Electronic paste microfluidic negative pressure ultra-fine classification system for electronic material manufacturing

Abstract

The application provides an electronic paste microfluidic negative pressure ultra-micro classification system for electronic material manufacturing, and relates to the technical field of electronic paste filtering and separation and particle classification processing. The system is characterized in that: the electronic paste to be classified is subjected to low-shear pre-dispersion, steady-flow feeding and inlet negative pressure defoaming, and then enters a multi-stage microfluidic classification channel, and a laminar flow deviation is formed in a curved deviation section, so that coarse particles or agglomerated particles are enriched to a lateral negative pressure diversion port and introduced into a coarse particle collection branch, and the target particle size paste is output along the main flow direction. The system adjusts the suction strength of each stage of lateral negative pressure according to the inlet pressure, the outlet pressure, the lateral negative pressure, the channel pressure difference, the pressure difference growth rate and the flow attenuation rate, and performs parallel buffering, reverse pulse or exhaust treatment on the abnormal channel, and performs backflow re-classification on the redispersible coarse particles. Therefore, the electronic paste classification continuity, the target particle size retention rate and the functional particle utilization rate are improved.

Description

Technical Field

[0001] This invention relates to the field of electronic slurry filtration, separation, and particle classification technology, specifically to a microfluidic negative pressure ultra-micro classification system for electronic slurries used in electronic material manufacturing. Background Technology

[0002] Electronic pastes are widely used in electronic material manufacturing processes such as photovoltaic cell electrode preparation, multilayer ceramic capacitor manufacturing, fine circuit printing, thick film circuits, low-temperature sintering conductive layers, and electronic packaging material preparation. Electronic pastes typically consist of conductive metal powders, ceramic powders, glass powders, organic carriers, resins, solvents, and dispersants. Their particle size distribution, content of agglomerated coarse particles, microbubble content, solid content stability, and viscosity directly affect the quality of subsequent screen printing, slot coating, inkjet printing, sintering, and conductive layer formation.

[0003] In current electronic paste preparation processes, methods such as stirring and dispersion, grinding, filtration, centrifugation, or fixed negative pressure filtration are commonly used to remove coarse particles and impurities. While these methods achieve a certain degree of particle removal, they still have shortcomings in electronic pastes with high solids content, high viscosity, and thixotropic properties. On the one hand, fixed negative pressure filtration can easily cause conductive or ceramic particles to be compacted at the filtration interface, forming a filter cake layer or causing local blockage. This leads to the mis-retention of particles of the target particle size, resulting in a deviation in the paste's solids content and the loss of effective functional particles. On the other hand, single-layer filter screens mainly rely on pore size to determine "pass through or retain," making it difficult to distinguish between non-redispersible hard impurities and reversibly agglomerated particles. This can easily lead to the discharge of still usable precious metal powders or functional powders as waste, increasing manufacturing costs.

[0004] Furthermore, electronic slurries are prone to entraining microbubbles during mixing, transfer, pumping, and classification. These microbubbles, once inside the microchannels, alter the local flow field, causing abnormal fluctuations in channel pressure differential and flow rate, and even leading to bubble blockage. Existing classification equipment typically only shuts down for cleaning or increases suction intensity after blockage occurs, lacking a dynamic judgment mechanism based on inlet pressure, outlet pressure, lateral negative pressure, flow rate attenuation, and slurry viscosity. This prevents advance adjustments before particle deposition, agglomeration, blockage, or bubble blockage occur. Summary of the Invention

[0005] The purpose of this invention is to provide a microfluidic negative pressure ultrafine classification system for electronic slurries in electronic material manufacturing. This system can perform low-shear pre-dispersion and negative pressure degassing before the electronic slurry enters the classification channel. During the microfluidic classification process, laminar flow offset and lateral negative pressure suction are used to separate the target particle size slurry from the coarse particle slurry. Simultaneously, the lateral negative pressure suction intensity at each stage is dynamically adjusted according to the channel pressure difference, flow rate attenuation, and rheological state. When deposition, jamming, or bubble blockage occurs, parallel buffering, reverse pulse, or venting treatments are implemented. Redispersible coarse particles are re-flowed and reclassified, thereby improving the classification stability, target particle size retention rate, and functional particle utilization rate of the electronic slurry, thus solving the problems mentioned in the background art.

[0006] A microfluidic negative pressure ultra-micro classification system for electronic pastes used in electronic material manufacturing, comprising: The electronic slurry pre-dispersion feeding module is used to receive the electronic slurry to be graded and to perform low-shear pre-dispersion, steady-flow feeding and inlet negative pressure degassing treatment on the electronic slurry to be graded, forming the slurry to be graded that enters the microfluidic grading channel; The microfluidic negative pressure classification module is used to allow the slurry to be classified to enter the multi-stage microfluidic classification channel and form a laminar flow shift state in the microfluidic classification channel. This causes coarse particles or agglomerated particles with a particle size exceeding the target particle size range to be enriched towards the lateral negative pressure diversion port, while electronic slurry with a particle size within the target particle size range enters the target slurry outlet along the mainstream direction. The rheological state and channel pressure difference acquisition module is used to acquire the viscosity of the electronic slurry to be graded, the inlet pressure, outlet pressure, lateral negative pressure branch pressure, channel pressure difference, pressure difference growth rate, channel flow rate and flow rate decay rate of each microfluidic grading channel, and generate the channel deposition risk results of the corresponding microfluidic grading channel. The dynamic negative pressure distribution and control module is used to adjust the suction intensity of the corresponding lateral negative pressure diversion port of each microfluidic grading channel according to the rheological state data of the electronic slurry to be graded, the channel flow rate, the flow rate decay state and the channel pressure difference change results. The bypass buffer and reverse pulse unblocking module is used to open the parallel buffer channel, reverse pulse flushing channel or exhaust branch when particle accumulation, agglomeration blockage or bubble blockage occurs in the corresponding microfluidic graded channel. The coarse particle redispersion return module is used to receive the coarse particle slurry separated from the side negative pressure diversion port, perform low-shear redispersion of the redispersible agglomerated particles in the coarse particle slurry, and send the redispersed electronic slurry back to the electronic slurry pre-dispersion feeding module. The target paste collection module is used to collect electronic paste with particle size within the target particle size range and output graded electronic paste for use in electronic material printing, coating or sintering processes.

[0007] Compared with the prior art, the beneficial effects of the present invention are: This invention employs an electronic slurry pre-dispersion feeding module to sequentially perform low-shear pre-dispersion, steady-flow feeding, and inlet negative pressure degassing treatment on the electronic slurry to be graded. This pre-loosens reversibly agglomerated particles before they enter the microfluidic grading channel, and allows entrained microbubbles to be discharged through the inlet negative pressure degassing buffer chamber. This improves the inlet stability of the slurry entering the microfluidic grading channel and reduces flow field disturbances, channel pressure fluctuations, and bubble blockage problems caused by agglomerated particles and microbubbles entering the microchannels in high-viscosity electronic slurries.

[0008] This invention utilizes a microfluidic negative pressure classification module to create laminar flow displacement of the electronic paste to be classified within the main microchannel and the curved offset section. Coarse or agglomerated particles are extracted through a lateral negative pressure diversion port located on the particle enrichment side, allowing electronic paste with particle sizes within the target range to enter the target paste outlet along the mainstream direction. This improves the targeting of electronic paste particle classification and reduces the problems of mis-retention of target-size particles, loss of effective functional particles, and post-classification solids content deviation that occur with single-layer filter methods.

[0009] This invention acquires inlet pressure, outlet pressure, lateral negative pressure, channel pressure difference, pressure difference growth rate, and flow rate decay rate through a rheological state and channel differential pressure acquisition module. It then adjusts the suction intensity of the corresponding lateral negative pressure distribution port through a dynamic negative pressure distribution and control module. When sedimentation, particle jamming, or bubble blockage occurs, parallel buffering, reverse pulse, or venting processes are executed respectively. This improves the abnormal handling capability during the operation of the microfluidic staged channel and reduces particle compaction, local blockage, and the frequency of shutdowns for cleaning caused by fixed negative pressure filtration. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall system flow of the present invention; Figure 2 This is a schematic diagram of the channel pressure difference, flow attenuation, and dynamic negative pressure control of the present invention; Figure 3 This is a schematic diagram of the bypass buffer and reverse pulse unblocking process of the present invention; Figure 4 This is a schematic diagram illustrating the microfluidic laminar flow shift and lateral negative pressure grading principle of the present invention; Figure 5 This is a schematic diagram illustrating the verification of coarse particle redispersion reflux and target slurry discharge in this invention; Figure 6 This is a schematic diagram of the pre-dispersed feeding and inlet negative pressure degassing structure of the present invention. Detailed Implementation

[0011] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0012] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0013] This embodiment is applied to the preparation and pretreatment of electronic pastes in electronic material manufacturing, and is particularly suitable for conductive silver paste for photovoltaic cells, low-temperature sintered copper paste, ceramic paste for multilayer ceramic capacitors, glass powder paste, and functional paste for fine circuit printing. These pastes typically exhibit high solids content, high viscosity, thixotropy, a tendency to entrain microbubbles, a tendency for functional particles to form reversible agglomerates, and the presence of small amounts of hard impurities. If only fixed negative pressure filtration or single-layer filter screen retention is used, problems such as microchannel inlet compaction, accidental retention of target particle size, direct discarding of coarse particle agglomerates, and solids content deviation after classification can easily occur.

[0014] Example 1: This invention provides a technical solution: a microfluidic negative pressure ultra-micro classification system for electronic pastes used in electronic material manufacturing, comprising: The electronic slurry pre-dispersion feeding module is used to receive the electronic slurry to be graded and to perform low-shear pre-dispersion, steady-flow feeding and inlet negative pressure degassing treatment on the electronic slurry to be graded, forming the slurry to be graded that enters the microfluidic grading channel; The microfluidic negative pressure classification module is used to allow the slurry to be classified to enter the multi-stage microfluidic classification channel and form a laminar flow shift state in the microfluidic classification channel. This causes coarse particles or agglomerated particles with a particle size exceeding the target particle size range to be enriched towards the lateral negative pressure diversion port, while electronic slurry with a particle size within the target particle size range enters the target slurry outlet along the mainstream direction. The rheological state and channel pressure difference acquisition module is used to acquire the viscosity of the electronic slurry to be graded, the inlet pressure, outlet pressure, lateral negative pressure branch pressure, channel pressure difference, pressure difference growth rate, channel flow rate and flow rate decay rate of each microfluidic grading channel, and generate the channel deposition risk results of the corresponding microfluidic grading channel. The dynamic negative pressure distribution and control module is used to adjust the suction intensity of the corresponding lateral negative pressure diversion port of each microfluidic grading channel according to the rheological state data of the electronic slurry to be graded, the channel flow rate, the flow rate decay state and the channel pressure difference change results. The bypass buffer and reverse pulse unblocking module is used to open the parallel buffer channel, reverse pulse flushing channel or exhaust branch when particle accumulation, agglomeration blockage or bubble blockage occurs in the corresponding microfluidic graded channel. The coarse particle redispersion return module is used to receive the coarse particle slurry separated from the side negative pressure diversion port, perform low-shear redispersion of the redispersible agglomerated particles in the coarse particle slurry, and send the redispersed electronic slurry back to the electronic slurry pre-dispersion feeding module. The target paste collection module is used to collect electronic paste with particle size within the target particle size range and output graded electronic paste for use in electronic material printing, coating or sintering processes.

[0015] Please see Figures 1 to 6 , Figure 1 The connection relationships between the raw material storage chamber, the low-shear pre-dispersion chamber, the steady-flow feeding chamber, the inlet negative pressure degassing buffer chamber, the multi-stage microfluidic classification channel, the target slurry collection chamber, the coarse particle redispersion reflux path, and the dynamic negative pressure distribution and control module are shown. Figure 2 The process is illustrated by showing that the inlet pressure detection, outlet pressure detection, lateral negative pressure detection, channel differential pressure detection, flow rate attenuation detection, slurry viscosity detection, and agglomeration particle detection results of each level of microfluidic graded channel are input into the dynamic negative pressure distribution and control module, and the module adjusts each lateral negative pressure diversion port and parallel buffer channel respectively. Figure 3 The diagram illustrates the process of executing reverse pulse, exhaust branch, parallel buffer channel, stop feeding, and liquid discharge reset procedures based on particle jamming, bubble blocking, sedimentation, and severe abnormal conditions after the channel abnormality trigger value enters the blockage type determination. Figure 4 The diagram illustrates the classification process where, after the electronic slurry to be classified enters the main microchannel, particles migrate within the curved offset section. Coarse or agglomerated particles accumulate on the outside of the curve and enter the coarse particle collection branch through the lateral negative pressure diversion port. Particles of the target particle size enter the target slurry outlet along the mainstream direction. Figure 5 The process is shown in the diagram where coarse particle slurry sequentially passes through coarse particle storage, hard impurity identification, small sample redispersion detection, low shear redispersion, and reflux judgment before entering either the reflux path or the waste discharge path. Simultaneously, the process is shown where target slurry, after particle size window verification, solid content stabilization, trial printing detection, and output quality matching judgment, enters the qualified slurry outlet, returns to the secondary grading channel, returns to the primary grading channel, or is introduced into the circulating grading inlet. Figure 6 The pretreatment path of the electronic slurry to be graded is shown, which sequentially passes through the raw material storage chamber, the low shear pre-dispersion chamber, the steady flow feeding chamber, and the inlet negative pressure degassing buffer chamber. The arrangement of the online rotational viscometer, online particle size detection device, microflow meter, bubble image detection device, gas-liquid separation membrane, thin-layer spreading channel, and independent exhaust negative pressure port is also shown.

[0016] This embodiment corresponds to the electronic slurry pre-dispersion feeding module, which is applied to the pretreatment scenario before the electronic slurry to be graded enters the microfluidic negative pressure grading module. The module consists of a raw material storage chamber, a low-shear pre-dispersion chamber, a steady-flow feeding chamber, and an inlet negative pressure degassing buffer chamber. It is used to pre-loosen reversibly agglomerated particles without damaging the original morphology of functional particles, and to remove entrained microbubbles before they enter the microfluidic channel.

[0017] S101. The raw material storage chamber receives the electronic slurry to be graded and obtains the current slurry viscosity through an online rotational viscometer, denoted as S101. The unit is The target slurry viscosity is read from the process formula table and recorded as follows: The unit is The proportion of agglomerated coarse particles was obtained using an online particle size analyzer and denoted as . The unit is %; the upper limit reference value of the proportion of agglomerated coarse particles is read from the classification process parameter table and recorded as %. The unit is %; the microbubble volume fraction is obtained by a bubble image detection device and denoted as %. The unit is %; the upper limit reference value of microbubble volume fraction is read from the inlet degassing process parameter table and recorded as . The unit is %; the feed flow rate of the constant flow feeding chamber is continuously collected by a micro-flow meter, and the feed flow rate fluctuation coefficient is obtained based on the ratio of the standard deviation of the feed flow rate to the average feed flow rate, denoted as . , which is a dimensionless value; the upper limit reference value of the feed flow fluctuation coefficient is read from the debugging records of the constant flow feed equipment, and recorded as . , which is a dimensionless value; the current shear rate corresponding to the stirring element in the low-shear pre-dispersion chamber is obtained by a speed detector and denoted as . The unit is The target shear rate for low-shear pre-dispersion was read from the pre-dispersion process parameter table and denoted as . The unit is .

[0018] S102. Convert the above parameters into dimensionless evaluation terms and calculate the pre-dispersion feeding adaptation coefficient, denoted as... ;

[0019] In the formula, The pre-dispersed feeding adaptation coefficient has a value range of 0 to 1; Indicates how close the viscosity is to the target viscosity; Indicates the degree of control over agglomerated coarse particles; Indicates the degree of microbubble control; Indicates the stability of the material supply flow rate; This indicates the degree of adaptation to low-shear pre-dispersion strength. `clip(x,0,1)` means that when the calculated value is less than 0, it is 0; when the calculated value is greater than 1, it is 1; and when the calculated value is between 0 and 1, the original value is retained. The technical principle of the formula is that before the electronic slurry enters the microfluidic classification channel, deviations in viscosity, increases in the proportion of agglomerated coarse particles, increases in bubble content, or increases in feed flow fluctuations will all disrupt the continuous laminar flow state within the microfluidic channel. By unifying these factors into pre-dispersion feed adaptation coefficients, it is possible to determine whether the slurry to be classified is suitable for direct entry into the microfluidic classification channel. `a1`, `a2`, `a3`, `a4`, and `a5` are weighting coefficients. Preferably, ; The first pre-dispersion admission threshold is preset and denoted as... The preferred value is 0.75; the preset second pre-dispersion compounding threshold is denoted as... The preferred value is 0.55.

[0020] when When the electronic slurry to be graded is determined to meet the inlet pretreatment requirements, it is allowed to enter the microfluidic negative pressure grading module; when If the inlet state of the electronic slurry to be graded has not yet met the requirements for direct grading, the low shear pre-dispersion time or the inlet negative pressure degassing time is extended. when If the electronic slurry to be graded is found to have problems such as viscosity deviation, coarse particle agglomeration, or abnormal bubble content, it will be returned to the raw material storage chamber for compounding or pretreatment. The data for Example 1 are shown in Tables 1 and 2 below.

[0021] Table 1: Example Parameters of Electronic Slurry Pre-dispersion Feeding Module

[0022] Table 2: Example Table of Pre-processing Judgment for Electronic Slurry Pre-dispersion Feeding Module

[0023] Table 1 illustrates the sources of pretreatment parameters for electronic slurries before they enter microfluidic classification, focusing on whether the slurry viscosity, proportion of agglomerated coarse particles, bubble content, and shear conditions meet the requirements for subsequent negative pressure classification inlet. Table 2 provides the pretreatment judgment results for different electronic slurry samples. A higher pre-dispersion fit value indicates a more stable slurry inlet state; when agglomeration, bubbles, or viscosity fluctuations are high, extended pre-dispersion, degassing, or compounding treatments are performed.

[0024] Example 2: This example corresponds to a microfluidic negative pressure classification module, applied to a separation scenario where electronic slurry, after pre-dispersion, steady-flow feeding, and inlet negative pressure degassing in Example 1, enters a multi-stage microfluidic classification channel. This module includes a primary microfluidic classification channel, a secondary microfluidic classification channel, a main microchannel, a curved offset section, a lateral negative pressure branch outlet, a coarse particle collection branch, and a target slurry outlet. The slurry to be classified output from Example 1 first enters the primary main microchannel, undergoes coarse classification, and then enters the secondary microfluidic classification channel for fine classification.

[0025] S201, the constant flow feeding chamber delivers the electronic slurry to be graded, which meets the first pre-dispersion admission threshold, to the primary main microchannel, and collects the real-time flow rate of the main channel of the primary main microchannel through a microflow meter. The unit is Simultaneously, the lateral negative pressure diversion flow rate is collected through a micro-flow meter in the lateral branch. The unit is This step is used to determine the main flow rate and lateral suction rate entering the microfluidic cascading channel, providing a basis for subsequent calculations of the lateral diversion ratio.

[0026] S202. The median particle size of the slurry to be graded is collected using an online particle size detection device. Equivalent particle size of coarse particles All units are The target particle size is read from the electronic paste manufacturing process table. The upper limit of the target particle size window is read from the classification process parameter table. This step is used to determine the degree of deviation between the slurry to be classified and the target particle size window.

[0027] S203, the primary main microchannel causes the electronic slurry to be classified to form a low Reynolds number laminar flow along the mainstream direction. The tortuous offset section causes coarse particles or agglomerated particles with a particle size exceeding the upper limit of the target particle size window to migrate to the particle enrichment side on the outside of the bend. The lateral negative pressure diversion port is set on the particle enrichment side and guides the coarse particle slurry into the coarse particle collection branch. This step is used to achieve gentle classification through laminar flow offset and lateral negative pressure suction, rather than relying on hard filter retention.

[0028] S204, the secondary microfluidic classification channel receives the intermediate slurry output from the primary main microfluidic channel and repeats the main channel conveying, bending offset, and lateral negative pressure diversion process; the target particle size slurry after secondary classification enters the target slurry outlet, and the laterally separated coarse particle slurry enters the coarse particle collection branch. This step is used to reduce the proportion of coarse particles remaining after primary classification.

[0029] S205, based on real-time traffic flow of the main channel and lateral negative pressure diversion flow rate Calculate the lateral negative pressure split ratio , Then, the effective coefficient of microfluidic laminar flow classification is calculated based on laminar flow stability, lateral migration ratio, lateral splitting ratio, target particle size window particle ratio, and median particle size proximity. The formula is as follows:

[0030] In the formula, This is the effective coefficient for microfluidic laminar flow classification, with a value ranging from 0 to 1; Indicates the degree of laminar flow stability. The Reynolds number is calculated based on the hydraulic diameter, flow velocity, slurry density, and viscosity of the main microchannel. The Reynolds number is used as a reference for laminar flow determination and is read from the microfluidic channel design parameter table; This indicates the degree to which coarse particles migrate towards the enrichment side where the lateral negative pressure diversion port is located. The number of coarse particles captured by the lateral diversion port. This represents the total number of coarse particles entering this stage of the channel; This indicates that the lateral negative pressure diversion ratio is close to the target diversion ratio. To what extent, Read from the classification process parameter table; This indicates the proportion of particles that fall within the target particle size window after grading. The number of particles within the target particle size window. To detect the total number of particles; This indicates the degree to which the median particle size after grading approaches the target particle size. For weighting coefficients, preferably, Furthermore, the sum of all weighting coefficients is 1. The technical principle of this formula is that microfluidic negative pressure classification does not rely on hard interception by the filter screen aperture, but utilizes low Reynolds number laminar flow, lateral migration of particles generated by the tortuous offset section, and directional suction of the lateral negative pressure diversion port to allow coarse or agglomerated particles to enter the coarse particle collection branch, so that the slurry of the target particle size is output along the mainstream direction.

[0031] Preset first level effective threshold Second-level review threshold Third-level reflux threshold .

[0032] when At that time, the graded slurry is introduced into the slurry collection chamber of the target particle size; when At the same time, increase the frequency of lateral shunting verification in the secondary microfluidic cascading channel; when At this time, the intermediate slurry is returned to the primary microfluidic classification channel; when At that time, the batch of slurry was introduced into the coarse particle collection branch. The data for Example 2 are shown in Tables 3 and 4 below.

[0033] Table 3: Example Table of Parameters for Microfluidic Negative Pressure Grading Module

[0034] Table 4: Example Table of Grading Determination for Microfluidic Negative Pressure Grading Module

[0035] Table 3 illustrates the particle size, flow rate, and split ratio parameters required for microfluidic negative pressure classification, clearly defining the correspondence between coarse particle migration, lateral suction, and target particle size maintenance. Table 4 displays the classification results for different electronic pastes. The higher the value, the more fully the target particle size is retained; If the temperature is too low, coarse or agglomerated particles need to be directed to the recycling branch.

[0036] Example 3: This example corresponds to the rheological state and channel pressure difference acquisition module, applied to the status monitoring scenario during the continuous operation of a microfluidic graded channel. This module uses an inlet pressure detection unit, an outlet pressure detection unit, a lateral negative pressure detection unit, a micro-flow rate detection unit, and a slurry viscosity detection unit to determine in real time whether there is particle deposition, agglomeration blockage, or flow channel obstruction in the microfluidic channel.

[0037] S301, The inlet pressure detection unit collects the inlet pressure at the inlet of each stage of the microfluidic cascading channel. The outlet pressure detection unit collects the outlet pressure at the corresponding outlet. All units are The lateral negative pressure detection unit collects the pressure of the lateral negative pressure branch. The unit is This step is used to establish the basic data for channel pressure differential and lateral suction status.

[0038] S302, Differential Pressure Growth Judgment Unit according to Calculate the channel pressure difference and obtain the channel pressure difference growth rate per unit time based on continuous sampling. The unit is Simultaneously, the channel differential pressure reference value is read from the staged channel design parameter table. Reference value for the upper limit of the pressure difference growth rate This step is used to determine whether the channel resistance continues to increase.

[0039] S303, Micro-flow detection unit collects real-time flow of the current channel. And read the reference feed flow rate output from the constant flow feed chamber. All units are ;according to Calculate flow attenuation rate The slurry viscosity detection unit synchronously collects the current slurry viscosity. and read the viscosity of the target slurry. This step is used to correlate changes in channel resistance with the rheological state of the slurry.

[0040] S304. The pressure fluctuation analysis unit calculates the pressure fluctuation coefficients of the inlet and outlet pressures within a preset sampling window. And read the reference value of the pressure fluctuation coefficient. When pressure fluctuations are accompanied by flow rate decline, they are used as an auxiliary signal to determine whether there is particle deposition or bubble blockage.

[0041] S305, the differential pressure growth determination unit calculates the channel deposition risk coefficient based on the channel differential pressure, differential pressure growth rate, flow rate attenuation, viscosity deviation, and pressure fluctuation. The formula is as follows:

[0042] In the formula, The channel deposition risk coefficient ranges from 0 to 1. These are the weighting coefficients. Preferably, .

[0043] Preset first differential pressure risk warning threshold Second differential pressure risk trigger threshold .

[0044] when During this period, maintain normal monitoring; when When the corresponding channel is detected as having a deposition warning, the warning result is sent to the dynamic negative pressure distribution and control module. when When a high risk of blockage is detected in the corresponding channel, negative pressure reduction or unblocking is triggered. Data from Example 3 are shown in Tables 5 and 6 below.

[0045] Table 5: Example Table of Parameters for Rheological State and Channel Pressure Difference Acquisition Module

[0046]

[0047] Table 6: Examples of Monitoring by the Rheological State and Channel Pressure Difference Acquisition Module

[0048] Table 5 illustrates the data sources for channel status monitoring, including inlet and outlet pressure difference, lateral negative pressure, and flow attenuation, providing a basis for subsequent negative pressure adjustment. Table 6 shows the correspondence between monitoring results and treatment status. Low indicates stable channel resistance. An increase indicates an increased risk of deposits, blockages, or bubble blockages.

[0049] Example 4: This example corresponds to the dynamic negative pressure distribution and control module, applied to a scenario where, after outputting the deposition risk coefficient of the channel in Example 3, the lateral negative pressure branches of each level of microfluidic hierarchical channel are independently adjusted. The control principle of this module is: maintain lateral suction when the channel is stable, and reduce the intensity of lateral negative pressure suction when the deposition risk increases, rather than continuing to increase the negative pressure.

[0050] S401, The negative pressure graded matching unit receives the channel deposition risk coefficient output in Example 3. Flow attenuation rate Lateral negative pressure branch pressure and the current slurry viscosity Simultaneously receive the proportion of agglomerated coarse particles output by the online particle size analyzer. This step is used to incorporate channel risk, flow rate attenuation, slurry viscosity, and coarse particle ratio into negative pressure regulation.

[0051] S402, Negative Pressure Grading Matching Unit Reads Initial Lateral Negative Pressure Reference value for the upper limit of differential pressure growth rate Reference value for upper limit of flow attenuation rate Reference value for the upper limit of the proportion of agglomerated coarse particles and target slurry viscosity .because and All values ​​are negative pressure values; absolute values ​​are used when calculating suction intensity. and This indicates the intensity of negative pressure suction.

[0052] S403. Calculate the negative pressure distribution adaptation value based on channel deposition risk, flow rate attenuation, coarse particle ratio, and the degree of deviation of the current suction intensity. The formula is as follows:

[0053] In the formula, Assign an adaptation value to the negative pressure, with a value range from 0 to 1; The channel deposition risk coefficient; For flow attenuation rate, This is a reference value for the upper limit of the flow attenuation rate; The proportion of coarse particles in agglomeration. This is a reference value for the upper limit of the proportion of agglomerated coarse particles; Real-time negative pressure for the lateral negative pressure branch. Initial lateral negative pressure; Given the current viscosity of the slurry, The target slurry viscosity. All terms in the formula are obtained through comparison with similar parameters and are dimensionless evaluation terms. The higher the value, the better the channel level is for maintaining the current lateral suction. The lower the value, the more likely continued suction will cause particle compaction, requiring a reduction in suction intensity or switching to a bypass. For weighting coefficients, preferably, ; S404, Adjustment value based on negative pressure. Calculate the target suction intensity correction factor The target negative pressure at the corresponding lateral negative pressure diversion port is adjusted by the negative pressure regulating valve. The formula is as follows:

[0054] In the formula, The correction factor for the target suction intensity. The target is lateral negative pressure. Because... When it is negative, When decreasing, A decrease in the absolute value indicates a reduction in the lateral negative pressure suction intensity.

[0055] S405, negative pressure reduction control unit according to Adjustments are made: Preset the first negative pressure distribution adaptation threshold. The second negative pressure reduction threshold and third bypass switching threshold .

[0056] when At the same time, maintain the current lateral negative pressure; when At that time, reduce the suction intensity of the corresponding lateral negative pressure diversion port and continue monitoring; when When this happens, reduce the suction intensity and open the parallel buffer channel; when At this time, the original channel suction is stopped and the bypass is switched. The data for Example 4 are shown in Tables 7 and 8 below.

[0057] Table 7: Example Table of Parameters for Dynamic Negative Pressure Distribution and Control Module

[0058] Table 8: Example of Adjustment for Dynamic Negative Pressure Distribution Control Module

[0059]

[0060] Table 7 illustrates the basis for negative pressure adjustment in the dynamic negative pressure distribution and control module, emphasizing that the system does not use fixed filtration but dynamically distributes negative pressure based on pressure difference increases and flow rate decreases. Table 8 displays the negative pressure adjustment results under different slurry conditions. When both pressure difference and flow rate decrease increase simultaneously, the system reduces the negative pressure to prevent particle compaction and filter cake formation.

[0061] Example 5: This example corresponds to the bypass buffer and reverse pulse unblocking module, applied to abnormal handling scenarios where channel anomalies were identified in Example 3 or where flow rate attenuation still occurred after reducing the suction intensity in Example 4. This module includes a blockage type determination unit, a parallel buffer execution unit, a reverse pulse execution unit, and a bubble blocking and removal unit.

[0062] S501, The blockage type determination unit receives the differential pressure growth rate output in Embodiment 3. Flow attenuation rate Instantaneous pressure difference change Duration of step drop in flow rate Bubble blocking fluctuation frequency and microbubble volume fraction This step is used to differentiate between slow deposition, particle entrapment, and bubble blockage.

[0063] S502, Blockage type determination unit reads instantaneous pressure difference change threshold. Flow step drop duration threshold Bubble blocking fluctuation frequency threshold upper limit reference value for microbubble volume fraction And calculate the channel abnormal trigger value. .

[0064]

[0065] In the formula, This is the channel anomaly trigger value, ranging from 0 to 1; For differential pressure growth rate, For flow attenuation rate, This refers to the instantaneous change in pressure difference. The duration of the step drop in flow rate. To block the fluctuation frequency of the bubble. For weighting coefficients, preferably, ; S503, Preset channel abnormality trigger threshold The preferred value is 0.45; the preset threshold for severe abnormal supply interruption is... The preferred value is 0.85; the preset threshold for differential pressure growth rate. The preferred value is Preset flow attenuation rate threshold The preferred value is 0.20; the preset threshold for instantaneous pressure difference change is... The preferred value is Preset threshold for the duration of the step drop in flow rate The preferred value is 3s; the preset bubble blocking fluctuation frequency threshold is... The preferred value is Preset microbubble volume fraction threshold The preferred value is 1.0%.

[0066] When the channel is abnormally triggered <Channel Abnormal Trigger Threshold If necessary, the corresponding microfluidic grading channel is determined to be unblocked and the current grading state is maintained.

[0067] When the channel is abnormally triggered ≥Severe abnormality supply interruption threshold When the corresponding microfluidic grading channel is determined to be in a severely abnormal state, the steady flow feeding chamber is stopped from feeding material into the abnormal channel, the lateral negative pressure diversion port corresponding to the abnormal channel is closed, the reverse pulse execution unit is started to perform reverse pulse unblocking, and the stagnant slurry in the abnormal channel is discharged through the drainage reset branch; after the unblocking is completed, the channel pressure difference, flow rate attenuation rate, instantaneous pressure difference mutation amount and bubble blockage fluctuation frequency are resent to the rheological state and channel pressure difference acquisition module for verification.

[0068] When the channel abnormally triggers the threshold ≤ Channel abnormal trigger value <Severe Abnormal Supply Interruption Threshold At that time, the blockage type determination process begins.

[0069] When the channel is abnormally triggered ≥ Channel abnormal trigger threshold And instantaneous pressure difference change > Threshold for instantaneous pressure difference change Duration of step drop in flow rate >Threshold for the duration of the step drop in flow rate When the corresponding microfluidic grading channel is determined to be blocked by particulate entrapment, the reverse pulse actuator applies a short-duration reverse pulse pressure to the corresponding microfluidic grading channel. This causes stuck particles to detach from the side negative pressure diversion port or the wall of the microchannel.

[0070] When the channel is abnormally triggered ≥ Channel abnormal trigger threshold And the bubble blocks the fluctuation frequency > Bubble blocking fluctuation frequency threshold or microbubble volume fraction > Microbubble volume fraction threshold When the corresponding microfluidic grading channel is determined to be blocked by a bubble, the bubble blocking and removal unit opens the exhaust branch and reduces the inlet feed rate to allow the bubbles to be discharged through the exhaust branch.

[0071] When the channel is abnormally triggered ≥ Channel abnormal trigger threshold Furthermore, the channel pressure difference growth rate is satisfied in three consecutive sampling periods. ≥ Pressure difference growth rate threshold Flow attenuation rate ≥Flow rate attenuation threshold And instantaneous pressure difference change ≤Instantaneous pressure difference threshold Bubble blocking fluctuation frequency ≤ Bubble blocking fluctuation frequency threshold Microbubble volume fraction ≤ Microbubble volume fraction threshold When the corresponding microfluidic grading channel is determined to be blocked by deposition, the parallel buffer execution unit opens the bypass switching valve at the inlet of the abnormal channel, diverting the electronic slurry to be graded from the inlet of the abnormal channel to the parallel buffer channel, and then flowing into the downstream of the abnormal channel or the next stage of the microfluidic grading channel through the outlet of the parallel buffer channel; at the same time, the suction intensity of the corresponding lateral negative pressure diversion port of the abnormal channel is reduced, so that a low flow rate flushing state is maintained in the abnormal channel to slow down the continued compaction and deposition of particles. The data of Example 5 are shown in Tables 9 and 10 below.

[0072] Table 9: Example Table of Parameters for Bypass Buffer and Reverse Pulse Unblocking Modules

[0073] Table 10: Examples of Bypass Buffer and Reverse Pulse Unblocking Module Processing

[0074] Table 9 illustrates the judgment parameters for the bypass buffer and reverse pulse unblocking modules, focusing on distinguishing between deposition-type blockage, particulate-type blockage, and bubble-type blockage. Table 10 displays the unblocking strategies for abnormal channels. When the differential pressure suddenly increases and the flow rate drops sharply, a reverse pulse is executed; when the fluctuation frequency increases, bubble blockage is prioritized for removal.

[0075] Example 6: This example corresponds to a coarse particle redispersibility recirculation module, applied to the post-processing of coarse particle slurry separated by a side negative pressure diverter. Since coarse particles in electronic slurries are not necessarily all unusable impurities, some may be reversible aggregates formed by functional particles, resin, and organic carriers. Direct disposal would result in the loss of precious metal powders or functional powders. Therefore, this example first determines the feasibility of redispersing the coarse particle slurry before deciding whether to recirculate or discard it.

[0076] S601, the coarse particle temporary storage chamber receives coarse particle slurry from the lateral negative pressure diversion port and the coarse particle collection branch, and collects the coarse particle concentration through an online concentration detection device. The unit is %; at the same time, the source grading channel and diversion time of this batch of coarse particle slurry are recorded.

[0077] S602, the hard impurity identification unit identifies particle edge morphology through a microscopic image detection device, identifies metallic hard impurities through a magnetic impurity detection device, identifies high-density non-redispersible particles through a density grading detection device, and statistically analyzes the proportion of hard impurities. The unit is %.

[0078] S603, a low-shear redispersion chamber was used to conduct small-scale redispersion tests on coarse particle slurry. The redispersion was performed for a preset time using a flexible vibrating membrane, a low-speed agitator, or pulsed turbulent flow. Then, the change in the proportion of coarse particles before and after redispersion was compared using an online particle size detection device to obtain the recoverable proportion of agglomerated particles. The unit is %.

[0079] S604, The reflux judgment unit reads the upper limit reference value of coarse particle concentration. Reference value for the upper limit of hard impurities Lower limit of recoverable proportion of aggregated particles And the redistribution processing time range, and calculate the redistribution reflux fit value. The formula is as follows:

[0080] In the formula, The value is the redistribution reflux adaptation value, ranging from 0 to 1; This refers to the concentration of coarse particles. This is a reference value for the upper limit of coarse particle concentration; The proportion of hard impurities, This is a reference value for the upper limit of the proportion of hard impurities; The recoverable proportion of agglomerated particles. This represents the lower limit of the recoverable proportion of agglomerated particles; For low shear redispersion processing time, This is the maximum permissible redistribution processing time; The volume of reflux slurry collected by the reflux control valve. This is a reference value for the reflux volume. For weighting coefficients, preferably, The technical principle behind the formula is that redispersible agglomerates typically exhibit a low proportion of hard impurities, coarse particle sizes that do not exceed the low-shear redispersibility of the equipment, a high recovery rate of the redispersed sample, and controllable yield stress. In contrast, non-redispersible hard impurities are characterized by a high proportion of hard impurities, excessively large coarse particle sizes, or a low recovery rate of the small sample.

[0081] S605, Preset first redistribution reflux threshold Second redistribution re-inspection threshold and the threshold for third waste output .when At that time, after the low-shear redispersion chamber completes the redispersion process, the slurry is returned to the inlet negative pressure degassing buffer chamber through the reflux control valve.

[0082] when At that time, it was determined that the batch of coarse particle slurry still contained reversible agglomerates, but the degree of redispersion was insufficient. Therefore, the low-shear redispersion treatment time was extended and the sample was tested again. .

[0083] when When it is determined that there are both recyclable and non-recyclable parts in the coarse particle slurry, the system will return the redispersible part and introduce the part with a higher proportion of hard impurities into the waste discharge chamber.

[0084] when If the batch of coarse particle slurry is determined to consist mainly of non-redispersible hard impurities or excessively agglomerated particles, the waste discharge chamber receives and discharges the batch of coarse particle slurry, and it is no longer returned to the inlet negative pressure degassing buffer chamber. The data for Example 6 are shown in Tables 11 and 12 below.

[0085] Table 11: Example Parameters of the Coarse Particle Redispersion Reflux Module

[0086]

[0087] Table 12: Example of coarse particle redispersion reflux module processing

[0088] Table 11 illustrates the key parameters of the coarse particle redispersibility recirculation module, focusing on distinguishing between redispersible agglomerates and non-redispersible hard impurities to reduce the loss of effective functional particles. Table 12 shows the criteria for determining whether coarse particle slurry should be recirculated or discarded. A higher redispersibility recirculation fit value indicates that the coarse particles are mainly reversible agglomerates, suitable for recirculation and reclassification.

[0089] Example 7: This example corresponds to the target slurry collection module, applied to the scenario of judging the qualified slurry discharge after microfluidic negative pressure classification. This module includes a target particle size slurry collection chamber, a particle size window verification unit, a solid content stabilization unit, and a discharge switching unit, used to determine whether the classified electronic slurry meets the stability requirements of subsequent screen printing, slot coating, inkjet printing, or sintering processes.

[0090] S701, the target particle size slurry collection chamber receives the target particle size slurry output from each stage of the microfluidic grading channel, and collects the median particle size of the target slurry through an online particle size detection device. and 90% cumulative particle size All units are Read the target median particle size from the process flow chart. and 90% cumulative particle size limit .

[0091] S702, Particle Size Window Verification Unit: Statistical Analysis of Coarse Particle Residual Ratio in Target Slurry and the proportion of particles within the target particle size window And read the upper limit reference value of the proportion of coarse particles remaining. This step is used to confirm whether coarse particles have been effectively separated.

[0092] S703, the solids content stabilization unit collects the solids content of the target slurry through a solids content detection device. And read the target solids content from the electronic paste formulation table. The viscosity of the target slurry was collected using an online viscometer. and read the viscosity of the target slurry. If the solid content is below the target range, reduce the lateral diversion ratio and increase the recirculation compensation; if the solid content is above the target range, increase the coarse particle branch diversion verification and introduce it into the circulation classification inlet.

[0093] S704. The trial printing testing device performs small-sample linewidth stability testing on the target paste and obtains the linewidth deviation. And read the upper limit of line width deviation from the printing process specification sheet. This step is used to link the classification results to the performance of subsequent electronic material manufacturing.

[0094] S705, the discharge switching unit calculates the discharge quality adaptation value based on the target particle size window, solid content, viscosity, coarse particle residual ratio, and linewidth deviation. The formula is as follows:

[0095] In the formula, This is the output quality adaptation value, ranging from 0 to 1; The target slurry median particle size, The target median particle size; For the target slurry cumulative particle size, The cumulative particle size limit is 90%. The proportion of coarse particles remaining. This is a reference value for the upper limit of the proportion of coarse particles remaining; The target slurry solids content, Target solid content; For line width deviation, This represents the upper limit of linewidth deviation. The technical principle behind the formula is that the grading quality of electronic paste cannot be determined solely by the coarse particle removal rate; it must also simultaneously meet the target particle size window, solid content stability, viscosity stability, and subsequent printing linewidth stability. By evaluating multiple results through the output quality coefficient, it is possible to avoid outputting pastes with solid content deviations or abnormal viscosity simply because the particle size is within acceptable limits. This represents the weight corresponding to the proportion of particles within the target particle size window, with a preferred value of 0.30; The weight corresponding to the degree to which the solid content is close to the target solid content is indicated, with a preferred value of 0.20; The weight corresponding to the degree to which the viscosity approaches the target viscosity is preferably 0.15; The weight corresponding to the degree of control over residual agglomerated particles is 0.20; The weight corresponding to the degree of control over line width deviation in trial printing is 0.15, with the preferred value being 0.15.

[0096] S706, Preset first qualified discharge threshold Second reflux threshold and the third reflux threshold .when At that time, the target slurry is introduced into the qualified slurry outlet.

[0097] when If the slurry is determined to be close to the target requirements after classification but still has coarse particles or linewidth fluctuations, the discharge switching unit will return the slurry to the secondary microfluidic classification channel for fine classification.

[0098] when If the particle size distribution or solid content of the slurry deviates significantly, the discharge switching unit will return the slurry to the primary microfluidic classification channel for reclassification.

[0099] when If the target slurry does not meet the requirements for graded discharge, the discharge switching unit will either guide the slurry into the circulating grading inlet or return it to the electronic slurry pre-dispersion feeding module for reprocessing, and record the cause of the batch anomaly. Data from Example 7 are shown in Tables 13 and 14 below.

[0100] Table 13: Example Table of Parameters for Target Slurry Collection Module

[0101] Table 14: Example Table of Discharge Judgment for Target Slurry Collection Module

[0102]

[0103] Table 13 illustrates the output verification parameters of the target slurry collection module, focusing on whether the graded slurry meets the particle size window, solid content stability, and subsequent printing process requirements. Table 14 displays the final output judgment of the target slurry. A higher output quality fit value indicates that the slurry particle size, solid content, and trial printing stability better meet the requirements of electronic material manufacturing.

[0104] It should be noted that all calculation formulas in this application employ, but are not limited to, regression analysis from machine learning algorithms, to deeply analyze the collected relevant parameters and identify their natural trends and interrelationships. Specialized software, such as... of Alternatively, the R language can be used to automatically generate a mathematical model that matches the data. Then, the model performance is objectively evaluated using methods such as cross-validation, and continuous feedback and optimization are combined to ensure that the created formula truly reflects the inherent laws of the data, thereby guaranteeing its effectiveness and accuracy. In all calculation formulas of this application, the parameters in each formula undergo dimensionless processing within a consistent range to ensure that different physical quantities are compared on the same scale; dimensionless processing techniques include, but are not limited to, max-min normalization (...). ), standardization; The algorithm method of the present invention is implemented as a The program script. Before executing the core logic, the program first executes a data loading module (e.g., using...). Widely used in China The library is configured to read the aforementioned spreadsheet file and load its contents into the program's working memory (e.g., ...). (In the data structure). Subsequent algorithmic steps will directly query and retrieve the required configuration parameters from this in-memory data structure.

[0105] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An electronic paste microfluidic negative pressure ultra-fractionation system for electronic material manufacturing, characterized in that, include: The electronic slurry pre-dispersion feeding module is used to receive the electronic slurry to be graded and to perform low-shear pre-dispersion, steady-flow feeding and inlet negative pressure degassing treatment on the electronic slurry to be graded, forming the slurry to be graded that enters the microfluidic grading channel; The microfluidic negative pressure classification module is used to allow the slurry to be classified to enter the multi-stage microfluidic classification channel and form a laminar flow shift state in the microfluidic classification channel. This causes coarse particles or agglomerated particles with a particle size exceeding the target particle size range to be enriched towards the lateral negative pressure diversion port, while electronic slurry with a particle size within the target particle size range enters the target slurry outlet along the mainstream direction. The rheological state and channel pressure difference acquisition module is used to acquire the viscosity of the electronic slurry to be graded, the inlet pressure, outlet pressure, lateral negative pressure branch pressure, channel pressure difference, pressure difference growth rate, channel flow rate and flow rate decay rate of each microfluidic grading channel, and generate the channel deposition risk results of the corresponding microfluidic grading channel. The dynamic negative pressure distribution and control module is used to adjust the suction intensity of the corresponding lateral negative pressure diversion port of each microfluidic grading channel according to the rheological state data of the electronic slurry to be graded, the channel flow rate, the flow rate decay state and the channel pressure difference change results. The bypass buffer and reverse pulse unblocking module is used to open the parallel buffer channel, reverse pulse flushing channel or exhaust branch when particle accumulation, agglomeration blockage or bubble blockage occurs in the corresponding microfluidic graded channel. The coarse particle redispersion return module is used to receive the coarse particle slurry separated from the side negative pressure diversion port, perform low-shear redispersion of the redispersible agglomerated particles in the coarse particle slurry, and send the redispersed electronic slurry back to the electronic slurry pre-dispersion feeding module. The target paste collection module is used to collect electronic paste with particle size within the target particle size range and output graded electronic paste for use in electronic material printing, coating or sintering processes.

2. The electronic paste microfluidic negative pressure ultra-micro classification system for electronic material manufacturing according to claim 1, characterized in that: The electronic slurry pre-dispersion feeding module includes a raw material storage chamber, a low-shear pre-dispersion chamber, a steady-flow feeding chamber, and an inlet negative pressure degassing buffer chamber; The raw material storage chamber is used to hold the electronic paste to be graded, which contains conductive particles, ceramic particles, glass powder, organic carrier, resin and solvent. The low-shear pre-dispersion chamber is used to pre-disperde electronic slurries to be graded by a flexible scraper or a low-speed agitator, so that temporarily agglomerated particles are loosened before entering the microfluidic grading channel. The constant flow feeding chamber is used to deliver the pre-dispersed electronic paste to the inlet negative pressure degassing buffer chamber at a stable flow rate. The inlet negative pressure degassing buffer chamber is used to remove entrained microbubbles before the electronic slurry to be graded enters the microfluidic grading channel and to reduce the interference of microbubbles on subsequent laminar flow offset grading.

3. The microfluidic negative pressure ultra-micro classification system for electronic pastes in electronic material manufacturing according to claim 2, characterized in that: The inlet negative pressure degassing buffer chamber includes a thin-layer spreadable channel, a gas-liquid separation membrane, and an independent exhaust negative pressure port; Thin-layer spreading channels are used to allow the electronic paste to be graded to form a thin layer of flow before entering the microfluidic grading channel; The gas-liquid separation membrane is positioned above the thin-layer spread channel to block the passage of the electronic paste bulk and allow entrained microbubbles to migrate toward the independent exhaust negative pressure port; An independent exhaust negative pressure port is used to remove entrained microbubbles from the electronic paste to be graded, so that the electronic paste entering the microfluidic grading channel remains in a continuous flow state.

4. The microfluidic negative pressure ultra-micro classification system for electronic pastes in electronic material manufacturing according to claim 1, characterized in that: The microfluidic negative pressure classification module includes at least two stages of microfluidic classification channels arranged in series. Each stage of the microfluidic classification channel includes a main microchannel, a curved offset section, a lateral negative pressure diversion port, a coarse particle collection branch, and a target slurry outlet. The main microchannel is used to receive the electronic paste to be graded and form a laminar flow field flowing along the main flow direction; The curved offset section is used to enrich coarse particles or agglomerated particles that exceed the target particle size range towards the outer region of the curved offset section. The lateral negative pressure diversion port is located on the particle enrichment side of the curved offset section, and is used to guide coarse particles or agglomerated particles into the coarse particle collection branch under the action of lateral negative pressure. The target slurry outlet is located at the end of the main microchannel and is used to output electronic slurry with a particle size within the target particle size range.

5. The microfluidic negative pressure ultra-micro classification system for electronic pastes in electronic material manufacturing according to claim 4, characterized in that: Each level of microfluidic tiered channel has a lateral negative pressure diversion port connected to an independent negative pressure branch. Each independent negative pressure branch is equipped with a negative pressure regulating valve, a negative pressure buffer chamber, and a negative pressure detection device. The negative pressure regulating valve is used to change the suction intensity of the corresponding lateral negative pressure diversion port; The negative pressure buffer chamber is used to reduce instantaneous pressure fluctuations generated during negative pressure regulation; The negative pressure detection device is used to detect the real-time negative pressure value of the corresponding independent negative pressure branch; The dynamic negative pressure distribution and control module adjusts each independent negative pressure branch according to the channel pressure difference change and flow attenuation state of each microfluidic tier channel, so that different tier channels correspond to different suction intensities.

6. The microfluidic negative pressure ultra-micro classification system for electronic pastes in electronic material manufacturing according to claim 5, characterized in that: The rheological state and channel pressure difference acquisition module includes an inlet pressure detection unit, an outlet pressure detection unit, a lateral negative pressure detection unit, a micro-flow detection unit, a slurry viscosity detection unit, a pressure fluctuation analysis unit, and a pressure difference growth determination unit. The inlet pressure detection unit is used to detect the inlet pressure at the inlet of each stage of the microfluidic cascade channel; The outlet pressure detection unit is used to detect the outlet pressure at the outlet of each stage of the microfluidic grading channel; The lateral negative pressure detection unit is used to detect the real-time negative pressure of the corresponding lateral negative pressure branch of each level of microfluidic hierarchical channel; The microflow detection unit is used to detect the real-time flow rate of electronic paste in each stage of the microfluidic grading channel, and to generate the flow rate decay rate based on the reference feed flow rate and the real-time flow rate. The slurry viscosity detection unit is used to detect the current viscosity of the electronic slurry before it enters the microfluidic grading channel; The pressure fluctuation analysis unit is used to acquire the pressure fluctuation status of the inlet and outlet pressures within a preset sampling window; The differential pressure growth determination unit is used to generate channel deposition risk results for the corresponding microfluidic graded channels based on inlet pressure, outlet pressure, channel differential pressure, differential pressure growth rate, flow rate decay rate, current viscosity, and pressure fluctuation status.

7. The microfluidic negative pressure ultra-micro classification system for electronic pastes in electronic material manufacturing according to claim 6, characterized in that: The dynamic negative pressure distribution and control module includes a negative pressure grading and matching unit, a negative pressure distribution adaptation value generation unit, a target negative pressure generation unit, a negative pressure reduction control unit, and a parallel buffer switching unit; The negative pressure classification matching unit is used to receive channel deposition risk results, flow attenuation rate, real-time negative pressure of lateral negative pressure branches, current slurry viscosity, and proportion of agglomerated coarse particles; The negative pressure distribution adaptation value generation unit is used to generate negative pressure distribution adaptation values ​​based on channel deposition risk results, flow attenuation rate, proportion of agglomerated coarse particles, deviation between real-time negative pressure and initial lateral negative pressure, and deviation between current slurry viscosity and target slurry viscosity. The target negative pressure generation unit is used to generate the target lateral negative pressure of the corresponding lateral negative pressure diversion port according to the negative pressure distribution adaptation value; The negative pressure reduction control unit is used to reduce the suction intensity of the corresponding lateral negative pressure diversion port when the negative pressure distribution adaptation value is lower than the preset negative pressure distribution adaptation threshold. The parallel buffer switching unit is used to activate the buffer channel connected in parallel with the current microfluidic classification channel when the flow rate still decreases after reducing the suction intensity, so that the electronic slurry to be classified can bypass the particle deposition area and continue to be classified.

8. The microfluidic negative pressure ultra-micro classification system for electronic pastes in electronic material manufacturing according to claim 7, characterized in that: The bypass buffer and reverse pulse unblocking module includes a blockage type determination unit, a parallel buffer execution unit, a reverse pulse execution unit, a bubble blocking and removal unit, and a drainage and reset unit. The blockage type determination unit is used to receive differential pressure growth rate, flow rate attenuation rate, instantaneous differential pressure change, flow rate step drop duration, bubble blockage fluctuation frequency, and microbubble volume fraction, and to generate channel anomaly triggering results; The reverse pulse execution unit is used to apply short-term reverse pulse pressure to the corresponding microfluidic grading channel when the abnormal triggering result of the channel meets the particle jamming judgment condition, so that the jammed particles detach from the side negative pressure diversion port or the microchannel wall. The bubble blocking and elimination unit is used to open the exhaust branch and reduce the inlet feeding speed when the abnormal triggering result of the channel meets the bubble blocking judgment condition, so that the bubbles are discharged through the exhaust branch. The parallel buffer execution unit is used to open the bypass switching valve at the front end of the abnormal channel inlet when the channel differential pressure growth rate and flow rate decay rate both exceed the corresponding thresholds within multiple consecutive sampling periods, and the particle jamming judgment condition and bubble blockage judgment condition are not met. This allows the electronic slurry to be graded to be diverted from the front end of the abnormal channel inlet to the parallel buffer channel, and then flow into the downstream of the abnormal channel or the next level of microfluidic grading channel through the outlet of the parallel buffer channel. The drain reset unit is used to drain the slurry retained in the abnormal channel when the abnormal trigger result of the channel reaches the severe abnormal supply stop condition. After the blockage is cleared, the channel pressure difference, flow rate attenuation rate, instantaneous pressure difference change amount and bubble blockage fluctuation frequency are resent to the rheological state and channel pressure difference acquisition module for verification.

9. The microfluidic negative pressure ultra-micro classification system for electronic pastes in electronic material manufacturing according to claim 1, characterized in that: The coarse particle redispersion reflux module includes a coarse particle storage chamber, a hard impurity identification unit, a small sample redispersion detection unit, a low-shear redispersion chamber, a reflux judgment unit, a reflux control valve, and a waste discharge chamber. The coarse particle storage chamber is used to receive the coarse particle slurry discharged from the lateral negative pressure diversion port and to record the source grading channel and diversion time of the coarse particle slurry. The hard impurity identification unit is used to identify the proportion of hard impurities in coarse-particle slurry; The small-sample redispersion test unit is used to conduct a low-shear redispersion test on coarse particle slurry for a preset time, and to obtain the recoverable proportion of agglomerated particles based on the change in the proportion of coarse particles before and after redispersion. The reflux judgment unit is used to generate redispersibility and reflux adaptation results based on the concentration of coarse particles, the proportion of hard impurities, the recoverable proportion of agglomerated particles, the redispersibility treatment time, and the volume of reflux slurry. The low-shear redispersion chamber is used to redisper coarse particle slurry when the redispersion reflux adaptation results meet the reflux conditions. The reflux control valve is used to return the redispersed electronic slurry to the inlet negative pressure degassing buffer chamber; The waste discharge chamber is used to receive and discharge non-redispersible coarse particle slurry when the redispersibility reflux adaptation results meet the waste discharge conditions.

10. The microfluidic negative pressure ultra-micro classification system for electronic pastes in electronic material manufacturing according to claim 1, characterized in that: The target slurry collection module includes a target particle size slurry collection chamber, a particle size window verification unit, a solid content stabilization unit, a trial printing detection unit, an output quality adaptation value generation unit, and an output switching unit. The target particle size slurry collection chamber is used to receive the target particle size electronic slurry output from each stage of the microfluidic grading channel; The particle size window verification unit is used to detect the median particle size, cumulative particle size, proportion of coarse particles remaining, and proportion of particles within the target particle size window of the electronic paste with the target particle size. The solid content stabilization unit is used to detect the solid content and viscosity of the target particle size electronic paste, and adjusts the suction intensity of the reflux control valve and the corresponding independent negative pressure branch when the solid content is lower or higher than the preset range. The trial printing detection unit is used to test the linewidth stability of electronic paste with target particle size and to obtain the linewidth deviation. The discharge quality adaptation value generation unit is used to generate discharge quality adaptation results based on median particle size, cumulative particle size, coarse particle residual ratio, solid content, viscosity and linewidth deviation. The discharge switching unit is used to introduce the target particle size electronic paste into the qualified paste discharge port when the discharge quality adaptation result meets the qualified discharge conditions. When the output quality meets the secondary reflux conditions, the target particle size electronic slurry is returned to the secondary microfluidic classification channel; When the output quality meets the first-level reflux conditions, the target particle size electronic slurry is returned to the first-level microfluidic classification channel. When the output quality does not meet the requirements for graded output, the target particle size electronic slurry is introduced into the circulating grading inlet or returned to the electronic slurry pre-dispersion feeding module for reprocessing.

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