A method for integrally forming a pre-buried nut composite material and a mold

Abstract

The application discloses a kind of embedded nut integrated forming composite forming method and mould, including the fixed hole of the fixed pin of installation embedded nut being arranged on the lower mould of composite forming mould;Embedded nut groove for cooperating fixed hole is arranged on the upper mould of composite forming mould;The fixed pin of embedded nut is installed in fixed hole, then embedded nut is installed on fixed pin;The preform of composite is correspondingly installed on the lower mould of composite forming mould, then the closing of the lower mould and the upper mould of composite forming mould is carried out by press, so that the preform of composite is cured and formed;Wherein, the part of embedded nut into embedded nut groove forms embedded nut boss on the surface of cured and formed preform;After demoulding, the product of cured and formed is separated from the lower mould of composite forming mould, then fixed pin and embedded nut are separated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material preparation, in particular to a pre-buried nut integrated forming composite material forming method and a mold. BACKGROUND

[0002] In the current composite material product market, due to the advantages of high specific strength and specific modulus, strong wear resistance, good processability and designability, effective prevention of fatigue crack propagation, good high-temperature ablation resistance, excellent chemical stability, etc., it is often used to make and replace original metal material automobile parts. In view of the requirements of automobile lightweighting and performance improvement of parts materials, especially for sealing covers, boxes, maintenance cover plates, tray bottom plates and other parts, composite material products are often used to replace original metal parts. In the composite material forming process, for thermosetting resin-based glass fiber composite materials, several common processes are SMC process, PCM molding process, wet molding process, autoclave process, etc. Among them, PCM process occupies the mainstream position in the composite material market with the advantages of fast forming speed, good product surface quality, thin product wall thickness and excellent mechanical properties.

[0003] Composite material laminated plate products are usually formed by PCM rapid molding process, but the integrated molding molding process requires that the box or cover meet the demolding requirements when designed, with smooth surface structure transition and simple structure. Compared with metal parts and injection molded parts, although they have high lightweight degree, good mechanical properties and good chemical stability, the product functionality is single and the assembly method is limited. At present, only through the use of bolts and mounting accessories after drilling can multiple parts be assembled and limited, and the drilled parts will lead to a decrease in sealing and stress concentration after assembly. SUMMARY

[0004] The purpose of the present application is to provide a pre-buried nut integrated forming composite material forming method and a mold to solve the technical problems of the existing technology that the drilled parts will lead to a decrease in sealing and stress concentration after assembly due to the production process of the existing composite material laminated plate during production.

[0005] To solve the above technical problems, the present application specifically provides the following technical solutions:

[0006] A pre-buried nut integrated forming composite material forming method includes the following specific steps:

[0007] Step 100, arranging a fixed hole for installing a fixed pin of a pre-buried nut in a row on a lower mold of a composite material forming mold; arranging a pre-buried nut groove for matching the fixed hole in a row on an upper mold of the composite material forming mold;

[0008] Step 200, install the fixing pin of the embedded nut in the fixing hole, and then install the embedded nut on the fixing pin, wherein the embedded nut and the fixing pin are threadedly connected, and the bottom of the embedded nut just contacts the upper surface of the lower mold of the composite forming mold;

[0009] Step 300, install the preform of the composite material on the lower mold of the composite forming mold, and then close the lower mold and the upper mold of the composite forming mold through the press machine, so that the preform of the composite material is cured and formed;

[0010] The part of the embedded nut entering the embedded nut groove forms an embedded nut boss on the surface of the cured and formed preform.

[0011] Step 400, after demolding, separate the cured and formed product from the lower mold of the composite forming mold, and then separate the fixing pin and the embedded nut.

[0012] As a preferred scheme of the present application, in step 100, a silica gel sealing ring is preset on the fixing pin, the threads between the fixing pin and the embedded nut are matched, and the embedded nut is pressed into the orifice of the fixing hole through a rotating motion.

[0013] As a preferred scheme of the present application, in step 300, the preparation method of the preform of the composite material comprises:

[0014] Based on the position of the fixing hole arranged on the lower mold of the composite forming mold, the layup simulation is performed on the set number of prepreg sheets forming the preform, the outer contour of the preform, the opening position of each prepreg sheet, and the opening degree of each prepreg sheet in the thickness direction of the preform are determined; the opening degree includes the opening shape and the opening size.

[0015] As a preferred scheme of the present application, the specific method that the part of the embedded nut entering the embedded nut groove forms an embedded nut boss on the surface of the cured and formed preform comprises:

[0016] In step 200, the thermosetting resin-based chopped fiber prepreg is cut into a filling strip, the width of the filling strip is the height of the embedded nut boss part, and the length of the filling strip is determined according to the condition that the prepreg sheet can be inserted into the embedded nut groove arranged on the upper mold of the composite forming mold after being rolled up;

[0017] Then, in step 300, the lower mold and the upper mold of the composite forming mold are closed, the embedded nut is arranged through the opening of the prepreg sheet, the embedded nut extrudes the filling strip, and the filling strip is extruded and deformed and combined with the prepreg sheet of the preform to form an embedded nut boss.

[0018] As a preferred scheme of the present application, the distance between the embedded nut boss and the outer surface of the embedded nut is greater than or equal to 2 mm.

[0019] The present application provides a kind of embedded nut integrated forming composite material forming die for realizing the embedded nut integrated forming composite material forming method,

[0020] Including:

[0021] Lower die of forming die, a plurality of fixed holes are arranged on the lower die of forming die, a fixed pin is installed through the fixed hole, the upper portion of the fixed pin is threadedly connected with an embedded nut, and a silica gel sealing ring is sleeved on the pin body of the fixed pin below the embedded nut;

[0022] Upper die of forming die, embedded nut grooves corresponding to the fixed holes are arranged on the upper die of forming die.

[0023] As a preferred scheme of the present application, the lower die of forming die includes a base plate, a cavity is arranged on the base plate, a first forming panel, a second forming panel and a third forming panel are arranged inside the cavity along the length direction of the cavity at one time;

[0024] The first forming panel and the third forming panel are installed on the base plate in the cavity through a synchronous lifting assembly, and a plurality of fixed holes are arranged on the second forming panel;

[0025] The synchronous lifting assembly is used to make the first forming panel and the third forming panel higher than the second forming panel when the cavity is not placed with a prefabricated part.

[0026] The synchronous lifting assembly makes the first forming panel and the third forming panel move downward until they are kept level with the second forming panel when they are stressed when the lower die of forming die and the upper die of forming die are closed.

[0027] As a preferred scheme of the present application, the fixed hole includes a regular polygonal bottom cavity and a sealing ring matching cavity concentrically arranged on the upper portion of the regular polygonal bottom cavity, and the sealing ring matching cavity forms an open port on the surface of the second forming panel.

[0028] The outer diameter of the sealing ring matching cavity is greater than the regular polygonal bottom cavity.

[0029] As a preferred scheme of the present application, the synchronous lifting assembly includes a plurality of wedge-shaped displacement members arranged on the side edge of the base plate and a trigger lever arranged on the upper die of forming die and corresponding to the plurality of wedge-shaped displacement members, and the wedge-shaped displacement members are movably connected with the bottom of the first forming panel or the second forming panel.

[0030] Wherein, when the lower mold and the upper mold of the forming mold are closed, the trigger rod contacts the wedge displacement member, forces all the wedge displacement members to move along the plane direction of the base plate, and synchronously lifts the first forming panel and the third forming panel.

[0031] As a preferred scheme of the present application, the pre-buried nut comprises an internally threaded column and ring bodies mounted at both ends of the internally threaded column, and the internally threaded column is threadedly connected with the fixing pin.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] The present application solves the problem of integrally forming the mounting point of the laminated board product through the pre-buried nut, simplifies the subsequent assembly mode, and improves the assembly efficiency. The present application solves the uncertainty of the dimensional characteristics such as the position, flatness, and perpendicularity of the pre-buried part of the composite laminated board product through mold design and fixing pin matching. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can also be obtained from the provided drawings without creative labor.

[0035] Figure 1 The figure is a top view of the mold, laminated board, pre-buried nut, and pre-buried nut fixing pin position of the embodiment of the present application.

[0036] Figure 2 The figure is a top view of the mold, laminated board, pre-buried nut, and pre-buried nut fixing pin position of the embodiment of the present application.

[0037] Figure 3 The figure is a structure schematic diagram of the pre-buried nut of the embodiment of the present application.

[0038] Figure 4 The figure is a structure schematic diagram of the pre-buried nut of the embodiment of the present application.

[0039] Figure 5 The figure is a longitudinal sectional structure schematic diagram of the pre-buried nut boss and the fixing pin, and the pre-buried nut connection of the embodiment of the present application.

[0040] Figure 6 The figure is a top view of the lower mold of the forming mold of the embodiment of the present application.

[0041] Figure 7 The figure is a top view of the lower mold of the forming mold of the embodiment of the present application.

[0042] Figure 8 The fixed hole top view structure schematic diagram of the embodiment of the present application.

[0043] The reference signs in the drawings represent the following respectively:

[0044] 1- lower mold of forming mold; 2- upper mold of forming mold; 3- fixed hole; 4- embedded nut; 5- silica gel sealing ring; 6- fixed pin; 7- embedded nut groove; 8- synchronous lifting assembly; 9- prefabricated part; 10- embedded nut boss;

[0045] 11- base plate; 12- first forming panel; 13- second forming panel; 14- third forming panel; 15- cavity;

[0046] 31- regular polygon bottom cavity; 32- sealing ring matching cavity;

[0047] 41- internally threaded column; 42- ring body;

[0048] 81- wedge-shaped displacement piece; 82- trigger lever. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0050] As shown in Figure 1 , the present application provides a kind of embedded nut integrated forming composite material forming method, including specific steps:

[0051] Step 100, the fixed hole for installing embedded nut fixed pin in row is arranged on the lower mold of composite material forming mold;The embedded nut groove for matching the fixed hole is arranged in row on the upper mold of composite material forming mold;

[0052] Step 200, the fixed pin of embedded nut is installed in the fixed hole, then embedded nut is installed on fixed pin, wherein embedded nut and fixed pin are threadedly connected, the bottom of embedded nut just contacts the upper surface of the lower mold of the composite material forming mold;

[0053] Step 300, the prefabricated part of composite material is correspondingly installed on the lower mold of the composite material forming mold, then the closing of the lower mold and the upper mold of the composite material forming mold is carried out by press machine, so that the prefabricated part of composite material is cured and formed;

[0054] The part of the embedded nut entering the embedded nut groove forms an embedded nut boss on the surface of the solidified and formed product;

[0055] Step 400, after demolding, the solidified and formed product is separated from the lower mold of the composite material forming mold, and then the fixing pin and the embedded nut are separated.

[0056] In step 100, the silica gel sealing ring is preset on the fixing pin, the threads between the fixing pin and the embedded nut are matched, and the embedded nut is rotated to press the silica gel sealing ring into the orifice of the fixed hole.

[0057] In step 300, the preparation method of the product of the composite material includes:

[0058] Based on the position of the fixed hole provided on the lower mold of the composite material forming mold, the laying simulation is performed on the set number of prepreg sheets forming the product, the outer contour of the product, the opening position of each prepreg sheet, and the opening degree of each prepreg sheet in the thickness direction of the product are determined; the opening degree includes the opening shape and the opening size;

[0059] The specific method that the part of the embedded nut entering the embedded nut groove forms an embedded nut boss on the surface of the solidified and formed product includes:

[0060] In step 200, the thermosetting resin-based chopped fiber prepreg is cut into a filling strip, the width of the filling strip is the height of the embedded nut boss part, and the length of the filling strip is determined according to the length that the prepreg sheet can be inserted into the embedded nut groove provided on the upper mold of the composite material forming mold after being rolled up;

[0061] Then, in step 300, the lower mold and the upper mold of the composite material forming mold are closed, the embedded nut is provided through the opening of the prepreg sheet, the filling strip is extruded, the filling strip is extruded and deformed, and the prepreg sheet of the product is combined to form an embedded nut boss.

[0062] The distance between the embedded nut boss and the outer surface of the embedded nut is greater than or equal to 2 mm.

[0063] In the mold design, the fixed hole of the fixing pin of the embedded nut is designed to make the embedded nut consistent with the predetermined embedded position of the prepreg sheet with the assistance of the fixing pin, and to avoid deviation. The part of the embedded nut and the fixing pin fixed on the mold is designed as a hexagon to prevent rotation, and the part fixed on the embedded nut is a threaded shaft, which can be quickly separated from the embedded nut by means of a hand drill after the mold is opened. Because the threads between the fixing pin and the embedded nut are matched, the embedded nut is tightly matched without gaps through the rotating movement, so that the embedded nut is flush with the surface of the laminate without resin covering or protruding. Because it is perpendicular to the hole position on the mold, the position and perpendicularity of the embedded nut are ensured.

[0064] Take the integrally formed laminated plate with embedded nuts in a flat state as an example, the forming steps are:

[0065] 1. The product is simulated for layering to determine its outer contour and internal opening position, and a cutting drawing is provided to cut the prepreg sheet according to the cutting drawing;

[0066] 2. The corresponding sheet is preformed for layering, and attention is paid to the fact that all embedded nut hole positions need to be aligned and cannot be covered, and the number of layers is determined according to the design thickness of the laminated plate;

[0067] 3. The thermosetting resin-based chopped fiber prepreg is cut into a strip, the width of the strip is the height of the embedded nut boss part, and the length of the strip is determined according to the length that can be inserted into the embedded nut boss part on the mold after the sheet is rolled up;

[0068] 4. The rolled thermosetting resin-based chopped fiber prepreg strip is placed vertically at the center position above the embedded nut hole according to the number and position, and needs to be pressed tightly so as not to fall easily;

[0069] 5. The corresponding number of fixing pins and embedded nuts are tightened, then the fixing pin hexagonal head is inserted into the corresponding opening on the mold, and the rubber hammer is used to knock it into place to ensure that the embedded nut is flush with the surface of the laminated plate or reaches the design height;

[0070] 6. The preform is taken out of the preform mold and placed on the mold, and the press is pressed to solidify and form;

[0071] 7. The product is taken out and placed upside down on the prepared tray, and the fixing pin is unscrewed from the embedded nut using a pistol drill, at this time the embedded nut is tightly combined with the laminated plate, the surface is flat, and the torque requirement is met.

[0072] The embedded nut integrally formed composite laminated plate mold mainly adds the following design structures to meet the embedded requirements:

[0073] 1. The upper mold of the forming mold is combined with the upper surface of the product design, and no special treatment is required.

[0074] 2. The lower mold of the forming mold is opened at the position corresponding to the embedded nut, and attention is paid to the fact that the opening position is combined with the fixing pin, and the feeding gap is reduced to avoid resin flowing in while maintaining the perpendicularity and position of the fixing pin.

[0075] 3. When designing the mold, pay attention to avoid the opening position of the internal heating pipe, the inductive thermocouple, and the ejection structure.

[0076] Specifically:

[0077] The fibers in the scheme are not limited to glass fibers, and common composite fibers on the market can be replaced.

[0078] The resin in the scheme is not limited to epoxy resin-based resin, polyurethane resin-based resin, etc., and includes all thermosetting resin-based resins.

[0079] The fixed pin column head in the scheme is not limited to a hexagon, and any shape of column that can be limited can be replaced.

[0080] The molding process in the scheme is not limited to the PCM molding process, and the SMC molding process, the STM wet molding process, etc. can be used to realize the forming production requirements of the embedded nut product in cooperation with the fixed pin and the mold design.

[0081] The laminated board in the scheme is not limited to a flat piece, and the composite product made by using the molding process and having the demand for embedded nuts can be formed by using this scheme.

[0082] As shown in Figures 1 to 7 The application provides a composite material forming mold for integrally forming an embedded nut, which is used for realizing the composite material forming method for integrally forming an embedded nut,

[0083] The composite material forming mold comprises:

[0084] The lower mold 1 of the forming mold is provided with a row of fixed holes 3, and the fixed pins 6 are installed in the fixed holes 3. The upper part of the fixed pins 6 is threadedly connected with the embedded nuts 4, and the pin body of the fixed pins 6 below the embedded nuts 4 is sleeved with the silica gel sealing ring 5.

[0085] The upper mold 2 of the forming mold is provided with an embedded nut groove 7 corresponding to the row of fixed holes 3.

[0086] The lower mold 1 of the forming mold comprises a base plate 11, and the base plate 11 is provided with a cavity 15. The cavity 15 is internally provided with a first forming panel 12, a second forming panel 13 and a third forming panel 14 arranged along the length direction of the cavity 15.

[0087] The first forming panel 12 and the third forming panel 14 are installed on the base plate 11 in the cavity 15 through a synchronous lifting assembly 8, and the second forming panel 13 is provided with a row of fixed holes 3.

[0088] The synchronous lifting assembly 8 is used to make the first forming panel 12 and the third forming panel 14 higher than the second forming panel 13 when the cavity 15 is not placed with a prefabricated part.

[0089] The synchronous lifting assembly 8 makes the first forming panel 12 and the third forming panel 14 move downward until they are kept level with the second forming panel 13 when they are stressed when the lower mold 1 of the forming mold and the upper mold 2 of the forming mold are closed.

[0090] In the present application, in order to avoid the material entering the fixing hole 3 during the extrusion molding process, a specific implementation of the fixing hole 3 is provided, including a regular polygon bottom cavity 31 (cooperating with one end of the fixing pin 6) and a sealing ring cooperating cavity 32 concentrically arranged on the upper part of the regular polygon bottom cavity 31, the sealing ring cooperating cavity 32 forms an open port on the surface of the second molding panel 13, and the sealing ring cooperating cavity 32 is used to make the sealing ring 5 on the fixing pin 6 enter the sealing ring cooperating cavity 32 when the fixing pin 6 is installed. It prevents resin from flowing into the mold fixing hole 3 and also plays a role in preventing slipping.

[0091] In the present application, the outer diameter of the sealing ring cooperating cavity 32 is greater than the regular polygon bottom cavity 31.

[0092] In the present application, the first molding panel 12 and the third molding panel 14 need to be driven synchronously to rise and fall, and there are many ways to achieve synchronous lifting of the first molding panel 12 and the third molding panel 14, such as pneumatic cylinders or synchronous lifters, but they all need to be controlled by independent electric control systems. In the present application, it is hoped that during the closing action of the upper mold of the molding mold and the lower mold of the molding mold, the stress changes of the pre-embedded nut during the extrusion of the preform between the prepreg sheets are adapted, and the main purpose is to adapt to the stress changes of the prepreg sheet during the generation of the boss.

[0093] That is, when the upper mold of the molding mold and the lower mold of the molding mold are closed, the prepreg sheet has not been completely pressed at this time, so the pre-embedded nut passes through or penetrates the opening on the prepreg sheet, and there is a relative displacement process between the pre-embedded nut and the prepreg sheet being pressed downward. At this time, the stress change during the generation of the boss is smaller compared to the stress change caused by the pre-embedded nut directly penetrating the opening of the prepreg sheet to generate the boss.

[0094] Therefore, the present application provides a specific implementation of a synchronous lifting assembly 8, which cooperates with the action of the upper mold of the molding mold and the lower mold of the molding mold when closing, gradually reduces the height of the first molding panel 12 and the third molding panel 14 until the height of the second molding panel 13 is consistent.

[0095] The synchronous lifting assembly 8 includes a plurality of wedge-shaped displacement members 81 arranged on the side edges of the base plate 11 and a trigger lever 82 arranged on the upper mold of the molding mold 2 and corresponding to the plurality of wedge-shaped displacement members 81, and the wedge-shaped displacement members 81 are movably connected to the bottom of the first molding panel 12 or the second molding panel 13. That is, the edges of the first molding panel 12 and the third molding panel 14 are arranged on the inclined surface of the wedge-shaped displacement member 81, and the height of the inclined surface gradually decreases from the outside of the mold to the inside of the mold.

[0096] When the upper mold of the molding mold and the lower mold of the molding mold are closed, the inclined surface of the plurality of wedge-shaped displacement members 81 moves outwardly of the mold, so that the first molding panel 12 and the third molding panel 14 are lowered synchronously.

[0097] That is, the trigger lever 82 contacts one end of the wedge displacement member 81, and of course one end of the wedge displacement member 81 is provided with a pressure receiving inclined surface that cooperates with the trigger lever 82, and the bottom of the trigger lever 82 is provided with a force applying inclined surface that presses the pressure receiving inclined surface, forcing all of the wedge displacement members 81 to move in the planar direction of the base plate 11, causing the first molding face plate 12 and the third molding face plate 14 to be synchronized in lifting.

[0098] Further, the present application provides a specific embodiment of a pre-embedded nut 4, including an internally threaded column 41 and ring bodies 42 installed at both ends of the internally threaded column 41, the internally threaded column 41 being threadedly connected with the fixing pin 6, the purpose being that the pre-embedded nut 4 can be stably and tightly embedded in the prefabricated part, and the position after pre-embedding is limited by two ring bodies 42 with a diameter larger than the internally threaded column 41, one end of the internally threaded column 41 passing through the ring body 42 on one side to form an opening connected with the fixing pin 6.

[0099] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements shall also be considered to fall within the protection scope of the present application.

Claims

1. A method for forming a composite material with an embedded nut integrally formed, characterized in that: Including specific steps: Step 100: Arrange rows of fixing holes for mounting fixing pins of embedded nuts on the lower mold of the composite material forming mold; and arrange rows of embedded nut grooves for matching the fixing holes on the upper mold of the composite material forming mold; Step 200: Install the fixing pin of the embedded nut into the fixing hole, and then install the embedded nut on the fixing pin, wherein the embedded nut and the fixing pin are threadedly connected, and the bottom of the embedded nut just contacts the upper surface of the lower mold of the composite material forming mold; Step 300: Mounting the composite material preform on the lower mold of the composite material forming mold, and then closing the lower mold and the upper mold of the composite material forming mold by a press, so that the composite material preform is cured and formed; Wherein, the portion of the embedded nut entering the embedded nut groove forms an embedded nut boss on the surface of the solidified preform; Step 400: After demoulding, the cured product is separated from the lower mold of the composite material molding mold, and then the fixing pin and the embedded nut are separated; The composite material forming mold comprises: A molding die lower die (1), wherein the molding die lower die (1) is provided with rows of fixing holes (3), and the molding die lower die (1) is provided with a fixing pin (6) through the fixing hole (3), the upper portion of the fixing pin (6) is threadedly connected to an embedded nut (4), and a silicone sealing ring (5) is sleeved on the pin body of the fixing pin (6) located below the embedded nut (4); A forming mold upper die (2), wherein the forming mold upper die (2) is provided with embedded nut grooves (7) corresponding one-to-one to the rows of fixing holes (3); The lower mold (1) of the molding die comprises a base plate (11), a molding cavity (15) is provided on the base plate (11), and a first molding panel (12), a second molding panel (13) and a third molding panel (14) are arranged inside the molding cavity (15) along the length direction of the molding cavity (15); The first molding panel (12) and the third molding panel (14) are mounted on the base plate (11) in the mold cavity (15) via a synchronous lifting assembly (8), and the second molding panel (13) is provided with a row of the fixing holes (3); The synchronous lifting assembly (8) is used to make the first molding panel (12) and the third molding panel (14) higher than the second molding panel (13) when no prefabricated part is placed in the mold cavity (15); When the lower mold (1) and the upper mold (2) of the molding die are closed, the synchronous lifting assembly (8) causes the first molding panel (12) and the third molding panel (14) to move downward under force until they are flush with the second molding panel (13).

2. The method for integrally forming a composite material for embedded nuts according to claim 1, characterized in that: In step 100, a silicone seal ring is preset on the fixing pin, and the threads between the fixing pin and the embedded nut are matched. The embedded nut presses the silicone seal ring into the orifice of the fixing hole through rotation.

3. The method for integrally forming a composite material for embedded nuts according to claim 2, characterized in that: In step 300, the method for preparing a composite material preform includes: Based on the fixed hole positions set on the lower mold of the composite material forming mold, a layup simulation is performed on a set number of prepreg sheets that form the preform to determine the outer contour of the preform, the opening position of each prepreg sheet, and the opening degree of each prepreg sheet in the thickness direction of the preform; the opening degree includes the opening shape and opening size.

4. The method for integrally forming a composite material for embedded nuts according to claim 3, characterized in that: The specific method for forming an embedded nut boss on the surface of the cured preformed part by the portion of the embedded nut entering the embedded nut groove includes: In step 200, the thermosetting resin-based chopped fiber prepreg is cut into filling strips. The width of the filling strips is equal to the height of the embedded nut boss. The length of the filling strips is determined so that the rolled sheet can be inserted into the embedded nut groove provided in the upper mold of the composite material forming mold. Subsequently, in step 300, the lower mold and the upper mold of the composite material forming mold are closed, the embedded nut passes through the opening set in the prepreg sheet, and the filling strip is squeezed and deformed by extrusion and combined with the prepreg sheet of the preform to form an embedded nut boss.

5. The method for integrally forming a composite material with embedded nuts according to claim 4, characterized in that: The distance between the embedded nut boss and the outer surface of the embedded nut is greater than or equal to 2 mm.

6. A composite material molding method for integrally molding embedded nuts according to claim 1, wherein the fixing hole (3) comprises a regular polygonal bottom cavity (31) and a sealing ring matching cavity (32) concentrically arranged on the upper portion of the regular polygonal bottom cavity (31), and the sealing ring matching cavity (32) forms an open opening on the surface of the second molding panel (13); in, The outer diameter of the sealing ring fitting cavity (32) is larger than the regular polygonal bottom cavity (31).

7. The method for integrally forming a composite material for embedded nuts according to claim 1, characterized in that: The synchronous lifting assembly (8) comprises a plurality of wedge-shaped displacement members (81) arranged on the side of the base plate (11) and a trigger rod (82) arranged on the upper mold (2) of the forming mold and corresponding to the plurality of wedge-shaped displacement members (81) one by one, and the wedge-shaped displacement members (81) are movably connected to the bottom of the first forming panel (12) or the second forming panel (13); When the lower mold (1) and the upper mold (2) of the molding mold are closed, the trigger rod (82) contacts the wedge-shaped displacement members (81), forcing all the wedge-shaped displacement members (81) to move along the plane direction of the base plate (11), thereby causing the first molding panel (12) and the third molding panel (14) to rise and fall synchronously.

8. The method for integrally forming a composite material for embedded nuts according to claim 1, characterized in that: The embedded nut (4) comprises an internal thread column (41) and ring bodies (42) mounted on both ends of the internal thread column (41), and the internal thread column (41) is threadedly connected to the fixing pin (6).

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