Preparation method of mixed pressure plate and mixed pressure plate

Abstract

The invention belongs to the technical field of PCB manufacturing, and discloses a mixed pressure plate preparation method and a mixed pressure plate. The preparation method of the mixed pressing plate is used for preparing the mixed pressing plate formed by pressing at least two pressing plates, through a pre-test, measurement and comparison of shrinkage coefficients of all the pressing plates, the pressing plate with the minimum coefficient is selected as a base material, the remaining pressing plates serve as pretreatment materials, and pretreatment parameters of the pretreatment materials are obtained; the preparation method comprises the following steps: preparing a mixed pressing plate, treating a pretreatment material according to pretreatment parameters, stacking and pressing a base material and the treated pretreatment material to obtain the mixed pressing plate, measuring and comparing the shrinkage coefficients of the pressing plate, and independently treating the pressing plate with a larger coefficient as the pretreatment material, so that the shrinkage coefficient of the pressing plate can be reduced; the shrinkage coefficients of the pressing plate are close, thermal shrinkage is consistent during pressing, and the warping problem caused by the difference of the thermal shrinkage performance of materials is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB manufacturing, and particularly to a method for preparing a mixed laminate and a mixed laminate. Background Art

[0002] The preparation of a mixed laminate is a circuit board design technology. By integrating various circuit components and functional modules on different layers, high integration and optimized design are achieved. It combines different types of circuits such as analog, digital, communication, and power, providing multiple functions with the smallest space occupation.

[0003] In the prior art, a mixed laminate is obtained by pressing different materials. However, due to the difference in the thermal shrinkage performance of the materials, warping problems are likely to occur after pressing. Especially for a mixed laminate with an asymmetric structure, the problem of abnormal warping degree is extremely likely to occur, affecting subsequent circuit board processing.

[0004] Therefore, there is an urgent need to provide a method for preparing a mixed laminate and a mixed laminate to effectively improve the warping problem caused by the difference in the thermal shrinkage performance of different materials during mixed pressing. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a mixed laminate and a mixed laminate to effectively improve the warping problem caused by the difference in the thermal shrinkage performance of different materials during mixed pressing.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing a mixed laminate for preparing a mixed laminate formed by pressing at least two laminates. The method for preparing the mixed laminate includes the following steps:

[0008] Pre-experiment: Measure and compare the shrinkage coefficients of all the laminates, select the laminate with the smallest shrinkage coefficient as the base material, and use the remaining laminates as pretreatment materials, and obtain the pretreatment parameters of the pretreatment materials;

[0009] Prepare the mixed laminate: Process the pretreatment materials according to the pretreatment parameters, and stack and press the base material and the processed pretreatment materials to obtain the mixed laminate.

[0010] As an optional technical solution of the method for preparing a mixed laminate, the mixed laminate is formed by pressing two laminates, and the two laminates are a first laminate and a second laminate respectively. The first laminate is provided with at least two layers, and / or the second laminate is provided with at least two layers;

[0011] Measure and compare the shrinkage coefficients of the first pressing plate and the second pressing plate; if the shrinkage coefficient of the first pressing plate is greater than that of the second pressing plate, then use the second pressing plate as the base material and the first pressing plate as the pretreatment material; if the shrinkage coefficient of the first pressing plate is less than that of the second pressing plate, then use the first pressing plate as the base material and the second pressing plate as the pretreatment material.

[0012] As an alternative technical solution of the method for preparing a hybrid pressing plate, the preliminary test includes: pre-pressing all the pressing plates, and calculating the shrinkage coefficient of each pressing plate according to the dimensions of the pressing plate before and after the preliminary pre-pressing.

[0013] As an alternative technical solution of the method for preparing a hybrid pressing plate, processing the pretreatment material according to the pretreatment parameters includes: baking the pretreatment material for a shrinkage treatment time, and the shrinkage treatment time is positively correlated with the difference between the shrinkage coefficient of the pretreatment material and the shrinkage coefficient of the base material.

[0014] As an alternative technical solution of the method for preparing a hybrid pressing plate, the steps for obtaining the dimensions before and after the preliminary pre-pressing are as follows: before the preliminary pre-pressing, set at least one set of measuring rings on each pressing plate;

[0015] Before the preliminary pre-pressing, record the center position of the measuring ring as the first position and measure the center distance between two corresponding measuring rings in the same group; after the preliminary pre-pressing, record the center position of the measuring ring as the second position, calculate the difference between the first position and the second position to obtain the shrinkage amount, and the ratio of the shrinkage amount to the center distance is the shrinkage coefficient.

[0016] As an alternative technical solution of the method for preparing a hybrid pressing plate, there are two sets of measuring rings, one set includes at least two measuring rings arranged at intervals in the X direction, and the other set includes at least two measuring rings arranged at intervals in the Y direction, and the X direction and the Y direction are arranged at an angle.

[0017] As an alternative technical solution of the method for preparing a hybrid pressing plate, before the preliminary pre-pressing, set a layer number on each pressing plate.

[0018] As an alternative technical solution of the method for preparing a hybrid pressing plate, before the preliminary pre-pressing, perform a first inner layer pattern making on the base material and the pretreatment material.

[0019] As an alternative technical solution of the method for preparing a hybrid pressing plate, after processing the pretreatment material according to the pretreatment parameters and before pressing, perform a second inner layer pattern making on the pretreatment material.

[0020] The present invention provides a composite laminate, which is processed by the above-mentioned method for preparing a composite laminate.

[0021] Advantageous effects:

[0022] The present invention provides a method for preparing a composite laminate for preparing a composite laminate formed by laminating at least two laminates. Through preliminary tests, the shrinkage coefficients of all laminates are measured and compared. The laminate with the smallest coefficient is selected as the base material, and the remaining laminates are used as pre-treatment materials, and the pre-treatment parameters of the pre-treatment materials are obtained; a composite laminate is prepared. The pre-treatment materials are processed according to the pre-treatment parameters, and the base material and the processed pre-treatment materials are stacked and laminated to obtain a composite laminate. By measuring and comparing the shrinkage coefficients of the laminates, the laminates with larger coefficients are used as pre-treatment materials for separate treatment, so that their shrinkage coefficients can be reduced, the shrinkage coefficients of the laminates are made closer, and the thermal shrinkage is consistent during lamination, effectively improving the warping problem caused by differences in the thermal shrinkage performance of materials.

[0023] The present invention provides a composite laminate. The composite laminate obtained by the above-mentioned method for preparing a composite laminate has closer shrinkage coefficients of different laminates, and improves the warping problem caused by differences in the thermal shrinkage performance of materials. Description of the drawings

[0024] Figure 1 is a schematic diagram of the laminated structure of the composite laminate provided by the embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of the structure of the laminate provided by the embodiment of the present invention;

[0026] Figure 3 is a schematic diagram of the expansion and contraction marks of the laminate provided by the embodiment of the present invention;

[0027] Figure 4 is a flowchart of the method for preparing a composite laminate provided by the embodiment of the present invention;

[0028] Figure 5 is a flowchart of preparing a composite laminate from a first laminate and a second laminate provided by the embodiment of the present invention;

[0029] Figure 6 is a flowchart of the method for preparing a composite laminate from a first laminate and a second laminate (with a preliminary test link) provided by the embodiment of the present invention.

[0030] In the figure:

[0031] 1. Laminate; 1a. First laminate; 1b. Second laminate. Detailed implementation manners

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the convenience of description, only the parts related to the present invention rather than all the structures are shown in the drawings.

[0033] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0034] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0035] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "left", and "right" are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meanings.

[0036] In traditional PCB manufacturing, usually only one material is used for lamination. As the transmission signals become faster and faster, materials with lower energy loss are required to meet the signal transmission requirements. After the lamination material of the PCB is heated during lamination, there will be a shrinkage phenomenon. When the same material is used in the lamination design and the graphic design has good consistency, the shrinkage amounts of each layer are basically not very different; if different materials are used for mixed lamination, due to the differences in the resin systems of the materials, the shrinkage amounts of the materials after lamination are also inconsistent. Because the materials of the two lamination plates are different, different shrinkage amounts of the symmetric layers after lamination will cause warping problems. Once serious warping occurs, it will have a great impact on the subsequent size collection of the PCB, the grinding uniformity of the copper on the board surface, and the subsequent surface mounting processing of the PCB. Therefore, it is of great significance to solve the warping problem of mixed lamination of different materials.

[0037] After the lamination plate is heated during lamination, there will be a shrinkage phenomenon; when the same material is used for the lamination plate and the image design on the lamination plate has good consistency, the shrinkage amounts of each lamination layer are not very different; but when the lamination plate materials are different, when the copper foil thickness, substrate thickness, material type, resin content, and fiberglass cloth are symmetrically the same in the lamination design, after lamination is completed, the thermal shrinkage is also symmetric, and at this time, the force balance can be achieved and no board warping problem will occur; if the shrinkage amounts on the symmetric sides after lamination are different, it will cause warping problems (such as smile-shaped cross-section warping or crying-face warping).

[0038] As Figures 1 to 6 shown, on the one hand, this embodiment provides a method for preparing a mixed lamination plate for preparing a mixed lamination plate formed by laminating at least two lamination plates 1. The method for preparing the mixed lamination plate specifically includes the following steps:

[0039] Step S1, pre-experiment, measure and compare the shrinkage coefficients of all the lamination plates 1, select the lamination plate 1 with the smallest shrinkage coefficient as the base material, and use the remaining lamination plates 1 as the pretreatment materials, and obtain the pretreatment parameters of the pretreatment materials.

[0040] Optionally, taking two lamination plates 1 as an example. The mixed lamination plate is formed by laminating two lamination plates 1, and the two lamination plates 1 are respectively a first lamination plate 1a and a second lamination plate 1b. The first lamination plate 1a has at least two layers, and / or the second lamination plate 1b has at least two layers; measure and compare the shrinkage coefficients of the first lamination plate 1a and the second lamination plate 1b, and select the first lamination plate 1a or the second lamination plate 1b as the pretreatment material according to the shrinkage coefficient; if the shrinkage coefficient of the first lamination plate 1a is greater than the shrinkage coefficient of the second lamination plate 1b, then use the second lamination plate 1b as the base material and the first lamination plate 1a as the pretreatment material; if the shrinkage coefficient of the first lamination plate 1a is less than the shrinkage coefficient of the second lamination plate 1b, then use the first lamination plate 1a as the base material and the second lamination plate 1b as the pretreatment material.

[0041] By comparing the shrinkage coefficients of the first pressing plate 1a and the second pressing plate 1b, and taking the pressing plate 1 with the larger shrinkage coefficient as the pretreatment material, after separate treatment to reduce the shrinkage coefficient, the shrinkage coefficients of the first pressing plate 1a and the second pressing plate 1b are closer, which can effectively improve the difference in shrinkage amount.

[0042] See Figure 1 , the pressing plate 1 is composed of a base material and a copper foil attached to the surface of the base material. The base material of the first pressing plate 1a is a low-loss material, and the base material of the second pressing plate 1b is a conventional-loss material. The overall laminated structure is asymmetric, and the shrinkage amounts are different after the low-loss material and the conventional-loss material are laminated, resulting in a large difference in shrinkage amounts on the upper and lower sides of the overall structure, and the warping phenomenon is relatively serious.

[0043] Furthermore, in this embodiment, the shrinkage coefficients of the first pressing plate 1a and the second pressing plate 1b are measured by means of pre-test pre-lamination.

[0044] Pre-test pre-laminate the first pressing plate 1a and the second pressing plate 1b, and calculate the shrinkage coefficient of the first pressing plate 1a according to the dimensions of the first pressing plate 1a before and after pre-test pre-lamination, and calculate the shrinkage coefficient of the second pressing plate 1b according to the dimensions of the second pressing plate 1b before and after pre-test pre-lamination.

[0045] Before the actual pre-test starts, the first pressing plate 1a and the second pressing plate 1b need to be cut into small pieces to adapt to the processing dimensions of the production equipment. Cutting into small pieces also helps to improve the material utilization rate and processing efficiency to achieve maximum utilization and reduce waste.

[0046] Optionally, in the pre-test, before pre-test pre-lamination, the first inner layer pattern is made on the base material and the pretreatment material. By making the first inner layer pattern on the base material and the pretreatment material before pre-lamination to simulate the pattern in the formal preparation process, the pre-lamination process is closer to the lamination process of the preparation process, so as to improve the accuracy of the pretreatment parameters obtained from the pre-test.

[0047] In this embodiment, before pre-test pre-lamination, the first inner layer pattern is made on the small pieces of the first pressing plate 1a and the second pressing plate 1b; after pre-test pre-lamination, the shrinkage coefficients of the first pressing plate 1a and the second pressing plate 1b are collected and recorded.

[0048] Optionally, before pre-test pre-lamination, a layer number is set on each pressing plate 1. By setting the layer number, it is convenient to comprehensively consider the overall laminated design structure to clarify the corresponding symmetric layers in the laminated design.

[0049] Optionally, the steps for obtaining the dimensions before and after the pre-test pre-pressing are as follows: Before the pre-test pre-pressing, at least one set of measuring rings is arranged on each pressing plate 1; before the pre-test pre-pressing, record the center position of the measuring ring as the first position and measure the center distance between the corresponding two measuring rings in the same group; after the pre-test pre-pressing, record the center position of the measuring ring as the second position, calculate the difference between the first position and the second position to obtain the shrinkage amount, and the ratio of the shrinkage amount to the center distance is the shrinkage coefficient.

[0050] By arranging the measuring rings and measuring the shrinkage amount of the pressing plate 1 according to the center distance of the corresponding measuring rings before and after the pre-test pre-pressing to calculate the shrinkage coefficient, the difference in the shrinkage coefficients of different pressing plates 1 can be intuitively compared, and the pretreatment parameters of the pretreated material can be obtained.

[0051] Optionally, two sets of measuring rings are arranged. One set includes at least two measuring rings arranged at intervals in the X direction, and the other set includes at least two measuring rings arranged at intervals in the Y direction. The X direction and the Y direction are arranged at an angle.

[0052] See Figure 3 , in this embodiment, numbers and measuring rings are etched on each pressing plate 1; two sets of measuring rings are arranged. The X direction is the width direction of the pressing plate 1, and the Y direction is the length direction of the pressing plate 1; one set includes two rows of measuring rings arranged at intervals in the X direction, and each row includes six measuring rings arranged at equal intervals in the Y direction; the other set includes two rows of measuring rings arranged at intervals in the Y direction, and each row includes six measuring rings arranged at equal intervals in the X direction. By arranging multiple measuring rings in each row, it helps to ensure the accuracy of the measurement and reduce the influence caused by measurement errors.

[0053] By etching numbers and measuring rings in both the X direction and the Y direction on each pressing plate 1, and measuring the center distance of the corresponding measuring rings on the pressing plate 1 before and after the pre-test pre-pressing, the partial shrinkage amount of the pressing layer can be obtained. For example, the measurement values of the pressing plate 1 before the pre-test pre-pressing are X 2-1 、Y 2-1 , and the measurement values after the pre-test pre-pressing are X 2-2 、Y 2-2 , then the shrinkage coefficient of the pressing plate 1 in the X direction is λ X =(X 2-1 -X 2-2 ) / (X 2-1 ), and the shrinkage coefficient in the Y direction is λ Y =(Y 2-1 -Y 2-2 ) / (Y 2-1 ). Integrating the shrinkage coefficients in the X direction and the Y direction can obtain the overall shrinkage coefficient of the pressing plate 1.

[0054] Specifically, the pre-treated material is subjected to a shrinkage treatment according to the pre-treatment parameters. The shrinkage treatment includes a pressing and baking treatment or a reflow soldering treatment. In this embodiment, the pressing and baking treatment is taken as an example for the shrinkage treatment. In other embodiments, the reflow soldering treatment can also be used instead of the pressing and baking treatment, and the reflow soldering can cause the material to shrink at a higher temperature.

[0055] In the preliminary test, the pre-treatment parameters include the shrinkage treatment time of the pre-treated material. The shrinkage treatment time is positively correlated with the difference between the shrinkage coefficient of the pre-treated material and the shrinkage coefficient of the base material. If the difference in the shrinkage coefficients of the pre-treated material and the base material is large, the shrinkage treatment time is long.

[0056] The factors affecting the shrinkage coefficient of the pressing plate 1 during pressing and baking are the pressing and baking pressure, the pressing and baking temperature, and the pressing and baking time. It can be understood that when the pressing and baking pressure and the pressing and baking temperature are kept constant, the shrinkage amount of the material during pressing and baking is determined. Through experimental measurement, when the pressing and baking pressure is 450 PSI and the pressing and baking temperature is 210 °C, for every 1 minute of pressing and baking, the material will shrink by 0.000146%, that is, the shrinkage coefficient per unit time of pressing and baking △λ = 0.000146%.

[0057] Taking the case where the shrinkage coefficient of the first pressing plate 1a is greater than that of the second pressing plate 1b, for example, using the second pressing plate 1b as the base material and the first pressing plate 1a as the pre-treated material; it is necessary to perform a shrinkage treatment on the first pressing plate 1a.

[0058] Under the conditions of a pressing and baking pressure of 450 PSI and a pressing and baking temperature of 210 °C for the first pressing plate 1a, according to T = (A λ - B λ ) / △λ, the pressing and baking time T is calculated. Wherein, A λ is the shrinkage coefficient of the first pressing plate 1a before and after pressing, B λ is the shrinkage coefficient of the second pressing plate 1b before and after pressing, and △λ is the shrinkage coefficient of the material after every 1 minute of pressing and baking under the conditions of a pressing and baking pressure of 450 PSI and a pressing and baking temperature of 210 °C. Taking the calculated pressing and baking time T as the standard for subsequent preparation can make the shrinkage coefficients of the first pressing plate 1a and the second pressing plate 1b after the pressing and baking treatment close to each other.

[0059] Step S2, preparing a mixed pressing plate. The pre-treated material is processed according to the pre-treatment parameters, and the base material and the processed pre-treated material are stacked and pressed to obtain a mixed pressing plate.

[0060] In this embodiment, the pre-treated material is subjected to a shrinkage treatment according to the pre-treatment parameters. After the shrinkage treatment, the first pressing plate 1a and the second pressing plate 1b are stacked. A material is filled between the first pressing plate 1a and the second pressing plate 1b, and they are pressed to obtain a mixed pressing plate.

[0061] Optionally, after the pre-treatment material is processed according to the pre-treatment parameters and before lamination, a second inner layer pattern is made on the pre-treatment material. For example, when the shrinkage coefficient of the first pressing plate 1a is greater than that of the second pressing plate 1b, the first pressing plate 1a is pre-baked first, then the first pressing plate 1a and the second pressing plate 1b are cut into small pieces, and then the second inner layer pattern is made. Finally, the mixed pressing plate is obtained by lamination.

[0062] Specifically, the production process and pattern of the first inner layer pattern in the preliminary test are the same as those of the second inner layer pattern when preparing the mixed pressing plate. Therefore, the preliminary test can be used to simulate the preparation process to obtain more accurate pre-treatment parameters, so as to prepare the mixed pressing plate according to the pre-treatment parameters subsequently. During the preparation process, the pre-treatment material is pre-baked first, and then the second inner layer pattern is made on the preliminary test material to ensure that the preliminary test material shrinks and deforms more uniformly during the pre-baking process.

[0063] It can be understood that the first pressing plate 1a is cut into small pieces to make the inner layer pattern after pre-baking, and the second pressing plate 1b can be cut into small pieces and make the inner layer pattern without pre-baking. The inner layer pattern making of the first pressing plate 1a and the second pressing plate 1b can be carried out together or separately. Pre-baking will reduce the lamination shrinkage coefficient of the first pressing plate 1a. If the copper foil materials attached to the front and back surfaces of the base material of the pressing plate 1 are different, the shrinkage coefficient difference between the two copper foil materials during lamination can be reduced, and the warping problem of the first pressing plate 1a can be improved.

[0064] By measuring and comparing the shrinkage coefficients of all the pressing plates 1, the pressing plate 1 with the smallest coefficient is selected as the base material, and the remaining pressing plates 1 are used as pre-treatment materials; each pre-treatment material is subjected to a separate shrinkage treatment to reduce its shrinkage coefficient; after the shrinkage treatment, the pressing plates 1 are stacked, a filling material is arranged between adjacent pressing plates 1, and the mixed pressing plate is obtained by lamination. By measuring and comparing the shrinkage coefficients of the pressing plates 1, the pressing plate 1 with a larger coefficient is used as the pre-treatment material for separate shrinkage treatment, so that its shrinkage coefficient can be reduced, the shrinkage coefficients of the pressing plates 1 are made closer, and the thermal shrinkage is consistent during lamination, effectively improving the warping problem caused by the difference in the thermal shrinkage performance of the materials.

[0065] On the other hand, this embodiment provides a mixed pressing plate processed by the above-mentioned mixed pressing plate preparation method. For the mixed pressing plate processed by the above-mentioned mixed pressing plate preparation method, the shrinkage coefficients of different pressing plates 1 are closer, and the warping problem caused by the difference in the thermal shrinkage performance of the materials is improved.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a mixed pressure plate, characterized in that: Used to prepare a mixed pressed board formed by pressing at least two pressed boards (1), the mixed pressed board preparation method comprising the following steps: Preliminary test, measuring and comparing the shrinkage coefficients of all the press plates (1), selecting the press plate (1) with the smallest shrinkage coefficient as the base material, and using the remaining press plates (1) as pretreatment materials, and obtaining pretreatment parameters of the pretreatment materials; The mixed pressed board is prepared by treating the pretreated material according to the pretreatment parameters, and stacking and pressing the base material and the treated pretreated material to obtain the mixed pressed board.

2. The method for preparing a mixed-pressed board according to claim 1, characterized in that: The mixed press plate is formed by pressing two press plates (1) together, wherein the two press plates (1) are respectively a first press plate (1a) and a second press plate (1b), wherein the first press plate (1a) is provided with at least two layers, and / or the second press plate (1b) is provided with at least two layers; Measure and compare the shrinkage coefficients of the first pressing plate (1a) and the second pressing plate (1b); if the shrinkage coefficient of the first pressing plate (1a) is greater than the shrinkage coefficient of the second pressing plate (1b), then the second pressing plate (1b) is used as the base material and the first pressing plate (1a) is used as the pretreatment material; if the shrinkage coefficient of the first pressing plate (1a) is less than the shrinkage coefficient of the second pressing plate (1b), then the first pressing plate (1a) is used as the base material and the second pressing plate (1b) is used as the pretreatment material.

3. The method for preparing a mixed pressure plate according to claim 1, characterized in that: The pre-test comprises: pre-pressing all the pressing plates (1), and calculating the shrinkage coefficient of the pressing plate (1) based on the dimensions of the pressing plates (1) before and after the pre-pressing in the pre-test.

4. The method for preparing a mixed pressure plate according to claim 1, characterized in that: Processing the pre-treated material according to the pre-treatment parameters includes: pressing and baking the pre-treated material for a shrinkage processing time, wherein the shrinkage processing time is positively correlated with a difference between a shrinkage coefficient of the pre-treated material and a shrinkage coefficient of the base material.

5. The method for preparing a mixed pressure plate according to claim 3, characterized in that: The steps of obtaining the dimensions before and after the pre-test pre-pressing are as follows: before the pre-test pre-pressing, at least one set of measuring rings is arranged on each of the pressing plates (1); Before the pre-test pre-pressing, the center position of the measuring ring is recorded as the first position and the center distance of the two corresponding measuring rings in the same group is measured; after the pre-test pre-pressing, the center position of the measuring ring is recorded as the second position, the difference between the first position and the second position is calculated, and the shrinkage amount is obtained, and the ratio of the shrinkage amount to the center distance is the shrinkage coefficient.

6. The method for preparing a mixed-pressed board according to claim 5, characterized in that: The measuring rings are arranged in two groups, one of which includes at least two measuring rings spaced apart along the X direction, and the other includes at least two measuring rings spaced apart along the Y direction, wherein the X direction and the Y direction are arranged at an angle.

7. The method for preparing a mixed-pressed board according to claim 5, characterized in that: Before the pre-test pre-pressing, a layer number is set on each of the pressing plates (1).

8. The method for preparing a mixed-pressed board according to claim 3, characterized in that: Before the pre-test and pre-lamination, the first inner layer pattern is produced on the base material and the pre-treated material.

9. The method for preparing a mixed-pressed board according to any one of claims 1 to 6, characterized in that: After the pre-processing material is processed according to the pre-processing parameters and before lamination, a second inner layer pattern is produced on the pre-processing material.

10. Mixed pressure plate, characterized in that: The mixed-pressed board is manufactured by the mixed-pressed board preparation method as described in any one of claims 1 to 9.

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