacuum storage chamber executing the discharging process are all taken out, the vacuum storage chamber is controlled to be switched to execute a feeding process; the above steps are cyclically executed, so that each vacuum storage chamber is cyclically switched between the feeding process, the defoaming process and the discharging process.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board processing technology, and in particular to an online continuous vacuum defoaming method. Background Technology

[0002] This section provides only background information relevant to this disclosure and is not necessarily prior art.

[0003] With the rapid development of printed circuit board (PCB) technology, the line density of HDI boards in the consumer electronics field is increasing daily, with line spacing reduced to below 50 micrometers. Simultaneously, the copper layer thickness of power boards and server boards is constantly increasing, with some products reaching 5 ounces of copper thickness. In the solder mask printing process for these high-density, fine-line, and thick-copper boards, the ink can trap air bubbles between the lines during printing. The smaller the line spacing and the thicker the copper layer, the more difficult it is for these bubbles to escape automatically after printing. These residual air bubbles eventually form voids between the lines, leading to decreased insulation performance and severely affecting the electrical reliability and lifespan of the product.

[0004] To address the issue of residual air bubbles between circuit lines after solder mask printing, independent vacuum defoaming equipment has emerged in the industry. The working principle of this equipment is as follows: the circuit board after solder mask printing is manually moved by the operator into the vacuum defoaming machine for defoaming treatment in a vacuum environment. After defoaming is completed, the operator manually removes the circuit board and sends it to the next baking process.

[0005] Even with a three-layer independent drawer-type storage box, where the PCB boards with completed screen printing ink are laid flat in each layer, these operations still require manual loading and unloading. This necessitates manual handling between the screen printing machine and the oven, increasing the number of manual steps and labor intensity. Furthermore, due to manual loading and unloading, production efficiency is limited by the operator's handling speed. During manual handling, collisions or friction between circuit boards can easily cause ink scratches or circuit damage, affecting the finished product yield.

[0006] Alternatively, a conveyor system can be used to transfer the printed PCBs to a fixture in a circulation module, from which a circular conveyor belt transports the fixture to a vacuum degassing machine for defoaming. This solution integrates the degassing process into the PCB printing production line, reducing manual handling to some extent. However, in this solution, the vacuum degassing machine is mounted on a circular conveyor belt, which is still a serial processing mode, meaning that feeding, degassing, and discharging are performed sequentially at the same station or along the same path.

[0007] When a batch of PCBs is being defoamed under pressure in a vacuum degassing machine, the upstream printing module must wait or stop feeding, and the downstream pre-baking module may also face the risk of material shortage, making it difficult to achieve truly continuous and uninterrupted production. Summary of the Invention

[0008] The objective of this invention is to at least solve the problem of low production efficiency in offline production equipment. This objective is achieved through the following technical solution:

[0009] This invention provides an online continuous vacuum defoaming method for receiving printed circuit boards (PCBs) after solder resist printing by a screen printing machine and conveying the defoamed PCBs to a baking process. The method is applied to a vacuum defoaming device with multiple vacuum storage chambers, each chamber equipped with a layered storage mechanism capable of vertically stacking multiple PCBs while maintaining spacing between them. The method includes the following steps: Step 1: The printed circuit boards are fed one by one into the layered storage mechanism in at least one of the multiple vacuum storage chambers, so that the printed circuit boards are stacked vertically and spaced apart from each other in the vacuum storage chamber; after the vacuum storage chamber is filled by the layered storage mechanism, the vacuum storage chamber is controlled to stop feeding and be closed, and it is switched to perform the defoaming process. Step 2: After the vacuum storage chamber that performs the defoaming process has completed the defoaming treatment, control the vacuum storage chamber to switch to the discharge process; Step 3: After all the printed circuit boards in the vacuum storage chamber that is performing the unloading process are removed, control the vacuum storage chamber to switch to the feeding process; repeat steps 1 to 3 above, so that each vacuum storage chamber cycles between the feeding process, the defoaming process and the unloading process.

[0010] By using a layered storage mechanism to stack multiple printed circuit boards vertically in a single vacuum storage chamber, a single defoaming process can be performed in batches, improving production efficiency. By executing the feeding, defoaming, and discharging processes in parallel and rotating them in different vacuum storage chambers, the feeding, defoaming, and discharging processes overlap in time, eliminating equipment waiting periods and forming a continuous online assembly line operation. At the same time, the device is directly connected to upstream and downstream processes (screen printing machine and baking process), avoiding manual handling and reducing labor intensity.

[0011] In one embodiment of the online continuous vacuum defoaming method of the present invention, the "cyclic execution of steps one to three above" further includes: at any given time, at least one of the vacuum storage chambers performs the feeding process, at least one of the vacuum storage chambers performs the defoaming process, and at least one of the vacuum storage chambers performs the discharging process.

[0012] By ensuring that the vacuum storage chamber is in the feeding, defoaming, and discharging processes at any given moment, the parallel overlap of the three processes on the time axis is guaranteed, so that no process is idle at any instant, thereby maximizing equipment utilization and optimizing production cycle.

[0013] In one embodiment of the online continuous vacuum defoaming method of the present invention, the number of vacuum storage chambers is at least three, and the three vacuum storage chambers are rotated in the order of the feeding process, the defoaming process, and the discharging process, wherein at the same time, the three vacuum storage chambers are respectively in different processes.

[0014] By setting up at least three vacuum storage chambers and having them operate in different processes at the same time, a stable three-station parallel production line is formed. Each storage chamber completes the entire process of feeding, defoaming, and discharging in sequence, so that the overall production cycle is determined by the longest time in a single process rather than the total time of the processes, thereby significantly improving the output per unit time.

[0015] In one embodiment of the online continuous vacuum defoaming method of the present invention, the "cyclic execution of steps one to three above" is further performed in chronological order as follows: In the first time period, the first vacuum storage chamber performs the feeding process, the second vacuum storage chamber performs the defoaming process, and the third vacuum storage chamber performs the discharging process; in the second time period, the first vacuum storage chamber switches to performing the defoaming process, the second vacuum storage chamber switches to performing the discharging process, and the third vacuum storage chamber switches to performing the feeding process; in the third time period, the first vacuum storage chamber switches to performing the discharging process, the second vacuum storage chamber switches to performing the feeding process, and the third vacuum storage chamber switches to performing the defoaming process; the first time period, the second time period, and the third time period are repeated in sequence.

[0016] By dividing the state switching of the three vacuum storage chambers into three fixed time periods in a cyclical rotation, each storage chamber experiences feeding, defoaming, and discharging in sequence, with the total duration of the three time periods being equal. This achieves synchronization and standardization of the process cycle, simplifies the control logic, facilitates matching with the production cycle of upstream and downstream equipment, and ensures balanced load of each storage chamber, avoiding long-term idleness or overload of some storage chambers.

[0017] In one embodiment of the online continuous vacuum defoaming method of the present invention, in "step one", after each printed circuit board is received, the layered storage mechanism moves one station height to prepare to receive the next printed circuit board.

[0018] By moving the station height by one level after receiving each printed circuit board, the layered storage mechanism can automatically and orderly store multiple printed circuit boards in storage positions at different heights. This achieves automatic layering during batch feeding, avoids ink smudging caused by multiple printed circuit boards coming into contact with each other during storage, and ensures that the feeding and unloading mechanisms are always aligned with empty storage positions, thus improving the automation level and positioning accuracy of loading and unloading.

[0019] In one embodiment of the online continuous vacuum defoaming method of the present invention, in "step three", the unloading process further includes: the layered storage mechanism in the vacuum storage chamber moves step by step to transfer the printed circuit boards on each storage station to the loading and unloading mechanism in sequence.

[0020] By moving the tiered storage mechanism step by step and sequentially transferring the printed circuit boards to each storage station, the unloading process is made orderly and automated, avoiding collisions or scratches that may occur when multiple printed circuit boards exit at the same time. At the same time, it forms symmetrical control with the step-by-step lifting operation during feeding, simplifying the difficulty of software programming and debugging.

[0021] In one embodiment of the online continuous vacuum defoaming method of the present invention, the "cyclic execution of steps one to three above" further includes: feeding and removing the printed circuit board through a movable loading and unloading mechanism, wherein the loading and unloading mechanism selectively docks with one of the vacuum storage chambers in the feeding process and the discharging process.

[0022] By selectively docking with different vacuum storage chambers through a movable loading and unloading mechanism, a single loading and unloading mechanism can serve multiple vacuum storage chambers, reducing the number of equipment parts, lowering manufacturing costs and maintenance complexity, while ensuring speed and docking accuracy when switching between different storage chambers.

[0023] In one embodiment of the online continuous vacuum defoaming method of the present invention, in the feeding process, the printed circuit board is fed into the vacuum storage chamber by a feeding and unloading mechanism disposed on one side of the vacuum storage chamber; in the discharging process, the printed circuit board is removed from the vacuum storage chamber by a discharging and unloading mechanism disposed on the opposite side of the vacuum storage chamber.

[0024] By setting the feeding and unloading mechanisms on opposite sides of the vacuum storage chamber, the feeding and unloading channels are physically separated, avoiding interference between the loading and unloading paths. This allows feeding and unloading to proceed simultaneously without affecting each other, further improving the efficiency of parallel operations and simplifying the structural design of the loading and unloading mechanism.

[0025] In one embodiment of the online continuous vacuum defoaming method of the present invention, the defoaming process includes: reducing the pressure in the vacuum storage chamber to a preset defoaming vacuum level and maintaining it for a preset pressure holding time, so that the bubbles on the surface of the printed circuit board can escape.

[0026] By reducing the pressure in the vacuum storage chamber to a preset defoaming vacuum level and maintaining the pressure for a specified time, the air bubbles in the ink on the surface of the printed circuit board are allowed to fully expand and escape under negative pressure, thereby effectively eliminating void defects between lines after solder resist printing, improving insulation performance and electrical reliability. At the same time, the preset vacuum level and pressure holding time can be adjusted according to different ink characteristics, enhancing process adaptability.

[0027] In one embodiment of the online continuous vacuum defoaming method of the present invention, before performing step one, an initialization step is further included: pre-evacuating each of the vacuum storage chambers to achieve a preset initial vacuum level in each of the vacuum storage chambers.

[0028] By pre-vacuuming each vacuum storage chamber before starting the assembly line operation and achieving the preset initial vacuum level, the start-up delay caused by waiting for vacuuming in the first feeding cycle is avoided, allowing the equipment to enter continuous operation from the moment of startup. At the same time, the initial vacuum level of each storage chamber is consistent, which facilitates pressure balance control during subsequent process switching and reduces the impact of pressure changes on the ink on the surface of the printed circuit board. Attached Figure Description

[0029] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart of the online continuous vacuum defoaming method of the present invention; Figure 2 This is a flowchart of the feeding process in the online continuous vacuum defoaming method of the present invention; Figure 3 This is a flowchart illustrating the working state of the three vacuum storage chambers in the online continuous vacuum defoaming method of the present invention. Figure 4 This is a flowchart of the discharge process of the online continuous vacuum defoaming method of the present invention. Detailed Implementation

[0030] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0031] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0032] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0033] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0034] The following are embodiments of the online continuous vacuum defoaming method of the present invention with reference to the accompanying drawings. The drawings and embodiments are only used to explain the present invention and should not be construed as limiting the present invention.

[0035] Combination Figures 1 to 4 The embodiments of the online continuous vacuum defoaming method of the present invention are as follows: Figure 1 The flowchart of the online continuous vacuum defoaming method of the present invention is as follows: Figure 1 As shown, the online continuous vacuum defoaming method of the present invention first performs an initialization step: pre-vacuuming each vacuum storage chamber to achieve a preset initial vacuum level, thereby avoiding start-up delays caused by vacuuming waiting in the first feeding cycle, and ensuring that the initial vacuum level of each storage chamber is consistent to facilitate pressure balance during subsequent process switching.

[0036] After initialization, proceed to step one: send the printed circuit boards one by one into the layered storage mechanism of at least one of the multiple vacuum storage chambers, so that the printed circuit boards are stacked vertically and spaced apart from each other in the vacuum storage chamber.

[0037] Once the vacuum storage chamber is full by the layered storage mechanism, the vacuum storage chamber is stopped from feeding and sealed, and then switched to the defoaming process.

[0038] This step increases the amount of defoaming processed per cycle by storing multiple printed circuit boards in batches within a single vacuum storage chamber using a layered storage mechanism.

[0039] Then proceed to step two: After the vacuum storage chamber that performs the defoaming process has completed the defoaming treatment, control the vacuum storage chamber to switch to the discharge process.

[0040] Then proceed to step three: After all the printed circuit boards in the vacuum storage chamber that is performing the unloading process have been removed, control the vacuum storage chamber to switch to the feeding process.

[0041] Finally, steps one through three above are repeated in a cycle, so that each vacuum storage chamber cycles between the feeding process, the defoaming process, and the discharging process, thereby forming a continuous and uninterrupted online vacuum defoaming process.

[0042] In another embodiment, the initialization step also includes leak detection of each vacuum storage chamber, that is, after pre-vacuuming, the vacuum valve is closed and the pressure rise rate is monitored. If the pressure rise rate exceeds a preset threshold, an alarm is issued to ensure that the sealing of each storage chamber meets the defoaming process requirements.

[0043] In another embodiment, the "full" judgment condition in step one is not limited to all storage stations of the layered storage mechanism being filled, but can also be set to be filled to a preset quantity (e.g., 80% of the total capacity) according to process requirements, so as to balance the defoaming time and the feeding time.

[0044] In another embodiment, the triggering condition for the cyclic rotation is not limited to the three driving modes of full storage, defoaming completion, and material discharge completion. A timed rotation mode can also be adopted, that is, each vacuum storage chamber is forced to switch to the defoaming process after staying in the feeding process for a fixed time, so as to adapt to the defoaming time requirements of different ink characteristics.

[0045] In another embodiment, the online continuous vacuum defoaming method also includes a fault handling step: when any vacuum storage chamber experiences abnormal pressure or the sealing door cannot be closed during the defoaming process, the controller marks the storage chamber as faulty and suspends its operation, while the remaining normal storage chambers continue to rotate operations; a maintenance request can also be issued at the same time to achieve non-stop maintenance.

[0046] In another embodiment, the online continuous vacuum defoaming method further includes a data recording step: the controller records the feed quantity, defoaming time, pressure curve and discharge quantity for each batch in each vacuum storage chamber, and uploads this data to the control system for quality recording, process traceability and process optimization.

[0047] Figure 2 This is a flowchart of the feeding process in the online continuous vacuum defoaming method of the present invention. Figure 2 As shown, the feeding process of the present invention specifically includes: first, controlling the loading and unloading mechanism to dock with the target vacuum storage chamber, and the loading and unloading mechanism moving along the guide to the loading and unloading port position of the vacuum storage chamber and completing precise positioning.

[0048] Then, a printed circuit board is fed into the layered storage mechanism in the vacuum storage chamber through the conveying assembly of the loading and unloading mechanism. The rollers on the conveying assembly support the edge of the printed circuit board and drive it forward, avoiding contact between the rollers and the effective area of ​​the board surface, thereby protecting the ink layer.

[0049] After each printed circuit board is fed in, the layered storage mechanism immediately rises or falls by one station height, aligning the next vacant storage position with the loading / unloading port in preparation for receiving the next printed circuit board.

[0050] Repeat the above feeding and lifting actions until the vacuum storage chamber is filled with the layered storage mechanism.

[0051] Finally, the full vacuum storage chamber is sealed and switched to the defoaming process.

[0052] By moving the station height by one for each board delivered, the layered storage mechanism can automatically and orderly store multiple printed circuit boards at different heights, avoiding ink smudging caused by contact between boards. At the same time, it ensures that the loading and unloading mechanism is always aligned with the empty storage position, improving the automation level and positioning accuracy of loading and unloading.

[0053] In another embodiment, the feeding process is adapted to the output board rate of the upstream screen printing machine. The controller controls the loading and unloading mechanism to receive the printed circuit boards one by one with a matching efficiency based on the signal of the output board of the screen printing machine. When the output speed of the upstream screen printing machine fluctuates, the controller dynamically adjusts the board picking frequency of the loading and unloading mechanism to avoid backlog or material interruption at the feed port.

[0054] In another embodiment, a width adjustment step is included before the printed circuit board is fed in: the controller drives the width adjustment component according to the width parameter of the current printed circuit board, so that the two conveying units of the loading and unloading mechanism move synchronously to the appropriate width, thereby adapting to printed circuit boards of different specifications.

[0055] In another embodiment, the lifting of the layered storage mechanism is achieved by using a servo motor in conjunction with an absolute encoder. The controller records the absolute height coordinates of each storage location, and after the equipment restarts, it can directly locate the previously interrupted workstation without returning to zero, thus shortening the production preparation time.

[0056] In another embodiment, the lifting drive of the hierarchical storage mechanism is a servo motor, and is equipped with an absolute encoder, the output of which is electrically connected to the input of the controller.

[0057] During the initial commissioning of the equipment, the controller executes a calibration program: it drives the layered storage mechanism to move sequentially to the preset mechanical positions of each storage station, reads and records the absolute encoder values ​​corresponding to each station, and stores these values ​​as absolute height coordinates in non-volatile memory.

[0058] During normal operation of the equipment, the controller directly drives the tiered storage mechanism to move to the target position based on the absolute height coordinates of the target workstation.

[0059] When the equipment restarts due to power failure or malfunction, the controller directly reads the absolute position of the current station from the absolute encoder, calculates the moving distance between the current station and the target station based on the stored absolute height coordinates, and then drives the layered storage mechanism to move directly to the target station without performing a zero-return operation.

[0060] Using the above method, the equipment can resume operation without having to find the mechanical origin again after restarting, and it can also avoid the risk of collision caused by limit switch failure or mechanical jamming during the zeroing process.

[0061] In another embodiment, a stop positioning step is also provided during the feeding process: when the printed circuit board is transported to the end of the storage position, the stop component extends upward to block the printed circuit board from continuing to move forward, so that it stops accurately at the predetermined handover position. At the same time, the photoelectric sensor on the stop component feeds back the positioning signal to the controller. After receiving the signal, the controller immediately stops the drive of the rolling wheel to prevent excessive squeezing from causing damage to the board edge.

[0062] In another embodiment, when the current vacuum storage chamber is detected to be about to be full (e.g., only one empty slot remains), the controller sends a deceleration or pause signal to the previous process (screen printing machine) in advance to avoid a backlog caused by the arrival of new printed circuit boards at the moment of switching the defoaming process.

[0063] In another embodiment, the determination of "full" is achieved by a position sensor located at the end of the storage position of the layered storage mechanism. When the last storage position is occupied by the printed circuit board, the position sensor sends a full signal to the controller. Upon receiving the signal, the controller determines that the vacuum storage chamber is full and triggers a switching action.

[0064] The full storage determination can also be achieved by the controller through counting. Each time a printed circuit board is sent in, the counter increments. When the count value reaches the total number of storage stations of the layered storage mechanism, it is determined that the storage is full.

[0065] In another embodiment, the lifting height of each station in the feeding process can be dynamically calibrated according to the actual thickness of the printed circuit board: the layered storage mechanism is lowered to the lowest position when unloaded, and the actual distance between the current storage position and the loading and unloading port is measured by a laser range sensor. The controller corrects the lifting step size accordingly to eliminate the cumulative error caused by mechanical wear or temperature deformation.

[0066] Figure 3 The flowchart shows the working state of the three vacuum storage chambers in the online continuous vacuum defoaming method of the present invention, as follows: Figure 3 As shown, the three vacuum storage chambers of this invention operate cyclically in chronological order: In the first time period, the first vacuum storage chamber performs the feeding process, the second vacuum storage chamber performs the defoaming process, and the third vacuum storage chamber performs the discharging process.

[0067] In the second time period, the first vacuum storage chamber switches to perform the defoaming process, the second vacuum storage chamber switches to perform the discharge process, and the third vacuum storage chamber switches to perform the feeding process.

[0068] In the third time period, the first vacuum storage chamber switches to the discharge process, the second vacuum storage chamber switches to the feeding process, and the third vacuum storage chamber switches to the defoaming process.

[0069] The first, second, and third time periods are then repeated in a cyclical manner.

[0070] With this timing arrangement, at any given time, the three vacuum storage chambers are in different processes, with at least one chamber performing feeding, one performing defoaming, and one performing discharging. The three processes completely overlap in time, eliminating equipment waiting idle periods. This allows each storage chamber to sequentially experience the entire process of feeding, defoaming, and discharging, achieving continuous and uninterrupted online defoaming operation.

[0071] In another embodiment, the durations of the first, second, and third time periods are determined by preset process parameters. The durations of the three time periods are independent of each other and can be adjusted separately. When the durations of the three time periods are equal, a constant-rate pipeline is formed. When the durations of the three time periods are not equal, the longest time period determines the overall efficiency. After the longest time period is completed, the controller synchronously triggers the state switching of all storage chambers.

[0072] In another embodiment, the duration of each of the three time periods can be independently adjusted according to actual process requirements. The duration of the feeding process is determined by the total capacity of the layered storage mechanism and the output efficiency of the upstream screen printing machine; the duration of the defoaming process is determined by the ink characteristics and vacuum requirements; and the duration of the discharging process is determined by the receiving speed of the downstream baking process.

[0073] The controller dynamically adjusts the timing of time period switching based on the actual completion time of each process. When a process is completed ahead of schedule, the switching is triggered immediately to avoid idle waiting.

[0074] In another embodiment, when there are four or more vacuum storage chambers, the rotation sequence is extended accordingly: for example, when there are four storage chambers, two storage chambers perform the defoaming process simultaneously to extend the total defoaming time without reducing the working efficiency, and the other two storage chambers perform the feeding and discharging processes respectively, forming a four-station parallel production line.

[0075] In another embodiment, a transition period is also provided in the switching sequence: before switching, the balancing valve between the two storage chambers is briefly opened to equalize the pressure, and then the sealing door is opened to avoid the printed circuit board shaking or ink impact caused by excessive pressure difference.

[0076] The length of the transition period is dynamically determined by the differential pressure value detected by the pressure sensor; the larger the differential pressure, the longer the transition time.

[0077] In another embodiment, when a vacuum storage chamber fails to complete the current process on time due to a malfunction, the controller skips the storage chamber and continues to rotate the remaining normal storage chambers in the original order. At the same time, the faulty storage chamber is marked as pending maintenance and will be added back to the rotation sequence manually or automatically after maintenance is completed.

[0078] In another embodiment, the switching signal for the rotation sequence is uniformly controlled by the controller. The movement and lifting actions of the sealing doors, vacuum valves, and loading and unloading mechanisms of each vacuum storage chamber are all executed in coordination to ensure strict synchronization of the three time periods and avoid conflicts caused by two storage chambers simultaneously connecting to the same loading and unloading mechanism due to timing deviations.

[0079] Figure 4 The flowchart of the discharge process of the online continuous vacuum defoaming method of the present invention is as follows: Figure 4 As shown, the discharge process of the online continuous vacuum defoaming method of the present invention specifically includes: after a vacuum storage chamber completes the vacuum defoaming treatment, the controller first controls the loading and unloading mechanism (specifically the discharge loading and unloading mechanism) to move to the loading and unloading port position of the vacuum storage chamber and complete the docking.

[0080] Then the layered storage mechanism moves step by step, transferring the printed circuit boards on each storage station to the loading and unloading mechanism in sequence; after each printed circuit board is transferred, the layered storage mechanism moves one station height so that the printed circuit board on the next storage station is aligned with the loading and unloading port.

[0081] After receiving the printed circuit board, the loading and unloading mechanism transports the printed circuit board to the downstream baking process through its conveying components.

[0082] Repeat the above steps until all printed circuit boards in the vacuum storage chamber have been transferred.

[0083] Finally, the vacuum storage chamber is switched to the feeding process.

[0084] By moving and transferring materials step by step, the unloading process is automated and orderly, avoiding collisions or scratches that may occur when multiple printed circuit boards exit at the same time. At the same time, it forms symmetrical control with the step-by-step lifting operation during feeding, simplifying the control logic.

[0085] In another embodiment, the direction of movement of the unloading process is opposite to the direction of lifting and lowering during the feeding process: if the layered storage mechanism rises from the bottom to the top layer during feeding, then it descends from the top to the bottom layer during unloading to ensure the first-in-first-out operation sequence and avoid the printed circuit board staying in the vacuum storage chamber for too long.

[0086] In another embodiment, a posture detection step is also provided in the unloading process: before the loading and unloading mechanism receives the printed circuit board, the placement posture of the printed circuit board is detected by a vision sensor set at the loading and unloading port. If the printed circuit board is found to be tilted or offset, the controller controls the flipping cylinder to drive the edge rolling wheel to flip and form a guide slope, guiding the edge of the printed circuit board smoothly into the loading and unloading mechanism.

[0087] In another embodiment, after the unloading process is completed, a vacuum breaking control step is also included: before switching to the feeding process, the vacuum storage chamber is slowly filled with air through the vacuum breaking valve to restore the internal pressure to normal pressure. The filling rate is controlled by the flow regulating valve to avoid the airflow generated by rapid air intake from impacting the ink on the board surface.

[0088] In another embodiment, the moving position of the layered storage mechanism in the unloading process is automatically determined by the controller based on the storage status of each station recorded during feeding: if a certain storage station is not used during feeding for some reason (e.g., due to insufficient number of printed circuit boards), then the unloading process skips that station and moves directly to the next station with boards, thereby saving unloading time.

[0089] In another embodiment, a buffer step is provided between the unloading process and the next process (baking process): when the baking process is temporarily unable to receive the printed circuit board, the unloading mechanism will temporarily store the unloaded printed circuit board on the transition buffer rack, and continue to transport it after the baking process is ready, thereby avoiding the entire unloading process from being forced to stop due to a brief blockage downstream, and ensuring that the vacuum storage chamber can be emptied in time and switched to the feeding state.

[0090] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An online continuous vacuum defoaming method, characterized in that, This method is used to receive printed circuit boards after solder resist printing by a screen printing machine and to transport the defoamed printed circuit boards to the baking process. The method is applied to a vacuum defoaming device with multiple vacuum storage chambers, each of which is equipped with a layered storage mechanism capable of stacking multiple printed circuit boards vertically while maintaining spacing between them. The method includes the following steps: Step 1: The printed circuit boards are fed one by one into the layered storage mechanism in at least one of the multiple vacuum storage chambers, so that the printed circuit boards are stacked vertically and spaced apart from each other in the vacuum storage chamber; after the vacuum storage chamber is filled by the layered storage mechanism, the vacuum storage chamber is controlled to stop feeding and be closed, and it is switched to perform the defoaming process, reducing the pressure in the vacuum storage chamber to a preset defoaming vacuum degree and maintaining the preset pressure holding time, so that the air bubbles on the surface of the printed circuit board can escape. Step 2: After the vacuum storage chamber that performs the defoaming process has completed the defoaming treatment, control the vacuum storage chamber to switch to the discharge process; Step 3: After all the printed circuit boards in the vacuum storage chamber that is performing the unloading process have been removed, control the vacuum storage chamber to switch to the feeding process. Steps one through three above are repeated in a loop, so that each vacuum storage chamber cycles between the feeding process, the defoaming process, and the discharging process. At any given time, at least one of the vacuum storage chambers performs the feeding process, at least one of the vacuum storage chambers performs the defoaming process, and at least one of the vacuum storage chambers performs the discharging process. The printed circuit board is fed in and taken out by a movable loading and unloading mechanism, which selectively docks with one of the vacuum storage chambers during the feeding process and the discharging process.

2. The online continuous vacuum defoaming method according to claim 1, characterized in that, The number of vacuum storage chambers is at least three, and the three vacuum storage chambers are rotated in a cycle according to the order of the feeding process, the defoaming process, and the discharging process. At any given time, the three vacuum storage chambers are in different processes.

3. The online continuous vacuum defoaming method according to claim 2, characterized in that, The step of "repeatedly executing steps one through three above" is further executed in chronological order as follows: In the first time period, the feeding process is performed in the first vacuum storage chamber, the defoaming process is performed in the second vacuum storage chamber, and the discharging process is performed in the third vacuum storage chamber. In the second period, the first vacuum storage chamber switches to perform the defoaming process, the second vacuum storage chamber switches to perform the discharging process, and the third vacuum storage chamber switches to perform the feeding process. In the third time period, the first vacuum storage chamber switches to perform the discharge process, the second vacuum storage chamber switches to perform the feeding process, and the third vacuum storage chamber switches to perform the defoaming process. The first time period, the second time period, and the third time period are repeated in sequence.

4. The online continuous vacuum defoaming method according to claim 1, characterized in that, In "Step 1", after each printed circuit board is received, the layered storage mechanism moves one station height to prepare to receive the next printed circuit board.

5. The online continuous vacuum defoaming method according to claim 1, characterized in that, In "Step Three", the unloading process further includes: the layered storage mechanism in the vacuum storage chamber moves step by step to transfer the printed circuit boards on each storage station to the loading and unloading mechanism in sequence.

6. The online continuous vacuum defoaming method according to claim 1, characterized in that, In the feeding process, the printed circuit board is fed into the vacuum storage chamber by a feeding and unloading mechanism located on one side of the vacuum storage chamber; In the unloading process, the printed circuit board is removed from the vacuum storage chamber by an unloading mechanism located on the opposite side of the vacuum storage chamber.

7. The online continuous vacuum defoaming method according to claim 1, characterized in that, Before performing step one, an initialization step is also included: pre-evacuating each of the vacuum storage chambers to bring each of the vacuum storage chambers to a preset initial vacuum level.

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