Multilayer pcb winding press alignment method for high frequency planar transformer

Abstract

The present application relates to the technical field of printed circuit control, and in particular to a multi-layer PCB winding pressing alignment method for high-frequency planar transformers. The method obtains a PCB layout and divides a grid, calculates the copper foil area proportion of each grid; determines the radial unit vector of each positioning pin based on the vector relationship between the positioning pin area and the layout geometric center; in the pressing process, the resin extrusion trend scalar is generated by combining the real-time obtained deformation height of each grid under pressure and the copper foil area proportion, and the two-dimensional flow vector is obtained through local space partial derivative analysis; then the vector and the radial unit vector are combined to calculate the radial extrusion component of each positioning pin area, and finally the pressing process is dynamically controlled according to the numerical distribution of all components to realize high-precision alignment control.

Description

Technical Field

[0001] This invention relates to the field of printed circuit control technology, and more specifically to a method for aligning and bonding multilayer PCB windings for high-frequency planar transformers. Background Technology

[0002] High-frequency planar transformers, due to their low leakage inductance and high power density, are widely used in various switching power supply devices. Their multilayer printed circuit board (PCB) core board manufacturing typically employs a non-uniform distribution design with thick copper windings in the central area and copper-free blank areas at the edges. During the lamination process of the multilayer PCB, the laminator applies high temperature and vertical downward pressure to the stacked layers. During the heat softening stage, the liquid resin, under vertical extrusion, overflows laterally from the thick copper area with high central resistance to the copper-free area with low edge resistance. This asymmetrical lateral overflow impacts the metal locating pins at the edge of the lamination fixture used to maintain interlayer alignment. When the accumulated local force exceeds the material's elastic limit, the locating pins undergo permanent plastic deformation, bending outwards. This deformation causes the upper and lower thick copper windings to deviate from the preset vertical alignment axis, leading to insufficient electrical insulation spacing or interlayer short circuits within the transformer, resulting in irreversible process misalignment.

[0003] Existing pressing control systems primarily adjust the equipment by monitoring the overall temperature of the pressing plate or the global downward pressure of the hydraulic master cylinder. Due to the extremely narrow and enclosed space between the layers of the printed circuit board, it is impossible to place physical sensors on-site to directly measure the local extrusion strength characteristics of the internal liquid resin. Relying on simple vertical displacement monitoring by external sensors can only yield a scalar value of thickness compression, resulting in unreliable pressing and alignment control of the PCB windings and low control accuracy. Summary of the Invention

[0004] To address the technical problem of unreliable PCB winding alignment control and low control accuracy in related technologies, this invention provides a method for multilayer PCB winding alignment in high-frequency planar transformers. The specific technical solution adopted is as follows: This invention proposes a method for aligning and bonding multilayer PCB windings for high-frequency planar transformers, the method comprising: Obtain the layout diagram of the PCB board to be laminated, and divide it into different grid areas on an average basis; determine the copper foil area ratio of each grid area; The grid area where the locating pins of each edge of the layout is located is taken as the locating pin area. Based on the vector analysis of the locating pin area and the geometric center point of the layout, the radial unit vector of each locating pin area is determined. At different sampling moments during the lamination process, the compressive deformation height of different grid areas on the PCB board is obtained. Based on the ratio of compressive deformation height to copper foil area at each sampling moment, the resin extrusion trend scalar of each locating pin area is determined. Local spatial partial derivative analysis is performed on the resin extrusion trend scalar to obtain a two-dimensional flow vector. By combining the two-dimensional flow vector and the radial unit vector, the radial compression component of the locating pin area is determined, and the PCB winding pressing alignment control is performed based on the numerical distribution of the radial compression component of all locating pin areas.

[0005] Furthermore, obtaining the compressive deformation height of different grid regions on the PCB board includes: Install high-precision displacement sensors at the four physical corners of the PCB board; After the pressing begins, the thickness values ​​of the four corners are read at fixed sampling intervals; based on the thickness value at the initial pressing moment, the cumulative pressing amount at each sampling moment is calculated; By using a spatial bilinear interpolation algorithm, the cumulative downward pressure at the four corners is extended to all grid areas of the layout, thus obtaining the compressive deformation height of each grid area.

[0006] Furthermore, the method for determining the resin extrusion trend vector of each positioning pin region includes: For each grid region, its compressive deformation height is multiplied by the proportion of the copper foil area in that grid region, and this product is used as a scalar of resin extrusion tendency.

[0007] Furthermore, the method for determining the two-dimensional flow vector includes: For the resin extrusion trend scalar of each locating pin region, calculate its local first-order difference on the adjacent sides; The difference value in any direction of the grid region is taken as the first directional component, and the difference value in the other direction is taken as the second directional component. These components are combined to form a preliminary flow vector. The direction of this preliminary flow vector is then reversed to obtain the final two-dimensional flow vector.

[0008] Furthermore, the method for determining the radial compression component of the locating pin region includes: Perform a spatial vector dot product operation between the two-dimensional flow vector of each locating pin region and the corresponding radial unit vector to obtain a scalar value. If the scalar value is greater than zero, it is taken as the radial compression component of the locating pin region. If the scalar value is less than or equal to zero, the radial compression component of the locating pin region is set to zero.

[0009] Furthermore, the step of controlling the PCB winding pressing alignment based on the radial compression component distribution of all locating pin areas includes: A preset reference value for allowable deformation displacement is set; the radial compression component of each locating pin area is compared with the preset reference value in real time; when the radial compression component of any locating pin area exceeds the preset reference value, a pressure reduction command is generated, which is used to switch the hydraulic system to a low-pressure holding state.

[0010] Furthermore, the preset benchmark value is obtained through offline sampling test calibration, specifically including: Install a contact displacement dial indicator on the outside of the test locating pin; The radial compression component is compressed and output synchronously; When the dial gauge reading reaches the preset critical value of permanent plastic deformation, the radial compression component value at the corresponding moment is captured. The 80th percentile of multiple test results is taken as the preset benchmark value.

[0011] Furthermore, after switching to the low-voltage holding state, the absolute value of the transient displacement increment of different physical corners of the PCB board between adjacent sampling times is continuously monitored; When the absolute value of the transient displacement increment of all physical corners is less than the preset noise tolerance threshold within a preset number of consecutive sampling times, a pressure boosting command is generated. The pressure boosting command is used to make the hydraulic system exit the low-pressure holding state and restore it to the set initial pressure.

[0012] Furthermore, the average division into different grid regions includes: cutting the PCB board layout image at equal intervals along the two adjacent sides of the image to form a rectangular grid array of M rows and N columns; wherein the values ​​of M and N are determined according to the PCB board size and the positioning pin position accuracy requirements to ensure that each positioning pin falls into a complete grid region.

[0013] Furthermore, the method for determining the copper foil area ratio of each grid region includes: The copper foil areas of different grid regions are determined based on the PCB board design drawings; The ratio of the copper foil area within a given grid region to the total area of ​​the grid region is used as the percentage of copper foil area.

[0014] The present invention has the following beneficial effects: To address the technical problem of existing pressing control systems relying primarily on monitoring the overall temperature of the pressing plate or the global downward pressure of the hydraulic master cylinder for equipment adjustment, and limited by the extremely narrow, enclosed space between printed circuit board layers, which prevents direct measurement of the local extrusion intensity characteristics of the internal liquid resin, resulting in low control accuracy, this invention obtains the layout diagram of the PCB board to be pressed and divides it into different grid regions. The copper foil area ratio of each grid region is determined, providing basic data for subsequent accurate modeling. Then, based on vector analysis of the locating pin regions and geometric center points, the radial unit vector of each locating pin region is determined, clarifying the key force direction of each locating pin. During the pressing process, the compressive deformation height of different grid regions is monitored in real time, and the resin extrusion trend scalar is calculated based on the copper foil area ratio. Then, a two-dimensional flow vector is generated using local spatial partial derivative analysis, indirectly inferring the actual flow direction and intensity of the resin. Finally, the two-dimensional flow vector is combined with the radial unit vector to extract the radial compression component of the locating pin regions. Dynamic pressing alignment control is then performed based on the numerical distribution of the radial compression components of all locating pin regions. This series of steps does not require embedded physical sensors and relies entirely on external measurable signals and offline design data, effectively overcoming the limitations of traditional methods that can only provide thickness compression scalars and cannot capture resin flow details, thus greatly improving the control accuracy and reliability of PCB winding pressing and alignment. Attached Figure Description

[0015] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart illustrating a method for aligning and bonding multilayer PCB windings for a high-frequency planar transformer, provided as an embodiment of the present invention. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a multilayer PCB winding lamination and alignment method for a high-frequency planar transformer proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, 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 invention pertains.

[0019] The following describes in detail, with reference to the accompanying drawings, a specific scheme for a multilayer PCB winding lamination and alignment method for a high-frequency planar transformer provided by the present invention.

[0020] Please see Figure 1 The diagram illustrates a flowchart of a method for aligning and bonding multilayer PCB windings for a high-frequency planar transformer, according to an embodiment of the present invention. The method includes: S101: Obtain the layout of the PCB board to be laminated in the batch, and divide it into different grid areas on an average basis; determine the copper foil area ratio of each grid area.

[0021] High-frequency planar transformers, due to their low leakage inductance and high power density, are widely used in various switching power supply devices. Their multilayer printed circuit board (PCB) core board manufacturing typically employs a non-uniform distribution design with thick copper windings in the central area and copper-free blank areas at the edges. During the lamination process of the multilayer PCB, the laminator applies high temperature and vertical downward pressure to the stacked layers. During the heat-softening stage, under vertical extrusion, the liquid resin overflows laterally from the thick copper area with high central resistance to the copper-free areas with low edge resistance.

[0022] This asymmetrical lateral overflow flow exerts a squeezing impact on the metal locating pins at the edge of the pressing fixture, which are used to maintain interlayer alignment. When the accumulated local stress exceeds the elastic limit of the material, the locating pins undergo permanent plastic deformation, bending outwards. This deformation causes the upper and lower thick copper windings to deviate from the preset vertical alignment axis, resulting in insufficient electrical insulation spacing or interlayer short circuits within the transformer, leading to irreversible process misalignment.

[0023] Existing lamination control systems primarily regulate the equipment by monitoring the overall temperature of the lamination plate or the global downward pressure of the hydraulic master cylinder. However, due to the extremely narrow, enclosed space between printed circuit board layers, it is impossible to place physical sensors on-site to directly measure the local extrusion strength characteristics of the internal liquid resin. Relying solely on external sensors for vertical displacement monitoring can only yield scalar values ​​of thickness compression, resulting in unreliable lamination alignment control of the PCB windings and low control accuracy. In this embodiment of the invention, the layout of the PCB boards to be laminated is analyzed to accurately identify and implement pressure reduction and holding intervention operations.

[0024] In the process of laminating multilayer PCBs for high-frequency planar transformers, the resin flow behavior is highly dependent on the non-uniformity of local copper foil distribution. High copper areas are rigid and difficult to compress, while low copper areas are easily filled by resin and deformed. If this spatial heterogeneity cannot be quantified, it will be difficult to accurately predict the internal stress transmission path.

[0025] Therefore, in this embodiment of the invention, by obtaining the layout of the PCB board to be laminated in batches and dividing it into multiple grid areas on an average basis, the proportion of copper foil area in each grid area to its total area is calculated, i.e., the copper foil area ratio.

[0026] Furthermore, in some embodiments of the present invention, the PCB board layout is divided into different grid regions on an average basis, including: cutting the layout image of the PCB board at equal intervals along the two adjacent sides of the image to form a rectangular grid array of M rows and N columns; wherein the values ​​of M and N are determined according to the PCB board size and the positioning pin position accuracy requirements to ensure that each positioning pin falls into a complete grid region.

[0027] It is understood that in this embodiment of the invention, in order to perform average division, each grid area is the same in proportion to the layout. It should be noted that M and N are both positive integers greater than 1, specifically M is 5 and N is 5. Thus, it is divided into 25 grid areas. Alternatively, it can be divided according to actual needs to ensure that each positioning pin falls completely into a grid area, which is convenient for subsequent positioning analysis.

[0028] Furthermore, in some embodiments of the present invention, the method for determining the copper foil area ratio of each grid region includes: determining the copper foil area of ​​different grid regions based on the PCB board design drawing; and calculating the ratio of the copper foil area area within the grid region to the total area of ​​the grid region as the copper foil area ratio.

[0029] The PCB design drawing is the graphic data of the PCB in the relevant design software. The design drawing contains the copper foil arrangement and distribution information of the PCB. By dividing the design drawing into the same grid area, the copper foil area area of ​​each grid area can be effectively identified, and the ratio of the copper foil area to the total area of ​​the grid area is used as the copper foil area percentage.

[0030] Obtaining the grid area and copper foil area ratio transforms complex layout geometry information into a structured numerical matrix, enabling digital characterization of the micro-stiffness distribution of the entire board. This lays a crucial data foundation for subsequent accurate modeling of resin extrusion trends.

[0031] S102: Take the grid area where the positioning pins of each edge in the layout drawing are located as the positioning pin area. Perform vector analysis based on the positioning pin area and the geometric center point of the layout drawing to determine the radial unit vector of each positioning pin area.

[0032] During the lamination process of multilayer PCBs, the direction of the lateral extrusion force borne by the edge positioning pins is closely related to their spatial orientation relative to the center of the board. If the force is evaluated only by global coordinates, it cannot accurately reflect the true load direction of each positioning pin under the action of local resin flow. Furthermore, due to the asymmetrical layout of positioning pins in different positions, their dangerous deformation directions are also different.

[0033] In this embodiment of the invention, the number of locating pins can be four, that is, one locating pin is located at each of the four corners of the layout. The grid area where each edge locating pin falls in the layout is defined as a locating pin area. A spatial vector is constructed based on the locating pin area and the geometric center point of the layout. Through vector processing, a unique radial unit vector for each locating pin area is determined. Thus, the physical layout is transformed into a directional reference, realizing personalized modeling of the force-sensitive direction of each locating pin, and providing a unified and comparable directional reference system for subsequent accurate extraction of radial extrusion components.

[0034] It should be noted that, in this embodiment of the invention, during the multilayer PCB lamination process, the resin flowing under heat will generate a lateral thrust on the edge positioning pins. Whether this thrust is dangerous depends not only on its magnitude but also on its direction.

[0035] Each locating pin is located in a different corner of the board (such as the upper left, lower right, etc.). The direction in which they are "most easily bent" is the direction from the center of the board towards the locating pin. This is analogous to pulling a rope; if you pull a corner outward from the center, that corner is most likely to deform. Therefore, it is necessary to define a "sensitive direction" for each locating pin, which is the so-called "radial unit vector".

[0036] First, locate the representative position of the locating pin within the grid area. To simplify calculations, the center point of the locating pin area can be used to represent the position of the locating pin. PCB layouts are typically rectangular, and the geometric center point is the exact center of this rectangle, serving as the "starting point" for calculations in all directions. Then, for each locating pin position, draw a straight line from the center point of the layout to the center point of the locating pin area. The direction of this line represents the main path of "pushing the locating pin outward from the inside of the board," i.e., the "radial direction."

[0037] The geometric center point is extended infinitely outwards along the direction pointing to the center point of the locating pin area, thus extracting a two-dimensional direction vector pointing from the inside of the layout to the outer edge. After extracting this two-dimensional direction vector, a mathematical normalization operation is performed on it (i.e., dividing the x and y coordinate coefficients of the two-dimensional direction vector by the magnitude of the vector itself). After performing this normalization operation, the magnitude of the vector is normalized to 1, while preserving the original directional attributes. This yields the radial unit vector of the locating pin area.

[0038] Then, following the exact same sequence of geometric connections, outward extension, and mold length normalization, all locating pin areas are iterated sequentially to obtain the radial unit vector for each locating pin area. By establishing a line connecting the position of each locating pin to the geometric center of its PCB surface and normalizing the direction of this line to a standard-length arrow, a "radial unit vector" that only represents direction and is unaffected by distance is obtained. This vector is used for subsequent accurate assessment of the stress risk of the locating pin under the action of resin flow.

[0039] S103: At different sampling times during the pressing process, the compressive deformation height of different grid areas of the PCB board is obtained. Based on the ratio of compressive deformation height to copper foil area at each sampling time, the resin expulsion trend scalar of each positioning pin area is determined. Local spatial partial derivative analysis is performed on the resin expulsion trend scalar to obtain a two-dimensional flow vector.

[0040] During the lamination process of multilayer PCBs, the resin softens when heated and will flow non-uniformly due to local pressure differences, but its internal flow state cannot be directly observed. If only the overall pressure or deformation at a single location is relied upon, it is difficult to capture the dynamic trend of resin migration to the edge positioning pin area, thus making it impossible to predict the lateral extrusion force caused by this.

[0041] Therefore, in this embodiment of the invention, at multiple sampling moments during the pressing process, the compressive deformation height of each positioning pin area on the PCB board is obtained. Combined with the copper foil area ratio of the positioning pin area, a scalar value representing the resin expulsion trend for each positioning pin area is calculated. Then, by performing local spatial partial derivative analysis on this scalar field, a two-dimensional flow vector is determined. This operation transforms the invisible internal resin flow behavior into quantifiable and directional vector information, achieving an indirect but effective characterization of the resin migration direction and intensity, providing crucial physical evidence for subsequent accurate identification of the positioning pin stress risk.

[0042] Furthermore, in some embodiments of the present invention, obtaining the compressive deformation height of different grid areas of the PCB board includes: installing high-precision displacement sensors at the four physical corners of the PCB board; reading the thickness values ​​of the four corners at fixed sampling intervals after the pressing begins; calculating the cumulative pressure at each sampling time based on the thickness value at the initial pressing moment; and extending the cumulative pressure at the four corners to all grid areas of the board layout using a spatial bilinear interpolation algorithm to obtain the compressive deformation height of each grid area.

[0043] The initial pressing moment is when the pressing equipment contacts the PCB board surface and applies continuous pressure. As pressing progresses, the thickness values ​​at the four corners can be periodically acquired (e.g., every 0.1 seconds) using a high-precision displacement sensor. The pressure reduces the PCB board thickness, and the thickness reduction at different sampling moments represents the cumulative pressure. This value, obtained from on-site engineering data, eliminates interference from air during compaction and represents the true dimension of vertical thickness compression caused by heat and pressure on the internal resin.

[0044] Since external displacement sensors can only acquire the absolute values ​​of the depression at four isolated physical corners, and the resin overflow from inside the printed circuit board is caused by the difference in compressive pressure gradient across a continuous two-dimensional area of ​​the entire board, and the amount of copper foil laid inside directly changes the size of the structural gaps where resin overflows, it is necessary to continuously expand the depression values ​​at the four independent corners according to the geometric area of ​​the entire board and combine them one by one with the residual copper ratio data of the internal structure to reflect the true degree of local compression resulting from the superposition of stress depression and internal structural obstruction. Therefore, in this embodiment of the invention, a spatial bilinear interpolation algorithm is used to bilinearly interpolate the cumulative depression at the four corners, weighted according to the distance to different grid areas, and extended to all grid areas of the board layout to obtain the compressive deformation height of each grid area.

[0045] For example, if the distances of a certain grid area from the four corners are 1cm, 2cm, 3cm, and 4cm, the corresponding weights can be, for example, 0.4, 0.3, 0.2, and 0.1. That is, the closer the distance, the larger the weight value. The weighted sum of the cumulative downward pressure at different corners is calculated to obtain the compressive deformation height of the corresponding grid area. This represents the vertical subsidence dimension of each specific grid area on the entire plate at the corresponding sampling time.

[0046] Furthermore, in some embodiments of the present invention, the method for determining the resin extrusion trend vector of each positioning pin region includes: for each grid region, multiplying its compressive deformation height by the proportion of the copper foil area of ​​the grid region as a resin extrusion trend scalar.

[0047] It should be noted that the compressive deformation height can be pre-normalized, that is, using the compressive deformation height as the numerator and the total PCB board thickness as the denominator, and performing linear normalization of the maximum and minimum values ​​to avoid dimensional issues. Of course, in other calculations of this invention, when encountering dimensional issues, the maximum and minimum values ​​can also be determined based on this normalization method and the actual scenario to achieve linear normalization and avoid the influence of dimensions on the calculation. The linearly normalized compressive deformation height is multiplied by the proportion of copper foil area in the grid region to obtain the resin extrusion trend scalar.

[0048] The resin extrusion tendency scalar is a dimensionless data, which represents the superposition effect of external macroscopic vertical compression and internal microscopic gap resistance. The larger the value, the greater the vertical compression of the liquid resin in that specific local space. Furthermore, due to the space occupied by the thick copper, the gaps around it are extremely small, which makes the pressure tendency of the internal resin to be forced to seek an outlet and extrude is stronger.

[0049] Furthermore, in some embodiments of the present invention, the method for determining the two-dimensional flow vector includes: calculating the local first-order difference of the resin extrusion trend scalar of each positioning pin region on its adjacent sides; taking the difference value in any direction of the grid region as the first directional component and the difference value in the other direction as the second directional component, and combining them to form a preliminary flow vector; and reversing the direction of the preliminary flow vector to obtain the final two-dimensional flow vector.

[0050] Existing technologies cannot measure fluid flow within a closed stack and are prone to misjudgment due to localized uneven compression. This invention cleverly uses a scalar matrix constructed from external displacements to calculate the spatial gradient, thereby reversing the internal flow field; it transforms the directionless pressure scalar field into a two-dimensional vector field containing a precise propagation direction, i.e., a two-dimensional flow vector.

[0051] The resin extrusion trend scalar is merely a pure scalar data quantifying the pressure trend at each specific grid location, and cannot directly indicate the two-dimensional spatial movement direction of the pressure spreading outward. Consequently, it cannot determine the directional attribute of the edge positioning pin subjected to lateral impact. Within a confined space, the compressed fluid will inevitably seep and diffuse along the direction where the internal pressure decreases most rapidly from high to low. Therefore, this embodiment of the invention introduces a spatial gradient calculation method. By extracting the local rate of change of the resin extrusion trend scalar on the two-dimensional grid plane, the true direction of the invisible molten resin spreading from the high-pressure area to the low-pressure area can be derived.

[0052] Specifically, at the same sampling time, based on any positioning pin area Determine the left-right and up-down directions along adjacent edges (configured according to the actual PCB board layout, with both directions parallel to the edges of the PCB board respectively), and determine the adjacent grid area of ​​a preset size (e.g., 3x3) centered on it. Then, calculate the difference components in the two directions and extract the central grid. The resin expulsion trend scalar value of the adjacent grid on the right is subtracted from the resin expulsion trend scalar value of the adjacent grid on the left, and then divided by the physical span of the grid. This yields the rate of change of the value in the corresponding direction for that local region, which is the first directional component. Similarly, extract the central grid. The resin expulsion trend scalar value of the upper adjacent grid is subtracted from the resin expulsion trend scalar value of the lower adjacent grid, and then divided by the physical span of the grid to obtain the rate of change of the value in the corresponding direction for that local region, which is the second directional component. First directional component With the second direction component The partial derivatives of the corresponding sides are combined to form the initial flow vector. Since fluid always flows from areas of higher to lower values, the actual propagation direction is exactly opposite to the direction of the partial derivative gradient increase. Inverting the sign of the obtained partial derivative combination yields... . This forms a directed line segment in two-dimensional plane geometry. The negative sign operation ensures that the resulting vector points towards the locating pin region. The direction in which the internal pressure decreases most steeply, this vector. The larger the modulus (i.e., the absolute value), the larger the locating pin area. The more significant the pressure difference, the more intense the relative strength of the forced extrusion and spread of the high-temperature resin at that location.

[0053] It should be noted that if there are no adjacent grids within the preset size range, for example, if the positioning pin area is missing a grid adjacent to one side, the difference between the positioning pin area and its only adjacent grid is used as the partial derivative in the corresponding direction.

[0054] S104: Combining the two-dimensional flow vector and the radial unit vector, determine the radial compression component of the locating pin area, and perform PCB winding pressing and alignment control based on the numerical distribution of the radial compression component of all locating pin areas.

[0055] During the lamination process of multilayer PCBs, the lateral forces generated by the resin flow on each edge positioning pin have different directions and intensities. If control is based solely on the overall pressure or deformation at a single location, it is impossible to distinguish the actual load risk of different positioning pins, which can easily lead to alignment failure or excessive intervention. What truly affects the positioning accuracy is the extrusion force component along the sensitive radial direction of each positioning pin.

[0056] In this embodiment of the invention, a two-dimensional flow vector characterizing the direction and intensity of resin migration is spatially projected onto a predefined radial unit vector specific to each locating pin region. The radial compression component borne by each locating pin is extracted, and based on the numerical distribution of this component across all locating pin regions, a pressing alignment control command is dynamically generated. This operation achieves precise mapping from a multi-dimensional flow field to critical structural risk points, transforming pressing control from "global pressure equalization" to "on-demand response," significantly improving alignment accuracy and process robustness.

[0057] Furthermore, in some embodiments of the present invention, the method for determining the radial compression component of the positioning pin region includes: performing a spatial vector dot product operation on the two-dimensional flow vector of each positioning pin region and the corresponding radial unit vector to obtain a scalar value; if the scalar value is greater than zero, then taking it as the radial compression component of the positioning pin region; if the scalar value is less than or equal to zero, then setting the radial compression component of the positioning pin region to zero.

[0058] The specific formula for dot product is as follows: In the formula, This represents the scalar value of the first locating pin region; This represents the two-dimensional flow vector of resin actually being expelled outwards at the location of the first locating pin. This represents the radial unit vector of the first locating pin region. This represents the physical angle between two spatial vectors. This represents the cosine function.

[0059] In the formula The term represents the absolute projected length of the actual two-dimensional flow vector onto a fixed radial unit vector. Since the magnitude of the unit vector is 1, this product essentially uses the cosine of the included angle to filter out flow characteristic variables in all tangential directions perpendicular to the radial direction. The closer the included angle is to 0 degrees, the more perpendicularly the resin flow impacts the hardware, and the closer the projected value is to the maximum value of the actual intensity.

[0060] Then, determine the scalar value. Is it greater than zero? If the scalar value A value greater than zero indicates that the local actual fluid trend does indeed contain a displacing force pointing outwards towards the hardware. In this case, this value is directly taken as the radial compression component of the first locating pin region.

[0061] If the scalar value A value less than or equal to zero (i.e., an angle greater than 90 degrees) indicates that the fluid flow at that location is actually flowing inwards or dissipating in an irrelevant direction, without exerting any pushing effect on the outer locating pin. In this case, to avoid negative values ​​interfering with subsequent safety threshold comparisons, the radial compression component of the first locating pin region is forcibly assigned an absolute zero value.

[0062] Then, each locating pin area is analyzed to determine the radial compression component of each locating pin area. The analysis of the radial compression component can quantify the intensity of the lateral pushing force generated by the resin flow on each locating pin along its most sensitive direction (i.e., from the center of the plate to the pin), thereby accurately identifying which locating pin is about to bend and fail, and providing a direct criterion for dynamic control of the pressing pressure.

[0063] Furthermore, in some embodiments of the present invention, PCB winding pressing and alignment control is performed based on the radial compression component value distribution of all positioning pin areas, including: setting a preset reference value that allows deformation displacement; comparing the radial compression component of each positioning pin area with the preset reference value in real time; and generating a pressure reduction command when the radial compression component of any positioning pin area exceeds the preset reference value, wherein the pressure reduction command is used to switch the hydraulic system to a low-pressure holding state.

[0064] In this embodiment of the invention, a preset benchmark value is used as the maximum allowable deformation displacement through threshold analysis. That is, when the radial compression component is greater than the preset benchmark value, it indicates that the accumulated local force exceeds the elastic limit of the material, and the locating pin will undergo permanent plastic deformation by bending outward. At this time, it is necessary to reduce the applied pressure. Specifically, a pressure reduction command is generated to control the hydraulic system to switch to a low-pressure holding state.

[0065] Furthermore, in some embodiments of the present invention, the preset benchmark value is obtained through offline sampling test calibration, specifically including: installing a contact displacement dial gauge on the outside of the test positioning pin; performing compression and synchronous output of the radial compression component; when the dial gauge reading reaches the preset permanent plastic deformation threshold, intercepting the radial compression component value at the corresponding moment; and taking the 80th percentile of multiple test results as the preset benchmark value.

[0066] The preset reference value is a key threshold used to determine whether the locating pin faces the risk of bending failure. In this embodiment of the invention, it is an empirical safety upper limit calibrated through offline prototyping tests (i.e., actual pressing tests). It represents the maximum radial compression component that can be allowed without causing irreversible plastic deformation of the locating pin. When the radial compression component calculated during online pressing exceeds the preset reference value, the system immediately reduces the pressure to prevent the locating pin from permanently bending, thereby ensuring the winding alignment accuracy.

[0067] For a specific example, assume the locating pin used in a high-frequency planar transformer is made of stainless steel, with a diameter of 1.5mm and a cantilever length of 3mm. Material testing shows its elastic limit corresponds to a lateral displacement of 0.10mm. Twelve sample pressing cycles are performed. Each time the dial indicator shows a lateral displacement of 0.10mm for the locating pin, the radial compression component output by the algorithm is recorded. The results are as follows: 185, 192, 201, 188, 210, 195, 205, 198, 212, 200, 196, 208. The data is first averaged, yielding a mean of 199.17. Then, the 80th percentile position is calculated as 199.17 × 0.8 ≈ 159, which is the preset benchmark value. Extracting the 80th percentile position aims to allow a 20% safety margin for the mechanical response delay of the equipment's hydraulic valves.

[0068] Furthermore, in some embodiments of the present invention, after switching to the low-pressure holding state, the absolute value of the transient displacement increment of different physical corners of the PCB board between adjacent sampling times is continuously monitored; when the absolute value of the transient displacement increment of all physical corners is less than the preset noise tolerance threshold within a consecutive preset number of sampling times, a pressure boosting command is generated, and the pressure boosting command is used to make the hydraulic system exit the low-pressure holding state and restore it to the set initial pressure.

[0069] Understandably, the noise tolerance threshold, a very small empirical positive parameter (e.g., set to 0.005 mm), is used to mask normal mechanical and electronic background noise. In real industrial production environments, due to the inherent background noise from equipment mechanical vibration and the inherent minute jitter of the analog-to-digital conversion of displacement sensors, the physical reading of this transient displacement increment will never reach an absolute mathematical zero. To avoid the system falling into a logic deadlock, the noise tolerance threshold of the sensor is preset in the control program.

[0070] The preset quantity, for example, can be 5. This means that if the deformation remains within the allowable noise tolerance threshold for 5 consecutive sampling times during the low-pressure holding state, it indicates that the internal resin has entered the cross-linking and curing stage, generating a pressure boosting command. This command is sent to the proportional servo valve of the laminator's main hydraulic cylinder. After this command is issued, the laminator's main hydraulic cylinder responds and readjusts its hydraulic output power to the set initial pressure. After the pressure is increased, the laminator safely exits the low-pressure holding state set to prevent misalignment and returns to the high-pressure state that meets the PCB molding strength requirements.

[0071] The laminator continues to operate stably under restored high pressure until the entire curing process time is exhausted, at which point the system completes the winding lamination operation of the multilayer printed circuit board.

[0072] To address the technical problem of existing pressing control systems relying primarily on monitoring the overall temperature of the pressing plate or the global downward pressure of the hydraulic master cylinder for equipment adjustment, and limited by the extremely narrow, enclosed space between printed circuit board layers, which prevents direct measurement of the local extrusion intensity characteristics of the internal liquid resin, resulting in low control accuracy, this invention obtains the layout diagram of the PCB board to be pressed and divides it into different grid regions. The copper foil area ratio of each grid region is determined, providing basic data for subsequent accurate modeling. Then, based on vector analysis of the locating pin regions and geometric center points, the radial unit vector of each locating pin region is determined, clarifying the key force direction of each locating pin. During the pressing process, the compressive deformation height of different grid regions is monitored in real time, and the resin extrusion trend scalar is calculated based on the copper foil area ratio. Then, a two-dimensional flow vector is generated using local spatial partial derivative analysis, indirectly inferring the actual flow direction and intensity of the resin. Finally, the two-dimensional flow vector is combined with the radial unit vector to extract the radial compression component of the locating pin regions. Dynamic pressing alignment control is then performed based on the numerical distribution of the radial compression components of all locating pin regions. This series of steps does not require embedded physical sensors and relies entirely on external measurable signals and offline design data, effectively overcoming the limitations of traditional methods that can only provide thickness compression scalars and cannot capture resin flow details, thus greatly improving the control accuracy and reliability of PCB winding pressing and alignment.

[0073] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0074] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for aligning and bonding multilayer PCB windings for high-frequency planar transformers, characterized in that, The method includes: Obtain the layout diagram of the PCB board to be laminated, and divide it into different grid areas on an average basis; determine the copper foil area ratio of each grid area; The grid area where the locating pins of each edge of the layout is located is taken as the locating pin area. Based on the vector analysis of the locating pin area and the geometric center point of the layout, the radial unit vector of each locating pin area is determined. At different sampling moments during the lamination process, the compressive deformation height of different grid areas on the PCB board is obtained. Based on the ratio of compressive deformation height to copper foil area at each sampling moment, the resin extrusion trend scalar of each locating pin area is determined. Local spatial partial derivative analysis is performed on the resin extrusion trend scalar to obtain a two-dimensional flow vector. By combining the two-dimensional flow vector and the radial unit vector, the radial compression component of the locating pin area is determined, and the PCB winding pressing alignment control is performed based on the numerical distribution of the radial compression component of all locating pin areas.

2. The method for aligning and bonding multilayer PCB windings for high-frequency planar transformers as described in claim 1, characterized in that, The process of obtaining the compressive deformation height of different grid regions on the PCB board includes: Install high-precision displacement sensors at the four physical corners of the PCB board; After the pressing begins, the thickness values ​​of the four corners are read at fixed sampling intervals; based on the thickness value at the initial pressing moment, the cumulative pressing amount at each sampling moment is calculated; By using a spatial bilinear interpolation algorithm, the cumulative downward pressure at the four corners is extended to all grid areas of the layout, thus obtaining the compressive deformation height of each grid area.

3. The method for aligning and bonding multilayer PCB windings for high-frequency planar transformers as described in claim 1, characterized in that... The method for determining the resin extrusion trend vector of each positioning pin region includes: For each grid region, its compressive deformation height is multiplied by the proportion of the copper foil area in that grid region, and this product is used as a scalar of resin extrusion tendency.

4. The method for aligning and bonding multilayer PCB windings for high-frequency planar transformers as described in claim 1, characterized in that, The method for determining the two-dimensional flow vector includes: For the resin extrusion trend scalar of each locating pin region, calculate its local first-order difference on the adjacent sides; The difference value in any direction of the grid region is taken as the first directional component, and the difference value in the other direction is taken as the second directional component. These components are combined to form a preliminary flow vector. The direction of this preliminary flow vector is then reversed to obtain the final two-dimensional flow vector.

5. The method for aligning and bonding multilayer PCB windings for high-frequency planar transformers as described in claim 1, characterized in that, The method for determining the radial compression component of the locating pin region includes: Perform a spatial vector dot product operation between the two-dimensional flow vector of each locating pin region and the corresponding radial unit vector to obtain a scalar value. If the scalar value is greater than zero, it is taken as the radial compression component of the locating pin region. If the scalar value is less than or equal to zero, the radial compression component of the locating pin region is set to zero.

6. The method for aligning and bonding multilayer PCB windings for high-frequency planar transformers as described in claim 1, characterized in that, The step of controlling PCB winding bonding alignment based on the radial compression component distribution of all locating pin areas includes: A preset reference value for allowable deformation displacement is set; the radial compression component of each locating pin area is compared with the preset reference value in real time; when the radial compression component of any locating pin area exceeds the preset reference value, a pressure reduction command is generated, which is used to switch the hydraulic system to a low-pressure holding state.

7. The method for aligning and bonding multilayer PCB windings for a high-frequency planar transformer as described in claim 6, characterized in that, The preset benchmark value is obtained through offline sampling test calibration, specifically including: Install a contact displacement dial indicator on the outside of the test locating pin; The radial compression component is compressed and output synchronously; When the dial gauge reading reaches the preset critical value of permanent plastic deformation, the radial compression component value at the corresponding moment is captured. The 80th percentile of multiple test results is taken as the preset benchmark value.

8. The method for laminating and aligning multilayer PCB windings for high-frequency planar transformers as described in claim 6, characterized in that, After switching to low-voltage holding state, the absolute value of transient displacement increment of different physical corners of the PCB board between adjacent sampling times is continuously monitored; When the absolute value of the transient displacement increment of all physical corners is less than the preset noise tolerance threshold within a preset number of consecutive sampling times, a pressure boosting command is generated. The pressure boosting command is used to make the hydraulic system exit the low-pressure holding state and restore it to the set initial pressure.

9. The method for aligning and bonding multilayer PCB windings for high-frequency planar transformers as described in claim 1, characterized in that, The average division into different grid areas includes: cutting the PCB board layout image at equal intervals along the two adjacent sides of the image to form a rectangular grid array of M rows and N columns; wherein the values ​​of M and N are determined according to the PCB board size and the positioning pin position accuracy requirements to ensure that each positioning pin falls into a complete grid area.

10. The method for aligning and bonding multilayer PCB windings for a high-frequency planar transformer as described in claim 1, characterized in that, The method for determining the copper foil area ratio of each grid region includes: The copper foil areas of different grid regions are determined based on the PCB board design drawings; The ratio of the copper foil area within a given grid region to the total area of ​​the grid region is used as the percentage of copper foil area.

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