Preparation method of ultrahigh-pressure molded laminated power inductor
By real-time monitoring and dynamic adjustment of pressure, the problem of uneven pressure in the laminated green body is solved, ensuring the product quality and stability of the laminated power inductor.
Patent Information
- Application Number
- CN202511100685.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-07
- Publication Date
- 2025-09-12
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The traditional ultra-high pressure forming process transmits uneven pressure in the laminated green body, resulting in loose bonding or excessive extrusion between layers, affecting the dimensional accuracy and current carrying stability of the product.
By installing pressure sensors and thermocouple sensors in the laminated green body, pressure and temperature data are monitored in real time, pressure deviation and gradient are calculated, and pressure is dynamically adjusted to achieve uniform distribution. Electrodes are formed by combining cutting, debinding, sintering and other steps to ensure close bonding between layers.
A uniform pressure distribution of the laminated green body is achieved, local loosening or cracking is avoided, and the reliability and current carrying stability of the product are improved.
Smart Images
Figure CN120637067A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of power inductor preparation, and in particular to a method for preparing an ultra-high voltage molded laminated power inductor. Background Art
[0002] Power inductors are electronic components used to carry current, store energy, and filter power. They are widely used in power management and DC-DC circuit modules in devices such as mobile phones and TWS earphones. They come in a variety of sizes and specifications to meet the current and inductance requirements of different scenarios. Ultra-high pressure forming is a key manufacturing technology for power inductors. After forming the laminated green body through steps such as casting, perforation, and printing, ultra-high pressure equalization technology is used to apply pressure at a certain temperature. Combined with sintering and post-processing processes, this ensures a tight bond between the layers, thereby improving product reliability and integration.
[0003] Traditional ultra-high pressure forming (UHP) processes typically apply pressure to the entire green body at a fixed pressure and temperature, achieving initial bonding between the layers using a mechanical pressurizing device, before proceeding directly to the sintering stage. However, this method fails to account for the differences in material density across the green body and the distribution of interlaminar stresses. This results in uneven pressure transfer, potentially leading to localized loosening of interlaminar bonds or excessive compression, which can cause material cracking and compromise the product's dimensional accuracy and current-carrying stability. Summary of the Invention
[0004] In view of the above, it is necessary to provide a method for preparing an ultra-high voltage molded multilayer power inductor to solve the above problems.
[0005] One embodiment of the present application provides a method for preparing an ultra-high voltage molded laminated power inductor, the method comprising: Step 1: Prepare a magnetic ceramic film using a tape casting process. After opening the ceramic film, print a conductive paste. Stack multiple layers of printed ceramic films layer by layer to obtain a laminated green body. Obtain pressure data from each pressure sensor of the laminated green body at each moment and temperature data from each thermocouple sensor at each moment. Step 2: Analyze the distribution characteristics of the pressure data of all pressure sensors at each moment and determine the pressure deviation at each moment. Based on the difference between the pressure data of each pressure sensor and its adjacent pressure sensors at each moment, combined with the distance characteristics of the pressure sensor distribution, determine the pressure gradient deviation at each moment. Based on the pressure deviation and pressure gradient deviation at each moment, obtain the actual pressure deviation at each moment. Step 3: Analyze the distribution characteristics and discreteness of the pressure data collected by all pressure sensors at each moment, and determine the dynamic deviation threshold at each moment by combining the difference between the temperature data of all thermocouple sensors at each moment and the preset reference temperature. Compare the actual pressure deviation at each moment with the dynamic deviation threshold value to determine whether to perform a pressure hold operation. Step 4: Cut, debind, sinter, chamfer, and silver-sinter the laminated green body after equalization to form electrodes. After electroplating and package testing, the ultra-high voltage molded laminated power inductor is obtained.
[0006] The determination of the pressure deviation at each moment is specifically as follows: Get the average value of pressure data of all pressure sensors at each moment; The difference between the pressure data obtained by each pressure sensor at each moment and the average value is calculated; the differences obtained by all pressure sensors are accumulated to obtain the pressure deviation at each moment.
[0007] The determination of the pressure gradient deviation at each moment is specifically as follows: At each moment, obtain the maximum value of the pressure difference between each pressure sensor and all its adjacent pressure sensors, obtain the distance between the two sensors corresponding to the maximum value, and calculate the ratio between the maximum value obtained by each pressure sensor and the corresponding distance; determining a weight of each pressure sensor according to a distance between each pressure sensor and an edge of the laminated green body; The ratios of all pressure sensors are weighted and summed to obtain the pressure gradient deviation at each moment.
[0008] The weight of each pressure sensor is specifically the reciprocal of the shortest distance between each pressure sensor and the edge of the laminated green compact.
[0009] The actual pressure deviation at each moment is specifically the average value of the normalized value of the pressure deviation degree and the normalized value of the pressure gradient deviation at each moment.
[0010] The step of determining the dynamic deviation threshold at each moment includes: Determine the baseline deviation threshold at each moment based on the difference between the pressure data collected by all pressure sensors at each moment and the preset pressure value; Compare the discrete degree of pressure data of all pressure sensors at each moment with the discrete degree of pressure data at the previous moment to obtain the pressure distribution difference value at each moment; According to the difference between the temperature data collected by all thermocouple sensors at each moment and the preset reference temperature, combined with the pressure distribution difference value, the reference deviation threshold at each moment is corrected to obtain the dynamic deviation threshold at each moment.
[0011] The determination of the reference deviation threshold at each moment is specifically as follows: The average value of the pressure data collected by all pressure sensors at each moment is calculated and recorded as the average pressure value; the difference between the average pressure value at each moment and the preset reference pressure is used to obtain the basic deviation threshold at each moment.
[0012] The pressure distribution difference value at each moment is specifically: the absolute value of the difference between the discreteness of the pressure data of all pressure sensors at each moment and the discreteness of the pressure data at the previous moment.
[0013] The condition for performing the pressure maintaining operation is that the actual pressure deviation is greater than the normalized dynamic deviation threshold.
[0014] The process of performing the pressure holding operation is specifically as follows: When the actual pressure deviation is greater than the normalized dynamic deviation threshold, the pressure is maintained at the current pressure value. If either the pressure maintenance time reaches the preset duration or the actual pressure deviation is less than or equal to the normalized dynamic deviation threshold, the pressure is increased at the preset pressure increase rate until the target pressure is reached. After reaching the target pressure, the pressure is maintained for 5 to 10 minutes.
[0015] This application has at least the following beneficial effects: During the equalization process of the laminated green sheets, the present application determines the actual pressure deviation by monitoring the deviation between the pressure in the area where each pressure sensor is located and the average pressure, as well as the pressure gradient difference between adjacent areas. This method can not only accurately reflect the overall pressure deviation during the equalization process, but also reveal the local pressure unevenness; the dynamic deviation threshold is calculated by considering normal pressure fluctuations and changes caused by time and temperature, so as to exclude normal fluctuation factors and consider the influence of external factors; then, the actual pressure deviation is compared with the dynamic deviation threshold to help determine whether the pressure is uniform, so as to make necessary pressure adjustments. This method dynamically determines the acceptable pressure deviation, avoids too frequent pressure adjustments, and avoids the problem of decreased bonding strength due to local pressure unevenness or cracking due to excessive pressure. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 A flow chart of the method for preparing the ultra-high voltage molded laminated power inductor provided in this application; Figure 2 This is a flow chart for obtaining the dynamic deviation threshold provided in this application. DETAILED DESCRIPTION
[0017] In the description of the embodiments of this application, words such as "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "or," and "for example" is intended to present the relevant concepts in a concrete manner.
[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the art of this application. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0019] It should also be noted that the terms "first" and "second" in this application and its accompanying drawings are used to distinguish similar objects, rather than to describe a specific order or precedence. The methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the methods. Without departing from the scope of protection of this application, the order of execution of multiple steps can be interchanged with each other, and some steps can also be deleted.
[0020] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
[0021] The lamination process for power inductors includes tape casting, hole opening, printing, lamination, pressure equalization, cutting, electroplating, silver termination / burning, chamfering, sintering, debonding, six-sided appearance selection, and package testing. This application aims to solve the technical problems caused by ultra-high voltage conditions during the lamination step.
[0022] The present invention provides a method for preparing an ultra-high voltage molded laminated power inductor, which is applied to the technical field of power inductor preparation. Figure 1 , the method comprising: Step 1: Prepare a magnetic ceramic film using a tape casting process, open holes in the ceramic film, and then print a conductive paste; stack multiple layers of printed ceramic film layer by layer to obtain a laminated green body; obtain the pressure data of each pressure sensor of the laminated green body at each moment and the temperature data of each thermocouple sensor at each moment.
[0023] First, a magnetic ceramic film with uniform thickness is prepared through a casting process. Then, the ceramic film is perforated to obtain through holes for conductive connection. Then, a conductive paste is printed on the perforated ceramic film to form a preset coil pattern, so that the ceramic film has circuit function. After the single-layer ceramic film is processed, the ceramic film with multiple layers of printed coils is stacked layer by layer according to the design requirements, so that each layer of coil is accurately aligned to obtain a laminated green body.
[0024] Micro pressure sensors are installed on the pressure head of the pressure device, that is, the part in contact with the upper surface of the laminated green body, and the contact surface of the supporting platform, that is, the part in contact with the lower surface of the laminated green body. In this embodiment, the pressure sensor is 5 mm. Open grooves at even intervals of 5mm for installation. After embedding the sensor in the groove, fix it with high-temperature and high-voltage resistant insulating glue to ensure that the sensor sensing surface is flush with the pressure head and the surface of the carrying platform.
[0025] Install micro thermocouple sensors at the edge of the platform, 5-10 mm outside the laminated green body placement area. Place 4-6 sensors evenly, avoiding the laminated green body pressure area.
[0026] To synchronize the collected data, first calibrate the sampling frequency of each sensor. In this embodiment, the sampling frequency of all sensors is set to 10 Hz. By synchronously triggering sampling, the raw data of the pressure sensor and the thermocouple sensor are aligned according to the timestamp.
[0027] The sliding average filter method is used to filter the original data to eliminate the high-frequency fluctuations caused by vibration. The outliers are removed by using the rule, and the missing values in the original data are filled by the linear interpolation method to complete the data preprocessing. The rule and linear interpolation method are both existing well-known technologies and will not be described in detail in this application.
[0028] Step 2: Analyze the distribution characteristics of the pressure data of all pressure sensors at each moment and determine the pressure deviation at each moment; determine the pressure gradient deviation at each moment based on the difference between the pressure data of each pressure sensor and its adjacent pressure sensors at each moment, combined with the distance characteristics of the pressure sensor distribution; based on the pressure deviation and pressure gradient deviation at each moment, obtain the actual pressure deviation at each moment.
[0029] During the ceramic membrane lamination process, the thickness of each layer may vary, which will lead to uneven pressure transmission during the equalization process, resulting in localized uneven pressure and affecting the quality of the interlayer bonding. The surface of the pressure head or the supporting platform of the pressure device may be uneven. In addition, due to the installation of the sensor, the contact with the laminated green body is not close, which can also cause unbalanced pressure transmission. Because a certain temperature needs to be maintained during the pressure process, if the temperature distribution is uneven, the deformation of different areas of the green body may be different, which will also affect the uniformity of the pressure.
[0030] The above factors have little effect on the uneven pressure caused during the pressure application process, which can be improved through pressure control. If misalignment or wrinkles occur during the stacking process, it will cause greater uneven pressure. At this time, it cannot be improved by pressure adjustment and needs to be stopped for inspection.
[0031] When uneven pressure occurs during the pressing process, it may cause the layers in the laminated green body to be loosely bonded, resulting in gaps or stratification, reducing the structural strength of the finished product. Since the pressure in each area is inconsistent, the degree of densification in each area will be inconsistent, resulting in differences in the electrical properties of each area in the finished product, affecting stability, so pressure control is required during the pressing process.
[0032] First, the pressure deviation at each moment is calculated based on the pressure data of all measurement points at each moment, which is recorded as , its formula is , where N represents the number of pressure sensors, represents the pressure data collected by the i-th pressure sensor at each moment, Indicates the average pressure value collected by all pressure sensors at each moment.
[0033] It should be understood that the average value of all pressure data at the same moment is used as the standard for judging the pressure uniformity of each area. During the pressure equalization process, as the pressure gradually increases, the pressure data collected by each pressure sensor may deviate. By using the average value as a reference standard, when the pressure data of a sensor is lower than the average value, it indicates that the pressure in that area is too low; conversely, when the pressure data is higher than the average value, it indicates that the pressure in that area is too high.
[0034] A positive pressure deviation indicates high overall pressure, while a negative deviation indicates low overall pressure. A larger absolute value for the pressure deviation indicates a higher likelihood of uneven pressure distribution across different areas, requiring adjustments to prevent uneven pressure transmission. Conversely, a smaller absolute value indicates a more even pressure distribution and a smoother equalization process, requiring less pressure adjustment.
[0035] The pressure deviation can reflect the overall pressure deviation during the pressure equalization process. However, when there is pressure concentration, only a few areas will experience pressure deviation, resulting in a small absolute value of the pressure deviation, which cannot reflect the true situation of the pressure deviation in a timely manner. Therefore, the pressure deviation situation must be judged based on the pressure changes in adjacent areas and the pressure gradients in adjacent areas.
[0036] Therefore, the pressure gradient deviation can be calculated as ,in, represents the maximum value of the pressure difference between the i-th pressure sensor and its adjacent pressure sensor at each moment. In this embodiment, the pressure difference is calculated by the absolute value of the difference between the pressure data; It represents the distance between the i-th sensor and the adjacent sensor corresponding to its maximum value, which is used to normalize the pressure gradient, eliminate the influence of distance on pressure change, and quantify the pressure change within a unit distance. represents the weight of the i-th pressure sensor, which is set according to the importance of the region. In this embodiment, the reciprocal of the closest distance between each pressure sensor and the edge of the laminated green body is used as the weight of each pressure sensor, because the edge area is more likely to crack under uneven pressure.
[0037] By weighting the pressure gradients of adjacent areas of all pressure sensors, the pressure gradient level in the global range is obtained. The larger the value of the pressure gradient deviation, the more uneven the pressure distribution is, and the more likely it is that the local pressure is too high or too low. At this time, the pressure should be adjusted. Conversely, the more uniform the global pressure distribution is, the less likely it is that the local pressure is too high or too low.
[0038] By calculating the average of the normalized pressure deviation and the normalized pressure gradient deviation at each moment, the actual pressure deviation at each moment is obtained and further compared with the threshold to determine whether pressure adjustment is necessary. The normalization method uses the maximum and minimum value normalization method.
[0039] Step 3: Analyze the distribution characteristics and discreteness of the pressure data collected by all pressure sensors at each moment, and determine the dynamic deviation threshold at each moment by combining the difference between the temperature data of all thermocouple sensors at each moment and the preset reference temperature; compare the actual pressure deviation at each moment with the value of the dynamic deviation threshold to determine whether to perform a pressure holding operation.
[0040] However, in addition to the inherent output fluctuations of the hydraulic system itself, which can cause pressure fluctuations, the non-uniformity of the laminated green body material and the mismatch in the pressure application rate can also cause pressure fluctuations. Specifically, when high-density areas of the laminated green body are pressurized too quickly, the material's deformation rate may lag behind that of lower-density areas, resulting in transient pressure fluctuations. Therefore, using a fixed threshold to determine the timing of pressure adjustment may not accurately reflect the actual situation.
[0041] It should be noted that the set pressure fluctuation range should be larger than the maximum amplitude of normal pressure fluctuations to avoid unnecessary adjustments due to normal fluctuations; at the same time, it should be smaller than the critical fluctuation value that may cause damage to the laminated green body to ensure that timely adjustments can be made when abnormal fluctuations occur.
[0042] The formula for the dynamic deviation threshold is: , where Y represents the dynamic deviation threshold at each moment, Indicates the basic deviation threshold at each moment, that is, the absolute value of the difference between the reference pressure set by the hydraulic system and the average pressure value collected by all pressure sensors. It represents the pressure distribution difference value at each moment, that is, the difference between the discrete degrees of pressure data collected by all pressure sensors at each moment and the previous moment. In this embodiment, the discrete degrees between multiple variables are calculated using standard deviation, and the difference between variables is calculated using difference. The pressure distribution difference value reflects the pressure fluctuation over time. The larger the value, the less persistent the pressure fluctuation is, and it may be just a normal fluctuation caused by the output fluctuation of the hydraulic system. At this time, the threshold can be appropriately increased to avoid unnecessary pressure adjustment. Conversely, if the difference values between adjacent moments are small, it indicates that there may be continuous pressure fluctuations. In order to avoid damage to the green body, the threshold should be lowered so that pressure adjustment can be performed in time. The pressure distribution difference value reflects the pressure fluctuation over time. It represents the difference between the average temperature collected by all thermocouple sensors at each moment and the reference temperature. In this embodiment, the reference temperature is 145 ; Temperature has an important influence on the physical properties of the laminated green body. Excessive temperature deviation will lead to deformation differences in different areas. When the temperature is too low, the material becomes harder. Even if the pressure deviation is small, it may cause uneven pressure distribution, thereby causing cracking. Therefore, the threshold should be reduced and adjusted in time. When the temperature is too high, the material is softer. Under the same degree of deviation, the impact is smaller. At this time, the threshold can be increased to avoid unnecessary adjustments.
[0043] The flow chart for obtaining the dynamic deviation threshold is as follows: Figure 2 shown.
[0044] When the pressure equalization step begins, the pressure is increased at a rate of 50 MPa / min, the target pressure is 660 MPa, and the target temperature is 145 During the pressurization process, if the actual pressure deviation exceeds the dynamic deviation threshold, the pressure is maintained at the current pressure value and the pressure increase is stopped to prevent excessive pressure deviation accumulation. By maintaining the current pressure, the green body can fully deform under a stable stress state and eliminate interlayer gaps, thus strengthening the bonding between the layers. If the actual pressure deviation is less than or equal to the dynamic deviation threshold or the pressure is maintained for one minute, the pressure is increased at the preset speed until the target pressure is reached, and the target temperature is maintained during this process. After reaching the target pressure, the pressure is maintained for 5-10 minutes to complete the pressure equalization step.
[0045] Step 4: Cut, debind, sinter, chamfer, and silver-sinter the laminated green body after equalization to form electrodes. After electroplating and package testing, the ultra-high voltage molded laminated power inductor is obtained.
[0046] After the laminated green body is evenly pressed, it is cut into individual product units according to the preset size, and then the debinding step is carried out to remove the organic binder contained in the green body to prevent the volatilization of organic matter during subsequent sintering, which may cause pores or cracks. After debinding, sintering is carried out, combined with powder surface insulation technology, in order to improve the strength and density of the magnet structure. Chamfering is then carried out to treat the edges and corners to prevent stress concentration. Then, silver termination or silver burning operations are performed to form electrodes, and finally electroplating is performed to optimize the conductivity of the electrodes. The finished product is screened for appearance on six sides to screen out qualified products, and finally tested and packaged to obtain qualified ultra-high pressure molded laminated power inductors.
[0047] In order to verify the validity of this application, several comparative examples are set, specifically: Comparative Example 1: The pressure increasing rate was set to 50 MPa / min, and no pressure maintenance was performed during the pressure equalization process. The remaining steps were the same as those in the embodiment; Comparative Example 2: The pressure increase rate was set to 50 MPa / min, and a fixed pressure holding time interval was used during the pressure equalization process. In this comparative example, the pressure was held every 5 minutes for 1 minute. The remaining steps were consistent with the embodiment; Comparative Example 3: The pressure increase rate is set to 50 MPa / min, and a fixed threshold is used to compare with the actual pressure deviation during the pressure equalization process, wherein the fixed threshold is set to 0.5; the remaining steps are consistent with the embodiment.
[0048] All the finished ultra-high pressure molded laminated power inductors obtained in the examples and comparative examples were tested, and the comparative data are shown in the following table: Table 1: Comparison of ultra-high voltage stacking processes
[0049] From the comparison in the table, we can see that if no pressure maintenance operation is performed during the equalization process, local underpressure or overpressure will result, which may easily cause uneven density and residual pores between layers, resulting in insufficient bonding strength. If staged pressure maintenance is performed during the equalization process without considering the actual situation, uniform pressure penetration cannot be achieved, which will also lead to insufficient compaction between layers, density deviation and decreased bonding strength. If the threshold is fixed without considering normal pressure fluctuations, the pressure state may be misjudged, resulting in inaccurate pressure adjustment and product degradation.
[0050] The flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to the embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the part of the module, program segment or code contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. In the description corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action, or may be implemented by a combination of dedicated hardware and computer instructions.
[0051] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application.
Claims
1. A method for preparing an ultra-high voltage molded laminated power inductor, characterized in that: The method includes: Step 1: Prepare a magnetic ceramic film using a tape casting process. After opening the ceramic film, print a conductive paste. Stack multiple layers of printed ceramic films layer by layer to obtain a laminated green body. Obtain pressure data from each pressure sensor of the laminated green body at each moment and temperature data from each thermocouple sensor at each moment. Step 2: Analyze the distribution characteristics of the pressure data of all pressure sensors at each moment and determine the pressure deviation at each moment. Based on the difference between the pressure data of each pressure sensor and its adjacent pressure sensors at each moment and the distance characteristics of the pressure sensor distribution, determine the pressure gradient deviation at each moment. Based on the pressure deviation and pressure gradient deviation at each moment, obtain the actual pressure deviation at each moment. Step 3: Analyze the distribution characteristics and discreteness of the pressure data collected by all pressure sensors at each moment, and determine the dynamic deviation threshold at each moment by combining the difference between the temperature data of all thermocouple sensors at each moment and the preset reference temperature. Compare the actual pressure deviation at each moment with the dynamic deviation threshold value to determine whether to perform a pressure hold operation. Step 4: Cut, debind, sinter, chamfer, and silver-sinter the laminated green body after equalization to form electrodes. After electroplating and package testing, the ultra-high voltage molded laminated power inductor is obtained.
2. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 1, wherein: The determination of the pressure deviation at each moment is specifically as follows: Get the average value of pressure data of all pressure sensors at each moment; The difference between the pressure data obtained by each pressure sensor at each moment and the average value is calculated; the differences obtained by all pressure sensors are accumulated to obtain the pressure deviation at each moment.
3. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 1, wherein: The determination of the pressure gradient deviation at each moment is specifically as follows: At each moment, obtain the maximum value of the pressure difference between each pressure sensor and all its adjacent pressure sensors, obtain the distance between the two sensors corresponding to the maximum value, and calculate the ratio between the maximum value obtained by each pressure sensor and the corresponding distance; determining a weight of each pressure sensor according to a distance between each pressure sensor and an edge of the laminated green body; The ratios of all pressure sensors are weighted and summed to obtain the pressure gradient deviation at each moment.
4. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 3, wherein: The weight of each pressure sensor is specifically the reciprocal of the shortest distance between each pressure sensor and the edge of the laminated green body.
5. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 1, wherein: The actual pressure deviation at each moment is specifically an average value of the normalized value of the pressure deviation degree and the normalized value of the pressure gradient deviation at each moment.
6. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 1, wherein: Determining the dynamic deviation threshold at each moment includes: Determine the baseline deviation threshold at each moment based on the difference between the pressure data collected by all pressure sensors at each moment and the preset pressure value; Compare the discrete degree of pressure data of all pressure sensors at each moment with the discrete degree of pressure data at the previous moment to obtain the pressure distribution difference value at each moment; According to the difference between the temperature data collected by all thermocouple sensors at each moment and the preset reference temperature, combined with the pressure distribution difference value, the reference deviation threshold at each moment is corrected to obtain the dynamic deviation threshold at each moment.
7. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 6, wherein: The determination of the reference deviation threshold at each moment is specifically as follows: The average value of the pressure data collected by all pressure sensors at each moment is calculated and recorded as the average pressure value; the difference between the average pressure value at each moment and the preset reference pressure is used to obtain the basic deviation threshold at each moment.
8. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 6, wherein: The pressure distribution difference value at each moment is specifically: the absolute value of the difference between the discreteness of the pressure data of all pressure sensors at each moment and the discreteness of the pressure data at the previous moment.
9. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 1, wherein: The condition for performing the pressure maintaining operation is that the actual pressure deviation is greater than the normalized dynamic deviation threshold.
10. The method for preparing an ultra-high pressure molded laminated power inductor according to claim 1, wherein: The process of the pressure holding operation is specifically as follows: When the actual pressure deviation is greater than the normalized dynamic deviation threshold, the pressure is maintained at the current pressure value. If either the pressure maintenance time reaches the preset duration or the actual pressure deviation is less than or equal to the normalized dynamic deviation threshold, the pressure is increased at the preset pressure increase rate until the target pressure is reached. After reaching the target pressure, the pressure is maintained for 5 to 10 minutes.