A resin transfer molding-mold pressing combined molding method based on resin reaction state

Abstract

The present application belongs to the technical field of composite material forming, and particularly relates to a resin transfer molding-mold pressing combined forming method based on resin reaction state, which determines a preliminary transfer window according to the reaction state of a thermosetting resin system in a curing cross-linking reaction process; places a fiber preform in a resin transfer molding tool, injects the thermosetting resin system into the fiber preform and makes the fiber preform impregnated; pre-cures and heats under the preliminary transfer window, has a first pre-curing cross-linking reaction, and obtains a transfer window; within the transfer window, transfers the impregnated fiber preform to a mold pressing station or an integrated mold switched to a mold pressing working condition, makes the fiber preform contact, compact, solidify, cross-link and pressure-keeping cool, and obtains a product after demolding. The present application can consider full impregnation and efficient compaction, reduce defects such as dry spots, resin enrichment, interlayer separation, porosity and fiber disturbance, improve product thickness consistency and interface bonding state, and improve comprehensive performance.

Description

Technical Field

[0001] This invention belongs to the field of composite material molding technology, and particularly relates to a resin transfer molding-compression molding method based on the transfer window of the resin reaction state. Background Technology

[0002] High-performance fiber-reinforced resin matrix composites, due to their advantages such as high specific strength, high specific stiffness, corrosion resistance, and strong designability, have been widely used in aerospace, rail transportation, automotive lightweighting, wind power equipment, and protective structures. For these types of components, the molding process not only affects the geometric dimensions and appearance quality, but also directly determines the internal porosity, dry spots, resin enrichment, interfacial bonding state, and final service performance.

[0003] Currently, the production of high-quality resin-based composite parts still primarily relies on autoclave processes. While autoclave processes achieve lower porosity and better microstructure uniformity through coordinated temperature and pressure control, they suffer from drawbacks such as high equipment investment, high operating costs, long process cycles, high energy consumption, and limited adaptability to large and complex parts. With the increasing demand for non-autoclave manufacturing, developing high-quality molding technologies that can partially replace autoclave processes has become an important direction in the field of composite material manufacturing.

[0004] Resin transfer molding (RTM) and its vacuum-assisted form offer advantages in impregnation efficiency, mold size adaptability, and lower manufacturing costs. However, when using RTM alone, it is often difficult to fully compact the laminated structure after impregnation, leading to problems such as residual pores, thickness fluctuations, localized resin enrichment, and loose interlayer structures. Compression molding can achieve rapid densification through higher pressure, but this usually requires the material to already possess a certain degree of moldability or a relatively uniform resin distribution. Directly using compression molding to treat low-viscosity, unstable impregnated fiber systems can easily cause defects such as fiber disturbance, layup misalignment, localized dry spots, and interface discontinuities.

[0005] While there are attempts to combine RTM with molding in existing technologies, most of them focus on the sequential connection of process steps and lack systematic control over the resin reaction state, structural self-supporting ability, transfer timing and molding intervention boundary conditions. This results in unstable connection between different process stages, low process repeatability, and difficulty in consistently obtaining parts with quality levels close to those of autoclave molding.

[0006] Furthermore, while existing RTM-compression molding processes can balance impregnation and compaction to some extent, they lack clear and repeatable criteria for determining the transition of resin from a low-viscosity flow dynamic to a transferable viscous state. This results in the transfer timing between different workstations relying primarily on experience, which can easily lead to problems such as resin loss, fiber structure disturbance, interlayer misalignment, and insufficient densification. Therefore, it is necessary to propose an RTM-compression molding method with the resin reaction state transition window as the control core to improve process continuity stability and part quality consistency. Summary of the Invention

[0007] The purpose of this invention is to provide a resin transfer molding-compression molding method based on the resin reaction state transfer window control. By determining the reaction state of the resin system in the pre-curing stage, a suitable window range for transfer and compaction is determined, so that the RTM impregnation stage and the compression densification stage can be stably connected without disturbing the fiber structure, thereby taking into account sufficient resin impregnation, structural compaction and densification, and defect suppression.

[0008] This invention is achieved through the following technical solution: a resin transfer molding-compression molding method based on the resin reaction state transfer window, comprising the following steps:

[0009] (1) Prepare a thermosetting resin system and determine the initial transfer window based on the reaction state of the thermosetting resin system during the curing and crosslinking reaction;

[0010] The initial transfer window is the temperature-time program range corresponding to the thickening range of the thermosetting resin system that is higher than the initial viscosity but lower than the viscosity of the fully gelled state.

[0011] (2) The fiber preform is laid in the RTM fixture, which is equipped with a glue inlet channel, a glue outlet channel and a vacuum system. The thermosetting resin system is injected into the fiber preform and the thermosetting resin system is impregnated into the fiber preform.

[0012] (3) After the thermosetting resin system has impregnated the fiber preform, the glue inlet channel and glue outlet channel are sealed, and the impregnated fiber preform is pre-cured and heated under the initial transfer window to cause the thermosetting resin system to undergo the first pre-curing crosslinking reaction. The temperature-time program range of the initial transfer window is modified according to the reaction state of the thermosetting resin during the first pre-curing crosslinking reaction to obtain the transfer window.

[0013] The transfer window is the time interval during which the thermosetting resin system in the impregnated fiber preform has not yet fully gelled, and still possesses interfacial wetting, pore closure, and local strain coordination capabilities during the molding stage. Simultaneously, it must satisfy at least one of the following conditions:

[0014] ( During handling, flipping, mold alignment, or station switching, the thermosetting resin contained in the impregnated fiber preform does not leak or flow out.

[0015] ( Impregnated fiber preforms do not collapse, wrinkle, interlayer misalignment, or fiber structure disturbance under gravity;

[0016] ( The impregnated fiber preform does not collapse, wrinkle, interlayer misalignment or fiber structure disturbance during handling, flipping, mold alignment or station switching;

[0017] (4) Within the transfer window, under at least one of the following conditions—vacuum, partial support, and encapsulation—the first pre-cured impregnated fiber preform is transferred to the molding station or the integrated mold that is switched to the molding condition. A phased temperature-pressure action is applied to the first pre-cured impregnated fiber preform to make it contact-shaped, compacted and densified, cured and cross-linked, and held under pressure and cooled. After demolding, the part is obtained.

[0018] As a further improvement to the technical solution of the present invention, in step (1), the reaction state of the thermosetting resin during the curing and crosslinking reaction is determined by any of the following methods:

[0019] ( Curing kinetic parameters were obtained by non-isothermal differential scanning calorimetry, and the relationship between degree of cure, temperature, and time was established.

[0020] ( Viscosity-time relationship was established through isothermal rheological testing, and viscosity-temperature relationship was established through non-isothermal rheological testing.

[0021] ( ) Through in-mold temperature monitoring, pressure monitoring, or displacement monitoring.

[0022] As a further improvement to the technical solution of the present invention, the determination of the reaction state of the thermosetting resin includes at least one of the following parameters: viscosity, viscosity growth rate, gel time, degree of curing, and curing rate.

[0023] As a further improvement to the technical solution of the present invention, in step (2), the fiber preform is a continuous fiber reinforced preform; the continuous fiber is selected from at least one of carbon fiber, glass fiber, aramid fiber and basalt fiber; the layup method of the continuous fiber reinforced preform is one of unidirectional tape, two-dimensional woven fabric, multiaxial fabric, three-dimensional braided fabric and needle-punched preform.

[0024] As a further improvement to the technical solution of the present invention, in step (4), the phased process includes a pressure holding and cooling phase and at least two of the following phases:

[0025] ( Preheating contact stage; Low-pressure second pre-curing stage; () High-pressure densification stage; () Constant temperature curing stage.

[0026] As a further improvement to the technical solution of the present invention, in step (4), the pressure of the phased temperature-pressure action is 0.1-30MPa, the temperature is 25-250℃, and the heating rate is 0.5-20℃ / min.

[0027] As a further improvement to the technical solution of the present invention, in step (4), the component is one of the following: plate, shell, rib, cap-shaped component, sandwich panel, stiffened wall panel, component with local thickness variation and complex curved surface component.

[0028] Compared with the prior art, the method of the present invention has the following advantages:

[0029] 1) This invention uses the transfer window based on the resin reaction state as the control basis for the connection between the RTM process and the compression molding process, which can improve the predictability and repeatability of the process transfer timing.

[0030] 2) This invention, while utilizing the RTM molding process to ensure sufficient resin impregnation of the fiber preform, introduces a subsequent compaction and densification process based on compression molding. This helps reduce the porosity of the molded part and effectively solves problems such as thickness fluctuations and localized resin enrichment. Compared with single RTM or compression molding processes, this invention can achieve both sufficient impregnation and efficient densification, reducing defects such as dry spots, resin enrichment, interlayer separation, porosity, and fiber disturbance, improving the thickness consistency and interfacial bonding of the part, and enhancing overall performance.

[0031] 3) This invention is applicable to large-scale, complex curved surface and non-autoclave manufacturing scenarios, taking into account process quality, equipment adaptability and manufacturing cost control, and has good engineering promotion value. Attached Figure Description

[0032] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0033] To more clearly illustrate the technical solutions 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1This is a flowchart of a resin transfer molding-compression molding method based on the resin reaction state transfer window of the present invention.

[0035] Figure 2 Differential scanning calorimetry curves of the resin systems used in Examples 1-2 and Comparative Examples 1-2 at different heating rates.

[0036] Figure 3 The curing degree-temperature curves of the resin systems used in Examples 1-2 and Comparative Examples 1-2 under non-isothermal conditions are shown.

[0037] Figure 4 The viscosity-time isotherm curves are for the resin systems used in Examples 1-2 and Comparative Examples 1-2. Detailed Implementation

[0038] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0040] This invention provides a specific embodiment of a resin transfer molding-compression molding method based on a transfer window of resin reaction state, comprising the following steps:

[0041] (1) Prepare a thermosetting resin system and determine the initial transfer window based on the reaction state of the thermosetting resin system during the curing and crosslinking reaction;

[0042] The initial transfer window is the temperature-time program range corresponding to the thickening range of the thermosetting resin system that is higher than the initial viscosity but lower than the viscosity of the fully gelled state.

[0043] (2) The fiber preform is laid in the RTM fixture, which is equipped with a glue inlet channel, a glue outlet channel and a vacuum system. The thermosetting resin system is injected into the fiber preform and the thermosetting resin system is impregnated into the fiber preform.

[0044] (3) After the thermosetting resin system has impregnated the fiber preform, the glue inlet channel and glue outlet channel are sealed, and the impregnated fiber preform is pre-cured and heated under the initial transfer window to cause the thermosetting resin system to undergo the first pre-curing crosslinking reaction. The temperature-time program range of the initial transfer window is modified according to the reaction state of the thermosetting resin during the first pre-curing crosslinking reaction to obtain the transfer window.

[0045] The transfer window is the time interval during which the thermosetting resin system in the impregnated fiber preform has not yet fully gelled, and still possesses interfacial wetting, pore closure, and local strain coordination capabilities during the molding stage. Simultaneously, it must satisfy at least one of the following conditions:

[0046] ( During handling, flipping, mold alignment, or station switching, the thermosetting resin contained in the impregnated fiber preform does not leak or flow out.

[0047] ( Impregnated fiber preforms do not collapse, wrinkle, interlayer misalignment, or fiber structure disturbance under gravity;

[0048] ( The impregnated fiber preform does not collapse, wrinkle, interlayer misalignment or fiber structure disturbance during handling, flipping, mold alignment or station switching;

[0049] (4) Within the transfer window, under at least one of the following conditions—vacuum, partial support, and encapsulation—the first pre-cured impregnated fiber preform is transferred to the molding station or the integrated mold that is switched to the molding condition. A phased temperature-pressure action is applied to the first pre-cured impregnated fiber preform to make it contact-shaped, compacted and densified, cured and cross-linked, and held under pressure and cooled. After demolding, the part is obtained.

[0050] In one example provided by the present invention, in step (1), the reaction state of the thermosetting resin during the curing crosslinking reaction is determined by any of the following methods:

[0051] ( Curing kinetic parameters were obtained by non-isothermal differential scanning calorimetry, and the relationship between degree of cure, temperature, and time was established.

[0052] ( Viscosity-time relationship was established through isothermal rheological testing, and viscosity-temperature relationship was established through non-isothermal rheological testing.

[0053] ( ) Through in-mold temperature monitoring, pressure monitoring, or displacement monitoring.

[0054] In another example provided by the present invention, the determination of the reaction state of the thermosetting resin includes at least one of the following parameters: viscosity, viscosity growth rate, gel time, degree of curing, and curing rate.

[0055] In one example provided by the present invention, in step (2), the fiber preform is a continuous fiber reinforced preform; the continuous fiber is selected from at least one of carbon fiber, glass fiber, aramid fiber and basalt fiber; the layup of the continuous fiber reinforced preform is one of unidirectional tape, two-dimensional woven fabric, multiaxial fabric, three-dimensional braid and needle-punched preform.

[0056] In another example provided by the present invention, step (4) includes a pressure holding and cooling stage and at least two of the following stages:

[0057] ( Preheating contact stage; Low-pressure second pre-curing stage; () High-pressure densification stage; () Constant temperature curing stage.

[0058] In one example provided by the present invention, in step (4), the pressure of the phased temperature-pressure action is 0.1-30 MPa, the temperature is 25-250℃, and the heating rate is 0.5-20℃ / min.

[0059] In another example provided by the present invention, in step (4), the component is one of a plate, a shell, a rib, a cap-shaped component, a sandwich panel, a stiffened wall panel, a component with local thickness variation, and a component with a complex curved surface.

[0060] The technical solution of the present invention will be described in detail below through specific embodiments.

[0061] Example 1:

[0062] A method for RTM-compression molding of carbon fiber / epoxy resin laminates based on resin reaction state-controlled transfer window includes the following steps:

[0063] (1) Resin system preparation and preliminary transfer window determination:

[0064] The thermosetting resin system consists of E51 type epoxy resin, an acid anhydride curing agent cis-hexahydrophthalic anhydride (HHPA), and accelerator 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30), with carbon fiber two-dimensional woven fabric as reinforcement.

[0065] The epoxy resin and curing agent were mixed according to the ratio of E51:HHPA=1:0.8, and then accelerator DMP-30 was added at 3‰ of the total resin mass. After mixing evenly, the mixture was degassed under reduced pressure to obtain the epoxy resin system.

[0066] Differential scanning calorimetry (DSC) and isothermal rheological tests were performed on the epoxy resin system to obtain non-isothermal DSC curves (see...). Figure 2 ), Curing degree-temperature profile (see) Figure 3 ) and viscosity-time curves (see Figure 4 A curing kinetic model and viscosity evolution relationship were established. The initial point of viscosity increase and the pre-gel workable time interval were used as the criteria for determining the initial transfer window. Figure 4 The initial transfer window was determined to be: a temperature of 115℃ and a time interval of 30.7-32.5 min.

[0067] (2) Precast concrete laying and RTM tooling preparation

[0068] The multi-layer carbon fiber fabric is laid in the RTM tooling mold according to the designed layering sequence. Release cloth, flow guide net, vacuum bag film, and sealing strip are then arranged sequentially. The inlet and outlet pipes are connected, and an airtightness test is performed (see...). Figure 1 ).

[0069] (3) RTM impregnation

[0070] The resin system was injected into the carbon fiber preform at 60°C using the RTM process. Under vacuum assistance, the resin was fully impregnated into the carbon fiber preform. After resin without obvious air bubbles was continuously discharged from the discharge end, the impregnation was deemed complete, and the inlet and outlet were sealed.

[0071] (4) Determine the transfer window

[0072] The impregnated carbon fiber preform was pre-cured at 115°C to induce the first pre-curing crosslinking reaction of the thermosetting resin system. Starting from 30.7 min, the time interval of the initial transfer window was adjusted according to the reaction state of the thermosetting resin in the impregnated carbon fiber preform, and the final transfer window was 115°C and 30.7 min.

[0073] (5) Pre-curing and transfer

[0074] After the impregnated carbon fiber preform is pre-cured at 115℃ for 30.7 min (i.e., the transfer window), it is smoothly transferred to the molding die by RTM tooling under local support.

[0075] (6) Molding and obtaining the part

[0076] Curing and crosslinking are carried out in a staged temperature-pressure process in a molding die. First, the temperature is increased to 140°C at a rate of 5°C / min, and a pressure of about 15MPa is applied and maintained for 120min. Then, the pressure is maintained and the temperature is cooled to below 100°C before demolding to obtain the laminated part.

[0077] The laminate formed in this embodiment has an average thickness of 2.62 mm, a thickness standard deviation of 0.025 mm, a fiber volume fraction of 65.5%, a porosity of 1.5%, a tensile strength of 1068.38 MPa, a tensile modulus of 100.70 GPa, a flexural strength of 1249.60 MPa, and a flexural modulus of 77.20 GPa. Ultrasonic C-scan after low-velocity impact showed an internal damage area of ​​approximately 290 mm². 2 .

[0078] Comparative Example 1

[0079] The same material system, fiber preform structure, and RTM injection conditions as in Example 1 were used, but only a single RTM process was employed for resin impregnation and thermosetting, without subsequent molding and compaction steps. That is:

[0080] Steps (1)-(3): Same as steps (1)-(3) in Example 1.

[0081] (4) The preform that has been impregnated is directly heated to 140°C and kept warm for curing according to the conventional curing system. After curing, it is demolded to obtain a single RTM process molded laminate part.

[0082] The laminate formed in Comparative Example 1 had an average thickness of 3.34 mm, a standard deviation of 0.11 mm, a fiber volume fraction of 58.1%, a porosity of 2.8%, a tensile strength of 759.5 MPa, a tensile modulus of 92.6 GPa, a flexural strength of 740.5 MPa, and a flexural modulus of 65.3 GPa. Ultrasonic C-scan after low-velocity impact showed an internal damage area of ​​approximately 402 mm². 2 .

[0083] The results of Comparative Example 1 show that although the single RTM process can complete the resin impregnation of the preform well, due to the lack of subsequent compaction and densification process, the molded part has a large thickness and obvious thickness fluctuation, low fiber volume fraction and large internal damage expansion range compared with Example 1, and the static mechanical properties and impact damage resistance are significantly lower.

[0084] Comparative Example 2

[0085] The same material system and fiber preform structure as in Example 1 were used, but instead of RTM impregnation, the resin system was directly brushed onto the surface of each preform layer and then molded and cured.

[0086] Specifically, the resin system of Example 1 was brushed onto the surface of each carbon fiber cloth layer according to the set resin mass fraction to form a semi-impregnated molded preform. Then, it was placed in a molding mold, heated to 140°C at 5°C / min, and cured under pressure of 15MPa for 120 min. Then, it was cooled to below 100°C under pressure and demolded to obtain the laminated board part.

[0087] The laminate formed in Comparative Example 2 had an average thickness of 3.59 mm, a standard deviation of 0.14 mm, a fiber volume fraction of 57.8%, and a porosity of 2.5%. Its tensile strength was 845.7 MPa, tensile modulus was 95.1 GPa, flexural strength was 895.4 MPa, and flexural modulus was 69.7 GPa. The internal damage zone area after low-velocity impact was approximately 391 mm². 2 .

[0088] The results of Example 1 and Comparative Example 2 show that although the single molding process can achieve structural compaction to a certain extent, due to the lack of sufficient impregnation of the fiber preform in the RTM stage, the material is prone to insufficient impregnation, uneven resin distribution and local interface defects, resulting in the overall mechanical properties and damage inhibition ability being inferior to the parts formed by the method of the present invention.

[0089] Example 2:

[0090] An RTM-compression molding method for glass fiber / epoxy resin laminates based on the transfer window of the resin reaction state includes the following steps:

[0091] The reinforcing material used in this embodiment is two-dimensional woven glass fiber fabric, the resin system is the same as in Embodiment 1, the part is a flat laminate structure with a size of 300 × 200 mm and a designed thickness of 2.8 mm.

[0092] (1) Resin system preparation and preliminary transfer window determination:

[0093] Same as step (1) of Example 1, except that the initial transfer window is determined to be: temperature of 110°C and time of 38.2-39.1 min.

[0094] (2) Precast concrete laying and RTM tooling preparation

[0095] Same as step (2) in Example 1.

[0096] (3) RTM impregnation

[0097] The same as step (3) in Example 1, except that the resin system is injected into the glass fiber preform at 65°C.

[0098] (4) Determine the transfer window

[0099] The impregnated glass fiber preform was pre-cured at 110°C to induce the first pre-curing crosslinking reaction of the thermosetting resin system. Starting from 38.2 min, the time interval of the initial transfer window was adjusted according to the reaction state of the thermosetting resin in the impregnated glass fiber preform, and the final transfer window was 110°C and 39.1 min.

[0100] (5) Pre-curing and transfer

[0101] After the impregnated glass fiber preform is pre-cured at 110℃ for 39.1 min (i.e., the transfer window), it is smoothly transferred to the molding die by RTM tooling under local support.

[0102] (6) Molding and obtaining the part

[0103] Curing and crosslinking were carried out in a staged temperature-pressure process in a molding die. First, the temperature was increased to 140°C at a heating rate of 5°C / min, and a pressure of 15 MPa was applied. The pressure was held for curing for 120 min, and then the die was removed by cooling to 80°C under the pressure to obtain a glass fiber / epoxy resin flat sheet.

[0104] The flat plate prepared in this embodiment has an average thickness of 2.93 mm and a thickness standard deviation of 0.06 mm; a fiber volume fraction of 54.8%; a porosity of 1.9%; a tensile strength of 428 MPa, a flexural strength of 612 MPa, and a flexural modulus of 24.8 GPa. The results show that the method of this invention is also applicable to the preparation of glass fiber reinforced composite flat plates, and can significantly improve the thickness uniformity of the flat plates, effectively controlling porosity and interfacial bonding quality.

[0105] In summary, the method of the present invention can significantly reduce the thickness and dispersion of the part, increase the fiber volume fraction, reduce porosity defects, and improve interface integrity and impact damage suppression ability by controlling the resin tackification state and transfer timing, combined with subsequent molding compaction and final curing, while ensuring sufficient resin impregnation.

[0106] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and all should be covered by the protection scope of the claims.

Claims

1. A method for resin transfer molding-compression molding assembly based on resin reaction state transfer window control, characterized in that, Includes the following steps: (1) Prepare a thermosetting resin system and determine the initial transfer window based on the reaction state of the thermosetting resin system during the curing and crosslinking reaction; The initial transfer window is the temperature-time program range corresponding to the thickening range of the thermosetting resin system that is higher than the initial viscosity but lower than the viscosity of the fully gelled state. (2) The fiber preform is placed in a resin transfer molding fixture, which is provided with a glue inlet channel, a glue outlet channel and a vacuum system. The thermosetting resin system is injected into the fiber preform and the thermosetting resin system is impregnated into the fiber preform. (3) After the thermosetting resin system has impregnated the fiber preform, the glue inlet channel and glue outlet channel are sealed, and the impregnated fiber preform is pre-cured and heated under the initial transfer window to cause the thermosetting resin system to undergo the first pre-curing crosslinking reaction. The temperature-time program range of the initial transfer window is modified according to the reaction state of the thermosetting resin during the first pre-curing crosslinking reaction to obtain the transfer window. The transfer window is the time interval during which the thermosetting resin system in the impregnated fiber preform has not yet fully gelled, and still possesses interfacial wetting, pore closure, and local strain coordination capabilities during the molding stage. Simultaneously, it must satisfy at least one of the following conditions: (I) The thermosetting resin contained in the impregnated fiber preform does not leak or run off during handling, flipping, mold alignment or station switching. (II) The impregnated fiber preform does not collapse, wrinkle, interlayer misalignment or fiber structure disturbance under gravity; (III) The impregnated fiber preform shall not collapse or wrinkle during handling, flipping, mold alignment, or station switching. Interlayer misalignment or fiber structure disturbance; (4) Within the transfer window, under at least one of the following conditions—vacuum, partial support, and encapsulation—the first pre-cured impregnated fiber preform is transferred to the molding station or the integrated mold that is switched to the molding condition. A phased temperature-pressure action is applied to the first pre-cured impregnated fiber preform to make it contact-shaped, compacted and densified, cured and cross-linked, and held under pressure and cooled. After demolding, the part is obtained.

2. The resin transfer molding-compression molding method based on the transfer window of the resin reaction state according to claim 1, characterized in that, In step (1), the reaction state of the thermosetting resin during the curing and crosslinking reaction is determined by any of the following methods: (I) Curing kinetic parameters were obtained by non-isothermal differential scanning calorimetry and the relationship between degree of curing, temperature and time was established; (II) Establish viscosity-time relationship through isothermal rheological testing, and establish viscosity-temperature relationship through non-isothermal rheological testing; (III) Monitoring the temperature, pressure or displacement within the mold.

3. The resin transfer molding-compression molding method based on the transfer window of the resin reaction state according to claim 1, characterized in that, The determination of the reaction state of the thermosetting resin is based on at least one of the following parameters: viscosity, viscosity growth rate, gel time, degree of curing, and curing rate.

4. The resin transfer molding-compression molding method based on the transfer window of the resin reaction state according to claim 1, characterized in that, In step (2), the fiber preform is a continuous fiber reinforced preform; the continuous fiber is selected from at least one of carbon fiber, glass fiber, aramid fiber and basalt fiber; the layup method of the continuous fiber reinforced preform is one of unidirectional tape, two-dimensional woven fabric, multiaxial fabric, three-dimensional braid and needle-punched preform.

5. The resin transfer molding-compression molding method based on the transfer window of the resin reaction state according to claim 1, characterized in that, In step (4), the phased process includes a pressure holding and cooling phase and at least two of the following phases: (I) Preheating contact stage; (II) Low-pressure second pre-curing stage; (III) Medium and high pressure densification stage; (IV) Constant temperature curing stage.

6. The resin transfer molding-compression molding method based on the transfer window of the resin reaction state according to claim 1, characterized in that, In step (4), the pressure of the phased temperature-pressure action is 0.1-30 MPa, the temperature is 25-250℃, and the heating rate is 0.5-20℃ / min.

7. The resin transfer molding-compression molding method based on the transfer window of the resin reaction state according to claim 1, characterized in that, In step (4), the component is one of the following: plate, shell, rib, cap-shaped component, sandwich panel, stiffened wall panel, component with local thickness variation, and complex curved surface component.

Images